Synthesis and biological evaluation of a series of N-alkylated imidazole alkanoic acids as mGAT3 selective GABA uptake inhibitors

European Journal of Medicinal Chemistry 124 (2016) 852e880

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Research paper

Synthesis and biological evaluation of a series of N-alkylated

imidazole alkanoic acids as mGAT3 selective GABA uptake inhibitors

*

€

Silke Kerscher-Hack, Thejavathi Renukappa-Gutke, Georg Hofner, Klaus T. Wanner

€

Ludwig-Maximilians-Universitat München, Department für Pharmazie e Zentrum für Pharmaforschung, Butenandtstr. 5-13, 81377, Munich, Germany

a r t i c l e i n f o

a b s t r a c t

Article history:

In this paper, we report the synthesis and biological evaluation of a series of 1,5- and 1,4- substituted

derivatives of 1H-imidazol-4-ylacetic acid, a series of 1,2-substituted 3-(1H-imidazol-2-yl)propanoic acid

and an N-substituted (2E)-3-(1H-imidazol-2-yl)prop-2-enoic acid as new mGAT3 inhibitors. The lipo-

philic moieties attached to the N-atom of the parent structures were delineated from the 2-[9-(4-

methoxyphenyl)-9H-ﬂuoren-9-yl]oxyethyl residue, known from a prototypic mGAT3 inhibitor. For the

structure-activity-relationship studies, the spacer between the N-atom of the imidazole ring and the 2-

[9-(4-methoxyphenyl)-9H-ﬂuoren-9-yl] moiety was varied in length from three to six atoms, and in

nature being either a pure saturated or unsaturated alkyl chain or an alkyl chain containing up to two

ether functions. The compounds were characterized for inhibitory potencies at mouse GABA transporter

proteins mGAT1emGAT4. Among the 1,2-substituted compounds, the N-alkylated (2E)-3-(1H-imidazol-

2-yl)prop-2-enoic acid 12e containing a C₅O spacer exhibits a pIC₅₀value of 5.13 0.04 at mGAT3, but is

devoid of signiﬁcant selectivity for this GABA transporter. However, the inhibitory potency displayed by

12e at mGAT3 nominally surpasses that of SNAP-5294 reported as the most potent inhibitor of mGAT3 so

far.

Received 3 May 2016

Received in revised form

21 July 2016

Accepted 3 September 2016

Available online 7 September 2016

Keywords:

GABA uptake

mGAT3

N-alkylimidazolealkanoic acids

1. Introduction

Ref. [12]). Since the biological activity of the compounds described

in this paper was evaluated using mouse transporters, the mouse

A number of CNS disorders such as epilepsy [1], Morbus Par-

kinson [2], Huntington's chorea [3], and migraine [4] are associated

with a reduced neurotransmission in the GABAergic system. Due to

the high incidence of these diseases, the GABAergic system exhibits

an important target in the development of new drugs. Apart from

direct receptor agonism as well as allosteric activation, it has been

shown that inhibition of GABA transport proteins, terminating

GABAergic signalling by the uptake in surrounding glial cells as well

as into presynaptic nerve terminals, augments the extracellular

concentration of GABA (1, Fig. 1) in the synaptic cleft enhancing

GABAergic neurotransmission [5e9]. To date, four distinct plasma

membrane GABA transporter proteins (GATs) have been identiﬁed

in different species including mice, rats, and humans by molecular

cloning techniques [10,11]. The subtypes of GABA transporters

originating from mouse cells are termed mGAT1, mGAT2, mGAT3,

and mGAT4 (for transporters, originating from humans and rats,

the nomenclature is different which is described in detail in

nomenclature will preferably be used in this publication. If test

results obtained for GABA transporters of other species are quoted,

the nomenclature of the respective species will be given.

mGAT1 and mGAT4, the most prevalent GATs in the brain are

responsible for neuronal and glial GABA uptake, respectively,

thereby playing an important role in the termination of GABAergic

neurotransmission [13,14]. mGAT2 and mGAT3 are predominant in

liver and kidney [15,16]. While mGAT2 is expressed in low levels at

the brain surface [15], the expression of mGAT3 is restricted to the

leptomeninges and a subpopulation of blood-brain vessels [16].

Interestingly, recent experiments with mGAT3 knock out mouse

indicated a taurine-exporting role at the blood-brain-barrier for

mGAT3 [16]. Due to the afﬁnity of mGAT3 to GABA, it may still play a

role in the peripheral GABA uptake [16]. Selective targeting and

modulation of GABA transporter subtypes is of fundamental

importance. Compounds selectively addressing GABA transporter

subtypes can provide essential information about the physiological

function of the different GATs and, additionally, about their thera-

peutic potential.

* Corresponding author.

E-mail address: klaus.wanner@cup.uni-muenchen.de (K.T. Wanner).

Some representative inhibitors of GATs developed over the past

http://dx.doi.org/10.1016/j.ejmech.2016.09.012

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

853

Fig. 1. Structures of GABA and representative GABA transporter inhibitors.

[23]. Similarly, varying the amino acid skeleton, the conforma-

tionally restricted GABA analogue 4 with a bicyclo[3.1.0]hexane

backbone has been developed which is the most highly potent and

selective inhibitor known to date for mGAT2 [24].

Up to date, many highly potent and selective mGAT1 inhibitors

have been reported in the literature [25,26]. Currently, mGAT2 has

also been in focus as exempliﬁed through the development of the

aforementioned mGAT2 inhibitor 4 [24,27], but only few selective

inhibitors for mGAT3 are published [21,28,29], since compounds

inhibiting this transporter are in the majority of cases also in-

hibitors of mGAT4 [21,28e30]. Therefore, the binding sites of the

transporters mGAT3 and mGAT4 are thought to be closely related

[8]. Due to the absence of compounds displaying high mGAT2,

mGAT3, and mGAT4 inhibitory potency in combination with good

subtype selectivity, the search for GABA uptake inhibitors

continues.

Continuing our research in this ﬁeld, we aimed to develop new

and potent GABA uptake inhibitors of mGAT3. Hereto, we had

previously reported the good inhibitory potency of 1H-imidazol-4-

ylacetic acid (9a) at mGAT3 with a pIC₅₀value of 4.76 0.08 in

combination with a reasonable preference for this transporter,

especially when compared to mGAT1 (35:1, Table 1, entry 1) [29].

Hence, 9a should make a promising starting point for the devel-

opment of new mGAT3 inhibitors. N-alkylation of 9a would lead to

the possibility of obtaining both 1,4- and 1,5-regioisomers resulting

from the substitution at either of the two non-equivalent nitrogen

atoms of the imidazole ring in 9a (formally delineated from

structure 9a and tautomer 10a, Fig. 3) [31]. By contrast, the higher

homologue and 2-substituted compound 11a (Table 1, entry 2) [29]

displays with a pIC₅₀value of 4.54 0.15 a slightly lower mGAT3

inhibitory potency than 9a, but exhibits with IC₅₀ratios between

mGAT3:mGAT2 ¼ 18:1 and mGAT3:mGAT4 ¼ 7:1 an improved

mGAT3 selectivity. Therefore, 3-(1H-imidazol-2-yl)propanoic acid

Fig. 2. Structure of the 2-[9-(4-methoxyphenyl)-9H-ﬂuoren-9-yl]oxyethyl moiety (b).

decades are exempliﬁed in Fig. 1 (compounds 2e8) [17e24].

Although the conformationally restricted GABA analogs (RS)-nipe-

cotic acid (2) and guvacine (3) show in vitro high GABA uptake

inhibition without intrinsic activity at GABA_Areceptors, the phar-

macological usefulness of these compounds is limited as they lack

the capability to cross the blood-brain barrier [17]. However, the

introduction of special lipophilic side chains resulted not only in an

improved capability of these compounds to cross the blood-brain

barrier, but also in the augmentation of their inhibitory potency

at and selectivity for the different subtypes of GABA transporter

[18e21]. Addition of the lipophilic moiety 4,4-bis-(3-

methylthiophene-2-yl)but-3-en-1-yl to the nitrogen atom of (R)-

nipecotic acid leads for example to the mGAT1 inhibitor tiagabine

(5) which has been introduced successfully in the therapy of epi-

lepsy validating mGAT1 as drug target [22]. The introduction of the

2-[9-(4-methoxyphenyl)-9H-ﬂuoren-9-yl]oxyethyl moiety to the

nitrogen atom of nipecotic acid [SNAP-5294 (6)] improves mGAT3

selectivity [21]. Nipecotic acid derivative (S)-SNAP-5114 (7) is a

compound showing high inhibitory potency at mGAT4 compared to

mGAT1, mGAT2, and mGAT3 [21], whereas compound rac-(u)-8

with 2-hydroxy-2-pyrrolidine-2-ylacetic acid as core amino acid

has comparatively better selectivity for mGAT4 than (S)-SNAP-5114

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Table 1

Representative mGAT3 selective partial structures and their GABA uptake inhibition at mGAT1e4 [29].

Entry

Compound

Uptake inhibition pIC₅₀

mGAT2

(

SEM, n ¼ 3)

mGAT1

mGAT3

mGAT4

1

2

3

9a^a

3.21 0.12

62.8%^b

3.99 0.05

3.28 0.19

77.3%^b

4.76 0.08

4.54 0.15

3.71 0.05

4.33 0.01

3.51 0.03

47.2%^b

11a^a

12a^a

73.7%^b

a

The pIC₅₀values originate from literature [29].

Percent inhibition at 100 mM.

b

(11a) [29] also represents, due to its good subtype selectivity, a

promising lead structure for further development of mGAT3 in-

hibitors with high potency and subtype selectivity. Similarly, the

unsaturated compound (2E)-3-(1H-imidazol-2-yl)prop-2-enoic

acid (12a, Table 1, entry 3) [29] possesses a pIC₅₀value of

in Table 1, and Schemes 1e3. Alkylating agents 21e26 were pre-

pared analogous to literature procedures [21] by treating 9-(4-

methoxyphenyl)-9H-ﬂuoren-9-ol (13) [21] with conc. H₂SO₄in

toluene followed by addition of the alcohols 14e19 at rt to afford

21e26 in 20%e92% yield (Table 2, entries 1e6). Only a maximum of

20% yield could be achieved for compound 26 (Table 2, entry 6),

which is to be accounted to the formation of a disubstituted side

product resulting from reaction of both hydroxyl groups of diol 19

with ﬂuorenyl derivative 13. The alcohols 14e19 employed in the

etheriﬁcation of 13 [21] were either prepared according to litera-

ture procedures (16 [33], 17 [34], 18 [35]) or obtained from com-

mercial sources (14, 15, 19).

3.71

0.05 for mGAT3 combined with a reasonable subtype

selectivity and could also serve as a promising lead structure.

Due to the fact that SNAP-5294 (6) exhibits, unlike nipecotic acid

(2), moderate afﬁnity at and a certain preference for mGAT3 [21],

the 2-[9-(4-methoxyphenyl)-9H-ﬂuoren-9-yl]oxyethyl moiety (b)

(Fig. 2) seemed to be a promising side chain to be introduced at the

N-atom of the parent compounds 9a-12a.

In order to determine the inﬂuence of the distance as well as the

spatial arrangement of the lipophilic and hydrophilic domain to the

inhibitory potencies at the GABA transporters subtypes of the test

compounds to be derived from 9ae12a, the structure of the lipo-

philic moiety starting from b [21] was systematically varied (see

Fig. 3). Thus, the spacer length between nitrogen and oxygen atom

was ﬁrst elongated from OC₂to OC₅(lipophilic moieties bee).

Based on the 4-[9-(4-methoxyphenyl)-9H-ﬂuoren-9-yl]oxybutyl

moiety (d), the lipophilic moieties h and i with a double bond

forming E- and Z-conﬁgurational isomers, respectively, were

designed to study the inﬂuence of unsaturation and side chain

geometry on the biological activity. In addition, the ethoxy linker of

moiety b was replaced by a prop-2-en-1-yl-group leading to moiety

f. Due to positive effects of an additional oxygen atom within the

spacer described in 2001 by Andersen et al. [32] also the ether

bridge containing moieties g and j were included in this study. To

summarize, the 1,4- (compounds 9be9f) and the 1,5-disubstituted

imidazoles (compounds 10be10f) of 1H-imidazol-4-yl-acetic acid

(9a), the 1,2-disubstituted imidazoles of 3-(1H-imidazol-2-yl)-

propanoic acid (11a), the N-alkyl derivatives 11be11j, and of (2E)-

3-(1H-imidazol-2-yl)prop-2-enoic acid (12a) compound 12e were

to be included in this study (Fig. 3). The synthesis and biological

evaluation of these compounds forms the content of this

publication.

The alcohol 27 required for the preparation of the mesylate 33

comprising two ether functions in the side chain was prepared

from 21 and sodium ethylene glycolate in 68% yield via Williamson

ether synthesis (Scheme 1). The preparation of 30 and its chain-

extended derivative 31 was realized starting from 9-(4-

methoxyphenyl)-9H-ﬂuoren-9-ol (13) [21]. The ﬂuorene deriva-

tive 13 was treated with allytributylstannane (28) and BF₃$Et₂O in

CH₂Cl₂analogous to a literature procedure [36] to yield the allyl

derivative 29 quantitatively. Subsequent chemoselective bromina-

tion of 29 according to the Wohl-Ziegler-method using AIBN as a

radical starter in analogy to a literature procedure [37] afforded

bromide 30 in 78% yield. Upon subjection of 30 to a Williamson

ether synthesis analogous to that employed in the preparation of 27,

the alcohol 31 was obtained in 51% yield (Scheme 2).

The mesylates 32e34 were obtained analogous to a standard

procedure [38] by, as shown in Scheme 3, treating the corre-

sponding alcohols 26, 27, and 31, with methanesulfonylchloride

and NEt₃at 0 ^ꢀC for 2 h (yield: 73%e97%).

2.2. Synthesis of N-alkylated 2-(1H-imidazol-5-yl)acetic acids

The regioselective synthesis of 1,5-disubstituted imidazole de-

rivatives 10be10f was performed based on the methods described

in the literature [39e42]. In order to ascertain a regioselective N-

alkylation of 1H-imidazol-4-yl-acetic acid (9a), the trityl derivative

35 was used in which N(1) is protected and which was synthesized

by a literature procedure. Initially, 35 [42] was ﬁrst reacted with 1.0

equiv. of 9-(2-bromoethoxy)-9-methoxyphenyl-9H-ﬂuorene (20)

[21] in CH₃CN at 55 ^ꢀC for a period of 3 days. The residue obtained

after evaporation containing the putative 1,3,4-trisubstituted imi-

dazolium derivative 36b was not isolated, but immediately sub-

jected to methanolysis under reﬂux conditions to remove the trityl

2. Chemistry

2.1. Synthesis of alkylating agents

The arylalkyl structures required for the modiﬁcation of the core

structures 9a, 11a, and 12a were prepared as their halides (20 [21],

21e25, 30), alcohols (26, 31), and mesylates (32e34) as described

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855

Fig. 3. Core structures, their 1,4-, 1,5-, and 1,2-disubstituted derivatives and the design of the lipophilic moieties cej.

group which provided the methyl ester 37b in 17% yield [39]. To

optimize the reaction, it was repeated under identical conditions

except that 1.3 equiv. of 20 was used. This increased the yield of 37b

to 22%. When in addition, the reaction time for the alkylation step

was extended from 3 to 8 days 40% of 37b could be isolated. The

optimal conditions were ﬁnally reached when the reaction tem-

perature was increased from 55 ^ꢀC to 60 ^ꢀC affording 37b in 58%

yield (Table 3, entry 1). In contrast, usage of 2.0 equiv. (instead of 1.3

equiv.) of 20 was counter productive, since then only 43% of 37b

could be isolated. The optimum reaction conditions for 37b

(Scheme 4) were then also used for the synthesis of the methyl

esters 37c and 37f which could be obtained in acceptable yields of

44% and 60%, respectively, by using the bromides 22 and 30 as

alkylating agents (Table 3, entry 2 and 5). For the N-alkylated 2-

(1H-imidazol-5-yl)acetic acid methyl esters 37d and 37e with a C₄O

and a C₅O spacer, generated by reacting 35 with the respective alkyl

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Scheme 1. Synthesis of 27.

Scheme 2. Synthesis of 30 and 31.

Scheme 3. Mesylation of alcohols 26, 27, and 31; ^a: see Fig. 3.

halides 23 and 24, the subsequent deprotection under reﬂux in

MeOH required the presence of 5% AcOH in analogy to a literature

procedure [41] to yield compounds 37d and 37e in 55% and 42%

yields (Table 3, entry 3 and 4). In absence of acid in case of com-

pound 37d, the yield amounted to only 17% (Table 3, entry 3).

Subsequent saponiﬁcation of the esters 37be37f afforded the

target compounds 10be10f in 65e100% yield (Scheme 4 and

Table 3, entries 1e5).

2.3. Synthesis of N-alkylated 2-(1H-imidazol-4-yl)acetic acids

According to literature, 1,4-disubstituted imidazole derivatives

such as 38be38f can be synthesized in a regioselective manner

[41]. The synthetic route, however, which in this case would

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

857

Table 2

Synthesis of the alkylating agents 21e26.

Entry

ROH

Product

Time [h]

Isolated yield [%]

1

20

92

I(CH₂)₂OH

14

2

20

90

Br(CH₂)₃OH

15

Br(CH₂)₄OH

3

20

18

79

16 [33]

Br(CH₂)₅OH

4

74

17 [34]

BrCH₂CH¼CHCH₂OH_(E)

5

60

18 [35]

(continued on next page)

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S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

Table 2 (continued )

Entry

ROH

Product

Time [h]

Isolated yield [%]

HOCH₂CH¼CHCH₂OH_(Z)

6

18

20

19

commence with the N-trityl protected imidazole derivative 35,

requires multiple steps including selective protection and depro-

tection of the N(1)- and N(3)-imidazol nitrogens in compound 35.

Therefore, we opted for an alternative, the synthesis of the N-

alkylated 2-(1H-imidazol-4-yl)acetic acids 9be9f by non-

regioselective alkylation of 1H-imidazol-4-ylacetic acid methyl

ester $ HCl (38a$HCl) [43,44] to ﬁrst give the respective esters

38be38f as a mixture with the regioisomers 37be37f of which the

former after separation should be transformed to the desired target

compounds 9be9f by hydrolysis as shown in Scheme 5. As

described in Scheme 5, the regioisomeric mixture of N-alkylated

compounds 38b and 37b was obtained by treatment of 38a$HCl

[44] with 2.2 equiv. tBuOK in DMF and subsequent reaction with 1.3

equiv. of the alkyl bromide 20 [21] at 40 ^ꢀC for 72 h. Though the

reaction had been carried out in analogy to literature conditions,

the yield was low (45%) [45]. In order to optimize the reaction, it

was repeated at elevated temperature of 60 ^ꢀC and 80 ^ꢀC which

yielded 57% and 51% of the isomeric mixture of 38b and 37b,

respectively. When the amount of tBuOK was reduced from 2.2

equiv. to 2.05 equiv. keeping the reaction temperature at 60 ^ꢀC, the

yield decreased from 57% to 51% (regioisomeric mixture of 38b and

37b). The best yield of the 1,4- and 1,5-disubstituted imidazole

derivatives 38b and 37b was ﬁnally obtained when at the beginning

2.2 equiv of tBuOK were applied, but the amount of alkylating agent

20 was raised from 1.3 to 2.0 equiv., then amounting to 64%

(mixture of 38b and 37b). The thus optimized conditions were then

also used for the alkylation of imidazole derivative, 38a$HCl [44]

with the alkylating agents 22, 23, and 30 which afforded the cor-

responding isomeric mixture in 43%e58% yield (see Table 4, entries

2, 3, 5, and Scheme 5). 38e was prepared starting from 38a [43] and

correspondingly less tBuOK (1.1 equiv) was used (Table 4, entry 4).

Particularly notable is that, upon extension of the chain length of

the alkylating agents from three to six atoms, the isolated yields of

the regioisomeric mixtures decreased whereas the regioselectivity

in favor of the 1,4-regioisomers improved (see Table 4, entries 1e4).

The 1,4-isomers 38be38f that had been isolated in pure form from

the mixture of regioisomers were ﬁnally hydrolyzed under alkaline

conditions which yielded the free amino acids 9be9f in good yields

(75%e94%) (Table 4, entries 1e5 and Scheme 5).

subsequent treatment with 1.3 equiv. of the alkylating agent 20

yielded only 28% of 39b. Raising the temperature to 40 ^ꢀC increased

the yield of 39b to 42%. A further increase in yield was observed

when the reaction was repeated using 1.1 equiv. of tBuOK, instead

with NaH, whereupon 39b was obtained in 52% yield. An increase in

temperature from 40 ^ꢀC to 60 ^ꢀC provided 39b ﬁnally in 83% yield

(Table 5, entry 3). By contrast, a further increase in temperature had

an adverse effect as N-alkylation of 52 at 80 ^ꢀC gave only 60% of 39b

compared to 83% yield at 60 ^ꢀC. Under these optimized reaction

conditions, ethyl ester 39a [29] was reacted with the alkylating

agents 22e25, 30, 32e34, 40 [19], and 41 [21] to afford the corre-

sponding N-alkylated esters 39ce39j, 42 and 43 (Table 5, entries

4e11, entry 1 and 2) in 46%e85% yield. The alkylating agents 4,4-

diphenylbut-3-en-1-yl bromide (40) [19] and 4,4,4-tris(4-

methoxyphenyl)but-2-enyl bromide (41) [21] (Table 5, entry 1

and 2) were included in this series as they are known from scaffolds

such as nipecotic acid to facilitate subtype selectivities in favor of

mGAT1 and mGAT4, respectively [19,21]. In case of synthesis of

compound 39j, it was found that reduction of the reaction time

from 72 h to 18 h improved the yield from 46% to 57% (Table 5, entry

11). Since treatment of 39a [29] with 4,4-diphenylbut-3-en-1-

ylbromide (40) [19] under the conditions optimized for the prep-

aration of 39b afforded compound 42 only in very low yield (6%), it

was repeated under modiﬁed conditions with tBuOK as base and,

NaI as additive (CH₃CN), which improved the yield from 6% to 21%

(Table 5, entry 1) [23,46]. Alkaline hydrolysis of the N-alkylated 3-

(1H-imidazol-2-yl)propanoic acid ethyl esters 42, 43, and 39be39j

afforded the desired ﬁnal compounds 44, 45 and 11be11j in 73%e

90% yield (Table 5, entries 1e11).

2.5. Synthesis of N-alkylated (2E)-3-(1H-imidazol-2-yl)prop-2-

enoic acid 12e

Additionally, compound 12e comprising (2E)-3-(1H-imidazol-2-

yl)prop-2-enoic acid as parent compound and the 9-(4-

methoxyphenyl)-9H-ﬂuoren moiety as lipophilic domain linked

via a C₅O spacer was prepared. The synthesis started from 46a [29],

which was treated at rt with tBuOK in DMF and subsequently with

the alkylating agent 24 to provide 46e in 97% yield. Subsequent

alkaline hydrolysis of the ester group with 2 M NaOH afforded

compound 12e in 77% yield (Scheme 7).

2.4. Synthesis of N-alkylated 3-(1H-imidazol-2-yl)propanoic acids

The synthesis of 3-(1H-imidazol-2-yl)propanoic acid derivatives

with appropriate N-substituents, i.e. compounds 11be11j, 44, and

45, was again accomplished by a two step procedure, the N-alkyl-

ation of the imidazole ring of the carboxylic acid ester 39a followed

by the alkaline hydrolysis of the ester function (Scheme 6). The

alkylation of 39a with the alkyl bromide 20 was selected as a model

reaction for the optimization of the reaction conditions.

3. Biological evaluation and discussion

The N-alkylated imidazolyl alkanoic acids 9be9f, 10be10f,

11be11j, 44, 45, and N-alkylated imidazolyl alkenoic acid 12e were

evaluated in [³H]GABA uptake assays for their inhibitory potency at

the four subtypes of GABA transporters, i.e. mGAT1, mGAT2,

mGAT3, and mGAT4. These [³H]GABA uptake assays were per-

formed in a uniform manner using HEK cell lines, each stably

The deprotonation of 39a [29] with 1.1 equiv. NaH and

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859

Table 3

Synthesis of N-alkylated 2-(1H-imidazol-5-yl)acetic acids 10be10f.

Entry

R-Br

Compound no.

Isolated yield [%]

Compound no.

Isolated yield [%]

1

37b

58^a

10b

90

2

37c

44^a

10c

65

55^b

17^a

3

37d

10d

74

4

37e

42^b

10e

77

5

37f

60^a

10f

quant.

a

Deprotection with MeOH reﬂux [39].

Deprotection with 5% HOAc in MeOH reﬂux [41].

b

expressing one of the four GABA transporter subtypes as described

in the literature [28,47]. The potency of the compounds is repre-

sented either as pIC₅₀SEM (for experiments done in triplicates,

n ¼ 3) or in exceptional cases just the pIC₅₀value when one indi-

vidual experiment was done. For compounds exhibiting lower

potency, the percentage of the remaining [³H]GABA uptake at the

3.1. Biological evaluation of N-1-substituted 1H-imidazol-4-yl

acetic acids 9b-f and 1H-imidazol-5-yl acetic acids 10b-f

The results of [³H]GABA uptake assays at the four subtypes of

GABA transporters mGAT1emGAT4 for the N-1-substituted 1H-

imidazol-4-ylacetic acids and 1H-imidazol-5-ylacetic acids, 9be9f

and 10be10f, respectively, and the parent compound 9a are sum-

marized in Table 6. Previous studies have shown that 1H-imidazol-

4-ylacetic acid (9a) exhibits good inhibitory activity especially

related to mGAT3 in combination with an acceptable preference for

mGAT3 compared to mGAT1 (mGAT3:mGAT1 ¼ 35:1, Table 6, entry

concentration of 100

m

M is given. A pIC₅₀value of ꢁ4 was assumed

for test compounds that do not reduce at 100 m

M the [³H]GABA

uptake to ꢁ 50% to collate the obtained results.

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Scheme 4. Synthesis of N-alkylated 2-(1H-imidazol-5-yl)acetic acids 10be10f.

Scheme 5. Synthesis of N-alkylated 2-(1H-imidazol-4-yl)acetic acids 9be9f.

1) [29]. Worth mentioning here are compounds 10d and 9d. Both,

the N-1-alkylated 1H-imidazol-5-ylacetic acid 10d and the N-1-

alkylated 1H-imidazol-4-ylacetic acid 9d which are characterized

by a spacer length of four C-atoms between nitrogen and oxygen

exhibit an acceptable inhibitory potency at mGAT2 (pIC₅₀value:

4.64 and 4.62, respectively, Table 6, entry 6 and 7). But both, 10d

and 9d, show only marginal if any subtype selectivity against

mGAT1, mGAT3, and mGAT4. The good inhibitory potencies of

compounds 10d and 9d at mGAT2 is to be attributed to the C₄O

spacer. All other imidazole acetic acids derivatives, i.e. 9b, 10b, 9c,

10c, 9e, 10e, 9f, and 10f show inhibitors potencies at mGAT1em-

GAT4 in a range so low that they are almost neglectable (Table 6,

entries 2e5 and entries 8e11).

tris(4-methoxyphenyl)but-2-en-1-yl unit characteristic for GABA

uptake inhibitors selective for mGAT1 and mGAT4, respectively,

attached to the core structure 11a have also been included to

achieve a more comprehensive set of compounds for the estab-

lishment of structure-activity-relationship (Table 7, entries 2 and

3). As shown in previous studies, the starting compound 11a dis-

plays slightly lower mGAT3 inhibitory potency than 2-(1H-imid-

azole-4-yl)acetic acid (9a), but exhibits an improved mGAT3

selectivity of 18-fold over mGAT2 and 7-fold over mGAT4 (Table 7,

entry 1) [29]. Contrary to the expectations for an improved inhib-

itory potency at mGAT3, the introduction of the 2-[9-(4-

methoxyphenyl)-9H-ﬂuoren-9-yl]oxyethyl moiety (b) into 11a,

generally enhancing mGAT3 potency, does not give rise to a sig-

niﬁcant enhancement of potency at this or any other of the GABA

transporter subtypes (Table 7, entry 4). For compound 44 in which

the 3-(1H-imidazol-2-yl)propanoic acid (11a) is provided with a

4,4-diphenylbut-3-en-1-yl moiety also no signiﬁcant improvement

of inhibitory potency as compared to 11a is observed, neither at

mGAT1 or at any of the other GABA transporter subtypes (Table 7,

entry 2). In contrast, with a pIC₅₀value of 5.10 0.04, 45 shows

good mGAT4 inhibitory activity combined with certain preference

3.2. Biological evaluation of N-1-substituted 3-(1H-imidazol-2-yl)

propanoic acids 11aej, 44, and 45

The results of the biological evaluation of 3-(1H-imidazol-2-yl)

propanoic acid (11a) [29] and the N-alkylated derivatives 11be11j,

and 44, 45 are presented in Table 7. In this series, compounds 44

and 45 containing the 4,4-diphenylbut-3-en-1-yl and the 4,4,4-

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

861

Table 4

N-Alkylated 2-(1H-imidazol-4-yl)acetic acids.

Entry

R-Br

Isolated yield of 1,4-isomer [%]

1,4-Isomer

1,5-Isomer

Compound no.

Isolated yield [%]

[Ratio 1,4-:1,5-isomer]^aTotal isolated yield [%]

38b

37b

1

42

27

29

9b

93

75

83

[0.76:0.24]

64

38c

37c

2

9c

[0.77:0.23]

50

38d

37d

3

9d

[0.8:0.2]

43

4

29^b

9e

88

38e

37e

[0.9:0.1]

34

38f

37f

5

28

9f

94

[0.6:0.4]

58

a

Ratio determined by ¹H NMR-Spectrum.

38a [43] was used as starting material. Correspondingly, less tBuOK (1.1 equiv.) was used.

b

for this subtype (subtype selectivity: mGAT4:mGAT1 ꢂ 13:1,

mGAT4:mGAT2 ꢂ 13:1 and mGAT4:mGAT3 ~ 3:1, Table 7, entry 3).

Worth mentioning are also compounds 11d, 11h, and 11i with a C₄O

spacer. Similar to the 1,5-isomer 10d (Table 6, entry 6) and the 1,4-

isomer 9d (Table 6, entry 7), the C₄O spacer of compound 11d also

has positive effects on the mGAT2 inhibitory activity (pIC₅₀value:

4.60 0.08). With a subtype selectivity of mGAT2:mGAT1 ¼ 6:1,

mGAT2:mGAT3 ¼ 4:1, and mGAT2:mGAT4 ¼ 7:1 (Table 7, entry 6)

11d displays an mGAT2 selectivity similar to that of the 1,5-isomer

10d. As compared to 11d possessing a C₄O spacer, the (2E)-4-

oxybut-2-ene-1-yl spacer of compound 11h hardly inﬂuences the

inhibitory potencies at mGAT1emGAT4 (Table 7, entry 10). In

contrast thereto, the change of the double bond conﬁguration in

11h from (E) to (Z) resulting in compound 11i leads to an

improvement in the potency at mGAT3 and mGAT4 from pIC₅₀

values of ~4 (11h, Table 7, entry 10) to pIC₅₀values 4.80 and

4.88 0.19, respectively (11i, Table 7, entry 11). The extension of the

spacer to a C₅O unit leads to compound 11e, which exhibits with a

pIC₅₀value of 4.93

0.03 an acceptable mGAT1 inhibition, but

misses subtype selectivity (Table 7, entry 7). The additional ether

oxygen within the spacer of compound 11j (C₂OC₂O) deteriorates

the inhibitory potencies relating to mGAT1, mGAT2, and mGAT4 as

compared to compound 11e, whereas the inhibitory potency at

mGAT3 is hardly inﬂuenced (Table 7, entry 12). Compound 11f,

which consists of the 3-(1H-imidazol-2-yl)propanoic acid core

structure (11a) and the (2E)-2-[9-(4-methoxyphenyl)-9H-ﬂuoren-

862

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

Scheme 6. Synthesis of N-alkylated 3-(1H-imidazol-2-yl)propanoic acids 44, 45, and 11be11j.

9-yl]prop-2-en-1-yl moiety (f), exhibits low to mediocre potency at

all four GABA transporter subtypes (Table 7, entry 8). Compound

11g, derived from 11f by a chain extension with a C₂O unit shows

similar inhibitory potencies (pIC₅₀¼ 4.51e4.66) at mGAT1emGAT4

(Table 7, entry 9).

To summarize, among the N-1-substituted 3-(1H-imidazol-2-yl)

propanoic acids 11b-j, compound 11d with a C₄O spacer showed

similar positive effects as compounds 9d and 10d on the mGAT2

inhibitory activity.

4. Conclusion

In summary, new series of potential GABA uptake inhibitors

derived from the core structures 2-(1H-imidazol-4-yl)acetic acid

(9a) and 3-(1H-imidazol-2-yl)propanoic acid (11a) as conforma-

tional restricted analogs of GABA (1) by linkage with a 2-[9-(4-

methoxyphenyl)-9H-ﬂuoren-9-yl] moiety via spacers of different

length attached to one of the ring nitrogens have been synthesized

and characterized for their biological activity at mGAT1emGAT4.

Compounds, 9b, 10b, and 11b comprising the core structure 9a and

11a, respectively, both of which exhibit good mGAT3 inhibition and

preference for this transporter subtype, and the 2-[9-(4-

methoxyphenyl)-9H-ﬂuoren-9-yl]oxyethyl moiety with an OC₂

spacer which residue is characteristic for mGAT3 inhibitors [21],

were found to be devoid of any signiﬁcant inhibitory potency at all

four GABA transporters. Upon elongation of the spacer-length be-

tween nitrogen, the ﬂuorene moiety from OC₂up to OC_4,a gain in

inhibitory potency at mGAT2 occurred. Thus, 9d, 10d, and 11d

displaying a C₄O spacer exhibit an acceptable mGAT2 inhibitory

activity with pIC₅₀values of, 4.62 4.64 and 4.60 0.08, respectively.

Of these, the imidazole acetic acid derivative 10d and the propanoic

acid derivative 11d show also a slight preference for mGAT2. Within

the series of imidazole-2-ylpropanoic acid and propenoic acids, the

propenoic acid derivative 12e was found to display a pIC₅₀value of

5.13 0.04 at mGAT3. With this pIC₅₀value 12e ranges among the

most potent mGAT3 inhibitors. But it is devoid of any signiﬁcant

subtype selectivity. The pIC₅₀value at mGAT3 though being

nominally the highest is similar to those for the other GABA

3.3. Biological evaluation of N-alkylated (2E)-3-(1H-imidazol-2-yl)

prop-2-enoic acid 12e

The results of the GABA uptake studies of SNAP-5294 (6) [21],

(2E)-3-(1H-imidazol-2-yl)prop-2-enoic acid 12a [29], and its N-

alkyl derivative 12e exhibiting the 2-[9-(4-methoxyphenyl)-9H-

ﬂuoren-9-yl]oxypentyl residue (e) are summarized in Table 8. Ac-

cording to results reported in literature [21], SNAP-5294 (6) ex-

hibits moderate inhibitory potency at rGAT2 (≡ mGAT3) in

combination with certain selectivity for this transporter (Table 8,

entry 1). But according to the data obtained employing our test

system based on HEK cell lines expressing mice transporters [28],

SNAP-5294 (6) possesses its highest inhibitory but still mediocre

potency at mGAT4 (pIC₅₀4.52

0.08) in combination with low

potency at mGAT3 (pIC₅₀4.03 0.05, Table 8, entry 2). The reason

for this reversal of the subtype selectivity of 6 at rGAT2 (≡ mGAT3)

and hGAT3 (≡ mGAT4) versus mGAT3 and mGAT4 is unclear.

Though not very likely this could be due to the different species, the

transporters are derived from. Interestingly, core structure 12a

shows a lower inhibitory potency at mGAT3 as compared to the

saturated analogue 11a (11a: pIC₅₀4.54 0.15; Table 7, entry 1; 12a:

pIC₅₀3.71 0.05; Table 8, entry 3). The opposite is true for the N-

substituted derivatives 12e and 11e both exhibiting the same res-

idue (e). With a pIC₅₀value of 5.13 0.04 (Table 8, entry 4), imid-

azole derivative 12e has gained about 1.5 log units in potency at

mGAT3 as compared to the parent compound 12a (pIC₅₀

3.71 0.05, Table 8, entry 3). This value surpasses the potency of its

saturated analogue 11e by about a half log unit (11e: pIC₅₀4.63,

Table 7, entry 7) and exceeds the potency of SNAP-5294 (6), the

prototypic inhibitor of mGAT3, at mGAT4 in the present test system

by a factor of 13 (Table 8, entry 4). Clearly, the improved inhibitory

potency at mGAT3 observed for imidazole derivative 12e as

compared to 11e is to be attributed to the additional double bond

present in the carboxylic acid side chain of this compound.

Compared to the clinically marketed drug tiagabine (5: an mGAT1

selective inhibitor, Table 8, entry 5), 12e shows a decrease in the

inhibitory potency at mGAT1, but an increase in potency at mGAT2

to mGAT4 so that pIC₅₀values at mGAT1-mGAT4 are all covering

the same range - around pIC₅₀of 5.0 e with the nominally highest

potency being displayed at mGAT3.

transporters as for example for mGAT4 (pIC₅₀4.99

0.13). In

contrast to SNAP-5294 (6) which in the present test system exhibits

its best inhibitory potency at mGAT4 and not at mGAT3 as pub-

lished [21], 12e shows an inhibitory potency of approximately one

log unit higher than that of 6 at mGAT3 (though this is similar to the

value at mGAT4 for 12e) (Table 8, entry 2 and 4).

Up to date, only few selective inhibitors of mGAT3 have been

published. In this study, the N-alkylated (2E)-3-(1H-imidazol-2-yl)

prop-2-enoic acid 12e has been identiﬁed as a reasonably potent

inhibitor at mGAT3 that in the present test system surpasses SNAP-

5294 (6), with regard to potency at and preference for mGAT3 over

mGAT4. Thus, 12e is to date the most potent mGAT3 inhibitor. This

structure can be regarded as the best lead for the development of

new uptake inhibitors of mGAT3 with high potency, their low

selectivity to this transporter protein notwithstanding. Efforts to

develop more potent and selective mGAT3 inhibitors are in

progress.

5. Experimental protocols

5.1. Chemistry

Solvents were p.a. quality and freshly distilled before use.

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

863

Table 5

N-Alkylated 3-(1H-imidazol-2-yl)propanoic acids.

Entry

X-R

Compound no.

Isolated yield [%]

Compound no.

Isolated yield [%]

6^a

1

42

44

85

21^b

2

43

70^a

45

85

3

39b

83^a

11b

90

4

39c

78^a

11c

73

5

39d

85^a

11d

80

6

39e

74^a

11e

83

7

39f

64^a

11f

90

(continued on next page)

864

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

Table 5 (continued )

Entry

X-R

Compound no.

Isolated yield [%]

Compound no.

Isolated yield [%]

8

39g

69^a

11g

88

9

39h

68^a

11h

82

10

39i

54^a

11i

73

46^a

57^c

11

39j

11j

78

a

tBuOK, DMF, r.t., 1 h 2. R-X, 60 ^ꢀC, 72 h.

R -X, C H₃CN, tBuOK, NaI, 60 ^ꢀC, 72 h.

tBuOK, DMF, r.t., 1 h 2. R-X, 60 ^ꢀC, 18 h.

b

c

Purchased reagents were used without further puriﬁcation. TLC

plates were made from silica gel 60 F₂₅₄on aluminium sheet

(Merck). Column chromatography (CC) was carried out using Merck

silica gel 60 (mesh 0.040e0.063 mm) as stationary phase. Melting

points: m.p. (uncorrected) were determined with a Büchi 512

Melting Point apparatus. NMR spectroscopy: ¹H NMR spectra were

recorded at rt with a JNMR-GX (JEOL, 400 or 500 MHz) using TMS as

internal standard and integrated with the NMR software MestRe-

Nova. IR spectroscopy: FT-IR Spectrometer 410 (Jasco); samples

were measured as KBr-pellets. Mass spectrometry (MS): Mass

Spectrometer 5989 A with 59980 B particle beam LC/MS interface

(Hewlett Packard) or Applied Biosystems LC-MS/MS-Mass Spec-

trometer API 2000; analysis was carried out using chemical

ionization (CH^þ₅) or electron impact ionization. High-resolution

mass spectrometry (HRMS): JEOL MS-Station JMS-700, FAB

(Xenon, 6 KV, MBA, reference PEG), LTQ FT (Thermo Finnigan).

Elementary analysis: Elementaranalysator Rapid (Heraeus); anal-

ysis indicated by the symbols of the elements were within 0.4% of

the theoretical values.

9-(4-methoxyphenyl)-9H-ﬂuoren-9-ol

bromobutanol (16) [33], 5-bromopentane-1-ol (17) [34], (2E)-4-

bromobut-2-en-1-ol (18) [35], 9-(2-bromoethoxy)-9-

(13)

[21],

4-

methoxyphenyl-9H-ﬂuorene (20) [21], (1-triphenylmethyl-1H-

imidazol-4-yl)acetic acid methyl ester (35) [42], 1H-imidazol-4-

ylacetic acid methyl ester HCl (38a$HCl) [43,44], 1H-imidazol-4-

ylacetic acid methyl ester (38a) [43], 3-(1H-imidazol-2-yl)

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

865

Scheme 7. Synthesis of 12e.

propanoic acid ethyl ester (39a) [29], and (2E)-3-(1H-Imidazol-2-

yl)prop-2-enoic acid ethyl ester (46a) [29] were prepared accord-

ing to standard procedures in the literature [21,29,33e35,43,44]. 2-

iodoethanol (14), 3-bromopropanol (15), (2Z)-but-2-ene-1,4-diol

(19), and allytributylstannane (28) were commercially available.

BrCH₂), 3.74 (s, 3 H, CH₃), 6.73e6.80 (m, 2 H, H_ar), 7.19e7.31 (m, 6 H,

H_ar), 7.36 (td, J ¼ 7.5/1.7 Hz, 2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H H_ar); ¹³

C

NMR (CDCl₃):

d

¼ 30.73 (t, 1 C, BrCH₂), 33.32 (t, 1 C, BrCH₂CH₂),

55.17 (q, 1 C, CH₃), 60.68 (t, 1 C, CH₂O), 88.19 (s, 1 C, CH₂OC), 113.48

(d, 2 C, C_ar), 119.93 (d, 2 C, C_ar), 125.19 (d, 2 C, C_ar), 126.69 (d, 2 C, C_ar),

128.15 (d, 2 C, C_ar), 128.97 (d, 2 C, C_ar), 135.61 (s, 1 C, C_ar), 140.56 (s,

2 C, C_ar), 147.18 (s, 2 C, C_ar), 158.73 (s, 1 C, C_ar); MS (EI, 70 eV) m/z (%):

410 (10, M^þ), 408 (10, M^þ), 271 (100); HRMS (EI, 70 eV):

(C₂₃H₂₁O₂Br) calc. 408.0725, found 408.0729.

5.1.1. General procedure for the synthesis of alkylating agents (GP1)

[21].

Conc. H₂SO₄(0.3 equiv.) was added to 9-(4-methoxyphenyl)

ﬂuoren-9-ol (13) (1.0 equiv.) in toluene and warmed up to 60 ^ꢀC for

15 min. After cooling the solution to rt the corresponding hydroxyl

alkyl halide (1.5 equiv) or the alkyldiol (2.0 equiv.) was added. The

reaction mixture was stirred at rt for the given time and then

partitioned between water and toluene. The organic phase was

dried over MgSO₄, ﬁltered, and concentrated to dryness. The crude

product was then puriﬁed by CC (iso-hexane/EtOAc ¼ 9.5:0.5).

5.1.1.3. 9-(4-Bromobutoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene (23).

According to GP1: 9-(4-methoxyphenyl)ﬂuoren-9-ol (13) [21]

(2.6 g, 9.0 mmol), toluene (19 mL), conc. H₂SO₄(275 mg,

2.81 mmol, 0.15 mL), 4-bromobutan-1-ol (16) [33] (2.10 g,

13.7 mmol), 20 h. Yield: 3.1 g (79%); colourless solid, m.p. 95e97 ^ꢀC;

TLC: R_f¼ 0.3 (iso-hexane/EtOAc ¼ 9.5:0.5); IR (KBr): 3037, 3003,

2935, 2867, 2837, 2042, 1968, 1933, 1899, 1830, 1646, 1605, 1508,

1450, 1441, 1297, 1247, 1178, 1165, 1101, 1071, 1029 cm^ꢃ1

;

¹H NMR

5.1.1.1. 9-(2-Iodoethoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene

(21).

(CDCl₃):

d

¼ 1.57e1.70 (m, 2 H, CH₂CH₂O), 1.89e2.03 (m, 2 H,

According to GP1: 9-(4-methoxyphenyl)ﬂuoren-9-ol (13) [21]

(1.4 g, 4.8 mmol), toluene (12 mL), conc. H₂SO₄(147 mg,

BrCH₂CH₂), 2.99 (t, J ¼ 6.0 Hz, 2 H, CH₂O), 3.37 (t, J ¼ 6.8 Hz, 2 H,

BrCH₂), 3.74 (s, 3 H, CH₃), 6.72e6.80 (m, 2 H, H_ar), 7.21e7.29 (m, 6 H,

H_ar), 7.31e7.42 (m, 2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR

1.50 mmol, 80.0

mL), 2-iodoethanol (14) (1.26 g, 7.35 mmol,

0.573 mL), 20 h. Yield: 2.0 g (92%); colourless solid, m.p. 96e98 ^ꢀC;

TLC: R_f¼ 0.24 (iso-hexane/EtOAc ¼ 9.5/0.5); IR (KBr): 3035, 2931,

2903, 2841, 2044, 1951, 1918, 1605, 1580, 1508, 1447, 1302, 1252,

(100 MHz, CDCl₃, 19.7 ^ꢀC, CDCl₃):

d

¼ 28.80 (t, 1 C, CH₂CH₂O), 29.94

(t, 1 C, BrCH₂CH₂), 34.05 (t, 1 C, BrCH₂), 55.39 (q, 1 C, CH₃), 62.23 (t,

1 C, CH₂O), 88.40 (s, 1 C, CH₂OC), 113.67 (d, 2 C, C_ar), 120.14 (d, 2 C,

C_ar),125.31 (d, 2 C, C_ar),126.92 (d, 2 C, C_ar),128.34 (d, 2 C, C_ar),129.12

(d, 2 C, C_ar), 135.92 (s, 1 C, C_ar), 140.78 (s, 2 C, C_ar), 147.65 (s, 2 C, C_ar),

158.88 (s, 1 C, C_ar); MS (EI, 70 eV) m/z (%): 424 (6, M^þ), 271 (100);

HRMS (EI, 70 eV): (C₂₄H₂₃BrO₂) calc. 422.0881, found 422.0883;

Anal. C₂₄H₂₃BrO₂(C, H, Br, O).

1184,1169,1107,1031, 993 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 3.15e3.20 (m,

2 H, CH₂O), 3.20e3.24 (m, 2 H, ICH₂), 3.75 (s, 3 H, CH₃), 6.76e6.81

(m, 2 H, H_ar), 7.26 (td, J ¼ 7.4/1.2 Hz, 2 H, H_ar), 7.29e7.32 (m, 2 H,

H_ar), 7.33 (d, J ¼ 7.4 Hz, 2 H, H_ar), 7.37 (td, J ¼ 7.4/1.2 Hz, 2 H, H_ar),

7.66 (d, J ¼ 7.4 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

¼ 4.43 (t, 1 C, ICH₂),

d

55.20 (q, 1 C, CH₃), 63.93 (t, 1 C, CH₂O), 88.42 (s, 1 C, CH₂OC), 113.55

(d, 2 C, C_ar), 120.00 (d, 2 C, C_ar), 125.43 (d, 2 C, C_ar), 126.84 (d, 2 C,

C_ar), 128.23 (d, 2 C, C_ar), 129.15 (d, 2 C, C_ar), 135.29 (s, 1 C, C_ar), 140.51

(s, 2 C, C_ar), 146.87 (s, 2 C, C_ar), 158.83 (s, 1 C, C_ar); MS (EI, 70 eV) m/z

(%): 442 (30, M^þ), 271 (100); HRMS (EI, 70 eV): (C₂₂H₁₉IO₂) calc.

442.0430, found 442.0475; Anal. C₂₂H₁₉IO₂(C, H, I, O).

5.1.1.4. 9-(5-Bromopentoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene (24).

According to GP1: 9-(4-methoxyphenyl)ﬂuoren-9-ol (13) [21]

(5.0 g, 17 mmol), toluene (35 mL), conc. H₂SO₄(514 mg,

5.24 mmol, 0.280 mL), 5-bromopentan-1-ol (17) [34] (3.34 g,

19.6 mmol), 20 h. Yield: 5.64 g (74%); light yellow crystals, m.p.

103e105 ^ꢀC; TLC: R_f¼ 0.24 (iso-hexane/EtOAc ¼ 9.5:0.5); IR (KBr):

3062, 3004, 2930, 2911, 2866, 2834, 1604, 1578, 1508, 1448, 1301,

5.1.1.2. 9-(3-Bromopropoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene (22).

According to GP1: 9-(4-methoxyphenyl)ﬂuoren-9-ol (13) [21]

(1.4 g, 4.9 mmol), toluene (12 mL), conc. H₂SO₄(147 mg,

1251,1167,1083,1033 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 1.43e1.55 (m, 4 H,

1.50 mmol, 80.0

mL), 3-bromopropan-1-ol (15) (1.02 g, 7.35 mmol,

CH₂CH₂CH₂O), 1.79 (tt, J ¼ 7.2/6.8 Hz, 2 H, BrCH₂CH₂), 2.97 (t,

J ¼ 5.8 Hz, 2 H, CH₂O), 3.38 (t, J ¼ 6.8 Hz, 2 H, BrCH₂), 3.74 (s, 3 H,

CH₃), 6.74e6.79 (m, 2 H, H_ar), 7.23e7.30 (m, 6 H, H_ar), 7.33e7.39 (m,

0.643 mL), 20 h. Yield: 1.8

g

(90%); colourless solid, m.p.

102e105 ^ꢀC; TLC: R_f¼ 0.39 (iso-hexane/EtOAc ¼ 9.5:0.5); IR (KBr):

3065, 3039, 3008, 2954, 2932, 2875, 2836, 2044, 1954, 1917, 1844,

1809,1608,1581,1509,1449,1417,1302,1284,1250,1216,1170,1103,

2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

¼ 24.86 (t,

d

1 C, CH₂CH₂CH₂O), 29.14 (t, 1 C, CH₂CH₂CH₂O), 32.46 (t, 1 C,

BrCH₂CH₂), 33.91 (t, 1 C, BrCH₂), 55.17 (q, 1 C, CH₃), 62.68 (t, 1 C,

CH₂O), 88.15 (s, 1 C, CH₂OC), 113.44 (d, 2 C, C_ar), 119.88 (d, 2 C, C_ar),

1066, 1035 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 1.98e2.05 (m, 2 H,

BrCH₂CH₂), 3.08 (t, J ¼ 5.7 Hz, 2 H, CH₂O), 3.54 (t, J ¼ 6.7 Hz, 2 H,

866

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

Table 6

pIC₅₀values of N-alkylated 2-(1H-imidazolyl)acetic acids 10be10f and 9ae9f at mGAT1emGAT4.

Entry

Compound

no.

mGAT1

mGAT2

mGAT3

mGAT4

Core structure

R ¼

H [29]

a

1

2

3

4

9a

10b

9b

3.21 0.12

67.2%^a

3.99 0.05

57.9%^a

4.76 0.08

50.8%^a

4.33 0.01

46.0%^a

56.6%^a

44.0%^a

46.7%^a

85.4%^a

10c

50.1%^a

70.1%^a

4.09 0.11

55.6%^a

5

6

9c

84.2%^a

70.8%^a

4.01 0.15

51.4%^a

41.7%^a

61.4%^a

59.0%^a

10d

4.64^b

7

8

9d

64.9%^a

4.10^b

4.62^b

4.40^b

4.31^b

10e

38.5%^a

68.0%^a

77.4%^a

9

9e

72.7%^a

4.21^b

4.01^b

3.98^b

10

10f

9f

3.90 0.09

62.4%^a

3.78 0.05

24.2%^a

4.10 0.12

4.32 0.06

3.96 0.09

4.40 0.07

11

a

Percent inhibition at 100

Value from a single experiment.

m

M.

b

125.15 (d, 2 C, C_ar), 126.72 (d, 2 C, C_ar), 128.07 (d, 2 C, C_ar), 128.84 (d,

2 C, C_ar), 135.86 (s, 1 C, C_ar), 140.55 (s, 2 C, C_ar), 147.54 (s, 2 C, C_ar),

158.64 (s, 1 C, C_ar); MS (EI, 70 eV) m/z (%): 436 (4, M^þ), 271 (100);

HRMS (EI, 70 eV): (C₂₅H₂₅BrO₂) calc. 436.1038, found 436.1054;

Anal. C₂₅H₂₅BrO₂(C, H, Br, O).

1028, 1006 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 3.55 (d_br, J ¼ 5.1 Hz, 2 H,

CH₂O), 3.74 (s, 3 H, CH₃), 3.91 (d, J ¼ 7.5 Hz, 2 H, BrCH₂), 5.74 (dt,

J ¼ 5.1/15.2 Hz, 1 H, CHCH₂O), 5.90 (dtt, J ¼ 15.2/7.5/1.5 Hz, 1 H,

BrCH₂CH), 6.73e6.82 (m, 2 H, H_ar), 7.21e7.32 (m, 6 H, H_ar), 7.37 (td,

J ¼ 7.5/1.4 Hz, 2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR

(CDCl₃):

d

¼ 32.47 (t, 1 C, BrCH₂), 55.17 (q, 1 C, CH₃), 63.06 (t, 1 C,

CH₂O), 88.46 (s, 1 C, CH₂OC), 113.48 (d, 2 C, C_ar), 119.95 (d, 2 C, C_ar),

125.25 (d, 2 C, C_ar), 126.78 (d, 2 C, C_ar), 127.13 (d, 1 C, BrCH₂CH),

128.20 (d, 2 C, C_ar), 129.07 (d, 2 C, C_ar), 132.50 (d, 1 C, CHCH₂O),

135.28 (s, 1 C, C_ar), 140.56 (s, 2 C, C_ar), 147.04 (s, 2 C, C_ar), 159.74 (s,

1 C, C_ar); MS (FAB, NBA) m/z (%): 422.2 (21, [MþH]^þ), 420.2 (21,

[MþH]^þ), 341.34 (10), 287.3 (23), 271.3 (100),; HRMS (EI, 70 eV):

(C₂₄H₂₁BrO₂) calc. 420.0725, found 420.0735.

5.1.1.5. 9-[(2E)-4-bromobut-2-en-1-yloxy]-9-(4-methoxyphenyl)-

9H-ﬂuorene (25). According to GP1: 9-(4-methoxyphenyl)ﬂuoren-

9-ol (13) [21] (4.77 g, 16.5 mmol), toluene (30 mL), conc. H₂SO₄

(496 mg, 5.05 mmol, 0.270 mL), (2E)-4-bromobut-2-en-1-ol (18)

[35] (3.74 g, 24.8 mmol), 18 h. Yield: 4.1 g (60%); light yellow solid,

m.p. 95e97 ^ꢀC; TLC: R_f¼ 0.21 (iso-hexane/EtOAc ¼ 9.5:0.5); IR

(KBr): 3037, 2999, 2960, 2906, 2858, 2836, 2040, 1968, 1933, 1897,

1829, 1717, 1643, 1605, 1508, 1450, 1297, 1247, 1178, 1165, 1102, 1053,

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

867

Table 7

pIC₅₀values of N-alkylated 3-(1H-imidazol-2-yl)propanoic acids 44, 45, 11ae11j at mGAT1emGAT4.

Entry

no.

mGAT1

mGAT2

mGAT3

mGAT4

H

a

1

2

11a [29]

62.8%^a

4.13^b

3.28 0.19

4.54 0.15

3.51 0.03

53.7%^a

44

4.23^b

48.1%^a

3

45

53.7%^a

65.4%^a

4.64^b

5.10 0.04

4

11b

64.8%^a

53.0%^a

43.2%^a

58.3%^a

5

11c

4.00 0.13

31.2%^a

48.6%^a

55.4%^a

6

11d

3.85 0.04

4.60 0.08

4.06 0.22

3.76 0.12

7

8

9

11e

11f

11g

4.93 0.03

4.90^b

4.60 0.11

4.51^b

4.63^b

4.45 0.05

4.61^b

4.53 0.04

48.5%^a

4.36 0.11

4.58^b

4.66^b

(continued on next page)

868

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

Table 7 (continued )

Entry

no.

mGAT1

mGAT2

mGAT3

mGAT4

10

11h

55.8%^a

4.49^b

43.9%^a

61.4%^a

11

11i

4.15^b

4.43^b

4.80^b

4.88 0.19

12

11j

4.43^b

48.3%^a

4.55^b

50.7%^a

a

Percent inhibition at 100 mM.

Value from a single experiment.

b

Table 8

Afﬁnities of SNAP-5294 (6) and compounds 12a and 12e.

Entry

1

Compound no.

IC₅₀

(

m

M)^a

hGAT-1

hBGT-1

rGAT-2

hGAT-3

6

133 50

27 10^c

51

4

142 21

b

pIC₅₀

mGAT1

mGAT2

mGAT3

mGAT4

2

3

4

5

6

73.1%^c

73.7%^c

4.90 0.08

6.88 0.12

66.3%^c

77.3%^c

4.54^d

52%^c

4.03 0.05

3.71 0.05

5.13 0.04

64%^c

4.52 0.08

47.2%^c

12a

12e

5

4.99 0.13

73%^c

pIC₅₀values in bold represent important inhibitory potencies.

a

Values originate from literature [21].

pIC₅₀values were determined in our lab using the biological assay described in Ref. [47].

b

c

Percent inhibition at 100

m

M.

d

Value from a single experiment.

5.1.1.6. (2Z)-4-[9-(4-methoxyphenyl)-9H-ﬂuoren-9-yloxy]but-2-enol

(26). According to GP1: 9-(4-methoxyphenyl)ﬂuoren-9-ol (13) [21]

(140 mg, 0.490 mmol), toluene (1.2 mL), conc. H₂SO₄(15 mg,

0.15 mmol, 8.0 L), (2Z)-but-2-en-1,4-diol (19) (8.6 mg, 1.0 mmol,

m

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

869

0.080 mL), 18 h. Yield: 53 mg (30%); colourless oil; TLC: R_f¼ 0.38

(iso-hexane/EtOAc ¼ 1:1); IR (KBr): 3316, 3065, 3019, 2930, 2842,

5.1.4. General procedure for Williamson ether synthesis (GP2)

Sodium (1.0 equiv) was added to dry ethane-1,2-diol (2.0 equiv.)

and stirred overnight at rt. The unreacted ethane-1,2-diol was

distilled at 80 ^ꢀC under pressure (1.4. 10^ꢃ2Torr). Required amount

of the Sodium monoethylene glycolate left as residue was sus-

pended in the given amount of DMF and warmed up to 60 ^ꢀC for

10 min before the alkyl bromide (1.0 equiv) was added. After stir-

ring at 60 ^ꢀC for 72 h, EtOAc (20 mL/mmol) was added and the

reaction mixture was washed with H₂O and brine three times. The

organic layers were dried over MgSO₄, ﬁltered, and concentrated to

dryness. The crude product was then puriﬁed by CC (iso-hexane/

EtOAc ¼ 1:1).

1607, 1509, 1449, 1302, 1249, 1169, 1102, 1033 cm^ꢃ^{1 1}H NMR

;

(CD₂Cl₂):

d

¼ 1.40 (t, J ¼ 5.9 Hz, 1 H, OH), 3.58 (d, J ¼ 4.4 Hz, 2 H,

CH₂O), 3.73 (s, 3 H, CH₃), 3.90 (dd, J ¼ 5.9/5.0 Hz, 2 H, HOCH₂),

5.59e5.67 (m, 2 H, CHCH), 6.73e6.79 (m, 2 H, H_ar), 7.20e7.25 (m,

2 H, H_ar), 7.25e7.31 (m, 4 H, H_ar), 7.36e7.43 (m, 2 H, H_ar), 7.71 (dt,

J ¼ 7.6/0.9 Hz, 2 H, H_ar); ¹³C NMR (CD₂Cl₂):

d

¼ 55.71 (q, 1 C, CH₃),

58.96 (t, 1 C, HOCH₂), 60.00 (t, 1 C, CH₂O), 89.15 (s, 1 C, CH₂OC),

113.98 (d, 2 C, C_ar), 120.61 (d, 2 C, C_ar), 125.75 (d, 2 C, C_ar), 127.25 (d,

2 C, C_ar), 128.69 (d, 2 C, C_ar), 129.17 (d, 1 C, CHCHCH₂O), 129.66 (d,

2 C, C_ar), 132.10 (d, 1 C, CHCHCH₂O), 135.92 (s, 1 C, C_ar), 141.18 (s, 2 C,

C_ar),147.69 (s, 2 C, C_ar),159.48 (s,1 C, C_ar); MS (EI, 70 eV) m/z (%): 358

(11, M^þ), 287 (9), 271 (100); HRMS (EI, 70 eV): (C₂₄H₂₂O₃) calc.

358.1569, found 358.1563.

5.1.4.1. 2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxyethoxy]ethanol

(27). According to GP2: Sodium monoethylene glycolate (85.5 mg,

1.01

methoxyphenyl)-9H-ﬂuoren (21) (150 mg, 0.339 mmol). Yield:

77 mg (60%); colourless oil; TLC: R_f0.21 (iso-hexane/

EtOAc ¼ 6:4); IR (KBr): 3451, 3061, 2926, 2869, 1608, 1509, 1449,

1301, 1249, 1170, 1081, 1033 cm^ꢃ^{1 1}H NMR (CDCl₃):

mmol),

DMF

(2.0

mL),

9-(2-iodoethoxy)-9-(4-

5.1.2. Synthesis of 9-allyl-9-(4-methoxyphenyl)-9H-ﬂuorene (29)

To 9-(4-methoxyphenyl)ﬂuoren-9-ol (13) [21] (288 mg,

1.00 mmol) and allyltributylstannane (28) (662 mg, 2.00 mmol,

0.620 mL) in CH₂Cl₂(4 mL) was added slowly BF₃$Et₂O (284 mg,

2.00 mmol, 0.254 mL). After stirring at rt for 72 h, saturated NaHCO₃

was added and the aqueous phase was washed three times with

CH₂Cl₂. The combined organic layers were subsequently dried over

MgSO₄, ﬁltered, and concentrated to dryness. Puriﬁcation was

realized by CC (iso-hexane/EtOAc ¼ 9.5:0.5). Yield: 320 mg (99%);

colourless crystals, m.p. 64e67 ^ꢀC; TLC: R_f¼ 0.22 (iso-hexane/

EtOAc ¼ 9.5:0.5); IR (KBr): 3003, 2905, 2857, 1607, 1509, 1446, 1248

¼

;

d

¼ 3.16 (t,

J ¼ 4.9 Hz, 2 H, CH₂OC), 3.54e3.60 (m, 4 H, CH₂OCH₂), 3.68e3.72

(m, 2 H, HOCH₂), 3.73 (s, 3 H, CH₃), 6.73e6.80 (m, 2 H, H_ar),

7.22e7.33 (m, 6 H, H_ar), 7.36 (td, J ¼ 7.5/1.3 Hz, 2 H, H_ar), 7.67 (d,

J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

¼ 55.35 (q, 1 C, CH₃), 62.02

d

(t, 1 C, HOCH₂), 63.17 (t, 1 C, CH₂OC), 70.77 (t, 1 C, CH₂CH₂OC), 72.30

(t, 1 C, NCH₂CH₂), 88.70 (s, 1 C, CH₂OC), 113.69 (d, 2 C, C_ar), 120.15 (d,

2 C, C_ar), 125.49 (d, 2 C, C_ar), 126.96 (d, 2 C, C_ar), 128.36 (d, 2 C, C_ar),

129.23 (d, 2 C, C_ar), 135.45 (s, 1 C, C_ar), 140.77 (s, 2 C, C_ar), 147.23 (s,

2 C, C_ar), 158.94 (s, 1 C, C_ar); MS (EI, 70 eV) m/z (%): 376 (4, M^þ), 271

(100); HRMS (EI, 70 eV): (C₂₄H₂₄O₄) calc. 376.1675, found 376.1674.

1182, 1032 cm^ꢃ1

;

¹H NMR (CD₃OD):

d

¼ 3.19 (d, J ¼ 7.0 Hz, 2 H,

CCH₂CH), 3.71 (s, 3 H, CH₃), 4.61 (d, J ¼ 10.1 Hz, 1 H, CCH₂CHCH₂),

4.75 (d, J ¼ 17.1 Hz, 1 H, CCH₂CHCH₂), 5.08 (ddt, J ¼ 17.1/10.1/7.0 Hz,

1 H, CCH₂CH), 6.74 (d, J ¼ 8.9 Hz, 2 H, H_ar), 7.07 (d, J ¼ 8.9 Hz, 2 H,

H_ar), 7.23 (d, J ¼ 4.0 Hz, 4 H, H_ar), 7.27e7.35 (m, 2 H, H_ar), 7.75 (d,

5.1.4.2. 3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-ylpropenyl]ethanol

(31). According to GP2: Sodium ethylene glycolate (36 mg,

0.43 mmol), DMF (1.5 mL), 9-[(1E)-3-Bromopropenyl]-9-(4-

methoxyphenyl)-9H-ﬂuorene (30) (150 mg, 0.339 mmol). Yield:

J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CD₃OD):

d

¼ 43.47 (t, 1 C, CCH₂CH),

55.65 (q, 1 C, CH₃), 59.17 (s, 1 C, C_ar), 114.70 (d, 2 C, C_ar), 117.91 (t, 1 C,

CCH₂CHCH₂), 120.82 (d, 2 C, C_ar), 125.72 (d, 2 C, C_ar), 128.28 (d, 2 C,

C_ar), 128.44 (d, 2 C, C_ar), 128.82 (d, 2 C, C_ar), 135.01 (d, 1 C, CCH₂CH),

137.75 (s, 1 C, C_ar), 142.00 (s, 2 C, C_ar), 152.81 (s, 2 C, C_ar), 159.73 (s,

1 C, C_ar); MS (CI, CH^þ₅) m/z (%): 313 (26, [MþH]^þ), 271 (62), 205

(100); HRMS (EI, 70 eV): (C₂₃H₂₀O) calc. 312.1514, found 312.1486;

Anal. C₂₃H₂₀O (C, H, O).

34 mg (35%); colourless oil; TLC: R_f

¼

0.34 (iso-hexane/

EtOAc ¼ 3:7). IR (KBr): 3418, 3062, 3035, 3007, 2932, 2860, 2045,

1951, 1915, 1809, 1606, 1582, 1508, 1447, 1354, 1297, 1248, 1178, 1117,

1032 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 3.50 (t, J ¼ 4.6 Hz, 2 H, HOCH₂CH₂),

3.69 (t, J ¼ 4.6 Hz, 2 H, HOCH₂), 3.74 (s, 3 H, CH₃), 4.00 (d, J ¼ 5.9 Hz,

2 H, CH₂CH), 5.52 (dt, J ¼ 15.5/5.9 Hz, 1 H, CH₂CH), 6.43 (d,

J ¼ 15.5 Hz, 1 H, CHC), 6.73e6.80 (m, 2 H, H_ar), 7.05e7.11 (m, 2 H,

H_ar), 7.24e7.30 (m, 4 H, H_ar), 7.32e7.40 (m, 2 H, H_ar), 7.76 (d,

5.1.3. Synthesis of 9-[(1E)-3-Bromopropenyl]-9-(4-

methoxyphenyl)-9H-ﬂuorene (30)

J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

¼ 55.40 (q, 1 C, CH₃), 61.29

d

(s, 1 C, CHC), 62.01 (t, 1 C, HOCH₂), 71.49 (t, 1 C, HOCH₂CH₂), 71.79 (t,

1 C, CH₂CH), 113.99 (d, 2 C, C_ar), 120.49 (d, 2 C, C_ar), 125.41 (d, 1 C,

CH₂CH), 125.70 (d, 2 C, C_ar), 127.64 (d, 2 C, C_ar), 127.75 (d, 2 C, C_ar),

128.46 (d, 2 C, C_ar), 136.11 (s, 1 C, C_ar), 136.28 (d, 1 C, CHC), 140.13 (s,

2 C, C_ar),150.31 (s, 2 C, C_ar),158.59 (s,1 C, C_ar); MS (EI, 70 eV) m/z (%):

372 (13, M^þ), 310 (19), 297 (100); HRMS (EI, 70 eV): (C₂₅H₂₄O₃) calc.

372.1726, found 372.1829.

To 9-Allyl-9-(4-methoxyphenyl)-9H-ﬂuorene (29) (200 mg,

0.640 mmol) in CCl₄(2.5 mL) was added NBS (160 mg, 0.960 mmol)

and AIBN (60 mg, 0.37 mmol). After reﬂuxing for 16 h, the solid

material was ﬁltered off and the solvent was evaporated. The res-

idue was puriﬁed by CC (iso-hexane/EtOAc ¼ 9:1). Yield: 194 mg

(78%); colourless crystals, m.p. 123e125 ^ꢀC; TLC: R_f¼ 0.10 (iso-

hexane/EtOAc ¼ 9:1); IR (KBr): 3100, 2998, 2954, 2831, 1648, 1604,

1506, 1447, 1298, 1245, 1203, 1177, 1031 cm^ꢃ1

;

¹H NMR (CDCl₃):

5.1.5. General procedure for mesylation (GP3) [38].

d

¼ 3.74 (s, 3 H, CH₃), 3.94 (d, J ¼ 7.6 Hz, 2 H, BrCH₂), 5.67 (dt,

To a solution of the 9-methoxyphenyl-9H-ﬂuorene derivative

(1.0 equiv.) and methanesulfonyl chloride (2.0 equiv.) in CH₂Cl₂

(7 mL/mmol) was treated with Et₃N (2.1 equiv.) at 0 ^ꢀC. After 2 h at

J ¼ 15.2/7.6 Hz, 1 H, CH₂CH), 6.47 (d, J ¼ 15.2 Hz, 1 H, CH₂CHCH),

6.74e6.80 (m, 2 H, H_ar), 7.04e7.10 (m, 2 H, H_ar), 7.23e7.33 (m, 4 H,

H_ar), 7.34e7.42 (t, J ¼ 7.5 Hz, 2 H, H_ar), 7.76 (d, J ¼ 7.5 Hz, 2 H, H_ar);

0

^ꢀC, H₂O was added and the solution was extracted three times

¹³C NMR (CDCl₃):

d

¼ 32.77 (t, 1 C, CH₂), 55.21 (q, 1 C, CH₃), 60.79 (s,

with CH₂Cl₂. The combined organic layers were dried over MgSO₄,

ﬁltered, and concentrated to dryness. The residue was puriﬁed by

CC.

1 C, CCH), 113.89 (d, 2 C, C_ar), 120.37 (d, 2 C, C_ar), 125.29 (d, 1 C,

CH₂CH), 125.48 (d, 2 C, C_ar), 127.61 (d, 2 C, C_ar), 127.65 (d, 2 C, C_ar),

128.20 (d, 2 C, C_ar), 135.62 (s, 1 C, C_ar), 138.34 (d, 1 C, CHC), 139.95 (s,

2 C, C_ar), 149.58 (s, 2 C, C_ar), 158.51 (s, 1 C, C_ar); MS (CI, CH^þ₅) m/z (%):

393 (32, [MþH]^þ), 313 (8), 311 (76), 285 (94), 283 (86), 203 (100);

HRMS (EI, 70 eV): (C₂₃H₁₉BrO) calc. 390.0619, found 390.0631;

Anal. C₂₃H₁₉BrO (C, H, Br, O).

5.1.5.1. 4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxybutenyloxy]

methane sulfonic acid (32). According to GP3: (2Z)-4-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]but-2-enol (26) (598 mg,

1.67 mmol), CH₂Cl₂(12 mL), methanesulfonyl chloride (382 mg,

870

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

3.34 mmol, 0.259 mL), Et₃N (355 mg, 3.51 mmol, 0.489 mL), CC (iso-

hexane/EtOAc ¼ 7:3). Yield: 533 mg (73%); colourless oil; TLC:

R_f¼ 0.42 (iso-hexane/EtOAc ¼ 6:4); IR (KBr): 3065, 3019, 2934,

2836, 1607, 1582, 1509, 1449, 1356, 1249, 1173, 1102, 1060,

5.1.6. General procedure for synthesis of N-alkylated 2-(1H-

imidazol-5-yl)acetic acid methyl esters (GP4) [39,40].

The corresponding alkyl bromide or alkyl mesylate (1.3 equiv.)

was added to (1-triphenylmethyl-1H-imidazol-4-yl)acetic acid

methyl ester (35) (1.0 equiv.) in CH₃CN. The reaction mixture was

stirred for 8 d at 60 ^ꢀC. After evaporating the solvent, the residue

was dissolved in MeOH (2 mL) and reﬂuxed for 45 min. The reaction

solution was then concentrated to dryness and the crude product

obtained was puriﬁed by CC.

1033 cm^ꢃ1

;

¹H NMR (CD₂Cl₂):

d

¼ 2.87 (s, 3 H, SO₂CH₃), 3.63 (d,

J ¼ 6.2 Hz, 2 H, CH₂O), 3.73 (s, 3 H, OCH₃), 4.59 (d, J ¼ 6.9 Hz, 2 H,

CH₂OSO₂), 5.61 (dtt, J ¼ 11.2/6.9/1.6 Hz, 1 H, SO₃CH₂CH), 5.84 (dtt,

J ¼ 11.2/6.2/1.3 Hz, 1 H, CHCH₂O), 6.74e6.79 (m, 2 H, H_ar), 7.22e7.25

(m, 2 H, H_ar), 7.27e7.31 (m, 4 H, H_ar), 7.37e7.44 (m, 2 H, H_ar), 7.72 (d,

J ¼ 7.6 Hz, 2 H, H_ar); ¹³C NMR (CD₂Cl₂):

d

¼ 38.30 (q, 1 C, SO₂CH₃),

55.70 (q, 1 C, OCH₃), 60.02 (t, 1 C, CH₂O), 66.33 (t, 1 C, CH₂OSO₂),

89.26 (s, 1 C, CH₂OC), 113.99 (d, 2 C, C_ar), 120.71 (d, 2 C, C_ar), 124.47

(d, 1 C, SO₃CH₂CH), 125.72 (d, 2 C, C_ar), 127.25 (d, 2 C, C_ar), 128.79 (d,

2 C, C_ar), 129.78 (d, 2 C, C_ar), 133.76 (d, 1 C, CHCH₂O), 135.68 (s, 1 C,

C_ar), 141.19 (s, 2 C, C_ar), 147.38 (s, 2 C, C_ar), 159.52 (s, 1 C, C_ar); MS (EI,

70 eV) m/z (%): 436 (9, M^þ), 287 (8), 271 (100); HRMS (EI, 70 eV):

(C₂₅H₂₄O₅S) calc. 436.1344, found 436.1353.

5.1.6.1. (1-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-1H-

imidazol-5-yl)acetic acid methyl ester (37b). According to GP4: (1-

Triphenylmethyl-1H-imidazol-4-yl)acetic acid methyl ester (35)

[42] (315 mg, 0.824 mmol), CH₃CN (2 mL), 9-(2-bromoethoxy)-9-

(4-methoxyphenyl)-9H-ﬂuorene (20) [21] (420 mg, 1.06 mmol), CC

(acetone/n-pentane ¼ 8:2). Yield: 217 mg (58%); yellow oil; TLC:

R_f¼ 0.15 (acetone/n-pentane ¼ 7:3); IR (KBr): 3100, 2952, 1740,

1608, 1509, 1449, 1250, 1170, 1106, 1033 cm^ꢃ^{1 1}H NMR (CDCl₃):

;

d

¼ 3.19 (t, J ¼ 5.2 Hz, 2 H, CH₂O), 3.51 (s, 2 H, CH₂COO), 3.60 (s, 3 H,

COOCH₃), 3.75 (s, 3 H, OCH₃), 4.03 (t, J ¼ 5.2 Hz, 2 H, NCH₂),

6.72e6.78 (m, 2 H, H_ar), 6.98 (s, 1 H, H_[4H-Imid.]), 7.05 (d, J ¼ 7.5 Hz,

2 H, H_ar), 7.12e7.17 (m, 2 H, H_ar), 7.21 (td, J ¼ 7.5/1.0 Hz, 2 H, H_ar),

7.35 (td, J ¼ 7.5/1.0 Hz, 2 H, H_ar), 7.62e7.67 (m, 3 H, H_[2H-Imid.], H_ar);

5.1.5.2. 2-{4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxyethoxy]

ethoxy}methane sulfonic acid (33). According to GP3: 2-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxyethoxy]ethanol (27) (691 mg,

1.84 mmol), CH₂Cl₂(13 mL), menthanesulfonyl chloride (422 mg,

3.67 mmol, 0.286 mL), Et₃N (391 mg, 3.86 mmol, 0.539 mL), CC (iso-

hexane/EtOAc ¼ 6:4). Yield: 641 mg (77%); colourless solid, m.p.

72e75 ^ꢀC; TLC: R_f¼ 0.29 (iso-hexane/EtOAc ¼ 6:4). IR (KBr): 3055,

3019, 2933, 2870, 2836, 1608, 1580, 1509, 1449, 1352, 1301, 1249,

¹³C NMR (CDCl₃):

d

¼ 30.14 (t, 1 C, CH₂COO), 45.36 (t, 1 C, NCH₂),

52.42 (q, 1 C, COOCH₃), 55.41 (q, 1 C, OCH₃), 62.75 (t, 1 C, CH₂O),

88.95 (s, 1 C, CH₂OC), 113.80 (d, 2 C, C_ar), 120.19 (d, 2 C, C_ar), 124.25

(s, 1 C, C_[5C-Imid.]), 125.30 (d, 2 C, C_ar), 126.89 (d, 2 C, C_ar), 128.58 (d,

2 C, C_ar), 128.83 (d, 1 C, C_[4C-Imid.]), 129.41 (d, 2 C, C_ar), 134.84 (s, 1 C,

C_ar), 138.94 (d, 1 C, C_[2C-Imid.]), 140.69 (s, 2 C, C_ar), 146.60 (s, 2 C, C_ar),

159.09 (s, 1 C, C_ar), 172.37 (s, 1 C, COO); MS (CI, CH^þ₅) m/z (%): 455

(34, [MþH]^þ), 271 (100); HRMS (EI, 70 eV): (C₂₈H₂₆N₂O₄) calc.

454.1893, found 454.1878.

1174, 1139, 1084, 1031 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 3.01 (s, 3 H,

SO₂CH₃), 3.15 (t, J ¼ 4.8 Hz, 2 H, CH₂OC), 3.58 (t, J ¼ 4.8 Hz, 2 H,

CH₂CH₂OC), 3.72e3.74 (m, 2 H, CH₂CH₂OSO₂), 3.74 (s, 3 H, OCH₃),

4.35e4.38 (m, 2 H, CH₂OSO₂), 6.74e6.79 (m, 2 H, H_ar), 7.23e7.30 (m,

6 H, H_ar), 7.35e7.39 (m, 2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C

NMR (CDCl₃):

d

¼ 37.77 (q, 1 C, SO₂CH₃), 55.19 (q, 1 C, OCH₃), 62.89

5.1.6.2. (1-{3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-

1H-imidazol-5-yl)acetic acid methyl ester (37c). According to GP4:

(1-Triphenylmethyl-1H-imidazol-4-yl)acetic acid methyl ester (35)

[42] (315 mg, 0.824 mmol), CH₃CN (4 mL), 9-(3-bromopropoxy)-9-

(4-methoxyphenyl)-9H-ﬂuorene (22) (436 mg, 1.07 mmol), CC

(CHCl₃/MeOH ¼ 100:1). Yield: 170 mg (44%); colourless oil; TLC:

R_f¼ 0.31 (CHCl₃/MeOH ¼ 100:3).; IR (KBr): 3061, 3038, 3004, 2951,

2874, 2837, 2044, 1868, 1844, 1740, 1608, 1509, 1449, 1249, 1170,

(t, 1 C, CH₂OC), 68.92 (t, 1 C, CH₂CH₂OSO₂), 69.52 (t, 1 C, CH₂OSO₂),

70.80 (t, 1 C, CH₂CH₂OC), 88.49 (s, 1 C, CH₂OC), 113.50 (d, 2 C, C_ar),

119.99 (d, 2 C, C_ar), 125.27 (d, 2 C, C_ar), 126.78 (d, 2 C, C_ar), 128.20 (d,

2 C, C_ar), 129.07 (d, 2 C, C_ar), 135.24 (s, 1 C, C_ar), 140.59 (s, 2 C, C_ar),

147.00 (s, 2 C, C_ar),158.79 (s,1 C, C_ar); MS (EI, 70 eV) m/z (%): 454 (16,

M^þ), 271 (100); HRMS (EI, 70 eV): (C₂₅H₂₆O₆S) calc. 454.1450, found

454.1449.

1107, 1078, 1033 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 1.86 (tt, J ¼ 7.2/5.6 Hz,

2 H, NCH₂CH₂), 3.00 (t, J ¼ 5.6 Hz, 2 H, CH₂O), 3.62 (s, 2 H, CH₂COO),

3.68 (s, 3 H, COOCH₃), 3.76 (s, 3 H, OCH₃), 4.02 (t, J ¼ 7.2 Hz, 2 H,

NCH₂), 6.79 (d, J ¼ 8.9 Hz, 2 H, H_ar), 6.91 (s, 1 H, H_[4H-Imid.]),

7.22e7.29 (m, 6 H, H_ar), 7.33e7.44 (m, 3 H, H_ar, H_[2H-Imid.]), 7.68 (d,

5.1.5.3. 3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxypropenyl]etha-

noxymethane sulfonic acid (34). According to GP3: 3-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-ylpropenyl]ethanol (31) (1.13 g,

3.03 mmol), CH₂Cl₂(20 mL), menthanesulfonyl chloride (695 mg,

6.07 mmol, 0.472 mL), Et₃N (644 mg, 6.36 mmol, 0.887 mL), CC (iso-

hexane/EtOAc ¼ 6:4). Yield: 1.33 mg (97%); light yellow oil; TLC:

R_f¼ 0.23 (iso-hexane/EtOAc ¼ 6:4). IR (KBr): 3061, 3031, 2936,

2906, 2863, 2838, 2945, 1921, 1607, 1580, 1508, 1448, 1353, 1249,

J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 29.99 (t, 1 C, CH₂COO),

31.46 (t, 1 C, NCH₂CH₂), 42.17 (t, 1 C, NCH₂), 52.44 (q, 1 C, COOCH₃),

55.31 (q,1 C, OCH₃), 59.74 (t,1 C, CH₂O), 88.43 (s,1 C, CH₂OC), 113.63

(d, 2 C, C_ar), 120.18 (d, 2 C, C_ar), 123.78 (s, 1 C, C_[5C-Imid.]), 125.17 (d,

2 C, C_ar), 126.77 (d, 2 C, C_ar), 128.38 (d, 2 C, C_ar), 128.86 (d, 1 C, C_[4C-

_Imid.]), 129.27 (d, 2 C, C_ar), 135.35 (s,1 C, C_ar), 137.90 (d,1 C, C_[2C-Imid.]),

140.70 (s, 2 C, C_ar), 147.12 (s, 2 C, C_ar), 158.89 (s, 1 C, C_ar), 170.26 (s,

1 C, COO); MS (CI, CH^þ₅) m/z (%): 469 (28, [MþH]^þ), 447 (8), 271

(100); HRMS (EI, 70 eV): (C₂₉H₂₈N₂O₄) calc. 468.2049, found

468.2043.

1176, 1120, 1031, 1014 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 2.93 (s, 3 H,

SO₂CH₃), 3.60e3.65 (m, 2 H, CH₂CH₂OSO₂), 3.73 (s, 3 H, OCH₃), 4.00

(dd, J ¼ 5.9/1.2 Hz, 2 H, CH₂CH), 4.28e4.34 (m, 2 H, CH₂OSO₂), 5.48

(dt, J ¼ 15.5/5.9 Hz, 1 H, CH₂CH), 6.44 (d, J ¼ 15.5 Hz, 1 H, CHC),

6.73e6.80 (m, 2 H, H_ar), 7.04e7.10 (m, 2 H, H_ar), 7.22e7.30 (m, 4 H,

H_ar), 7.32e7.38 (m, 2 H, H_ar), 7.75 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR

(CDCl₃):

d

¼ 37.79 (q, 1 C, SO₂CH₃), 55.37 (q, 1 C, OCH₃), 61.25 (s, 1 C,

5.1.6.3. (1-{4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-1H-

imidazol-5-yl)acetic acid methyl ester (37d). A) According to GP4:

(1-Triphenylmethyl-1H-imidazol-4-yl)acetic acid methyl ester (35)

[42] (315 mg, 0.824 mmol), CH₃CN (4 mL), 9-(4-bromobutoxy)-9-

(4-methoxyphenyl)-9H-ﬂuorene (23) (451 mg, 1.07 mmol), CC

(CHCl₃/MeOH ¼ 100:1). 69.5 mg (17%) 37d was obtained.

CHC), 67.94 (t, 1 C, CH₂CH₂OSO₂), 69.35 (t, 1 C, CH₂OSO₂), 71.66 (t,

1 C, CH₂CH), 113.98 (d, 2 C, C_ar), 120.50 (d, 2 C, C_ar), 124.72 (d, 1 C,

CH₂CH), 125.61 (d, 2 C, C_ar), 127.67 (d, 2 C, C_ar), 127.76 (d, 2 C, C_ar),

128.38 (d, 2 C, C_ar), 135.88 (s, 1 C, C_ar), 136.89 (d, 1 C, CHC), 140.06 (s,

2 C, C_ar), 150.17 (s, 2 C, C_ar), 158.59 (s, 1 C, C_ar); MS (EI, 70 eV) m/z (%):

450 (7, M^þ), 310 (8), 297 (100); HRMS (EI, 70 eV): (C₂₆H₂₆O₅S) calc.

450.1501, found 450.1484.

B) According to GP4: (1-Triphenylmethyl-1H-imidazol-4-yl)

acetic acid methyl ester (35)⁴²(315 mg, 0.824 mmol), CH₃CN

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

871

(4 mL), 9-(4-bromobutoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene

(23) (451 mg, 1.07 mmol), CC (CHCl₃/MeOH ¼ 100:1). For depro-

tection, the residue was dissolved, differing to GP4, in 5% CH₃COOH

in MeOH (2 mL) [41]. Yield: 217 mg (55%); colourless oil; TLC:

R_f¼ 0.28 (CH₂Cl₂/MeOH ¼ 100:3); IR (KBr): 3003, 2950, 1740, 1608,

46.83 (t, 1 C, NCH₂), 52.28 (q, 1 C, COOCH₃), 55.21 (q, 1 C, OCH₃),

60.98 (s, 1 C, CHC), 113.93 (d, 2 C, C_ar), 120.45 (d, 2 C, C_ar), 122.86 (d,

1 C, NCH₂CH), 124.00 (s, 1 C, C_[5C-Imid.]), 125.28 (d, 2 C, C_ar), 127.69 (d,

2 C, C_ar), 127.72 (d, 2 C, C_ar), 128.05 (d, 2 C, C_ar), 128.99 (d, 1 C, C_[4C-

_Imid.]), 135.26 (s, 1 C, C_ar), 137.79 (d, 1 C, C_[2C-Imid.]), 137.82 (d, 1 C,

CHC),139.84 (s, 2 C, C_ar),149.57 (s, 2 C, C_ar),158.52 (s,1 C, C_ar),170.01

(s, 1 C, COO); MS (CI, CH^þ₅) m/z (%): 451 (100, [MþH]^þ); HRMS (EI,

70 eV): (C₂₉H₂₆N₂O₃) calc. 450.1944, found 450.1920. Anal.

1509, 1449, 1249, 1169, 1108, 1077, 1033 cm^ꢃ^{1 1}H NMR (CDCl₃):

;

d

¼ 1.51 (tt, J ¼ 6.7/6.0, 2 H, CH₂CH₂O), 1.82 (tt, J ¼ 7.5/6.7 Hz, 2 H,

NCH₂CH₂), 2.99 (t, J ¼ 6.0 Hz, 2 H, CH₂O), 3.58 (s, 2 H, CH₂COO), 3.66

(s, 3 H, COOCH₃), 3.75 (s, 3 H, OCH₃), 3.85 (t, J ¼ 7.5 Hz, 2 H, NCH₂),

6.74e6.79 (m, 2 H, H_ar), 6.93 (s, 1 H, H_[5H-Imid.]), 7.21e7.29 (m, 6 H,

H_ar), 7.34e7.40 (m, 2 H, H_ar), 7.44 (s, 1 H, H_[2H-Imid.]), 7.67 (d,

C₂₉H₂₆N₂O₃(C, H, N, O).

5.1.7. General procedure for N-alkylation of 2-(1H-imidazol-4-yl)

acetic acid methyl esters, 3-(1H-imidazol-2-yl)propanoic acid ethyl

esters and (2E)-3-(1H-imidazol-2-yl)prop-2-enoic acid ethyl esters

(GP5) [45]

A suspension of tBuOK (1.1 equiv. or 2.2 equiv.) and the imid-

azole derivative (1.0 equiv.) in DMF (6 mL/mmol) was stirred at rt

for 1 h. The reaction mixture was treated with the corresponding

alkyl bromide or alkyl mesylate (1.3 equiv. or 2.0 equiv.) and the

temperature was raised up to 60 ^ꢀC and stirred at this temperature

for 72 h. The solution was then diluted with EtOAc (20 mL/mmol)

and washed three times with brine and H₂O. The organic layers

were dried over MgSO₄, ﬁltered, and concentrated. The crude

product was puriﬁed by CC.

J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 27.11 (t, 1 C, CH₂CH₂O),

27.83 (t, 1 C, NCH₂CH₂), 30.16 (t, 1 C, CH₂COO), 44.93 (t, 1 C, NCH₂),

52.52 (q, 1 C, COOCH₃), 55.37 (q, 1 C, OCH₃), 62.40 (t, 1 C, CH₂O),

88.43 (s, 1 C, CH₂OC), 113.68 (d, 2 C, C_ar), 120.18 (d, 2 C, C_ar), 123.87

(s, 1 C, C_[5C-Imid.]), 125.26 (d, 2 C, C_ar), 126.87 (d, 2 C, C_ar), 128.34 (d,

2 C, C_ar) 129.02 (d, 1 C, C_[4C-Imid.]or d, 2 C, C_ar), 129.18 (d, 1 C, C_[4C-

or d, 2 C, C_ar), 135.68 (s, 1 C, C_ar), 137.84 (d, 1 C, C_[2C-Imid.]),

Imid.]

140.75 (s, 2 C, C_ar), 147.47 (s, 2 C, C_ar), 158.91 (s, 1 C, C_ar), 170.31 (s,

1 C, COO); MS (CI, CH^þ₅) m/z (%): 483 (28, [MþH]^þ), 447 (12), 271

(100); HRMS (EI, 70 eV): (C₃₀H₃₀N₂O₄) calc. 482.2206, found

482.2207. Anal. C₃₀H₃₀N₂O₄(C, H, N, O).

5.1.6.4. (1-{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-

1H-imidazol-5-yl)acetic acid methyl ester (37e). According to GP4:

(1-Triphenylmethyl-1H-imidazol-4-yl)acetic acid methyl ester (35)

[42] (308 mg, 0.805 mmol), CH₃CN (4 mL), 9-(5-bromopentoxy)-9-

(4-methoxyphenyl)-9H-ﬂuorene (24) (458 mg, 1.05 mmol), CC

(CHCl₃/MeOH ¼ 100:1). For deprotection, the residue was dis-

solved, differing to GP4, in 5% CH₃COOH in MeOH (2 mL). Yield:

5.1.7.1. (1-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-1H-

imidazol-4-yl)acetic acid methyl ester (38b). According to GP5: 1H-

Imidazol-4-ylacetic acid methyl ester$HCl (38a·HCl) [43,44]

(150 mg, 0.850 mmol), DMF (5 mL), tBuOK (210 mg, 1.87 mmol),

9-(2-bromoethoxy)-9-methoxyphenyl-9H-ﬂuorene

(700 mg, 1.77 mmol), CC (acetone/n-pentane

(20)

8: 2). 64%

[21]

¼

180 mg (42%); colourless oil; TLC: R_f

MeOH ¼ 100:2); IR (KBr): 3059, 2936, 2865, 1740, 1608, 1509, 1449,

1249, 1169, 1109, 1078, 1032 cm^ꢃ^{1 1}H NMR (CDCl₃):

¼

0.28 (CH₂Cl₂/

(65.0 mg, 0.143 mmol) of a mixture of 1,4- and 1,5-disubtitued (1-

{2-[9-(4-methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-1H-imida-

zolyl)acetic acid methyl esters (38b, 37b) was obtained as a yellow

oil which could be separated by CC (acetone/n-pentane ¼ 7:3) to

yield 38b as yellow oil. Yield: 480 mg (42%); yellow oil; TLC:

R_f¼ 0.22 (acetone/n-pentane ¼ 7:3); IR (KBr): 3003, 2950, 2837,

;

d

¼ 1.31e1.43

(m, 2 H, NCH₂CH₂CH₂), 1.52 (tt, J ¼ 7.3/6.1 Hz, 2 H, CH₂CH₂O), 1.66

(tt, J ¼ 7.6/7.4 Hz, 2 H, NCH₂CH₂), 2.96 (t, J ¼ 6.1 Hz, 2 H, CH₂O), 3.59

(s, 2 H, CH₂COO), 3.68 (s, 3 H, COOCH₃), 3.75 (s, 3 H, OCH₃), 3.83 (t,

J ¼ 7.4 Hz, 2 H, NCH₂), 6.73e6.80 (m, 2 H, H_ar), 6.93 (s, 1H, H_[4H-

_Imid.]), 7.21e7.28 (m, 6 H, H_ar), 7.33e7.40 (m, 2 H, H_ar), 7.43 (s, 1 H,

1739, 1608, 1509, 1448, 1250, 1169 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 3.13

(t, J ¼ 5.1 Hz, 2 H, CH₂O), 3.60 (s, 2 H, CH₂COO), 3.64 (s, 3 H,

COOCH₃), 3.67 (s, 3 H, OCH₃), 3.89 (t, J ¼ 5.1 Hz, 2 H, NCH₂),

6.66e6.71 (m, 2 H, H_ar), 6.76 (s, 1 H, H_[5H-Imid.]), 7.02 (d, J ¼ 7.5 Hz,

2 H, H_ar), 7.07e7.12 (m, 2 H, H_ar), 7.14 (t, J ¼ 7.5 Hz, 2 H, H_ar), 7.28 (t,

J ¼ 7.5 Hz, 2 H, H_ar), 7.39 (s, 1 H, H_[2H-Imid.]), 7.58 (d, J ¼ 7.5 Hz, 2 H,

H

_[2H-Imid.]), 7.67 (d, J ¼ 7.5 Hz, 2 H,, H_ar); ¹³C NMR (CDCl₃):

¼ 23.25

d

(t,1 C, NCH₂CH₂CH₂), 29.45 (t,1 C, CH₂CH₂O), 29.99 (t,1 C, CH₂COO),

30.51 (t, 1 C, NCH₂CH₂), 44.93 (t, 1 C, NCH₂), 52.35 (q, 1 C, COOCH₃),

55.19 (q, 1 C, OCH₃), 62.59 (t, 1 C, CH₂O), 88.18 (s, 1 C, CH₂OC), 113.47

(d, 2 C, C_ar), 119.94 (d, 2 C, C_ar), 123.67 (s, 1 C, C_[5C-Imid.]), 125.09 (d,

2 C, C_ar), 126.71 (d, 2 C, C_ar), 128.09(d, 2 C, C_ar),128.73(s, 1 C, C_[4C-

_Imid.]), 129.91 (d, 2 C, C_ar), 135.70 (s, 1 C C_ar), 137.62 (d, 1 C, C_[2C-Imid.]),

140.56 (s, 2 C, C_ar), 147.44 (s, 2 C, C_ar), 158.70 (s, 1 C, C_ar), 170.13 (s,

1 C, COO); MS (ESIþ) m/z (%): 993.6 (6), 497.1 (86, [MþH]^þ), 271.0

(100),; HRMS (EI, 70 eV): (C₃₁H₃₂N₂O₄) calc. 496.2362, found

496.2371.

H_ar); ¹³C NMR (CDCl₃):

NCH₂), 52.00 (q, 1 C, COOCH₃), 55.20 (q, 1 C, OCH₃), 62.62 (t, 1 C,

d

¼ 34.43 (t, 1 C, CH₂COO), 47.42 (t, 1 C,

NCH₂CH₂), 88.64 (s, 1 C, CH₂OC), 113.58 (d, 2 C, C_ar), 117.51 (d, 1 C,

C_[5C-Imid.]), 119.99 (d, 2 C, C_ar), 125.16 (d, 2 C, C_ar), 126.70 (d, 2 C, C_ar),

128.33 (d, 2 C, C_ar), 129.19 (d, 2 C, C_ar),134.72 (s, 1 C, C_aror s, 1 C, C_[4C-

_Imid.]), 134.81 (s, 1 C, C_aror s, 1 C, C_[4C-Imid.]), 137.18 (d, 1 C, C_[2C-Imid.]),

140.49 (s, 2 C, C_ar), 146.43 (s, 2 C, C_ar), 158.84 (s, 1 C, C_ar), 171.83 (s,

1 C, COO); MS (EI, 70 eV) m/z (%): 454 (28, M^þ), 271 (100); HRMS (EI,

70 eV): (C₂₈H₂₆N₂O₄) calc. 454.1893, found 454.1888.

5.1.6.5. (1-{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]prop-2-

en-1-yl}-1H-imidazol-5-yl)acetic

acid

methyl

ester

(37f).

According to GP4: (1-Triphenylmethyl-1H-imidazol-4-yl)acetic

acid methyl ester (35) [42] (283 mg, 0.740 mmol), CH₃CN (4 mL), 9-

((1E)-3-bromopropenyl)-9-(4-methoxyphenyl)-9H-ﬂuorene (30)

(376 mg, 0.961 mmol), CC (acetone/n-pentane ¼ 8:2). Yield: 200 mg

(60%); yellow oil; TLC: R_f¼ 0.37 (CH₂Cl₂/MeOH ¼ 100:2); IR (KBr):

3034, 3003, 2950, 2835, 1739, 1606, 1508, 1447, 1340, 1249, 1177,

5.1.7.2. (1-{3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-

1H-imidazol-4-yl)acetic acid methyl ester (38c). According to GP5:

1H-imidazol-4-ylacetic acid methyl ester$HCl (38a·HCl) [43,44]

(145 mg, 0.820 mmol), DMF (4 mL), tBuOK (202 mg, 1.80 mmol),

9-(3-bromopropoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene

(22)

(671 mg, 1.64 mmol), CC (acetone/iso-hexane ¼ 7:3). Yield: 103 mg

(27%); yellow oil; TLC: R_f¼ 0.32 (CHCl₃/MeOH ¼ 100:3); IR (KBr):

30033063, 3005, 2951, 2875, 2837, 2044, 1739, 1608, 1509, 1449,

1109,1031 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 3.46 (s, 2 H, CH₂COO), 3.62 (s,

3 H, COOCH₃), 3.74 (s, 3 H, OCH₃), 4.50 (d, J ¼ 5.8 Hz, 2 H, NCH₂),

5.46 (dt, J ¼ 15.5/5.8 Hz, 1 H, NCH₂CH), 6.28 (d, J ¼ 15.5 Hz, 1 H,

CHC), 6.73e6.78 (m, 2 H, H_ar), 6.93 (s, 1 H, H_[4H-Imid.]), 6.98e7.04 (m,

2 H, H_ar), 7.20 (d, J ¼ 7.6 Hz, 2 H, H_ar), 7.27 (td, J ¼ 7.6/1.1 Hz, 2 H, H_ar),

7.36 (td, J ¼ 7.6/1.1 Hz, 2 H, H_ar), 7.42 (s, 1 H, H_[2H-Imid.]), 7.76 (d,

1249, 1169, 1081, 1033 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 1.84e1.94 (m,

2 H, NCH₂CH₂), 2.98 (t, J ¼ 5.7 Hz, 2 H, CH₂O), 3.60 (s, 2 H, CH₂COO),

3.70 (s, 3 H, COOCH₃), 3.76 (s, 3 H, OCH₃), 4.02 (t, J ¼ 7.0 Hz, 2 H,

NCH₂), 6.76e6.82 (m, 3 H, H_[5H-Imid.], H_ar), 7.23e7.27 (m, 6 H, H_ar),

7.29 (s, 1 H, H_[2H-Imid.]), 7.35e7.40 (m, 2 H, H_ar), 7.67 (d, J ¼ 7.6 Hz,

J ¼ 7.6 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 29.82 (t, 1 C, CH₂COO),

872

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

2 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 31.67 (t, 1 C, NCH₂CH₂), 34.37 (t, 1 C,

(38a·HCl) [43,44] (70 mg, 0.40 mmol), DMF (3 mL), tBuOK (100 mg,

CH₂COO), 44.31 (t, 1 C, NCH₂), 52.06 (q, 1 C, COOCH₃), 55.27 (q, 1 C,

OCH₃), 59.68 (t, 1 C, CH₂O), 88.39 (s, 1 C, CH₂OC), 113.64 (d, 2 C, C_ar),

117.10 (d, 1 C, C_[5C-Imid.]), 120.16 (d, 2 C, C_ar), 125.21 (d, 2 C, C_ar),

126.78 (d, 2 C, C_ar), 128.33 (d, 2 C, C_ar), 129.26 (d, 2 C, C_ar), 134.85 (s,

1 C, C_[4C-Imid.]), 135.41 (s, 1 C, C_ar), 136.61 (d, 1 C, C_[2C-Imid.]), 140.72 (s,

2 C, C_ar), 147.15 (s, 2 C, C_ar), 158.91 (s, 1 C, C_ar), 171.86 (s, 1 C, COO);

MS (EI, 70 eV) m/z (%): 468 (8, M^þ), 271 (100); HRMS (ESIþ):

(C₂₉H₂₉N₂O₄) calc. 469.2127, found 469.2125.

0.891 mmol), 9-((1E)-3-bromopropenyl)-9-(4-methoxyphenyl)-

9H-ﬂuorene (30) (200 mg, 0.511 mmol), CC: (acetone/iso-

hexane ¼ 7:3). Yield: 50 mg (28%); yellow oil; TLC: R_f¼ 0.40

(CH₂Cl₂/MeOH ¼ 100:2); IR (KBr): 3034, 3002, 2950, 2835, 1736,

1606, 1508, 1447, 1341, 1247, 1249, 1178, 1031 cm^ꢃ^{1 1}H NMR

;

(CDCl₃):

d

¼ 3.64 (s, 2 H, CH₂COO), 3.70 (s, 3 H, COOCH₃), 3.74 (s,

3 H, OCH₃), 4.45 (d, J ¼ 6.3 Hz, 2 H, NCH₂), 5.53 (dt, J ¼ 15.4/6.3 Hz,

1 H, NCH₂CH), 6.39 (d, J ¼ 15.4 Hz,1 H, CHC), 6.74e6.79 (m, 2 H, H_ar),

6.81 (s, 1 H, H_[5H-Imid.]), 7.00e7.06 (m, 2 H, H_ar), 7.22 (d, J ¼ 7.5 Hz,

2H, H_ar), 7.26e7.30 (m, 2H, H_ar), 7.34e7.39 (m, 3 H, H_ar, H_[2H-Imid.]),

5.1.7.3. (1-{4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-1H-

imidazol-4-yl) acetic acid methyl ester (38d). According to GP5: 1H-

imidazol-4-ylacetic acid methyl ester (38a) [44] (317 mg,

2.26 mmol), DMF (8 mL), tBuOK (278 mg, 2.48 mmol), 9-(4-

bromobutoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene (23) (1.63 g,

7.76 (d, J ¼ 7.5 Hz, 2 H, H_ar);¹³C NMR (CDCl₃):

d

¼ 34.21 (t, 1 C,

CH₂COO), 48.82 (t, 1 C, NCH₂), 52.03 (q, 1 C, COOCH₃), 55.21 (q, 1 C,

OCH₃), 60.98 (s, 1 C, CHC), 113.94 (d, 2 C, C_ar), 117.13 (d, 1 C, C_[5C-

_Imid.]), 120.44 (d, 2 C, C_ar), 123.00 (d, 1 C, NCH₂CH), 125.35 (d, 2 C,

C_ar), 127.69 (d, 2 C, C_ar), 127.72 (d, 2 C, C_ar), 128.09 (d, 2 C, C_ar), 134.87

(s, 1 C, C_[4C-Imid.]), 135.29 (s, 1 C, C_ar), 136.22 (d, 1 C, C_[2C-Imid.]), 138.34

(d, 1 C, CHC), 139.88 (s, 2 C, C_ar), 149.53 (s, 2 C, C_ar), 158.52 (s, 1 C,

C_ar), 171.67 (s, 1 C, COO); MS (CI, CH^þ₅) m/z (%): 451 (100, [MþH]^þ);

HRMS (EI, 70 eV): (C₂₉H₂₆N₂O₃) calc. 450.1944, found 450.1946.

3.84 mmol), CC (acetone/iso-hexane

¼

7:3 und CHCl₃/

MeOH ¼ 100:1). Yield: 316 mg (29%); colourless solid, m.p.

83e85 ^ꢀC; TLC: R_f¼ 0.40 (CH₂Cl₂/MeOH ¼ 100:2); IR (KBr): 3582,

3451, 3038, 2940, 2869, 2839, 2048, 1976, 1905, 1741, 1605, 1508,

1448, 1299, 1250, 1167, 1080, 1031 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 1.49

(tt, J ¼ 7.5/6.0 Hz, 2 H, CH₂CH₂O), 1.85 (tt, J ¼ 7.5/7.2 Hz, 2 H,

NCH₂CH₂), 2.98 (t, J ¼ 6.0 Hz, 2 H, CH₂O), 3.64 (s, 2 H, CH₂COO), 3.71

(s, 3 H, COOCH₃), 3.75 (s, 3 H, OCH₃), 3.84 (t, J ¼ 7.2 Hz, 2 H, NCH₂),

6.75e6.80 (m, 2 H, H_ar), 6.83 (s, 1 H, H_[5H-Imid.]), 7.22e7.27 (m, 6 H,

H_ar), 7.34 (s, 1 H, H_[2H-Imid.]), 7.35e7.40 (m, 2 H, H_ar), 7.67 (d,

5.1.7.6. 3-[1-(4,4-Diphenylbut-3-en-1-yl)-1H-imidazol-2-yl]prop-

anoic acid ethyl ester (42). A) To 3-(1H-Imidazol-2-yl)propanoic

acid ethyl ester (52) [29] (100 mg, 0.595 mmol) dissolved in CH₃CN

(4 mL), tBuOK (74 mg, 0.66 mmol), NaI (234 mg, 1.56 mmol) and

4,4-diphenylbut-3-en-1-ylbromide (40) [19] (224 mg, 0.780 mmol)

solved in CH₃CN (3 mL) was added. The reaction mixture was

warmed up to 60 ^ꢀC and stirred for 72 h. Having ﬁltered the solvent

was evaporated and the crude product was puriﬁed by CC (acetone/

iso-hexane ¼ 6:4 and CHCl₃/MeOH ¼ 100:1) [45].

J ¼ 7.6 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 26.85 (t, 1 C, CH₂CH₂O),

27.87 (t, 1 C, NCH₂CH₂), 34.32 (t, 1 C, CH₂COO), 46.87 (t, 1 C, NCH₂),

52.00 (q, 1 C, COOCH₃), 55.20 (q, 1 C, OCH₃), 62.19 (t, 1 C, CH₂O),

88.26 (s, 1 C, CH₂OC), 113.52 (d, 2 C, C_ar), 116.87 (d, 1 C, C_[5C-Imid.]),

119.99 (d, 2 C, C_ar), 125.09 (d, 2 C, C_ar), 126.71 (d, 2 C, C_ar), 128.15 (d,

2 C, C_ar), 129.00 (d, 2 C, C_ar), 134.86 (s, 1C, C_[4C-Imid.]), 135.54 (s, 1 C,

C_ar), 136.47 (d, 1 C, C_[2C-Imid.]), 140.60 (s, 2 C, C_ar), 147.33 (s, 2 C, C_ar),

158.76 (s,1 C, C_ar),171.82 (s,1 C, COO); MS (EI, 70 eV) m/z (%): 482 (8,

M^þ), 271 (100); HRMS (EI, 70 eV): (C₃₀H₃₀N₂O₄) calc. 482.2206,

found 482.2229.

B) According to GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl

ester (39a) (200 mg, 1.19 mmol), DMF (8 mL), tBuOK (147 mg,

1.31 mmol), 4,4-diphenylbut-3-en-1-ylbromide (40) (444 mg,

1.55 mmol), CC (acetone/iso-hexane

¼

6:4 and CHCl₃/

MeOH ¼ 100:1). 28 mg (6%) 42 was obtained. Yield: 46 mg (21%);

colourless oil; TLC: R_f¼ 0.24 (CH₂Cl₂/MeOH ¼ 100:2); IR (KBr):

3103, 3079, 3055, 3023, 2979, 2931, 1954, 1891, 1732, 1597, 1493,

5.1.7.4. (1-{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-

1H-imidazol-4-yl)acetic acid methyl ester (38e). According to GP5:

1H-imidazol-4-ylacetic acid methyl ester (38a) [44] (280 mg,

2.00 mmol), DMF (8 mL), tBuOK (246 mg, 2.20 mmol), 9-(5-

bromopentoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene (24) (1.75 g,

1444, 1374, 1277, 1175, 1120, 1074, 1021 cm^ꢃ^{1 1}H NMR (CDCl₃):

;

d

¼ 1.24 (t, J ¼ 7.1 Hz, 3 H, CH₃), 2.52 (dt, J ¼ 7.6/7.2 Hz, 2 H, CH₂CH),

2.74e2.90 (m, 4 H, CH₂CH₂COO), 3.98 (t, J ¼ 7.2 Hz, 2 H, NCH₂), 4.12

(q, J ¼ 7.1 Hz, 2 H, CH₂CH₃), 6.02 (t, J ¼ 7.6 Hz, 1 H, CH), 6.75 (d,

J ¼ 1.1 Hz, 1 H, H_[5H-Imid.]), 6.94 (d, J ¼ 1.1 Hz, 1 H, H_[4H-Imid.]),

6.96e7.01 (m, 2 H, H_ar), 7.15e7.20 (m, 2 H, H_ar), 7.23e7.28 (m, 2 H,

4.00 mmol), CC (acetone/iso-hexane

¼

7:3 and CHCl₃/

MeOH ¼ 100:1). Yield: 336 mg (29%); light yellow oil; TLC: R_f¼ 0.34

(CH₂Cl₂/MeOH ¼ 100:2); IR (KBr): 3063, 3038, 3004, 2938, 2866,

2044, 1960, 1901, 1740, 1676, 1608, 1581, 1509, 1449, 1249, 1169,

H_ar), 7.28e7.39 (m, 4 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 14.37 (q, 1 C

CH₃), 21.77 (t, 1 C, CH₂CH₂COO), 31.37 (t, 1 C, CH₂CH), 31.93 t, 1 C,

CH₂CH₂COO), 45.67 (t, 1 C, NCH₂), 60.73 (t, 1 C CH₂CH₃), 119.60 (d,

1 C, C_[5C-Imid.]), 123.81 (d, 1 C, CH), 127.28 (d, 2 C, C_ar), 127.42 59 (d,

1 C, C_[4C-Imid.]or d, 1 C, C_aror d, 1 C, C_ar), 127.50 (d, 1 C, C_[4C-Imid.]or d,

1 C, C_aror d, 1 C, C_ar), 127.59 (d, 1 C, C_[4C-Imid.]or d, 1 C, C_aror d, 1 C,

C_ar), 128.38 (d, 2 C, C_ar), 128.59 (d, 2 C, C_ar), 129.65 (d, 2 C, C_ar),

139.46 (s, 1 C, C_ar), 141.85 (s, 1 C, C_ar), 145.32 (s, 1 C, CHC), 146.36 (s,

1 C, C_[2C-Imid.]), 173.05 (s, 1 C, COO); MS (APCIþ) m/z (%): 523.2 (44),

509.4 (12), 375.0 (100, [MþH]^þ); HRMS (EI, 70 eV): (C₂₄H₂₆N₂O₂)

calc. 374.1994, found 374.1991.

1102, 1079, 1033 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 1.28e1.42 (m, 2 H,

NCH₂CH₂CH₂), 1.52 (tt, J ¼ 7.4/6.2 Hz, 2 H, CH₂CH₂O), 1.68 (tt, J ¼ 7.5/

7.2 Hz, 2 H, NCH₂CH₂), 2.95 (t, J ¼ 6.2 Hz, 2 H, CH₂O), 3.63 (s, 2 H,

CH₂COO), 3.70 (s, 3 H, COOCH₃), 3.74 (s, 3 H, OCH₃), 3.83 (t,

J ¼ 7.2 Hz, 2 H, NCH₂), 6.73e6.80 (m, 2 H, H_ar), 6.83 (s, 1 H, H_[5H-

_Imid.]), 7.21e7.28 (m, 6 H, H_ar), 7.32e7.40 (m, 3 H, H_ar, H_[2H-Imid.]), 7.67

(d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 23.22 (t, 1 C,

NCH₂CH₂CH₂), 29.37 (t, 1 C, CH₂CH₂O), 30.66 (t, 1 C, NCH₂CH₂),

34.32 (t, 1 C, CH₂COO), 47.04 (t, 1 C, NCH₂), 51.99 (q, 1 C, COOCH₃),

55.18 (q, 1 C, OCH₃), 62.58 (t, 1 C, CH₂O), 88.17 (s, 1 C, CH₂OC), 113.47

(d, 2 C, C_ar), 116.90 (d, 1 C, C_[5C-Imid.]), 119.93 (d, 2 C, C_ar), 125.10 (d,

2 C, C_ar), 126.70 (d, 2 C, C_ar), 128.08 (d, 2 C, C_ar), 128.90 (d, 2 C, C_ar),

134.84 (s, 1 C, C_[4C-Imid.]), 135.72 (s, 1 C, C_ar), 136.46 (d, 1 C, C_[2C-Imid.]),

140.55 (s, 2 C, C_ar), 147.46 (s, 2 C, C_ar), 158.68 (s, 1 C, C_ar), 171.86 (s,

1 C, COO); MS (EI, 70 eV) m/z (%): 496 (30, M^þ), 271 (100); HRMS (EI,

70 eV): (C₃₁H₃₂N₂O₄) calc. 496.2362, found 496.2375.

5.1.7.7. 3-(1-{2-[1-(Tris-4-methoxyphenyl)methoxy]ethyl}-1H-imi-

dazol-2-yl)propanoic acid ethyl ester (43). According to GP5: 3-(1H-

Imidazol-2-yl)propanoic acid ethyl ester (39a) [29] (95 mg,

0.56 mmol), DMF (3 mL), tBuOK (70 mg, 0.62 mmol), 4,4-tris(4-

methoxyphenyl)methoxyethylbromide (41) [21] (333 mg,

0.728 mmol), CC (CHCl₃/MeOH ¼ 100:1). Yield: 215.5 mg (70%);

colourless oil; TLC: R_f¼ 0.32 (CH₂Cl₂/MeOH ¼ 100:3); IR (KBr):

3104, 3036, 2999, 1952, 1836, 1038, 1903, 1732, 1607, 1582, 1508,

5.1.7.5. (1-{1-(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]pro-

penyl}-1H-imidazol-4-yl) acetic acid methyl ester (38f).

According to GP5: 1H-imidazol-4-ylacetic acid methyl ester$HCl

1463, 1442, 1374, 1302, 1250, 1175, 1095, 1034 cm^ꢃ1

;

¹H NMR

(CDCl₃):

d

¼ 1.24 (t, J ¼ 7.1 Hz, 3 H, CH₂CH₃), 2.84e2.91 (m, 2 H,

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

873

CH₂CH₂COO), 2.92e2.99 (m, 2 H, CH₂CH₂COO), 3.32 (t, J ¼ 5.2 Hz,

2 H, CH₂O), 3.77 (s, 9 H, OCH₃), 4.05 (t, J ¼ 5.2 Hz, 2 H, NCH₂), 4.13 (q,

J ¼ 7.1 Hz, 2 H, CH₂CH₃), 6.75e6.81 (m, 6 H, H_ar), 6.93 (d, J ¼ 1.3 Hz,

1 H, H_[5H-Imid.]), 7.00 (d, J ¼ 1.3 Hz, 1 H, H_[4H-Imid.]), 7.10e7.17 (m, 6 H,

5.1.7.10. 3-(1-{4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-

1H-imidazol-2-yl)propan-oic acid ethyl ester (39d). According to

GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl ester (39a) [29]

(50 mg, 0.30 mmol), DMF (2 mL), tBuOK (39 mg, 0.35 mmol), 9-

(4-bromobutoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene (23) (173 mg,

0.409 mmol), CC (CHCl₃/MeOH ¼ 100:1). Yield: 130 mg (85%);

colourless oil; TLC: R_f¼ 0.33 (CH₂Cl₂/MeOH ¼ 100:2); IR (KBr):

3065, 3006, 2871, 2837, 2045, 1955, 1898, 1732, 1609, 1509, 1449,

H_ar); ¹³C NMR (CDCl₃):

d

¼ 14.18 (q, 1 C CH₂CH₃), 21.70 (t, 1 C,

CH₂CH₂COO), 31.86 (t, 1 C, CH₂CH₂COO), 46.05 (t, 1 C, NCH₂), 55.21

(q, 3 C, OCH₃), 60.56 (t, 1 C CH₂CH₃), 62.97 (t, 1 C, CH₂O), 86.25 (s,

1 C, OC), 113.14 (d, 6 C, C_ar), 120.29 (d, 1 C, C_[5C-Imid.]), 127.04 (d, 1 C,

C

_[4C-Imid.]), 129.60 (d, 6 C, C_ar), 136.03 (s, 3 C, C_ar), 146.56 (s, 1 C, C_[2C-

1249, 1170, 1079, 1035 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 1.23 (t, J ¼ 7.1 Hz,

_Imid.]), 158.40 (s, 3 C, C_ar), 172.92 (s, 1 C, COO); MS (ESIþ) m/z (%):

545.2 (100, [MþH]^þ); HRMS (ESIþ): (C₃₂H₃₇N₂O₆) calc. 545.2652,

found 545.2646.

3 H, CH₂CH₃), 1.50 (tt, J ¼ 7.4/6.0 Hz, 2 H, CH₂CH₂OC), 1.81 (quin,

J ¼ 7.4 Hz, 2 H, NCH₂CH₂), 2.85e2.90 (m, 4 H, CH₂CH₂COO), 2.98 (t,

J ¼ 6.0 Hz, 2 H, CH₂OC), 3.74 (s, 3 H, OCH₃), 3.84 (t, J ¼ 7.4 Hz, 2 H,

NCH₂), 4.12 (q, J ¼ 7.1 Hz, 2 H, CH₂CH₃), 6.73e6.80 (m, 3 H, H_ar, H_[5H-

_Imid.]), 6.92 (s, 1 H, H_[4H-Imid.]), 7.20e7.28 (m, 6 H, H_ar), 7.32e7.40 (m,

5.1.7.8. 3-(1-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-

1H-imidazol-2-yl)propanoic acid ethyl ester (39b). According to

GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl ester (39a) [29]

(200 mg, 1.19 mmol), DMF (7 mL), tBuOK (146 mg, 1.31 mmol), 9-

2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

¼ 14.19 (q,

d

1 C, CH₂CH₃), 21.66 (t, 1 C, CH₂CH₂COO), 26.99 (t, 1 C, CH₂CH₂OC),

27.70 (t, 1 C, NCH₂CH₂), 31.71 (t, 1 C, CH₂CH₂COO), 45.54 (t, 1 C,

NCH₂), 55.18 (q, 1 C, OCH₃), 60.58 (t, 1 C, CH₂CH₃), 62.27 (t, 1 C,

CH₂O), 88.23 (s, 1 C, CH₂OC), 113.48 (d, 2 C, C_ar), 119.18 (d, 1 C, C_[5C-

_Imid.]), 119.98 (d, 2 C, C_ar), 125.09 (d, 2 C, C_ar), 126.69 (d, 2 C, C_ar),

127.00 (d, 1 C, C_[4C-Imid.]), 128.15 (d, 2 C, C_ar), 128.97 (d, 2 C, C_ar),

135.55 (s, 1 C, C_ar), 140.57 (s, 2 C, C_ar), 146.16 (s, 1 C, C_[2C-Imid.]), 147.32

(s, 2 C, C_ar), 158.72 (s, 1 C, C_ar), 172.89 (s, 1 C, COO); MS (CI, CH^þ₅) m/z

(%): 511 (46, [MþH]^þ), 271 (100); HRMS (EI, 70 eV): (C₃₂H₃₄N₂O₄)

calc. 510.2519, found 510.2566.

(2-bromoethoxy)-9-methoxyphenyl-9H-ﬂuorene

(20)

[21]

(610 mg, 1.54 mmol), CC (acetone/iso-hexane ¼ 8:2). Yield:

480 mg (83%); colourless crystals, m.p. 72e75 ^ꢀC; TLC: R_f¼ 0.45

(acetone/n-pentane ¼ 8:2); IR (KBr): 3063, 2934, 2872, 2836, 1731,

1608, 1509, 1449, 1249, 1171, 1105, 1034 cm^ꢃ^{1 1}H NMR (CDCl₃):

;

d

¼ 1.16 (t, J ¼ 7.1 Hz, 3 H, CH₂CH₃), 2.66e2.76 (m, 4 H, CH₂CH₂COO),

3.12 (t, J ¼ 5.3 Hz, 2 H, CH₂O), 3.66 (s, 3 H, OCH₃), 3.92 (t, J ¼ 5.3 Hz,

2 H, NCH₂), 4.03 (q, J ¼ 7.1 Hz, 2 H, CH₂CH₃), 6.64e6.70 (m, 2 H, H_ar),

6.76 (s, 1 H, H_[5H-Imid.]), 6.88 (s, 1 H, H_[4H-Imid.]), 6.96 (d, J ¼ 7.5 Hz,

2 H, H_ar), 7.06e7.11 (m, 2 H, H_ar), 7.13 (t, J ¼ 7.5 Hz, 2 H, H_ar), 7.28 (t,

J ¼ 7.5 Hz, 2 H, H_ar), 7.57 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

5.1.7.11. 3-(1-{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-

1H-imidazol-2-yl)prop-anoic acid ethyl ester (39e). According to

GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl ester (39a) [29]

(101 mg, 0.600 mmol), DMF (4 mL), tBuOK (74 mg, 0.66 mmol),

d

¼ 14.19 (q, 1 C, CH₂CH₃), 21.61 (t, 1 C, CH₂CH₂COO), 31.90 (t, 1 C,

CH₂CH₂COO), 46.02 (t, 1 C, NCH₂), 55.19 (q, 1 C, OCH₃), 60.51 (t, 1 C,

CH₂CH₃), 62.60 (t, 1 C, CH₂O), 88.73 (s, 1 C, CH₂OC), 113.57 (d, 2 C,

C_ar), 119.99 (d, 2 C, C_ar), 120.12 (d, 1 C, C_[5C-Imid.]), 125.12 (d, 2 C, C_ar),

126.70 (d, 2 C, C_ar), 126.83 (d, 1 C, C_[4C-Imid.]), 128.37 (d, 2 C, C_ar),

129.18 (d, 2 C, C_ar), 134.77 (s, 1 C, C_ar), 140.53 (s, 2 C, C_ar), 146.52 (s,

2 C, C_ar), 146.63 (s, 1 C, C_[2C-Imid.]), 158.86 (s, 1 C, C_ar), 172.87 (s, 1 C,

COO); MS (EI, 70 eV) m/z (%): 482 (12, M^þ), 437 (14), 409 (18), 271

(100); HRMS (EI, 70 eV): (C₃₀H₃₀N₂O₄) calc. 482.2206, found

482.2208; Anal. C₃₀H₃₀N₂O₄(C, H, N, O).

9-(5-bromopentoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene

(24)

(342 mg, 0.780 mmol), CC (CHCl₃/MeOH ¼ 100:1). Yield: 233 mg

(74%); colourless solid, m.p. 102e105 ^ꢀC; TLC: R_f¼ 0.24 (CH₂Cl₂/

MeOH ¼ 100:2); IR (KBr): 3109, 3057, 3037, 2996, 2931, 2902, 2869,

2839, 2046, 1961, 1927, 1831, 1732, 1604, 1508, 1447, 1374, 1298,

1250, 1168, 1078, 1034 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 1.23 (t, J ¼ 7.1 Hz,

3 H, CH₂CH₃), 1.33e1.41 (m, 2 H), 1.52 (tt, J ¼ 7.6/6.1 Hz, 2 H,

CH₂CH₂O), 1.66 (tt, J ¼ 7.5/7.4 Hz, 2 H), 2.84e2.93 (m, 4 H,

CH₂CH₂COO), 2.96 (t, J ¼ 6.1 Hz, 2 H, CH₂O), 3.74 (s, 3 H, OCH₃), 3.82

(t, J ¼ 7.4 Hz, 2 H), 4.13 (q, J ¼ 7.1 Hz, 2 H, CH₂CH₃), 6.74e6.79 (m,

3 H, H_ar, H_[5H-Imid.]), 6.92 (d, J ¼ 1.3 Hz, 1 H, H_[4H-Imid.]), 7.22e7.27 (m,

6 H, H_ar), 7.32e7.39 (m, 2 H, H_ar), 7.66 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C

5.1.7.9. 3-(1-{3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-

1H-imidazol-2-yl)propan-oic acid ethyl ester (39c). According to

GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl ester (39a) [29]

(101 mg, 0.600 mmol), DMF (4 mL), tBuOK (74 mg, 0.66 mmol),

NMR (CDCl₃):

d

¼ 14.19 (q, 1 C, CH₂CH₃), 21.74 (t, 1 C, CH₂CH₂COO),

9-(3-bromopropoxy)-9-(4-methoxyphenyl)-9H-ﬂuorene

(22)

23.38 (t, 1 C, NCH₂CH₂CH₂), 29.54 (t, 1 C, CH₂CH₂O), 30.61 (t, 1 C,

NCH₂CH₂), 31.79 (t, 1 C, CH₂CH₂COO), 45.65 (d, 1 C, NCH₂), 55.18 (q,

1 C, OCH₃), 60.55 (t, 1 C, CH₂CH₃), 62.66 (t, 1 C, CH₂O), 88.21 (s, 1 C,

CH₂OC), 113.50 (d, 2 C, C_ar), 119.19 (d, 1 C, C_[5C-Imid.]), 119.92 (d, 2 C,

C_ar), 125.13 (d, 2 C, C_ar), 126.73 (d, 2 C, C_ar), 127.16 (d, 1 C, C_[4C-Imid.]),

128.07 (d, 2 C, C_ar), 128.89 (d, 2 C, C_ar), 135.77 (s, 1 C, C_ar), 140.59 (s,

2 C, C_ar), 146.13 (s, 1 C, C_[2C-Imid.]), 147.53 (s, 2 C, C_ar), 158.73 (s, 1 C,

C_ar), 172.89 (s, 1 C, COO); MS (CI, CH^þ₅) m/z (%): 525 (18, [MþH]^þ),

271 (100); HRMS (EI, 70 eV): (C₃₃H₃₃N₂O₄) calc. 524.2675, found

524.2702. Anal. C₃₃H₃₆N₂O₄(C, H, N, O).

(319 mg, 0.780 mmol), CC (CHCl₃/MeOH ¼ 100:1). Yield: 231 mg

(78%); colourless oil; TLC: R_f¼ 0.30 (CHCl₃/MeOH ¼ 100:3); IR

(KBr): 3063, 3038, 2981, 2950, 2933, 2874, 2836, 2044, 1731, 1608,

1581, 1509, 1449, 1375, 1302, 1249, 1170, 1103, 1073, 1034 cm^ꢃ1; ¹H

NMR (CDCl₃):

d

¼ 1.23 (t, J ¼ 7.1 Hz, 3 H, CH₂CH₃), 1.87 (tt, J ¼ 7.2/

5.7 Hz, 2 H, NCH₂CH₂), 2.81e2.89 (m, 2 H, CH₂CH₂COO), 2.90e2.96

(m, 2 H, CH₂CH₂COO), 3.00 (t, J ¼ 5.7 Hz, 2 H, CH₂OC), 3.76 (s, 3 H,

OCH₃), 4.01 (t, J ¼ 7.2 Hz, 2 H, NCH₂), 4.12 (q, J ¼ 7.1 Hz, 2 H,

CH₂CH₃), 6.74 (s,1 H, H_[5H-Imid.]), 6.76e6.82 (m, 2 H, H_ar), 6.89 (s,1 H,

H

_[4H-Imid.]), 7.22e7.29 (m, 6 H, H_ar), 7.33e7.42 (m, 2 H, H_ar), 7.67 (d,

J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 14.18 (q, 1 C, CH₂CH₃),

5.1.7.12. 3-(1-{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]pro-

21.65 (t, 1 C, CH₂CH₂COO), 31.40 (t, 1 C, NCH₂CH₂), 31.72 (t, 1 C,

CH₂CH₂COO), 42.93 (t, 1 C, NCH₂), 55.20 (q, 1 C, OCH₃), 59.77 (t, 1 C,

CH₂O), 60.56 (t, 1 C, CH₂CH₃), 88.34 (s, 1 C, CH₂OC), 113.55 (d, 2 C,

C_ar), 119.37 (d, 1 C, C_[5C-Imid.]), 120.04 (d, 2 C, C_ar), 125.12 (d, 2 C, C_ar),

126.69 (d, 2 C, C_ar), 126.97 (d, 1 C, C_[4C-Imid.]), 128.24 (d, 2 C, C_ar),

129.12 (d, 2 C, C_ar), 135.31 (s, 1 C, C_ar), 140.61 (s, 2 C, C_ar), 146.14 (s,

1 C, C_[2C-Imid.]), 147.10 (s, 2 C, C_ar), 158.79 (s, 1 C, C_ar), 172.85 (s, 1 C,

COO); MS (EI, 70 eV) m/z (%): 496 (6, M^þ), 451 (18), 423 (10), 271

(76), 225 (100); HRMS (ESIþ): (C₃₁H₃₃N₂O₄) calc. 497.2439, found

497.2443.

penyl}-1H-imidazol-2-yl)propanoic

acid

ethyl

ester

(39f).

According to GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl ester

(39a) [29] (106 mg, 0.630 mmol), DMF (4 mL), tBuOK (78 mg,

0.70 mmol), 9-((1E)-3-bromopropenyl)-9-(4-methoxyphenyl)-9H-

ﬂuorene (30) (320 mg, 0.818 mmol), CC (acetone/iso-hexane ¼ 8:2).

Yield: 193 mg (64%); colourless oil; TLC: R_f¼ 0.4 (acetone/iso-

hexane ¼ 8:2). IR (KBr): 3035, 2930, 2834, 1730, 1606, 1508, 1447,

1374, 1248, 1177, 1931 cm^ꢃ1; ¹H NMR (CD₃OD):

d

¼ 1.17 (t, J ¼ 7.1 Hz,

3 H, CH₃), 2.62 (t, J ¼ 7.5 Hz, 2 H, CH₂COO), 2.78 (t, J ¼ 7.5 Hz, 2 H,

CH₂CH₂COO), 3.67 (s, 3 H, OCH₃), 4.05 (q, J ¼ 7.1 Hz, 2 H, CH₂CH₃),

874

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

4.48 (d, J ¼ 5.5 Hz, 2 H, NCH₂), 5.41 (dt, J ¼ 15.5/5.5 Hz, 1 H,

NCH₂CH), 6.18 (d, J ¼ 15.5 Hz, 1 H, CHC), 6.71e6.75 (m, 2 H, H_ar),

6.81 (d, J ¼ 1.4 Hz, 1 H, H_[4H-Imid.]), 6.85 (d, J ¼ 1.4 Hz,1 H, H_[5H-Imid.]),

6.91e7.04 (m, 2 H, H_ar), 7.16 (d, J ¼ 7.5 Hz, 2 H, H_ar), 7.22 (t, J ¼ 7.5 Hz,

113.49 (d, 2 C, C_ar), 119.49 (d, 1 C, C_[5C-Imid.]), 119.96 (d, 2 C, C_ar),

125.21 (d, 2 C, C_ar), 125.68 (d, 1 C, NCH₂CH), 126.75 (d, 2 C, C_ar),

127.19 (d, 1 C, C_[4C-Imid.]), 128.19 (d, 2 C, C_ar), 129.08 (d, 2 C, C_ar),

130.69 (d,1 C, CHCH₂O),135.26 (s,1 C, C_ar),140.54 (s, 2 C, C_ar),146.34

(s, 1 C, C_[2C-Imid.]), 147.01 (s, 2 C, C_ar), 158.75 (s, 1 C, C_ar), 172.85 (s, 1 C,

COO); MS (EI, 70 eV) m/z (%): 508 (10, M^þ), 463 (7), 373 (11), 271

(100); HRMS (EI, 70 eV): (C₃₂H₃₂N₂O₄) calc. 508.2362, found

508.2352.

2 H, H_ar), 7.32 (t, J ¼ 7.5 Hz, 2 H, H_ar), 7.77 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³

C

NMR (CD₃OD):

d

¼ 14.65 (q,1 C, CH₃CH₂), 22.62 (t,1 C, CH₂CH₂COO),

32.95 (t, 1 C, CH₂COO), 48.40 (t, 1 C, CH₂CH), 55.80 (q, 1 C, OCH₃),

61.79 (t, 1 C, CH₂CH₃), 62.38 (s, 1 C, CHC), 115.03 (d, 2 C, C_ar), 121.29

(d, 1 C, C_[5C-Imid.]), 121.53 (d, 2 C, C_ar), 125.15 (d, 1 C, NCH₂CH), 126.66

(d, 2 C, C_ar), 127.38 (d, 1 C, C_[4C-Imid.]), 128.79 (d, 2 C, C_ar), 128.85 (d,

2 C, C_ar), 129.34 (d, 2 C, C_ar), 137.00 (s, 1 C, C_ar), 138.06 (d, 1 C, CHC),

141.40 (s, 2 C, C_ar), 148.22 (s, 1 C, C_[2C-Imid.]), 151.40 (s, 2 C, C_ar), 160.18

(s, 1 C, C_ar), 173.99 (s, 1 C, COO); MS (EI, 70 eV) m/z (%): 478 (2, M^þ),

455 (2), 433 (2), 297 (46), 203 (42), 107 (100); HRMS (EI, 70 eV):

(C₃₁H₃₀N₂O₃) calc. 478.2257, found 478.2240.

5.1.7.15. 3-(1-{(2Z)-4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]

but-2-en-1-yl}-1H-imidazol-2-yl)propanoic acid ethyl ester (39i).

According to GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl ester

(39a) [29] (111 mg, 0.660 mmol), DMF (4 mL), tBuOK (82 mg,

0.73 mmol), 9-[(2Z)-4-(2-methylsulfonyloxy)but-2-en-1-yloxy]-9-

(4-methoxyphenyl)-9H-ﬂuorene (32) (375 mg, 0.858 mmol), CC

(CHCl₃/MeOH ¼ 100:1). Yield: 182 mg (54%); colourless solid, m.p.

85e87 ^ꢀC; TLC: R_f¼ 0.32 (CH₂Cl₂/MeOH ¼ 100:2); IR (KBr): 3135,

3105, 3055, 2971, 2925, 2840, 2041, 1967, 1900, 1730, 1605, 1508,

5.1.7.13. 3-[1-(2-{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]

propenyloxy}ethyl)-1H-imidazol-2-yl]-propanoic acid ethyl ester

(39g). According to GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl

ester (39a) [29] (100 mg, 0.595 mmol), DMF (4 mL), tBuOK (74 mg,

0.66 mmol), 9-{(1E)-3-[2-(2-methyl-sulfonyl)ethoxy]propenyl}-9-

(4-methoxyphenyl)-9H-ﬂuorene (34) (349 mg, 0.774 mmol), CC

(acetone/iso-hexane ¼ 8:2 and CH₂Cl₂/MeOH ¼ 100:0.75). Yield:

1449, 1246. 1170, 1076, 1031 cm^ꢃ1

;

¹H NMR (CD₂Cl₂):

d

¼ 1.21 (t,

J ¼ 7.1 Hz, 3 H, CH₂CH₃), 2.74e2.77 (m, 4 H, CH₂CH₂COO), 3.65 (d_br,

J ¼ 6.4 Hz, 2 H, CH₂O), 3.73 (s, 3 H, OCH₃), 4.08 (q, J ¼ 7.1 Hz, 2 H,

CH₂CH₃), 4.31 (d_br, J ¼ 6.7 Hz, 2 H, NCH₂), 5.50 (dtt, J ¼ 11.2/6.7/

1.6 Hz, 1 H, NCH₂CH), 5.76 (dtt, J ¼ 11.2/6.4/1.6 Hz, 1 H, CHCH₂O),

6.70 (d, J ¼ 1.3 Hz, 1 H, H_[5H-Imid.]), 6.74e6.79 (m, 2 H, H_ar), 6.79 (d,

J ¼ 1.3 Hz,1 H, H_[4H-Imid.]), 7.23e7.26 (m, 2 H, H_ar), 7.26e7.32 (m, 4 H,

H_ar), 7.38e7.42 (m, 2 H, H_ar), 7.73 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR

215 mg (68%); colourless oil; TLC: R_f

MeOH ¼ 100:3); IR (KBr): 3036, 2932, 2858, 2728, 1606, 1507, 1447,

1374, 1353, 1296, 1279, 1246, 1177, 1117, 1030 cm^ꢃ^{1 1}H NMR

(CD₂Cl₂):

¼ 1.21 (t, J ¼ 7.1 Hz, 3 H,CH₂CH₃), 2.78 (t, J ¼ 6.9 Hz, 2 H,

¼

0.35 (CH₂Cl₂/

;

d

(CD₂Cl₂):

d

¼ 14.41 (q,1 C, CH₂CH₃), 22.03 (t,1 C, CH₂CH₂COO), 31.92

CH₂CH₂COO), 2.89 (t, J ¼ 6.9 Hz, 2 H, CH₂CH₂COO), 3.61 (t_br,

J ¼ 5.4 Hz, 2 H, NCH₂CH₂), 3.73 (s, 3 H, OCH₃), 3.92 (dd, J ¼ 5.6/

1.3 Hz, 2 H, CH₂CH), 4.01 (t, J ¼ 5.4 Hz, 2 H, NCH₂), 4.08 (q, J ¼ 7.1 Hz,

2 H, CH₂CH₃), 5.42 (dt, J ¼ 15.5/5.6 Hz, 1 H, CH₂CH), 6.38 (d,

J ¼ 15.5 Hz, 1 H, CHC), 6.73e6.79 (m, 2 H, H_ar), 6.83 (s, 1 H, H_[4H-

_Imid.]), 6.84 (s, 1 H, H_[5H-Imid.]), 6.99e7.05 (m, 2 H, H_ar), 7.23 (d,

J ¼ 7.4 Hz, 2 H, H_ar), 7.29 (td, J ¼ 7.4/1.0 Hz, 2 H, H_ar), 7.37 (td, J ¼ 7.4/

1.0 Hz, 2 H, H_ar), 7.78 (d, J ¼ 7.4 Hz, 2 H, H_ar); ¹³C NMR (CD₂Cl₂):

(t, 1 C, CH₂CH₂COO), 43.22 (t, 1 C, NCH₂), 55.56 (q, 1 C, OCH₃), 59.71

(t, 1 C, CH₂O), 60.80 (t, 1 C, CH₂CH₃), 89.07 (s, 1 C, CH₂OC), 113.85 (d,

2 C, C_ar), 119.35 (d, 1C, C_[5C-Imid.]), 120.57 (d, 2 C, C_ar), 125.55 (d, 2 C,

C_ar), 127.11 (d, 2 C, C_aror NCH₂CH), 127.38 (d, 2 C, C_aror NCH₂CH),

127.38 (d, 1 C, C_[4C-Imid.]), 128.64 (d, 2 C, C_ar), 129.61 (d, 2 C, C_ar),

130.63 (d,1 C, CHCH₂O),135.63 (s, 1 C, C_ar), 141.07 (s, 2 C, C_ar), 146.66

(s, 1 C, C_[2C-Imid.]), 147.40 (s, 2 C, C_ar), 159.37 (s, 1 C, C_ar), 172.98 (s, 1 C,

COO); MS (CI, CH^þ₅) m/z (%): 509 (2, [MþH]^þ), 271 (100); MS (ESIþ)

m/z (%): 509.4 (100, [MþH]^þ); HRMS (ESIþ): (C₃₂H₃₃N₂O₄) calc.

509.2440, found 509.2435.

d

¼ 14.41 (q, 1 C CH₂CH₃), 22.13 (t, 1 C, CH₂CH₂COO), 32.09 (t, 1 C,

CH₂CH₂COO), 46.05 (t, 1 C, NCH₂), 55.58 (q, 1 C, OCH₃), 60.79 (t, 1 C,

CH₂CH₃), 61.46 (s, 1 C, CHC), 69.75 (t, 1 C, NCH₂CH₂), 71.62 (t, 1 C,

CH₂CH), 114.15 (d, 2 C, C_ar), 120.03 (d, 1 C, C_[5C-Imid.]), 120.72 (d, 2 C,

C_ar), 125.42 (d, 1 C, CH₂CH), 125.86 (d, 2 C, C_ar), 127.36 (d, 1 C, C_[4C-

_Imid.]), 127.88 (d, 2 C, C_ar), 127.96 (d, 2 C, C_ar), 128.51 (d, 2 C, C_ar),

136.09 (d, 1 C, CHC), 136.28 (s, 1 C, C_ar), 140.28 (s, 2 C, C_ar), 147.13 (s,

1 C, C_[2C-Imid.]), 150.56 (s, 2 C, C_ar), 158.97 (s, 1 C, C_ar), 173.15 (s, 1 C,

COO); MS (CI, CH^þ₅) m/z (%): 523 (100, [MþH]^þ); HRMS (ESIþ):

(C₃₃H₃₅N₂O₄) calc. 523.2597, found 523.2588.

5.1.7.16. 3-[1-(2-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]

ethoxy}ethyl)-1H-imidazol-2-yl]propanoic acid ethyl ester (39j).

According to GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl ester

(39a) [29] (100 mg, 0.595 mmol), DMF (4 mL), tBuOK (74 mg,

0.66 mmol), 9-{2-[2-(2-methylsulfonyloxy)ethoxy]-ethoxy}-9-(4-

methoxyphenyl)-9H-ﬂuorene (33) (352 mg, 0.774 mmol), CC

(acetone/iso-hexane ¼ 8:2 and CH₂Cl₂/MeOH ¼ 100:1). Yield:

177 mg (57%); colourless oil; TLC: R_f

¼

0.32 (CH₂Cl₂/

5.1.7.14. 3-(1-{(2E)-4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]

but-2-en-1-yl}-1H-imidazol-2-yl)propanoic acid ethyl ester (39h).

According to GP5: 3-(1H-Imidazol-2-yl)propanoic acid ethyl ester

(39a) [29] (101 mg, 0.600 mmol), DMF (4 mL), tBuOK (74 mg,

MeOH ¼ 100:2); IR (KBr): 3106, 3064, 3038, 2933, 2871, 1837, 2045,

1957, 1914,1732, 1698, 1581,1509,1449,1375, 1301,1282, 1249, 1171,

1132, 1102, 1082, 1034 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 1.23 (t, J ¼ 7.1 Hz,

3 H, CH₂CH₃), 2.85e2.92 (m, 2 H, CH₂CH₂COO), 2.92e3.00 (m, 2 H,

CH₂CH₂COO), 3.11 (t, J ¼ 4.9 Hz, 2 H, CH₂OC), 3.49 (t, J ¼ 4.9 Hz, 2 H,

CH₂CH₂OC), 3.70 (t, J ¼ 5.3 Hz, 2 H, NCH₂CH₂), 3.75 (s, 3 H, OCH₃),

4.07 (t, J ¼ 5.3 Hz, 2 H, NCH₂), 4.12 (q, J ¼ 7.1 Hz, 2 H, CH₂CH₃),

6.74e6.80 (m, 2 H, H_ar), 6.94 (d, J ¼ 1.2 Hz, 1 H, H_[4H-Imid.]), 6.96 (d,

J ¼ 1.2 Hz, 1 H, H_[5H-Imid.]), 7.21e7.29 (m, 6H, H_ar), 7.32e7.40 (m, 2 H,

0.66

mmol),

9-[(2E)-4-bromobut-2-en-1-yloxy]-9-(4-

methoxyphenyl)-9H-ﬂuorene (25) (329 mg, 0.780 mmol), CC

(CHCl₃/MeOH ¼ 100:1). Yield: 208 mg (68%); colourless oil; TLC:

R_f¼ 0.39 (CH₂Cl₂/MeOH ¼ 100:3); IR (KBr): 3062, 3039, 2979, 2933,

2859, 2045, 1963, 1732, 1608, 1509, 1449, 1249, 1170, 1107,

1034 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 1.23 (t, J ¼ 7.1 Hz, 3 H, CH₂CH₃),

H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

¼ 14.19 (q, 1 C,

d

2.79e2.92 (m, 4 H, CH₂CH₂COO), 3.52 (dd, J ¼ 5.0/1.3 Hz, 2 H, CH₂O),

3.74 (s, 3 H, OCH₃), 4.12 (q, J ¼ 7.1 Hz, 2 H, CH₂CH₃), 4.45 (dd, J ¼ 5.5/

1.3 Hz, 2 H, NCH₂), 5.46 (dt_br, J ¼ 15.5/5.0 Hz, 1 H, CHCH₂O), 5.77

(dt_br, J ¼ 15.5/5.5 Hz, 1 H, NCH₂CH), 6.72e6.80 (m, 3 H, H_ar, H_[5H-

_Imid.]), 6.93 (d, J ¼ 1.2 Hz, 1 H, H_[4H-Imid.]), 7.20e7.20 (m, 6 H, H_ar),

7.36 (td, J ¼ 7.5/1.6 Hz, 2 H, H_ar), 7.66 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C

CH₂CH₃), 21.62 (t,1 C, CH₂CH₂COO), 31.87 (t,1 C, CH₂CH₂COO), 45.89

(t, 1 C, NCH₂), 55.21 (q, 1 C, OCH₃), 60.60 (t, 1 C, CH₂CH₃), 62.86 (t,

1 C, CH₂OC), 70.24 (t, 1 C, NCH₂CH₂), 70.83 (t, 1 C, CH₂CH₂OC), 88.43

(s, 1 C, CH₂OC), 113.49 (d, 2 C, C_ar), 119.98 (d, 2 C, C_aror d, 1 C, C_[5C-

_Imid.]), 120.01 (d, 2 C, C_aror d, 1 C, C_[5C-Imid.]), 125.26 (d, 2 C, C_ar),

126.55 (d, 2 C, C_ar, or d, 1 C, C_[4C-Imid.]), 126.78 (d, 2 C, C_ar, or d, 1 C,

NMR (CDCl₃):

d

¼ 14.18 (q, 1 C, CH₂CH₃), 21.66 (t, 1 C, CH₂CH₂COO),

C_[4C-Imid.]), 128.19 (d, 2 C, C_ar), 129.04 (d, 2 C, C_ar), 135.32 (s, 1 C, C_ar),

31.75 (t, 1 C, CH₂CH₂COO), 47.14 (t, 1 C, NCH₂), 55.17 (q, 1 C, OCH₃),

60.56 (t, 1 C, CH₂CH₃), 63.09 (t, 1 C, CH₂O), 88.44 (s, 1 C, CH₂OC),

140.58 (s, 2 C, C_ar), 146.58 (s, 1 C, C_[2C-Imid.]), 147.05 (s, 2 C, C_ar),

158.76 (s, 1 C, C_ar), 172.95 (s, 1 C, COO); MS (CI, CH^þ₅) m/z (%): 527

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

875

(59, [MþH]^þ), 513 (5), 448 (6), 279 (6), 257 (100); HRMS (EI, 70 eV):

(65%); colourless solid, m.p. 115e120 ^ꢀC; IR (KBr): 3449, 2926, 2860,

1717, 1607, 1508, 1448, 1249, 1168, 1105, 1073, 1031 cm^ꢃ^{1 1}H NMR

(CD₃OD):

(C₃₂H₃₄N₂O₅) calc. 526.2468, found 526.2457.

;

d

¼ 1.89 (m, 2 H, NCH₂CH₂), 3.00 (t, J ¼ 5.5 Hz, 2 H, CH₂O),

5.1.7.17. 3-(1-{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-

3.65 (s, 2 H, CH₂COO), 3.72 (s, 3 H, CH₃), 4.23 (t, J ¼ 7.3 Hz, 2 H,

NCH₂), 6.78 (d, J ¼ 8.9 Hz, 2 H, H_ar), 7.16e7.20 (m, 3 H, H_[4H-Imid.],

H_ar), 7.22 (d, J ¼ 7.5 Hz, 2 H, H_ar), 7.27 (t, J ¼ 7.5 Hz, 2 H, H_ar), 7.38 (t,

J ¼ 7.5 Hz, 2 H, H_ar), 7.74 (d, J ¼ 7.5 Hz, 2 H, H_ar), 8.38 (s, 1 H, H_[2H-

1H-imidazol-2-yl)prop-2-enoic

acid

ethyl

ester

(46e).

According to GP5: (E)-3-(1H-Imidazol-2-yl)prop-2-enoic acid ethyl

ester (46a) [29] (72 mg, 0.43 mmol), DMF (3 mL), tBuOK (53 mg,

0.48 mmol), 9-(5-bromopentoxy)-9-(4-methoxyphenyl)-9H-ﬂuo-

rene (24) (246 mg, 0.563 mmol), CC (CHCl₃/MeOH ¼ 100:1). Yield:

220 mg (97%); light red solid, m.p. 131e133 ^ꢀC; TLC: R_f¼ 0.42

(CH₂Cl₂/MeOH ¼ 100:2); IR (KBr): 3037, 2995, 2933, 2902, 2871,

1709, 1634, 1508, 1474, 1448, 1296, 1250, 1167, 1079, 1033 cm^ꢃ1; ¹H

_Imid.]); ¹³C NMR (CD₃OD):

d

¼ 31.37 (t, 1 C, NCH₂CH₂), 32.49 (t, 1 C,

CH₂COO), 45.23 (t, 1 C, NCH₂), 55.67 (q, 1 C, CH₃), 60.96 (t, 1 C,

CH₂O), 89.80 (s, 1 C, CH₂OC), 114.54 (d, 2 C, C_ar), 121.21 (d, 2 C, C_ar),

121.71 (d, 1 C, C_[4C-Imid.]), 126.26 (d, 2 C, C_ar), 127.85 (d, 2 C, C_ar),

129.33 (d, 2 C, C_ar), 130.40 (d, 2 C, C_ar), 131.30 (s, 1 C, C_[5C-Imid.]),

136.49 (s, 1 C, C_ar), 136.68 (d, 1 C, C_[2C-Imid.]), 142.10 (s, 2 C, C_ar),

148.39 (s, 2 C, C_ar), 160.43 (s, 1 C, C_ar), 174.40 (s, 1 C, COO); MS (ESIþ)

m/z (%): 455.2 (30, [MþH]^þ), 271.2 (28), 154.1 (100); HRMS (ESIþ):

NMR (CDCl₃):

d

¼ 1.31 (t, J ¼ 7.1 Hz, 3 H, CH₂CH₃), 1.33e1.41 (m, 2 H,

NCH₂CH₂CH₂), 1.52 (tt, J ¼ 7.5/6.0 Hz, 2 H, CH₂CH₂O),1.70 (tt, J ¼ 7.7/

7.3 Hz, 2 H, NCH₂CH₂), 2.95 (t, J ¼ 6.0 Hz, 2 H, CH₂O), 3.75 (s, 3 H,

OCH₃), 3.99 (t, J ¼ 7.3 Hz, 2 H, NCH₂), 4.25 (q, J ¼ 7.1 Hz, 2 H,

CH₂CH₃), 6.74e6.80 (m, 2 H, H_ar), 6.85 (d, J ¼ 15.4 Hz, 1 H, CHCOO),

6.96 (d, J ¼ 1.0 Hz, 1 H, H_[5H-Imid.]), 7.15 (d, J ¼ 1.0 Hz, 1 H, H_[4H-Imid.]),

7.20e7.25 (m, 6 H, H_ar), 7.33e7.39 (m, 2 H, H_ar), 7.48 (d, J ¼ 15.4 Hz,

1 H, CHCHCOO), 7.66 (d, J ¼ 7.6 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

(C₂₈H₂₇N₂O₄) calc. 455.1971, found 455.1950. Anal. C₂₈H₂₆N₂O₄

0.45 H₂O (C, H, N, O).

x

5.1.8.3. (1-{4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-1H-

imidazol-5-yl)acetic acid (10d). According to GP6: (1-{4-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-1H-imidazol-5-yl)

acetic acid methyl ester (37d) (24.0 mg, 0.050 mmol), CH₃OH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 17.2 mg

(74%); colourless solid, m.p. 103e107 ^ꢀC; IR (KBr): 3424, 2930, 2868,

1924, 1718, 1608, 1508, 1449, 1248, 1169, 1103, 1076, 1032 cm^ꢃ1; ¹H

d

¼ 14.28 (q, 1 C CH₂CH₃), 23.32 (t, 1 C, NCH₂CH₂CH₂), 29.40 (t, 1 C,

CH₂CH₂O), 31.11 (t, 1 C, NCH₂CH₂), 46.15 (t, 1 C, NCH₂), 55.19 (q, 1 C,

OCH₃), 60.67 (t, 1 C, CH₂CH₃), 62.51 (t, 1 C, CH₂O), 88.18 (s, 1 C,

CH₂OC), 113.48 (d, 2 C, C_ar), 119.92 (d, 2 C, C_ar), 120.73 (d, 1 C,

CHCOO), 122.25 (d, 1 C, C_[5C-Imid.]), 125.10 (d, 2 C, C_ar), 126.71 (d, 2 C,

C_ar),128.09 (d, 2 C, C_ar),128.22 (d,1 C, CHCHCOO),128.90 (d, 2 C, C_ar),

130.24 (d, 1 C, C_[4C-Imid.]), 135.70 (s, 1 C, C_ar), 140.56 (s, 2 C, C_ar),

142.49 (s,1 C, C_[2C-Imid.]),147.44 (s, 2 C, C_ar),158.70 (s,1 C, C_ar), 167.03

(s, 1 C, COO); MS (ESIþ) m/z (%): 1045.4 (8), 545.2 (16, [MþNa]^þ),

523.4 (100, [MþH]^þ); HRMS (EI, 70 eV): (C₃₃H₃₄N₂O₄) calc.

522.2519, found 522.2552.

NMR (CDCl₃):

d

¼ 1.45 (tt, J ¼ 5.8/7.3 Hz, 2 H, CH₂CH₂O), 1.81 (tt,

J ¼ 7.3/7.4 Hz, 2 H, NCH₂CH₂), 2.94 (t, J ¼ 5.8 Hz, 2 H, CH₂O), 3.52 (s,

2 H, CH₂COO), 3.70 (s, 3 H, CH₃), 3.94 (t, J ¼ 7.4 Hz, 2 H, NCH₂),

6.71e6.77 (m, 2 H, H_ar), 7.02 (s, 1 H, H_[4H-Imid.]), 7.16e7.24 (m, 6 H,

H_ar), 7.29e7.37 (m, 2 H, H_ar), 7.64 (d, J ¼ 7.5 Hz, 2 H, H_ar), 7.90 (s, 1 H,

H

_[2H-Imid.]); ¹³C NMR (CDCl₃):

d

¼ 26.84 (t, 1 C, CH₂CH₂O), 27.11 (t,

5.1.8. General procedure for hydrolysis (GP6)

1 C, NCH₂CH₂), 31.58 (t, 1 C, CH₂COO), 45.99 (t, 1 C, NCH₂), 55.18 (q,

1 C, CH₃), 62.12 (t, 1 C, CH₂O), 88.28 (s, 1 C, CH₂OC), 113.54 (d, 2 C,

C_ar), 120.01 (d, 2 C, C_ar), 122.25 (d, 1 C, C_[4C-Imid.]), 125.08 (d, 2 C, C_ar),

126.71 (d, 2 C, C_ar), 128.21 (d, 2 C, C_ar, s, 1 C, C_[5C-Imid.]), 129.04 (d, 2 C,

C_ar), 134.93 (d, 1 C, C_[2C-Imid.]), 135.41 (s, 1 C, C_ar), 140.54 (s, 2 C, C_ar),

147.20 (s, 2 C, C_ar), 158.74 (s, 1 C, C_ar), 172.72 (s, 1 C, COO); MS (FAB,

NBA) m/z (%): 469.4 (59, [MþH]^þ), 271.3 (100); HRMS (EI, 70 eV):

(C₂₉H₂₈N₂O₄) calc. 468.2049, found 468.2055.

The carboxylic acid ester (1.0 equiv.) dissolved in excess of

MeOH or EtOH was treated with NaOH (2 M). The mixture was

stirred for 1 h and then the pH value was adjusted to 4e5 with HCl

(1 M). After extraction with CH₂Cl₂, the combined organic layers

were dried over MgSO₄, ﬁltered, and concentrated.

5.1.8.1. (1-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-1H-

imidazol-5-yl)acetic acid (10b). According to GP6: (1-{2-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-1H-imidazol-5-yl)ace-

tic acid methyl ester (37b) (21 mg, 0.046 mmol), CH₃OH (1 mL), 2 M

NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 18.3 mg (90%); col-

ourless solid; m.p. 90e95 ^ꢀC; IR (KBr): 2928, 1719, 1607, 1509, 1449,

5.1.8.4. (1-{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-

1H-imidazol-5-yl)acetic acid (10e). According to GP6: (1-{5-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-1H-imidazol-5-yl)

acetic acid methyl ester (37e) (24.0 mg, 0.048 mmol), CH₃OH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 18 mg

(77%); colourless solid, m.p. 103e108 ^ꢀC; IR (KBr): 3386, 2919, 2850,

1249, 1169, 1105, 1074, 1031 cm^ꢃ1

;

¹H NMR (CD₃OD):

d

¼ 3.24 (t,

J ¼ 4.9 Hz, 2 H, CH₂O), 3.64 (s, 2 H, CH₂COO), 3.73 (s, 3 H, CH₃), 4.28

(t, J ¼ 4.9 Hz, 2 H, NCH₂), 6.75e6.80 (m, 2 H, H_ar), 6.95 (d, J ¼ 7.5 Hz,

2 H, H_ar), 7.10e7.16 (m, 2 H, H_ar), 7.21 (td, J ¼ 7.5/1.0 Hz, 2 H, H_ar),

7.32 (s, 1 H, H_[4H-Imid.]), 7.39 (td, J ¼ 7.5/1.0 Hz, 2 H, H_ar), 7.75 (d,

J ¼ 7.5 Hz, 2 H, H_ar), 8.56 (s, 1 H, H_[2H-Imid.]); ¹³C NMR (CDCl₃):

1722, 1607,1509, 1449, 1366, 1248, 1169, 1015 cm^ꢃ1

(CDCl₃):

;

¹H NMR

d

¼ 1.27e1.36 (m, 2 H, NCH₂CH₂CH₂), 1.47 (tt, J ¼ 7.2/6.0 Hz,

2 H, CH₂CH₂O), 1.65 (tt, J ¼ 7.8/7.5 Hz, 2 H, NCH₂CH₂), 2.92 (t,

J ¼ 6.0 Hz, 2 H, CH₂O), 3.55 (s, 2 H, CH₂COO), 3.71 (s, 3 H, CH₃), 3.95

(t, J ¼ 7.5 Hz, 2 H, NCH₂), 6.72e6.78 (m, 2 H, H_ar), 7.10 (s, 1 H, H_[4H-

_Imid.]), 7.19e7.25 (m, 6 H, H_ar), 7.30e7.36 (m, 2 H, H_ar), 7.64 (d,

J ¼ 7.5 Hz, 2 H, H_ar), 8.16 (s, 1 H, H_[2H-Imid.]); ¹³C NMR (CDCl₃):

d

¼ 31.36 (t, 1 C, CH₂COO), 46.99 (t, 1 C, NCH₂), 55.42 (q, 1 C, CH₃),

61.89 (t, 1 C, CH₂O), 89.01 (s, 1 C, CH₂OC), 113.92 (d, 2 C, C_ar), 120.38

(d, 2 C, C_ar), 120.76 (d, 1 C, C_[4C-Imid.]), 125.01 (d, 2 C, C_ar), 126.81 (d,

2 C, C_ar), 128.72 (d, 2 C, C_ar), 129.67 (d, 2 C, C_ar), 134.38 (s, 1 C, C_ar),

135.61 (s, 2 C, C_[2C-Imid.], C_[5C-Imid.]), 140.69 (s, 2 C, C_ar), 146.21 (s, 2 C,

C_ar), 158.15 (s, 1 C, C_ar), 172.20 (s, 1 C, COO); MS (ESIþ) m/z (%): 441.2

(100, [MþH]^þ); HRMS (FAB, NBA): (C₂₇H₂₄N₂O₄) calc. 441.1814,

found 441.1845. Anal. C₂₇H₂₄N₂O₄x H₂O (C, H, N, O).

d

¼ 23.24 (t, 1 C, NCH₂CH₂CH₂), 29.45 (t, 1 C, CH₂CH₂O), 29.89 (t, 1 C,

NCH₂CH₂), 31.48 (t, 1 C, CH₂COO), 46.55 (t, 1 C, NCH₂), 55.29 (q, 1 C,

CH₃), 62.59 (t, 1 C, CH₂O), 88.28 (s, 1 C, CH₂OC), 113.60 (d, 2 C, C_ar),

120.09 (d, 2 C, C_ar), 120.85 (d, 1 C, C_[4C-Imid.]), 125.18 (d, 2 C, C_ar),

126.83 (d, 2 C, C_ar), 128.22 (d, 2 C, C_ar), 128.71 (s, 1 C, C_[5C-Imid.]),

129.07 (d, 2 C, C_ar), 134.56 (d, 1 C, C_[2C-Imid.]), 135.72 (s, 1 C, C_ar),

140.62 (s, 2 C, C_ar), 147.44 (s, 2 C, C_ar), 158.80 (s, 1 C, C_ar), 172.32 (s,

1 C, COO); MS (FAB, NBA) m/z (%): 483.4 (22, [MþH]^þ), 271.3 (100);

HRMS (ESIþ): (C₃₀H₃₀N₂O₄) calc. 483.2284, found 483.2277. Anal.

5.1.8.2. (1-{3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-

1H-imidazol-5-yl)acetic acid (10c). According to GP6: (1-{3-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-1H-imidazol-5-yl)

acetic acid methyl ester (37c) (28.0 mg, 0.060 mmol), CH₃OH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 17.7 mg

C₃₀H₃₀N₂O₄x 2.5 H₂O (C, H, N, O).

876

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

5.1.8.5. (1-{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]prop-2-

en-1-yl}-1H-imidazol-5-yl)acetic acid (10f). According to GP6: (1-

{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]prop-2-en-1-yl}-

1H-imidazol-5-yl)acetic acid methyl ester (37f) (38.0 mg,

0.084 mmol), CH₃OH (1 mL), 2 M NaOH (80.0 mg, 2.00 mmol,

1.00 mL). Yield: 37 mg (quant.); colourless solid, m.p. 135e145 ^ꢀC;

IR (KBr): 3432, 2929, 1717, 1607, 1508, 1447, 1298, 1249, 1179, 1106,

m/z (%): 455.4 (100, [MþH]^þ); HRMS (ESIþ): (C₂₈H₂₇N₂O₄) calc.

455.1970, found 455.1975.

5.1.8.8. (1-{4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-1H-

imidazol-4-yl)acetic acid (9d). According to GP6: (1-{4-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-1H-imidazol-4-yl)

acetic acid methyl ester (38d) (23.3 mg, 0.048 mmol), CH₃OH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 18.7 mg

(83%); colourless solid, m.p. 105e110 ^ꢀC; IR (KBr): 3424, 2928, 2867,

1924, 1718, 1608, 1508, 1448, 1301, 1248, 1168, 1076, 1031 cm^ꢃ1; ¹H

1031 cm^ꢃ1; ¹H NMR (CD₃OD):

d

¼ 3.56 (s, 2 H, CH₂COO), 3.69 (s, 3 H,

CH₃), 4.72 (d, J ¼ 5.9 Hz, 2 H, NCH₂), 5.48 (dt, J ¼ 5.9/15.5 Hz, 1 H,

NCH₂CH), 6.50 (d, J ¼ 15.5 Hz,1 H, CHC), 6.76 (d, J ¼ 8.8 Hz, 2 H, H_ar),

7.00 (d, J ¼ 8.8 Hz, 2H, H_ar), 7.18 (s, 1H, H_[4H-Imid.]), 7.20e7.29 (m, 4 H,

H_ar), 7.30e7.40 (m, 2 H, H_ar), 7.79 (d, J ¼ 7.5 Hz, 2 H, H_ar), 8.26 (s, 1 H,

NMR (CDCl₃):

d

¼ 1.40 (tt, J ¼ 7.4/5.9 Hz, 2 H, CH₂CH₂O), 1.77 (tt,

J ¼ 7.4/7.2 Hz, 2 H, NCH₂CH₂), 2.90 (t, J ¼ 5.9 Hz, 2 H, CH₂O), 3.58 (s,

2 H, CH₂COO), 3.67 (s, 3 H, CH₃), 3.79 (t, J ¼ 7.2 Hz, 2 H, NCH₂), 6.70

(m, 3H, H_ar, H_[5H-Imid.]), 7.13e7.21 (m, 6 H, H_ar), 7.25e7.33 (m, 2 H,

H_ar), 7.54 (s, 1 H, H_[2H-Imid.]), 7.60 (d, J ¼ 7.5 Hz, 2 H, H_ar), 7.77 (s, 1 H,

H

_[2H-Imid.]); ¹³C NMR (CD₃OD):

d

¼ 31.91 (t, 1 C, CH₂COO), 49.03 (t,

1 C, NCH₂), 55.67 (q, 1 C, CH₃), 62.36 (s, 1 C, CHC), 114.95 (d, 2 C, C_ar),

121.46 (d, 2 C, C_ar), 122.38 (d, 1 C, C_[4C-Imid.]), 123.16 (d, 1 C, NCH₂CH),

126.62 (d, 2 C, C_ar), 128.81 (d, 2 C, C_ar), 128.86 (d, 2 C, C_ar), 129.24 (d,

2 C, C_ar), 130.74 (s, 1 C, C_[5C-Imid.]), 136.66 (s, 1 C, C_ar), 136.79 (d, 1 C,

NH^þ); ¹³C NMR (CDCl₃):

d

¼ 26.94 (t, 1 C, CH₂CH₂O), 27.88 (t, 1 C,

NCH₂CH₂), 33.50 (t, 1 C, CH₂COO), 47.64 (t, 1 C, NCH₂), 55.40 (q, 1 C,

CH₃), 62.31 (t, 1 C, CH₂O), 88.47 (s, 1 C, CH₂OC), 113.72 (d, 2 C, C_ar),

116.92 (d, 1 C, C_[5C-Imid.]), 120.22 (d, 2 C, C_ar), 125.26 (d, 2 C, C_ar),

126.89 (d, 2 C, C_ar), 128.38 (d, 2 C, C_ar), 129.24 (d, 2 C, C_ar), 134.42 (s,

1 C, C_[4C-Imid.]), 135.62 (d, 1 C, C_[2C-Imid.], s, 1 C, C_ar), 140.77 (s, 2 C, C_ar),

147.42 (s, 2 C, C_ar), 158.95 (s, 1 C, C_ar), 172.88 (s, 1 C, COO); MS (FAB,

NBA) m/z (%): 469.4 (76, [MþH]^þ), 424.4 (13), 271.3 (100); HRMS

(FAB, NBA): (C₂₉H₂₉N₂O₄) calc. 469.2127, found 469.2111.

C

_[2C-Imid.]), 140.61 (d, 1 C, CHC), 141.30 (s, 2 C, C_ar), 151.01 (s, 2 C, C_ar),

160.12 (s, 1 C, C_ar), 173.75 (s, 1 C, COO); MS (FAB, NBA) m/z (%): 437.3

(100, [MþH]^þ); HRMS (ESIþ): (C₂₈H₂₅N₂O₃) calc. 437.1866, found

437.1873.

5.1.8.6. (1-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-1H-

imidazol-4-yl)acetic acid (9b). According to GP6: (1-{2-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-1H-imidazol-4-yl)ace-

tic acid methyl ester (38b) (14.4 mg, 0.032 mmol), CH₃OH (1 mL),

2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 130 mg (93%);

colourless solid, m.p. 100e105 ^ꢀC; IR (KBr): 3423, 3127, 2930, 1718,

5.1.8.9. (1-{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-

1H-imidazol-4-yl)acetic acid (9e). According to GP6: (1-{5-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-1H-imidazol-4-yl)

acetic acid methyl ester (38e) (24.5 mg, 0.049 mmol), CH₃OH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 20.7 mg

(88%); colourless solid, m.p. 95e100 ^ꢀC; IR (KBr): 3433, 3126, 3005,

2934, 2864, 2550, 1956, 1718, 1608, 1508, 1448, 1301, 1248, 1169,

1607, 1509, 1448, 1249, 1170, 1106, 1077, 1032 cm^ꢃ1

(CD₃OD):

;

¹H NMR

d

¼ 3.21 (t, J ¼ 4.8 Hz, 2 H, CH₂O), 3.65 (s, 2 H, CH₂COO),

3.72 (s, 3 H, CH₃), 4.19 (t, J ¼ 4.8 Hz, 2 H, NCH₂), 6.73e6.81 (m, 2 H,

H_ar), 7.00 (d, J ¼ 7.5 Hz, 2 H, H_ar), 7.11e7.15 (m, 2 H, H_ar), 7.17 (s, 1 H,

H

_[5H-Imid.]), 7.22 (td, J ¼ 7.5/1.0 Hz, 2 H, H_ar), 7.37 (td, J ¼ 7.5/1.0 Hz,

1101, 1078, 1032 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 1.29e1.39 (m, 2 H,

2 H, H_ar), 7.74 (d, J ¼ 7.5 Hz, 2 H, H_ar) 8.30 (s, 1 H, H_[2H-Imid.]); ¹³C

NCH₂CH₂CH₂), 1.51 (tt, J ¼ 7.0/6.1 Hz, 2 H, CH₂CH₂O), 1.69 (tt, J ¼ 7.4/

7.1 Hz, 2 H, NCH₂CH₂), 2.95 (t, J ¼ 6.1 Hz, 2 H, CH₂O), 3.65 (s, 2 H,

CH₂COO), 3.75 (s, 3 H, CH₃), 3.86 (t, J ¼ 7.1 Hz, 2 H, NCH₂), 6.74e6.80

(m, 3 H, H_ar, H_[5H-Imid.]), 7.19e7.29 (m, 6 H, H_ar), 7.32e7.41 (m, 2 H,

H_ar), 7.58 (s, 1 H, H_[2H-Imid.]), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar), 7.74 (s, 1 H,

NMR (CD₃OD):

d

¼ 34.30 (t, 1 C, CH₂COO), 49.17 (t, 1 C, NCH₂) 55.84

(t, 1 C, CH₂O), 63.73 (q, 1 C, CH₃), 90.13 (s, 1 C, CH₂OC), 114.72 (d, 2 C,

C_ar), 120.37 (d, 1 C, C_[5C-Imid.]), 121.32 (d, 2 C, C_ar), 126.35 (d, 2 C, C_ar),

127.95 (d, 2 C, C_ar), 129.57 (d, 2 C, C_ar), 130.61 (d, 2 C, C_ar), 133.91 (s,

1 C, C_[4C-Imid.]), 136.32 (s, 1 C, C_ar), 137.42 (s, 1 C, C_[2C-Imid.]), 142.19 (s,

2 C, C_ar), 147.95 (s, 2 C, C_ar), 160.63 (s, 1 C, C_ar), 174.65 (s, 1 C, COO);

MS (CI, CH^þ₅) m/z (%): 441 (12, [MþH]^þ), 411 (24), 362 (14), 271 (60),

236 (54), 200 (64), 171 (56), 128 (100); HRMS (EI, 70 eV):

NH^þ); ¹³C NMR (CDCl₃):

d

¼ 23.14 (t,1 C, NCH₂CH₂CH₂), 29.27 (t,1 C,

CH₂CH₂O), 30.44 (t, 1 C, NCH₂CH₂), 33.09 (t, 1 C, CH₂COO), 47.57 (t,

1 C, NCH₂), 55.20 (q, 1 C, CH₃), 62.52 (t, 1 C, CH₂O), 88.18 (s, 1 C,

CH₂OC), 113.48 (d, 2 C, C_ar), 116.57 (d, 1 C, C_[5C-Imid.]), 119.96 (d, 2 C,

C_ar), 125.08 (d, 2 C, C_ar), 126.69 (d, 2 C, C_ar), 128.08 (d, 2 C, C_ar),

128.93 (d, 2 C, C_ar), 134.25 (s, 1 C, C_[4C-Imid.]), 135.31 (d, 1 C, C_[2C-

_Imid.]),135.63 (s,1 C, C_ar),140.55 (s, 2 C, C_ar),147.40 (s, 2 C, C_ar),158.72

(s, 1 C, C_ar), 172.31 (s, 1 C, COO); MS (FAB, NBA) m/z (%): 483.4 (21,

[MþH]^þ), 438.4 (6), 271.3 (100); HRMS (EI, 70 eV): (C₃₀H₃₀N₂O₄)

calc. 482.2206, found 482.2214.

(C₂₇H₂₄N₂O₄) calc. 440.1736, found 440.1734; Anal. C₂₇H₂₄N₂O₄

2.25 H₂O (C, H, N, O).

x

5.1.8.7. (1-{3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-

1H-imidazol-4-yl)acetic acid (9c). According to GP6: (1-{3-[9-(4-

Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-1H-imidazol-4-yl)

acetic acid methyl ester (38c) (25.7 mg, 0.055 mmol), CH₃OH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 18.7 mg

(75%); colourless solid, m.p. 115e120 ^ꢀC; IR (KBr): 3422, 3134, 3005,

2931, 2872, 2835, 1868, 1844, 1829, 1792, 1717, 1608, 1508, 1449,

5.1.8.10. (1-{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]pro-

penyl}-1H-imidazol-4-yl) acetic acid (9f). According to GP6: (1-{1-

(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]-propenyl}-1H-imi-

dazol4-yl)acetic acid methyl ester (38f) (22.8 mg, 0.051 mmol),

CH₃OH (1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield:

20.8 mg (94%); colourless solid, m.p. 115e120 ^ꢀC. IR (KBr): 3431,

3036, 2937, 2853, 1718, 1606, 1508, 1447, 1382, 1297, 1249, 1179,

1301, 1248, 1169, 1104, 1081, 1032 cm^ꢃ1; ¹H NMR (CD₃OD):

d

¼ 1.98

(tt, J ¼ 6.5/5.8 Hz, 2 H, NCH₂CH₂), 2.96 (t, J ¼ 5.8 Hz, 2 H, CH₂O), 3.53

(s, 2 H, CH₂COO), 3.72 (s, 3 H, CH₃), 4.18 (t, J ¼ 6.5 Hz, 2 H, NCH₂),

6.75e6.80 (m, 2 H, H_ar), 7.12 (s, 1 H, H_[5H-Imid.]), 7.16e7.20 (m, 2 H,

H_ar), 7.21 (d, J ¼ 7.4 Hz, 2 H, H_ar), 7.26 (td, J ¼ 7.4/1.0 Hz, 2 H, H_ar),

7.37 (td, J ¼ 7.4/1.0 Hz, 2 H, H_ar), 7.73 (d, J ¼ 7.4 Hz, 2 H, H_ar), 8.14 (s,

1031 cm^ꢃ1; ¹H NMR (CD₃OD):

d

¼ 3.54 (s, 2 H, CH₂COO), 3.71 (s, 3 H,

CH₃), 4.64 (d, J ¼ 6.3 Hz, 2 H, NCH₂), 5.53 (dt, J ¼ 15.3/6.3 Hz, 1 H,

NCH₂CH), 6.55 (d, J ¼ 15.3 Hz, 1 H, CHC), 6.73e6.80 (m, 2 H, H_ar),

6.97e7.03 (m, 2 H, H_ar), 7.06 (s, 1 H, H_[5H-Imid.]), 7.19e7.29 (m, 4 H,

H_ar), 7.35 (td, J ¼ 7.5/1.5 Hz, 2 H, H_ar), 7.80 (d, J ¼ 7.5 Hz, 2 H, H_ar),

1 H, H_[2H-Imid.]); ¹³C NMR (CD₃OD):

d

¼ 31.09 (t,1 C, NCH₂CH₂), 34.09

(t, 1 C, CH₂COO), 47.01 (t, 1 C, NCH₂), 55.82 (q, 1 C, CH₃), 60.86 (t, 1 C,

CH₂O), 89.87 (s, 1 C, CH₂OC), 114.64 (d, 2 C, C_ar), 120.05 (d, 1 C, C_[5C-

_Imid.]), 121.33 (d, 2 C, C_ar), 126.39 (d, 2 C, C_ar), 127.96 (d, 2 C, C_ar),

129.42 (d, 2 C, C_ar), 130.52 (d, 2 C, C_ar), 133.63 (s, 1 C, C_[4C-Imid.]),

136.55 (d, 1 C, C_[2C-Imid.]), 136.70 (s, 1 C, C_ar), 142.21 (s, 2 C, C_ar),

148.51 (s, 2 C, C_ar), 160.57 (s, 1 C, C_ar), 174.66 (s, 1 C, COO); MS (ESIþ)

8.01 (s, 1 H, H_[2H-Imid.]); ¹³C NMR (CD₃OD):

d

¼ 32.85 (t, 1 C,

CH₂COO), 49.10 (t, 1 C, NCH₂), 54.32 (q, 1 C, CH₃), 60.96 (s, 1 C, CHC),

113.57 (d, 2 C, C_ar), 118.14 (d, 1 C, C_[5C-Imid.]), 120.07 (d, 2 C, C_ar),

122.67 (d, 1 C, NCH₂CH), 125.30 (d, 2 C, C_ar), 127.38 (d, 2 C, C_ar),

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

877

127.45 (d, 2 C, C_ar), 127.89 (d, 2 C, C_ar), 133.09 (s, 1 C, C_[4C-Imid.]),

135.23 (d, 1 C, C_[2C-Imid.]), 135.45 (s, 1 C, C_ar), 138.91 (d, 1 C, CHC),

139.99 (s, 2 C, C_ar), 149.75 (s, 2 C, C_ar), 158.77 (s, 1 C, C_ar), 173.47 (s,

1 C, COO); MS (ESIþ) m/z (%): 437.2 (84, [MþH]^þ), 311.2 (17), 203.3

(100); HRMS (ESIþ): (C₂₈H₂₅N₂O₃) calc. 437.1866, found 437.1872.

Anal. C₂₈H₂₄N₂O₃x 1.5H₂O (C, H, N, O).

(s, 1 C, C_[2C-Imid.]), 158.98 (s, 1 C, C_ar), 174.39 (s, 1 C, COO); MS (ESIþ)

m/z (%): 455.3 (58, [MþH]^þ), 271.1 (100); HRMS (FAB, NBA):

(C₂₈H₂₆N₂O₄) calc. 455.1971, found 455.1928; Anal. C₂₈H₂₆N₂O₄

H₂O (C, H, N, O).

x

5.1.8.14. 3-(1-{3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-

1H-imidazol-2-yl prop-anoic acid (11c). According to GP6: 3-(1-{3-

[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]propyl}-1H-imidazol-

2-yl) propanoic acid ethyl ester (39c) (29.0 mg, 0.058 mmol), EtOH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 20 mg

(73%); colourless solid, m.p. 125e127 ^ꢀC; IR (KBr): 2933, 1716, 1683,

5.1.8.11. 3-[1-(4,4-Diphenylbut-3-en-1-yl)-1H-imidazol-2-yl]prop-

anoic acid (44). According to GP6: 3-[1-(4,4-Diphenylbut-3-en-1-

yl)-1H-imidazol-2-yl]propanoic acid ethyl ester (42) (22.8 mg,

0.061 mmol), EtOH (1 mL), 2 M NaOH (80.0 mg, 2.00 mmol,

1.00 mL). Yield: 17.8 mg (85%); colourless solid, m.p. 105e110 ^ꢀC; IR

(KBr): 3431, 3048, 2924, 2500,1716,1597,1493,1443, 1213 cm^ꢃ1; ¹H

1608, 1508, 1302, 1249, 1169, 1103, 1074, 1033 cm^ꢃ1

;

¹H NMR

¼ 1.94 (m, 2 H, NCH₂CH₂), 2.61 (t, J ¼ 7.0 Hz, 2 H,

(CD₃OD):

d

NMR (CDCl₃):

d

¼ 2.54 (dt, J ¼ 7.7/7.2 Hz, 2 H, CH₂CH), 2.79 (s, 4 H,

CH₂CH₂COO), 2.96e3.05 (m, 4 H, CH₂O, CH₂CH₂COO), 3.72 (s, 3 H,

CH₃), 4.16 (t, J ¼ 7.1 Hz, 2 H, NCH₂), 6.75e6.81 (m, 2 H, H_ar), 7.04 (s,

1 H, H_[4H-Imid.]), 7.10 (s, 1 H, H_[5H-Imid.]), 7.17e7.21 (m, 2 H, H_ar), 7.22

(d, J ¼ 7.5 Hz, 2 H, H_ar), 7.26 (td, J ¼ 7.5/1.0 Hz, 2 H, H_ar), 7.38 (td,

J ¼ 7.5/1.0 Hz, 2 H, H_ar), 7.74 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR

CH₂CH₂COO), 4.08 (t, J ¼ 7.2 Hz, 2 H, NCH₂), 6.02 (t, J ¼ 7.7 Hz, 1 H,

CH), 6.81 (d, J ¼ 1.6 Hz, 1 H, H_[5H-Imid.]), 6.91e6.96 (m, 2 H, H_ar), 7.04

(d, J ¼ 1.6 Hz, 1 H, H_[4H-Imid.]), 7.13e7.18 (m, 2 H, H_ar), 7.21e7.28 (m,

3 H, H_ar), 7.30e7.39 (m, 3 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 21.01 (t, 1 C,

CH₂CH₂COO), 30.65 (t, 1 C, CH₂CH), 33.07 (t, 1 C, CH₂CH₂COO), 46.87

(t, 1 C, NCH₂), 120.49 (d, 1 C, C_[5C-Imid.]), 121.95 (d, 1 C, C_[4C-Imid.]),

122.43 (d, 1 C, CH), 127.23 (d, 2 C, C_ar), 127.82 (d, 1 C, C_ar), 127.87 (d,

1 C, C_ar), 128.50 (d, 2 C, C_ar), 128.81 (d, 2 C, C_ar), 129.43 (d, 2 C, C_ar),

139.10 (s, 1 C, C_ar), 141.36 (s, 1 C, C_ar), 146.29 (s, 1 C, CHC), 147.06 (s,

1 C, C_[2C-Imid.]),174.82 (s,1 C, COO); MS (FAB, NBA) m/z (%): 347.3 (60,

[MþH]^þ), 206.3 (8); HRMS (EI, 70 eV): (C₂₂H₂₂N₂O₂) calc. 346.1681,

found 346.1690.

(CD₃OD):

d

¼ 22.96 (t, 1 C, CH₂CH₂COO), 32.10 (t, 1 C, NCH₂CH₂),

34.98 (t, 1 C, CH₂CH₂COO), 45.26 (t, 1 C, NCH₂), 55.82 (q, 1 C, CH₃),

61.13 (t, 1 C, CH₂O), 89.92 (s, 1 C, CH₂OC), 114.69 (d, 2 C, C_ar), 121.34

(d, 2 C, C_ar), 121.92 (d, 1 C, C_[5C-Imid.]), 123.66 (d, 1 C, C_[4C-Imid.]),

126.41 (d, 2 C, C_ar), 127.98 (d, 2 C, C_ar), 129.42 (d, 2 C, C_ar), 130.52 (d,

2 C, C_ar), 136.67 (s, 1 C, C_ar), 142.22 (s, 2 C, C_ar), 148.56 (s, 2 C, C_ar),

149.04 (s, 1 C, C_[2C-Imid.]), 160.57 (s, 1 C, C_ar), 178.82 (s, 1 C, COO); MS

(ESIþ) m/z (%): 469.3 (100, [MþH]^þ); HRMS (ESIþ): (C₂₉H₂₉N₂O₄)

calc. 469.2127, found 469.2125.

5.1.8.12. 3-(1-{2-[1-(Tris-4-methoxyphenyl)methoxy]ethyl}-1H-imi-

dazol-2-yl)propanoic acid (45). According to GP6: 3-(1-{2-[1-(Tris-

4-methoxyphenyl)methoxy]ethyl}-1H-imidazol-2-yl)propanoic

acid ethyl ester (43) (27.1 mg, 0.050 mmol), EtOH (1 mL), 2 M NaOH

(80.0 mg, 2.00 mmol, 1.00 mL). Yield: 22 mg (86%); colourless solid,

m.p. 90e92 ^ꢀC; IR (KBr): 3433, 2932, 2836, 2547, 2035, 1717, 1607,

5.1.8.15. 3-(1-{4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-

1H-imidazol-2-yl)prop-anoic acid (11d). According to GP6: 3-(1-{4-

[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]butyl}-1H-imidazol-2-

yl) propanoic acid ethyl ester (39d) (49.0 mg, 0.097 mmol), EtOH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 36 mg

(80%); colourless solid, m.p. 95e98 ^ꢀC; IR (KBr): 3433, 3038, 2932,

2869, 1925, 1719, 1608, 1509, 1449, 1301, 1283, 1248, 1169, 1103,

1508, 1463, 1302, 1250, 1175, 1032 cm^ꢃ1

;

¹H NMR (CD₂Cl₂):

H,

d

¼

2.71e2.79 (m, H, CH₂CH₂COO), 2.90e2.98 (m, 2

2

CH₂CH₂COO), 3.32 (t, J ¼ 5.0 Hz, 2 H, CH₂O), 3.77 (s, 9 H, CH₃), 4.03

(t, J ¼ 5.0 Hz, 2 H, NCH₂), 6.76e6.82 (m, 6 H, H_ar), 6.97 (s, 1 H, H_[5H-

_Imid.]), 6.99 (s, 1H, H_[4H-Imid.]), 7.07e7.13 (m, 6 H, H_ar); ¹³C NMR

1078, 1032 cm^ꢃ1; ¹H NMR (CDCl₃):

d

¼ 1.49 (tt, J ¼ 7.4/6.2 Hz, 2 H,

CH₂CH₂O), 1.84 (tt, J ¼ 7.4/7.3 Hz, 2 H, NCH₂CH₂), 2.86 (t, J ¼ 6.2 Hz,

2 H, CH₂CH₂COO), 2.94e3.07 (m, 4 H, CH₂O, CH₂CH₂COO), 3.73 (s,

3 H, CH₃), 3.99 (t, J ¼ 7.3 Hz, 2 H, NCH₂), 6.74e6.79 (m, 2 H, H_ar), 6.88

(s, 1 H, H_[5H-Imid.]), 7.10 (s, 1 H, H_[4H-Imid.]), 7.19e7.29 (m, 6 H, H_ar),

7.33e7.40 (m, 2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar), 12.65 (s, 1 H,

(CD₂Cl₂):

d

¼ 19.84 (t, 1 C, CH₂CH₂COO), 31.68 (t, 1 C, CH₂CH₂COO),

44.80 (t, 1 C, NCH₂), 53.49 (q, 3 C, CH₃), 60.74 (t, 1 C, CH₂O), 84.66 (s,

1 C, OC), 111.41 (d, 6 C, C_ar), 119.04 (d, 1 C, C_[5C-Imid.]), 122.80 (d, 1 C,

C

_[4C-Imid.]), 127.78 (d, 6 C, C_ar), 134.19 (s, 3 C, C_ar), 146.25 (s, 1 C, C_[2C-

OH); ¹³C NMR (CDCl₃):

d

¼ 21.06 (t, 1 C, CH₂CH₂COO), 26.65 (t, 1 C,

_Imid.]), 156.91 (s, 3 C, C_ar), 171.96 (s, 1 C, COO); MS (FAB, NBA) m/z (%):

517.5 (24, [MþH]^þ), 333.4 (44), 307.3 (23); HRMS (FAB, NBA):

(C₃₀H₃₂N₂O₆) calc. 517.2339, found 517.2342.

CH₂CH₂O), 27.28 (t, 1 C, NCH₂CH₂), 32.88 (t, 1 C, CH₂CH₂COO), 46.70

(t, 1 C, NCH₂), 55.20 (q, 1 C, CH₃), 62.10 (t, 1 C, CH₂O), 88.28 (s, 1 C,

CH₂OC), 113.53 (d, 2 C, C_ar), 119.76 (d, 1 C, C_[5C-Imid.]), 120.05 (d, 2 C,

C_ar), 121.81 (d, 1 C, C_[4C-Imid.]), 125.05 (d, 2 C, C_ar), 126.69 (d, 2 C, C_ar),

128.20 (d, 2 C, C_ar), 129.07 (d, 2 C, C_ar), 135.32 (s, 1 C, C_ar), 140.55 (s,

2 C, C_ar), 146.80 (s, 1 C, C_[2C-Imid.]), 147.12 (s, 2 C, C_ar), 158.77 (s, 1 C,

C_ar), 174.72 (s, 1 C, COO); MS (FAB, NBA) m/z (%): 483.2 (100,

[MþH]^þ); HRMS (ESIþ): (C₃₀H₃₁N₂O₄) calc. 483.2284, found

483.2261.

5.1.8.13. 3-(1-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-

1H-imidazol-2-yl)propan-oic acid (11b). According to GP6: 3-(1-{2-

[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]ethyl}-1H-imidazol-2-

yl)propanoic acid ethyl ester (39b) (24.0 mg, 0.050 mmol), CH₃OH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 20 mg

(90%); colourless solid, m.p. 105e110 ^ꢀC; IR (KBr): 2925, 1717, 1608,

1509, 1449, 1249, 1169, 1105, 1083, 1031 cm^ꢃ1

;

¹H NMR (CDCl₃):

H,

5.1.8.16. 3-(1-{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-

1H-imidazol-2-yl)prop-anoic acid (11e). According to GP6: 3-(1-{5-

[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-1H-imidazol-

2-yl)propanoic acid ethyl ester (39e) (25.0 mg, 0.048 mmol), EtOH

(1 mL), 2 M NaOH (80.0 mg, 2.00 mmol, 1.00 mL). Yield: 20 mg

(83%); colourless solid, m.p. 87e90 ^ꢀC; IR (KBr): 3005, 2932, 2865,

2501, 1953, 1718, 1608, 1509, 1449, 1249, 1169, 1079, 1033 cm^ꢃ1; ¹H

d

¼

2.73e2.79 (m, H, CH₂CH₂COO), 2.79e2.86 (m, 2

2

CH₂CH₂COO), 3.19 (t, J ¼ 4.8 Hz, 2 H, CH₂O), 3.74 (s, 3 H, CH₃), 4.08 (t,

J ¼ 4.8 Hz, 2 H, NCH₂), 6.75 (d, J ¼ 8.8 Hz, 2 H, H_ar), 6.89 (s, 1 H, H_[4H-

_Imid.]or H_[5H-Imid.]), 6.96 (d, J ¼ 7.5 Hz, 2 H, H_ar), 7.05 (s,1 H, H_[4H-Imid.]

or H_[5H-Imid.]), 7.12 (d, J ¼ 8.8 Hz, 2 H, H_ar), 7.21 (t, J ¼ 7.5 Hz, 2 H, H_ar),

7.36 (t, J ¼ 7.5 Hz, 2 H, H_ar), 7.65 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR

(CDCl₃):

d

¼ 21.07 (t, 1 C, CH₂CH₂COO), 33.17 (t, 1 C, CH₂CH₂COO),

NMR (CDCl₃):

d

¼ 1.32e1.44 (m, 2 H, NCH₂CH₂CH₂), 1.52 (tt, J ¼ 7.2/

47.03 (t, 1 C, NCH₂), 55.23 (q, 1 C, CH₃), 61.92 (t, 1 C, CH₂O), 88.79 (s,

6.3 Hz, 2 H, CH₂CH₂O), 1.67 (tt, J ¼ 7.5/7.4 Hz, 2 H, NCH₂CH₂), 2.84

(m, 2 H, CH₂CH₂COO), 2.97 (m, 4 H, CH₂CH₂COO, CH₂O), 3.74 (s, 3 H,

CH₃), 3.87 (t, J ¼ 7.4 Hz, 2 H, NCH₂), 6.78 (m, 2 H, H_ar), 6.79 (s, 1 H,

1 C, CH₂OC), 113.66 (d, 2 C, C_ar), 120.15 (d, 2 C, C_ar), 120.87 (d, 1 C,

C

_[4C-Imid.]or C_[5C-Imid.]), 122.52 (d, 1 C, C_[4C-Imid.]or C_[5C-Imid.]), 124.84

(d, 2 C, C_ar), 126.56 (d, 2 C, C_ar), 128.50 (d, 2 C, C_ar), 129.46 (d, 2 C,

C_ar), 134.23 (s, 1 C, C_ar), 140.51 (s, 2 C, C_ar), 146.07 (s, 2 C, C_ar), 147.58

H_[5H-Imid.]), 6.99 (s, 1 H, H_[4H-Imid.]), 7.20e7.29 (m, 6 H, H_ar),

7.33e7.40 (m, 2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR

878

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

(CDCl₃):

d

¼ 21.45 (t, 1 C, CH₂CH₂COO), 23.25 (t, 1 C, NCH₂CH₂CH₂),

ester (39h) (23.0 mg, 0.045 mmol), EtOH (1 mL), 2 M NaOH

(80.0 mg, 2.00 mmol, 1.00 mL). Yield: 17.7 mg (82%); colourless

solid, m.p. 92e95 ^ꢀC; IR (KBr): 3448, 3005, 2927, 2854, 2486, 1924,

29.35 (t, 1 C, CH₂CH₂O), 30.25 (t, 1 C, NCH₂CH₂), 33.07 (t, 1 C,

CH₂CH₂COO), 46.34 (t, 1 C, NCH₂), 55.20 (q, 1 C, CH₃), 62.50 (t, 1 C,

CH₂O), 88.19 (s, 1 C, CH₂OC), 113.48 (d, 2 C, C_ar), 119.52 (d, 1C, C_[5C-

_Imid.]), 119.98 (d, 2C, C_ar), 123.80 (d, 1C, C_[4C-Imid.]), 125.07 (d, 2 C, C_ar),

126.70 (d, 2 C, C_ar), 128.10 (d, 2 C, C_ar), 128.95 (d, 2 C, C_ar), 135.63 (s,

1 C, C_ar), 140.56 (s, 2 C, C_ar), 146.86 (s, 1 C, C_[2C-Imid.]), 147.39 (s, 2 C,

C_ar), 158.72 (s, 1 C, C_ar), 174.71 (s, 1 C, COO); MS (ESIþ) m/z (%): 993.6

(9), 519.3 (6, [MþNa]^þ), 497.1 (76, [MþH]^þ), 271.0 (100); HRMS

(ESIþ): (C₃₁H₃₃N₂O₄) calc. 497.2440, found 497.2438.

1718, 1608, 1509, 1449, 1249, 1169, 1104, 1032 cm^ꢃ^{1 1}H NMR

;

(CDCl₃):

d

¼ 2.79e2.85 (m, 2 H, CH₂CH₂COO), 2.91e2.98 (m, 2 H,

CH₂CH₂COO), 3.54 (d, J ¼ 5.0 Hz, 2 H, CH₂O), 3.74 (s, 3 H, CH₃), 4.48

(d, J ¼ 5.7 Hz, 2 H, NCH₂), 5.51 (dt, J ¼ 15.5/5.0 Hz, 1 H, CHCH₂O),

5.77 (dt, J ¼ 15.5/5.7 Hz, 1 H, NCH₂CH), 6.74e6.79 (m, 2 H, H_ar), 6.79

(s, 1 H, H_[5H-Imid.]), 6.98 (s, 1 H, H_[4H-Imid.]), 7.21e7.31 (m, 6 H, H_ar),

7.34e7.40 (m, 2 H, H_ar), 7.67 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR

(CDCl₃):

d

¼ 21.46 (t, 1 C, CH₂CH₂COO), 32.99 (t, 1 C, CH₂CH₂COO),

5.1.8.17. 3-(1-{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]pro-

penyl}-1H-imidazol-2-yl)propanoic acid (11f). According to GP6: 3-

(1-{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]propenyl}-1H-

imidazol-2-yl) propanoic acid ethyl ester (39f) (29.0 mg,

0.061 mmol), EtOH (1 mL), 2 M NaOH (80.0 mg, 2.00 mmol,

1.00 mL). Yield: 24.5 mg (90%); colourless solid, m.p. 115e120 ^ꢀC; IR

(KBr): 3035, 3003,2930, 2835, 2484,1920, 1717, 1606, 1508, 1447,

47.77 (t, 1 C, NCH₂), 55.20 (q, 1 C, CH₃), 62.90 (t, 1 C, CH₂O), 88.50 (s,

1 C, CH₂OC), 113.55 (d, 2 C, C_ar), 119.78 (d, 1 C, C_[5C-Imid.]), 120.02 (d,

2 C, C_ar), 124.12 (d, 1 C, C_[4C-Imid.]or NCH₂CH), 124.22 (d, 1 C, C_[4C-

_Imid.]or NCH₂CH), 125.20 (d, 2 C, C_ar), 126.74 (d, 2 C, C_ar), 128.24 (d,

2 C, C_ar), 129.17 (d, 2 C, C_ar), 131.99 (d, 1 C, CHCH₂O), 135.11 (s, 1 C,

C_ar), 140.56 (s, 2 C, C_ar), 146.87 (s, 2 C, C_ar), 147.09 (s, 1 C, C_[2C-Imid.]),

158.81 (s, 1 C, C_ar), 174.54 (s, 1 C, COO); MS (ESIþ) m/z (%): 961.5 (7),

495.2 (22, [MþNa]^þ), 481.1 (100, [MþH]^þ), 271.0 (100); HRMS (EI,

70 eV): (C₃₀H₂₈N₂O₄) calc. 480.2049, found 480.2042.

1249, 1178, 1118, 1031 cm^ꢃ1

;

¹H NMR (CDCl₃):

d

¼ 2.69e2.77 (m,

2 H, CH₂CH₂COO), 2.80e2.87 (m, 2 H, CH₂CH₂COO), 3.74 (s, 3 H,

CH₃), 4.49 (d, J ¼ 5.7 Hz, 2 H, NCH₂), 5.42 (dt, J ¼ 15.4/5.7 Hz, 1 H,

NCH₂CH), 6.26 (d, J ¼ 15.4 Hz, 1 H, CHC), 6.73e6.80 (m, 3 H, H_ar,

5.1.8.20. 3-(1-{(2Z)-4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]

H_[5H-Imid.]), 6.96 (s, 1 H, H_[4H-Imid.]), 6.97e7.03 (m, 2 H, H_ar), 7.20 (d,

but-2-en-1-yl}-1H-imidazol-2-yl)propanoic

acid

(11i).

J ¼ 7.4 Hz, 2 H, H_ar), 7.28 (td, J ¼ 7.4/1.1 Hz, 2 H, H_ar), 7.37 (td, J ¼ 7.4/

According to GP6: 3-(1-{(2Z)-4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-

9-yloxy]but-2-en-1-yl}-1H-imidazol-2-yl)propanoic acid ethyl

ester (39i) (22.3 mg, 0.044 mmol), EtOH (1 mL), 2 M NaOH

(80.0 mg, 2.00 mmol, 1.00 mL). Yield: 15.4 mg (73%); colourless

solid, m.p. 75e77 ^ꢀC; IR (KBr): 3143, 3006, 2918, 2849, 1955, 1720,

1.1 Hz, 2 H, H_ar), 7.76 (d, J ¼ 7.4 Hz, 2 H, H_ar); ¹³C NMR (CDCl₃):

d

¼ 21.40 (t, 1 C, CH₂CH₂COO), 32.94 (t, 1 C, CH₂CH₂COO), 48.04 (t,

1 C, NCH₂), 55.24 (q, 1 C, CH₃), 61.00 (s, 1 C, CHC), 114.01 (d, 2 C, C_ar),

119.74 (d, 1 C, C_[5C-Imid.]), 120.53 (d, 2 C, C_ar), 121.88 (d, 1 C, NCH₂CH),

124.21 (d, 1 C, C_[4C-Imid.]), 125.23 (d, 2 C, C_ar), 127.80 (d, 2 C, C_ar),

127.82 (d, 2 C, C_ar), 128.01 (d, 2 C, C_ar), 135.00 (s, 1 C, C_ar), 138.51 (d,

1 C, CHC), 139.84 (s, 2 C, C_ar), 147.22 (s, 1 C, C_[2C-Imid.]), 149.36 (s, 2 C,

C_ar), 158.60 (s, 1 C, C_ar), 174.37 (s, 1 C, COO); MS (ESIþ) m/z (%): 451.3

(100, [MþH]^þ); HRMS (EI, 70 eV): (C₂₉H₂₆N₂O₃) calc. 450.1944,

found 450.1929; Anal. C₂₉H₂₆N₂O₃x 1.5H₂O (C, H, N, O).

1606, 1509, 1249, 1169, 1058, 1032 cm^ꢃ1

;

¹H NMR (CD₂Cl₂):

H, CH₂CH₂COO), 2.86e2.93 (m, H,

d

¼

2.78e2.83 (m,

2

CH₂CH₂COO), 3.65 (dd, J ¼ 6.2/1.5 Hz, 2 H, CH₂O), 3.73 (s, 3 H, CH₃),

4.46 (dd, J ¼ 6.8/1.5 Hz, 2 H, NCH₂), 5.50 (dtt, J ¼ 11.0/6.8/1.5 Hz, 1 H,

NCH₂CH), 5.84 (dtt, J ¼ 11.0/6.2/1.5 Hz, 1 H, CHCH₂O), 6.73e6.79 (m,

2 H, H_ar), 6.82 (d, J ¼ 1.4 Hz, 1 H, H_[5H-Imid.]), 7.01 (d, J ¼ 1.4 Hz, 1 H,

H

_[4H-Imid.]), 7.21e7.25 (m, 2 H, H_ar), 7.26e7.31 (m, 4 H, H_ar),

5.1.8.18. 3-[1-(2-{1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yl]pro-

7.37e7.44 (m, 2 H, H_ar), 7.73 (dt, J ¼ 7.6/0.8 Hz, 2 H, H_ar); ¹³C NMR

penyloxy}ethyl)-1H-imidazol-2-yl]propanoic

According to GP6: 3-[1-(2-{(1E)-3-[9-(4-Methoxyphenyl)-9H-ﬂuo-

ren-9-yl]propenyloxy}ethyl)-1H-imidazol-2-yl]-propanoic acid

acid

(11g).

(CD₂Cl₂):

d

¼ 19.28 (t, 1 C, CH₂CH₂COO), 30.86 (t, 1 C, CH₂CH₂COO),

42.22 (t, 1 C, NCH₂), 53.46 (q, 1 C, CH₃), 57.72 (t, 1 C, CH₂O), 87.05 (s,

1 C, CH₂OC), 111.78 (d, 2 C, C_ar), 118.04 (d, 1 C, C_[5C-Imid.]), 118.52 (d,

2 C, C_ar),120.52 (d,1 C, C_[4C-Imid.]),122.78 (d,1 C, NCH₂CH),123.38 (d,

2 C, C_ar), 124.95 (d, 2 C, C_ar), 126.56 (d, 2 C, C_ar), 127.61 (d, 2 C, C_ar),

130.45 (d,1 C, CHCH₂O),133.19 (s, 1 C, C_ar),138.94 (s, 2 C, C_ar),144.99

(s, 2 C, C_ar), 145.26 (s, 1 C, C_[2C-Imid.]), 157.31 (s, 1 C, C_ar), 171.76 (s, 1 C,

COO); MS (ESIþ) m/z (%): 961.6 (6), 481.3 (100, [MþH]^þ); HRMS

(ESIþ): (C₃₀H₂₉N₂O₄) calc. 481.2127, found 481.2117.

ethyl ester (39g) (22.2 mg, 0.046 mmol), EtOH (1 mL), 2 M NaOH

(16 mg, 0.40 mmol, 0.20 mL). Yield: 18.4 mg (88%); colourless solid,

m.p. 110e113 ^ꢀC; IR (KBr): 3036, 2931, 2858, 2485, 1917, 1711, 1606,

1507, 1447, 1354, 1246, 1177, 1117, 1029 cm^ꢃ1

;

¹H NMR (CD₂Cl₂):

d

¼

2.67e2.74 (m, 2 H, CH₂CH₂COO), 2.90e2.95 (m, 2 H,

CH₂CH₂COO), 3.59 (t_br, J ¼ 5.1 Hz, 2 H, NCH₂CH₂), 3.73 (s, 3 H, CH₃),

3.91 (dd, J ¼ 5.7/1.3 Hz, 2 H, CH₂CH), 4.00 (t, J ¼ 5.1 Hz, 2 H, NCH₂),

5.38 (dt, J ¼ 15.5/5.7 Hz, 1 H, CH₂CH), 6.36 (d, J ¼ 15.5 Hz, 1 H, CHC),

6.74e6.79 (m, 2 H, H_ar), 6.86 (s, 1 H, H_[5H-Imid.]), 6.89 (s, 1 H, H_[4H-

_Imid.]), 6.99e7.04 (m, 2 H, H_ar), 7.22 (d, J ¼ 7.5 Hz, 2 H, H_ar), 7.29 (td,

J ¼ 7.5/1.1 Hz, 2 H, H_ar), 7.37 (td, J ¼ 7.5/1.1 Hz, 2 H, H_ar), 7.79 (d,

5.1.8.21. 3-[1-(2-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]

ethoxy}ethyl)-1H-imidazol-2-yl]propanoic acid (11j). According to

GP6:

3-[1-(2-{2-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]

ethoxy}-ethyl)-1H-imidazol-2-yl] propanoic acid ethyl ester (39j)

(20.0 mg, 0.038 mmol), EtOH (1 mL), 2 M NaOH (16 mg, 0.40 mmol,

0.20 mL). Yield: 14.8 mg (78%); colourless solid, m.p. 93e97 ^ꢀC; IR

(KBr): 3349, 3061, 2927, 2869, 2501, 1953, 1710, 1607, 1508, 1448,

J ¼ 7.5 Hz, 2 H, H_ar); ¹³C NMR (CD₂Cl₂):

d

¼ 21.90 (t, 1 C,

CH₂CH₂COO), 33.68 (t, 1 C, CH₂CH₂COO), 46.70 (t, 1 C, NCH₂), 55.60

(q, 1 C, CH₃), 61.44 (s, 1 C, CHC), 69.28 (t, 1 C, NCH₂CH₂), 71.67 (t, 1 C,

CH₂CH), 114.16 (d, 2 C, C_ar), 120.44 (d, 1 C, C_[5C-Imid.]), 120.78 (d, 2 C,

C_ar), 124.72 (d, 1 C, C_[4C-Imid.]), 125.11 (d, 1 C, CH₂CH), 125.79 (d, 2 C,

C_ar), 127.95 (d, 2 C, C_ar), 128.00 (d, 2 C, C_ar), 128.48 (d, 2 C, C_ar),136.12

(s, 1 C, C_ar), 136.49 (d, 1 C, CHC), 140.26 (s, 2 C, C_ar), 148.52 (s, 1 C,

1247, 1168, 1099, 1078, 1030 cm^ꢃ1; ¹H NMR (CD₂Cl₂):

d

¼ 2.71e2.76

(m, 2 H, CH₂CH₂COO), 2.94e2.99 (m, 2 H, CH₂CH₂COO), 3.08 (t,

J ¼ 4.8 Hz, 2 H, CH₂OC), 3.49 (t, J ¼ 4.8 Hz, 2 H, CH₂CH₂OC), 3.69 (t,

J ¼ 5.0 Hz, 2 H, NCH₂CH₂), 3.74 (s, 3 H, CH₃), 4.04 (t, J ¼ 5.0 Hz, 2 H,

NCH₂), 6.75e6.79 (m, 2 H, H_ar), 6.93 (s, 1 H, H_[4H-Imid.]), 6.99 (s, 1H,

C

_[2C-Imid.]), 150.43 (s, 2 C, C_ar), 158.99 (s, 1 C, C_ar), 174.25 (s, 1 C, COO);

MS (FAB, NBA) m/z (%): 495.4 (9, [MþH]^þ); HRMS (ESIþ):

H

_[5H-Imid.]), 7.18e7.23 (m, 4 H, H_ar), 7.27 (td, J ¼ 7.5/1.1 Hz, 2 H, H_ar),

(C₃₁H₃₁N₂O₄) calc. 495.2284, found 495.2276.

7.39 (td, J ¼ 7.5/1.1 Hz, 2 H, H_ar), 7.70 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³C

NMR (CD₂Cl₂):

d

¼ 21.97 (t, 1 C, CH₂CH₂COO), 33.77 (t, 1 C,

5.1.8.19. 3-(1-{(2E)-4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]

CH₂CH₂COO), 46.78 (t, 1 C, NCH₂), 55.59 (q, 1 C, CH₃), 63.27 (t, 1 C,

CH₂OC), 70.40 (t, 1 C, NCH₂CH₂), 71.23 (t, 1 C, CH₂CH₂OC), 88.82 (s,

1 C, CH₂OC), 113.83 (d, 2 C, C_ar), 120.50 (d, 2 C, C_ar), 120.69 (d, 1 C,

but-2-en-1-yl}-1H-imidazol-2-yl)propanoic

acid

(11h).

According to GP6: 3-(1-{(2E)-4-[9-(4-Methoxyphenyl)-9H-ﬂuoren-

9-yloxy]but-2-en-1-yl}-1H-imidazol-2-yl)propanoic acid ethyl

C_[5C-Imid.]), 124.74 (d,1 C, C_[4C-Imid.]), 125.51 (d, 2 C, C_ar), 127.10 (d, 2 C,

S. Kerscher-Hack et al. / European Journal of Medicinal Chemistry 124 (2016) 852e880

Epilepsia 51 (2010) 1483e1492.

879

C_ar), 128.54 (d, 2 C, C_ar), 129.53 (d, 2 C, C_ar), 135.72 (s, 1 C, C_ar), 141.02

(s, 2 C, C_ar), 147.43 (s, 2 C, C_ar), 148.54 (s, 1 C, C_[2C-Imid.]), 159.37 (s, 1 C,

C_ar), 174.22 (s, 1 C, COO); MS (FAB, NBA) m/z (%): 499.3 (36,

[MþH]^þ), 271.2 (55); HRMS (ESIþ): (C₃₀H₃₁N₂O₅) calc. 499.2233,

found 499.2225. Anal. C₃₀H₃₀N₂O₅x 1.75H₂O (C, H, N, O).

[7] D.A. Richards, N.G. Bowery, Comaprative effects of the GABA uptake inhibitors,

tiagabine and NNC-711, on extracellular GABA levels in the rat ventrolateral

thalamus, Neurochem. Res. 21 (1996) 135e140.

[8] A. Scimemi, Structure, function, and plasticity of GABA transporters, Front. Cell

Neurosci. 8 (2014) 161/1e161/14.

[9] P. Kowalczyk, K. Kulig, GABA system as a target for new drugs, Curr. Med.

Chem. 21 (2014) 3294e3309.

ꢀ

[10] Q.-R. Liu, B. Lopez-Corcuera, S. Mandiyan, H. Nelson, N. Nelson, Molecular

5.1.8.22. 3-(1-{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-

1H-imidazol-2-yl)prop-2-enoic acid (12e). According to GP6: 3-(1-

{5-[9-(4-Methoxyphenyl)-9H-ﬂuoren-9-yloxy]pentyl}-1H-imida-

zol-2-yl)prop-2-enoic acid ethyl ester (46e) (27.0 mg, 0.052 mmol),

EtOH (2 mL), 2 M NaOH (160 mg, 4.00 mmol, 2.00 mL). Yield:

19.6 mg (77%); colourless solid, m.p. 143e145 ^ꢀC; IR (KBr): 3434,

2936, 2857, 2427, 1895, 1701, 1636, 1608, 1509, 1449, 1301, 1289,

characterization of four pharmacologically distinct

transporters in mouse brain, J. Biol. Chem. 268 (1993) 2106e2112.

[11] B. Christiansen, A.-K. Meinilid, A.A. Jensen, H. Brauner-Osborne, Cloning and

a -aminobutyric acid

€

characterization of a functional human

g -Aminobutyric acid (GABA) trans-

porter, Human GAT-2, J. Biol. Chem. 282 (2007) 19331e19341.

[12] K.K. Madsen, H.S. White, A. Schousboe, Neuronal and non-neuronal GABA

transporters as targets for antiepileptic drugs, Pharmacol. Ther. 125 (2010)

394e401.

1247, 1170, 1132, 1100, 1079, 1035 cm^ꢃ1

;

¹H NMR (CDCl₃):

[13] N.O. Dalby, Inhibition of

g -aminobutyric acid uptake: anatomy, physiology

and effects against epileptic seizures, Eur. J. Pharmacol. 479 (2003) 127e137.

[14] A. Minelli, S. DeBiasi, N.C. Brecha, L.V. Zuccarello, F. Conti, GAT-3, a high-

af ﬁ nity GABA plasma membrane transporter, is localized to astrocytic pro-

cesses, and it is not con ﬁ ned to the vicinity of GABAergic synapses in the

cerebral cortex, J. Neurosci. 16 (1996) 6255e6264.

[15] Y. Zhou, S. Holmseth, R. Hua, A.C. Lehre, A.M. Olofsson, I. Poblete-Naredo,

S.A. Kempson, N.C. Danbolt, The Betaine-GABA transporter (BGT1, slc6a12) is

predominantly expressed in the liver and at the lower levels in the kidneys

and at the brain surface, Am. J. Physiol. Ren. Physiol. 302 (2012) F316eF328.

d

¼ 1.32e1.42 (m, 2 H, NCH₂CH₂CH₂), 1.52 (tt, J ¼ 7.5/6.1 Hz, 2 H,

CH₂CH₂O), 1.70 (tt, J ¼ 7.6/7.4 Hz, 2 H, NCH₂CH₂), 2.95 (t, J ¼ 6.1 Hz,

2 H, CH₂O), 3.74 (s, 3 H, CH₃), 4.01 (t, J ¼ 7.4 Hz, 2 H, NCH₂),

6.74e6.80 (m, 2 H, H_ar), 6.95 (s, 1 H, H_[5H-Imid.]), 7.00 (d, J ¼ 15.5 Hz,

1 H, CHCOO), 7.21e7.28 (m, 6 H, H_ar), 7.35 (m, 3 H, H_ar, H_[4H-Imid.]),

7.51 (d, J ¼ 15.5 Hz, 1 H, CHCHCOO), 7.66 (d, J ¼ 7.5 Hz, 2 H, H_ar); ¹³

C

NMR (CDCl₃):

d

¼ 23.29 (t, 1 C, NCH₂CH₂CH₂), 29.37 (t, 1 C,

€

[16] Y. Zhou, S. Holmseth, C. Guo, B. Hassel, G. Hofner, H.S. Huitfeldt, K.T. Wanner,

CH₂CH₂O), 30.98 (t, 1 C, NCH₂CH₂), 46.47 (t, 1 C, NCH₂), 55.20 (q, 1 C,

CH₃), 62.52 (t, 1 C, CH₂O), 88.20 (s, 1 C, CH₂OC), 113.50 (d, 2 C, C_ar),

119.93 (d, 2 C, C_ar), 121.96 (d, 1 C, C_[5C-Imid.]), 123.58 (d, 1 C, CHCOO),

125.13 (d, 2 C, C_ar), 126.73 (d, 2 C, C_ar), 127.09 (d, 1 C, CHCHCOO),

128.12 (d, 2 C, C_ar), 128.92 (d, 1 C, C_[4C-Imid.], d, 2 C, C_ar), 135.69 (s, 1 C,

C_ar), 140.56 (s, 2 C, C_ar), 142.23 (s, 1 C, C_[2C-Imid.]), 147.43 (s, 2 C, C_ar),

158.71 (s, 1 C, C_ar), 169.43 (s, 1 C, COO); MS (ESIþ) m/z (%): 989.5

(11), 517.2 (96, [MþNa]^þ), 495.2 (100, [MþH]^þ); HRMS (ESIþ):

(C₃₁H₃₁N₂O₄) calc. 495.2284, found 495.2274.

N.C. Danbolt, Deletion of the

SLC6A 13) gene in mice leads to changes in liver and brain taurine contents,

J. Biol. Chem. 287 (2012) 35733e35746.

g -aminobutyric acid transporter 2 (GAT2 and

[17] S. Hog, J.R. Greenwood, K.B. Madsen, O.M. Larsson, B. Frolund, A. Schousboe,

P. Krogsgaard-Larsen, R.P. Clausen, Structure-activity relationships of selective

GABA uptake inhibitors, Curr. Top. Med. Chem. 6 (2006) 1861e1882.

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J.A. Jansen, K. Frederiksen, P.H. Andersen, A. Mortensen, P.D. Suzdak, (R )-N-

[4,4-Bis( 3-Methyl-2-Thienyl)but-3-en-1-yl]Nipecotic acid binds with high

af ﬁ nity to the brain y-Aminobutyric acid uptake carrier, J. Neurochem. 54

(1990) 639e647.

[19] F.E. Ali, W.E. Bondinell, P.A. Dandridge, J.S. Frazee, E. Garvey, G.R. Girard,

C. Kaiser, T.W. Ku, J.J. Lafferty, G.I. Moonsammy, H.-J. Oh, J.A. Rush, P.E. Setler,

O.D. Stringer, J.W. Venslavsky, B.W. Volpe, L.M. Yunger, C.L. Zirkle, Orally

active and potent inhibitors of y-aminobutyric acid uptake, J. Med. Chem. 28

(1985) 653e660.

5.2. Pharmacological methods

5.2.1. GABA uptake assays

[20] K.E. Andersen, C. Braestrup, F.C. Groenwald, A.S. Joergensen, E.B. Nielsen,

U. Sonnewald, P.O. Soerensen, P.D. Suzdak, L.J.S. Knutsen, The synthesis of

novel GABA uptake inhibitors. 1.Elucidation of the structure-activity studies

leading to the choice of (R )-1-[4,4-Bis(3-methyl-2-thienyl)-3-butenyl]-3-

piperidinecarboxylic acid (tiagabine) as an anticonvulsant drug candidate,

J. Med. Chem. 36 (1993) 1716e1725.

[³H]GABA uptake assays with mGAT1, mGAT2, mGAT3, and

mGAT4 expressing HEK293 cells were performed as described

earlier [47].

[21] T.G.M. Dhar, L.A. Borden, S. Tyagarajan, K.E. Smith, T.A. Branchek,

R.L. Weinshank, C. Gluchowski, Design, synthesis and evaluation of

substituted triarylnipecotic acid derivatives as GABA uptake inhibitors:

identi ﬁ cation of a ligand with moderate af ﬁ nity and selectivity for the cloned

human GABA transporter GAT-3, J. Med. Chem. 37 (1994) 2334e2342.

[22] E.B. Nielsen, P.D. Suzdak, K.E. Andersen, L.J.S. Knutsen, U. Sonnewald,

C. Braestrup, Characterization of tiagabine (NO-328), a new and potent and

selective GABA inhibitor, Eur. J. Pharmacol. 196 (1991) 257e266.

Acknowledgements

€

We would like to thank Dr. Jorg Pabel for discussion and sug-

gestions. Our acknowledgements go to Katharina Heimberger for

proof reading and editorial assistance.

€

[23] T. Steffan, T. Renukappa-Gutke, G. Hofner, K.T. Wanner, Design, synthesis and

Appendix A. Supplementary data

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Synthesis and biological evaluation of a series of N-alkylated imidazole alkanoic acids as mGAT3 selective GABA uptake inhibitors

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