Synthesis and pharmacological in vitro and in vivo evaluations of novel triazole derivatives as ligands of the ghrelin receptor. 1

J. Med. Chem. 2007, 50, 1939-1957

1939

Synthesis and Pharmacological in Vitro and in Vivo Evaluations of Novel Triazole Derivatives

as Ligands of the Ghrelin Receptor. 1

Luc Demange,^†Damien Boeglin,^†Aline Moulin,^†Delphine Mousseaux,^†Joanne Ryan,^†Gilbert Berge´,^†Didier Gagne,^†

Annie Heitz,^‡Daniel Perrissoud,^§Vittorio Locatelli, Antonio Torsello, Jean-Claude Galleyrand,^†Jean-Alain Fehrentz,*^,†,#and

Jean Martinez^†,#

Institut des Biomole´cules Max Mousseron, UMR 5247, CNRSsUniVersite´s Montpellier I et II, BP. 14491, Faculte´ de Pharmacie, 15 aVenue

Charles Flahault, 34093 Montpellier Cedex 5, France, CBS, UMR 5048, 29 rue de NaVacelles 34090 Montpellier, France, Zentaris GmbH,

Weismuellerstrasse 50, 60314 Frankfurt am Main, Germany, and Department of Experimental Medicine, School of Medicine, UniVersity of

Milano-Bicocca, Via Cadore 48, 20052 Monza (MI), Italy

ReceiVed January 9, 2007

A new series of growth hormone secretagogue (GHS) analogues based on the 1,2,4-triazole structure were

synthesized and evaluated for their in vitro binding and their ability to stimulate intracellular calcium release

to the cloned hGHS-1a ghrelin receptor expressed in LLC PK-1 cells. We have synthesized potent ligands

of this receptor, some of them behaving as agonists, partial agonists, or antagonists. Some compounds among

the most potent, i.e., agonist 29c (JMV2873), partial agonists including 21b (JMV2810), antagonists 19b

(JMV2866) and 19c (JMV2844), were evaluated for their in vivo activity on food intake, after sc injection

in rodents. Some compounds were found to stimulate food intake like hexarelin; some others were identified

as potent hexarelin antagonists in this assay. Among the tested compounds, 21b was identified as an in

vitro ghrelin receptor partial agonist, as well as a potent in vivo antagonist of hexarelin-stimulated food

intake in rodents. Compound 21b was without effect on GH release from rat. However, in this series of

compounds, it was not possible to find a clear correlation between in vitro and in vivo results.

Introduction

we recently described a new potent growth hormone secreta-

gogue, namely, JMV1843¹⁴(EP-1572),¹⁵which is orally active

in humans. As JMV1843 is a peptide derivative, we wanted to

limit the inherent flexibilities of the peptide backbone and side

chains. For this purpose we decided to introduce a cyclic

structure as scaffold bearing the three major pharmacophores

contained in JMV1843: a basic amino group (in our case

included in an amino-isobutyric acid residue) and two hydro-

phobic regions (indole rings). Several cyclic scaffolds were

tested such as piperazines, keto-piperazines, piperidines, and

triazinones (unpublished results). 1,2,4-Triazoles were found to

be the best templates. In this paper, we report on the identifica-

tion of a new series of potent nonpeptide analogues that acted

as ghrelin receptor ligands and exhibited agonist, partial agonist,

or antagonist properties.

1,2,4-Triazoles have gained considerable interest among

medicinal chemists because they display a wide range of

antifungal¹⁶and antibacterial¹⁷activities. This moiety was also

found in a series of potent agonist or antagonist G-protein

coupled receptor ligands.^18-211,2,4-Triazole derivatives have

been used as mimics^20-23or isosteres^24,25of the amide bond in

an attempt to increase the bioavailability of the parent bioactive

molecules. They have also been incorporated into peptides to

surrogate cis amide bonds.²⁶

Growth hormone (GH) is an important endocrine regulator

of growth and anabolic processes.¹The use of recombinant

human GH is beneficial in the treatment of GH-deficient

children²and has been shown to reverse some of the effects of

aging in the elderly.³In recent years, the GH releasing peptides

(GHRPs) and peptidomimetics have received considerable

attention as potential alternatives to the expensive recombinant

human GH. During their studies on enkephalin analogues

Bowers et al. discovered a series of peptides able to stimulate

GH release from rat pituitary, and in doing so, they opened a

new avenue for research.⁴This new family of peptides⁵

including GHRP-6, GHRP-1, GHRP-2, and hexarelin promotes

the release of GH in humans. This GH releasing mechanism

was found to be different from that of the endogenous growth

hormone releasing hormone (GHRH)⁶and to be mediated

through a G-protein coupled receptor named growth hormone

secretagogue receptor type1a (GHS-R1a).⁷The natural ligand

for this receptor, named ghrelin, has been isolated and recently

characterized from rat stomach⁸and further identified in

humans.⁹It is constituted of a 28 amino acid peptide in which

serine in position 3 is n-octanoylated. Several classes of small

nonpeptide molecule secretagogues (benzolactam biphenyl

tetrazoles,¹⁰camphor derivatives,¹¹and 4-spiropiperidines¹²)

have been described and are able to release GH from the

pituitary. Various peptide molecules, based on the GHRP-6

sequence, have been reported as potent GHRPs. Starting from

a tripeptide EP-51389, Aib-(D)-2-Me-Trp-(D)-2-Me-Trp-NH₂,¹³

Chemistry

Triazole derivatives were synthesized in five steps as shown

in Scheme 1, starting from Boc-(D)-Trp-OH. After coupling

to an amine, the formed amide 1 was transformed into the

thioamide 2 using Lawesson’s reagent. The obtained thioamide

2 was then treated with 2.0 equiv of hydrazide and 1.1 equiv

of mercury(II) acetate in THF, according to Hitotsuyanagi et

al.²⁷to obtain the cyclized triazole derivatives.²⁸Completion

of this step was monitored by reversed-phase HPLC, which

showed that cyclization into triazoles 3 was achieved within 2

* To whom correspondance should be addressed. Phone: 33 4 67 54 86

51. Fax: 33 4 67 54 86 54. E-mail: jean-alain.fehrentz@univ-montp1.fr.

^†CNRSsUniversite´s Montpellier I et II.

^‡CBS.

^§Zentaris GmbH.

University of Milano-Bicocca.

^#Equal contributors.

Published on Web 03/22/2007

1940 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

Scheme 1. General Synthetic Scheme for the Synthesis of

3,4,5-Trisubstituted 1,2,4-Triazoles^a

^a(i) BOP, H₂N-R₁, NMM, DCM; (ii) Lawesson’s Reagent, DME, 85

°C; (iii) H₂N-HN-COR₂, Hg(OAc)₂, room temperature, THF; (iv) HCl,

AcOEt; (v) Boc-Aib-OH, BOP, DIPEA, DCM; (vi) HCl, AcOEt.

Scheme 2. General Synthetic Scheme for the Synthesis of

3,5-Disubstituted 1,2,4-Triazoles^a

Figure 1. Structure and IC₅₀of the first synthesized triazoles.

Results and Discussion

Compounds 11-16 were tested for their ability to displace

¹²⁵I-His⁹-ghrelin from the cloned hGHS-1a receptor transiently

expressed in LLC PK-1 cells. Their binding affinities were found

in the micromolar range. Interestingly, comparison between

compounds 12, 13, 14, and 15, respectively, showed that a two-

carbon chain bearing the indole group in position 5 was well

accepted by the ghrelin receptor. Substitution of the nitrogen

at position 4 also had a beneficial effect (i.e., compound 16,

IC₅₀108 nM) (Figure 1). According to the observations that

affinity for the ghrelin receptor could be modulated by substitu-

tions at the position 4 and 5 of the triazole moiety, several

compounds were synthesized to explore R₁and R₂. Various aryl

and/or alkyl groups were introduced in positions 4 and 5 (R₁

and R₂groups). These compounds were synthesized according

to Schemes 1 and 2. The synthesized compounds were tested

for their ability to displace ¹²⁵I-His⁹-ghrelin from the cloned

hGHS-1a receptor transiently expressed in LLC PK-1 cells.

Binding affinities of human ghrelin and MK-0677 obtained with

this model were in accordance with the literature. Their

^a(i) H₂N-HN-COR₂, Hg(OAc)₂, room temperature, THF; (ii) HCl,

AcOEt; (iii) Boc-Aib-OH, BOP, DIPEA, DCM; (iv) HCl, AcOEt; (v)

TFA, DCM.

days. Compounds were purified by silica gel column chroma-

tography. Removing of the Boc protecting group by 4 M HCl

in AcOEt and coupling with Boc-Aib-OH in the presence of

BOP^a29and NMM in DCM produced the N-protected desired

compounds 4. The final compounds 5 were obtained after 4 M

HCl in AcOEt.

When R₁was a hydrogen atom, formation of the triazole

moiety was not observed. Careful examination of LC/MS spectra

revealed the presence of the corresponding nitrile derivative.

This “desulfuration” of nonsubstituted thioamides already

described on simple aliphatic and aromatic primary thioamides³⁰

illustrates that this synthetic pathway was not suitable for the

preparation of 3,5-disubstituted 1,2,4-triazoles. We therefore

decided to introduce a protecting group on the primary amide

function that could be cleaved after formation of the desired

triazole moiety (Scheme 2). For this purpose, 2,4-dimethoxy-

benzylamine was chosen as a protecting group that did not

interfere with the formation of the triazole moiety 7. After

completion of the synthesis compounds 9 and 10 were obtained,

substituted or not in position 4 of the triazole moiety.

biological in vitro activity was then evaluated on [Ca²⁺

]

i

mobilization in GHS-R1a at a concentration of 10^-5M of each

compound and expressed as a percent of the maximal response

induced by 10^-7M ghrelin (Table 1). The best compounds were

tested in vivo, for their ability to stimulate food intake or to

inhibit hexarelin-stimulated food intake.

The results of their biological activity at the GHS-1a receptor

are reported in Table 1. R₁aromatic groups in position 4 of the

triazole moiety were generally well tolerated for interaction with

the GHS-1a receptor. As shown for compounds 16-20, methoxy

substitutions on the aromatic moiety led to potent ghrelin

receptor ligands, the best compounds in this series bearing a

4-methoxybenzyl (19b, IC₅₀11 ( 4 nM; 19c, IC₅₀6 ( 3 nM)

or a 3-methoxybenzyl group (18a, IC₅₀18 ( 5 nM; 18b, IC₅₀

22 ( 4 nM) (Table 1). 2-Methoxybenzyl and dimethoxybenzyl

substitution at position 4 of the triazole moiety led to derivatives

presenting less affinity for the GHS-R1a compared to that of

the corresponding 3- or 4-methoxy derivatives (Table 1). We

then introduced various benzyl groups in position 4 of the

triazole moiety. Bromide-, fluoride-, and chloride-substituted

benzyl derivatives yielded less potent ligands for the GHS-1a

receptor (compounds 22a-c, 23a-c, and 24a-c). Electron-

A set of six initial compounds (11-16, Figure 1) were

synthesized as depicted in Schemes 1 and 2, all bearing an indole

group in position 5 of the triazole cycle with one or two carbon

atoms between the indole and the triazole.

^aAbbreviations: BOP, (benzotriazol-1-yloxy)-tris(dimethylamino)-phos-

phonium hexafluorophosphate; DME, ethylene glycol dimethyl ether; DCM,

dichloromethane; NMM, N-methyl-morpholine. Other abbreviations used

were those recommended by the IUPAC-IUB Commission [Eur. J. Biochem.

1984, 138, 9-37].

Triazole DeriVatiVes as Ghrelin Receptor Ligands

Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8 1941

Table 1. Binding Affinities and Biological Activities of Compounds of General Formula 5 in Scheme 1

binding IC₅₀

(nM)^a

% of max [Ca²⁺]i

biological

activity (nM)

compds

R₁

R₂

response at 10 µM^b

16

2,4-dimethoxybenzyl

3,5-dimethoxybenzyl

3-methoxybenzyl

4-methoxybenzyl

2-methoxybenzyl

benzyl

4-bromobenzyl

4-fluorobenzyl

3,4-dichlorobenzyl

phenethyl

1H-indole-3-yl-ethyl

benzyl

1H-indole-3-yl-propyl

phenethyl

1H-indole-3-yl-ethyl

phenethyl

benzyl

1H-indole-3-yl-ethyl

1H-indole-3-yl-propyl

phenethyl

benzyl

1H-indole-3-yl-methyl

phenethyl

1H-indole-3-yl-ethyl

phenylpropyl

benzyl

1H-indole-3-yl-propyl

benzyl

1H-indole-3-yl-ethyl

phenethyl

1H-indole-3-yl-ethyl

1H-indole-3-yl-propyl

benzyl

1H-indole-3-yl-ethyl

1H-indole-3-yl-propyl

benzyl

1H-indole-3-yl-ethyl

benzyl

phenethyl

1H-indole-3-yl-ethyl

benzyl

108 ( 17

560 ( 130

750 ( 100

60 ( 10

150 ( 31

>1000

0

antagonist; K_b, 14 ( 2

antagonist

partial agonist

antagonist; K_b, 17 ( 7

partial agonist

antagonist

partial agonist

partial agonist; EC₅₀, 4 ( 1

partial agonist; EC₅₀, 18 ( 3

partial agonist; EC₅₀, 45 ( 6

partial agonist

16a

16b

16c

17a

17b

17c

18a

18b

18c

18d

19a

19b

19c

19d

19e

19f

20a

20b

20c

21a

21b

21c

22a

22b

22c

23a

23b

23c

24a

24b

24c

25a

25b

25c

25d

25e

26a

26b

27a

27b

27c

27d

28a

28b

28c

29a

29b

29c

30a

30b

30c

30d

31

27 ( 1

0

22 ( 1

0

29 ( 1

63 ( 13

66 ( 11

82 ( 31

50 ( 18

0

66

50

80 ( 25

73 ( 13

30 ( 4

44 ( 10

27 ( 13

25 ( 9

16 ( 5

59 ( 16

60 ( 3

20 ( 9

28 ( 1

64 ( 12

53 ( 9

25 ( 6

88 ( 30

18 ( 3

85 ( 26

63 ( 13

60 ( 20

62 ( 7

78 ( 26

62 ( 2

54 ( 1

40 ( 12

67 ( 6

62 ( 33

32 ( 3

95 ( 9

82 ( 17

85 ( 22

16 ( 3

28 ( 4

69 ( 6

19 ( 15

26 ( 5

10 ( 4

78 ( 3

59 ( 20

82 ( 40

91 ( 9

97 ( 6

91 ( 4

110 ( 30

18 ( 5

22 ( 4

78 ( 15

120 ( 20

660 ( 40

11 ( 4

antagonist

antagonist; K_b, 5 ( 1

antagonist; K_b, 4 ( 1

antagonist; K_b, 14 ( 4

antagonist

antagonist; K_b, 12 ( 0.2

partial agonist

6 ( 3

12 ( 3

121 ( 33

145 ( 30

410 ( 110

96 ( 13

56 ( 18

15 ( 5

partial agonist

partial agonist; EC₅₀, 98 ( 17

partial agonist, EC₅₀, 64 ( 14

partial agonist; EC₅₀, 49 ( 14

partial agonist

partial agonist; EC₅₀, 210 ( 40

partial agonist

partial agonist; EC₅₀, 15 ( 2

partial agonist

agonist

partial agonist

agonist; EC₅₀, 140 ( 30

partial agonist; EC₅₀, 12 ( 0.7

partial agonist

partial agonist; EC₅₀, 630 ( 190

partial agonist

33 ( 7

500 ( 70

100 ( 30

150 ( 30

440 ( 50

66 ( 11

170 ( 60

400 ( 130

55 ( 8

520 ( 50

640 ( 10

80 ( 10

300 ( 60

11 ( 4

phenethyl

1H-indole-3-yl-ethyl

1H-indole-3-yl-methyl

1H-indole-3-yl-propyl

benzyl

phenethyl

benzyl

1H-indole-3-yl-ethyl

benzyl

1H-indole-3-yl-propyl

1H-indole-3-yl-ethyl

phenethyl

2,2-diphenylethyl

(naphtalen-1-yl)methyl

n-hexyl

>1000

310 ( 30

>1000

640 ( 250

220 ( 30

140 ( 3

125 ( 50

130 ( 1

470 ( 40

195 ( 35

240 ( 50

700 ( 120

150 ( 5

14 ( 2

benzyl

n-hexyl

1H-indole-3-yl-ethyl

1H-indole-3-yl-propyl

benzyl

1H-indole-3-yl-ethyl

1H-indole-3-yl-propyl

phenylpropyl

benzyl

1H-indole-3-yl-ethyl

phenethyl

benzyl

phenethyl

1H-indole-3-yl-ethyl

4-methylbenzyl

4-ethylbenzyl

21 ( 2

840 ( 220

28 ( 5

140 ( 30

44 ( 17

>1000

partial agonist; EC₅₀, 11 ( 5

weak agonist

partial agonist

agonist

agonist; EC₅₀, 23 ( 2

agonist; EC₅₀, 41 ( 3

32

4-nitrobenzyl

33a

33b

34

35

36

(pyridin-2-yl)methyl

4-methoxyphenethyl

(thiophen-2-yl)methyl

(furan-2-yl)methyl

phenyl

550 ( 50

570 ( 40

420 ( 100

140 ( 20

37

^aInhibition of ¹²⁵I-His⁹-ghrelin binding to membranes from hGHS-R1a transfected LLC cells. ^bMaximum calcium flux activity is reported relative to

ghrelin at 0.1 µM.

withdrawing groups such as 4-nitro or electron-donating groups

such as 4-methyl or 4-ethyl on the benzyl ring were also

introduced in position 4 of the triazole moiety. It clearly

appeared that electron-withdrawing groups were not tolerated

at this position of the molecule (compound 32), while electron-

donating groups were privileged (30a-d, 31). The significance

of the length of the carbon chain between the triazole and the

phenyl rings was studied. Phenyl, benzyl, and phenethyl groups

were introduced as R₁substituents (37, 21a, and 25a). The

benzyl group led to the compounds that exhibited the better

affinity for the GHS-1a receptor. Naphtalen-1-yl-methyl and 2,2-

diphenylethyl groups (26a,b, 27a-d) were introduced. The

affinity of the obtained compounds was lower than that of the

benzyl-containing derivatives. Pyridin-2-yl-methyl, thiophen-

2-yl-methyl, and furan-2-yl-methyl substituents led to com-

pounds (33a,b, 35, and 36) of low affinity for the GHS-1a

1942 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

Figure 2. Ability of compounds 16 (0), 19b (4), or 25c (b) to inhibit

binding of ¹²⁵I-His⁹-ghrelin to membranes from hGHS-R1a-trans-

fected LLC cells. Results are expressed as the percentage of radioactiv-

ity bound in the absence of added nonradioactive compounds. In each

experiment, each value was determined in triplicate, and the results

given are means from at least three separate experiments. Nonspecific

binding was determined in the presence of 10 µM ghrelin and was

always less than 20% of total binding.

Figure 3. Effects of compounds 18a (0), 18b (b), and 30a (9) on

[Ca²⁺]_iaccumulation in CHO cells expressing the hGHS-R1a. The

results are expressed as the percentage of the fluorescence signal

compared to the maximal response induced by 10 µM ghrelin. In each

experiment, each value was determined in triplicate, and the results

given are means from at least three separate experiments.

receptor. An indole group was also introduced at position 4 (29a

and 29b) without improving the affinity for the ghrelin receptor.

A three-carbon chain bearing the indole group in position 5 of

the triazole yielded compound 29c with an improved binding

affinity when compared with that of compound 29b. Introducing

a lipophilic chain (compounds 28a-c) at the 4 position of the

indole moiety to mimic the octanoyl group of the natural ghrelin

ligand led to compounds having less affinity.

In position 5 of the triazole moiety (R₂group), six different

phenyl and indole-derived substituents were explored linked to

the triazole moiety by an aliphatic chain composed of one, two,

or three carbon atoms. The best compounds were obtained with

a two-carbon chain length (18a, 19b, 19c, 21a, 30c, 31) (IC₅₀

ranging from 6 ( 3 nM for compound 19c to 44 ( 17 nM for

compound 31). In some derivatives, a three-carbon length chain

was well tolerated yielding analogues (16b, 18b, 19d, 19f, 21b,

22b, 25c, 27b, 28c, 29c, and 30a) with IC₅₀ranging from 11 (

4 for compound 25c to 750 ( 100 nM for compound 16b (Table

1). When triazole derivatives substituted by benzyl or 1H-indol-

3-yl-methyl groups in position R₂were compared, no precise

rule could be defined in terms of structure-activity relationships.

In some cases compounds having a benzyl group had a better

affinity (19e, IC₅₀121 ( 33 vs 19a, IC₅₀660 ( 40), in some

others those having a 1H-indol-3-yl-methyl group exhibited

better affinity for the GHS-1a receptor (25b, IC₅₀300 ( 60 vs

25d, IC₅₀> 1000 nM). In general, 1H-indole-3-yl-ethyl-

containing compounds at the R₂position were found better

ligands than those with phenethyl moieties (18a, IC₅₀18 ( 5

vs 18c, IC₅₀78 ( 15; 23a, IC₅₀66 ( 11 vs 23c, IC₅₀400 (

130; 24a, IC₅₀55 ( 8 vs 24c, IC₅₀640 ( 10; 25a, IC₅₀80 (

10 vs 25e, IC₅₀310 ( 30), although it was not always the case

(19b, IC₅₀11 ( 4 vs 19c, IC₅₀6 ( 3). However, when a three-

carbon chain was placed between the triazole ring and the

aromatic cycle, phenyl-containing compounds seemed to have

slightly better affinity for the GHS-1a receptor (19d, IC₅₀12 (

3 vs 19f, IC₅₀145 ( 30). As examples of competition studies,

displacement curves for compounds 16, 19b, and 25c (Figure

2) are reported.

Figure 4. Effects of compound 29c (0) on [Ca²⁺]_iaccumulation in

CHO cells expressing the hGHS-R1a. The results are expressed as the

percentage of the fluorescence signal compared to the maximal response

induced by 10 µM ghrelin. In each experiment, each value was

determined in triplicate, and the results given are means from at least

three separate experiments.

of the best ligands for the GHS-1a receptor of these partial

agonists were determined (18a, 63% total response, EC₅₀4 (

1 nM, 18b, 66% total response, 18 ( 3 nM, 25c, 18% total

response, 15 ( 2 nM, 30a, 16% total response, 12 ( 0.7 nM)

(Table 1). As an example, the dose-response curves of

compounds 18a, 18b, and 30a are reported (Figure 3). On the

basis of these biological results, it was not possible to establish

a clear structure-activity relationship for these partial agonists.

Among the compounds that behaved as full agonists (i.e., 25b,

25d, 29a-c, 35, 36, and 37), only 29c exhibited high affinity

for the GHS-1a receptor (IC₅₀14 ( 2) and moderate potency

on [Ca²⁺]_iaccumulation (EC₅₀120 ( 30 nM). However, it is

quite clear that the presence of a phenyl, 3-methoxybenzyl,

2-methoxybenzyl, 4-fluorobenzyl, phenethyl, 2,2-diphenylethyl,

(naphtalen-1-yl)-methyl, n-hexyl, and 1H-indole-3-yl-ethyl group

in the R₁position was sufficient to generate derivatives with

the best efficacy (particularly in the case of the 1H-indole-3-

yl-ethyl group in the R₂position). As an example, the dose-

response curve for compound 29c is reported in Figure 4. Some

of the compounds that were synthesized were not able to

promote [Ca²⁺]_iaccumulation, although they were able to

recognize the GHS-1a receptor. For all these compounds, the

R₁group was either a 4-methoxybenzyl or a 2,4-dimethoxy-

benzyl (i.e., 16, 16a, 16c, 19a-f) (Table 1). These compounds

were able to antagonize the [Ca²⁺]_iaccumulation induced by

ghrelin. Compounds 16 (K_b14 ( 2 nM), 19b (K_b5 ( 1 nM),

When tested for their ability to induce intracellular calcium

release, most of the compounds containing a 4-methoxy group

in R₁position were not able to stimulate intracellular calcium

levels (i.e., compounds 16, 16a, 16c, 19a-f). Compounds with

a different substitution in the R₁position were able to stimulate

[Ca²⁺]_iaccumulation, but a large majority were not fully

efficacious, inducing only 16 ( 3% (for compound 30a) to 88%

(for compound 25b) of the total response of ghrelin. The EC₅₀

Triazole DeriVatiVes as Ghrelin Receptor Ligands

Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8 1943

Table 2. Cumulative Food Intake at 6 h after sc Administration of

Compounds Alone or with Hexarelin^a

cumulative food intake

(g/100 g bw) at 6 h

for 160 µg compd

cumulative food intake

(g/100 g bw) at 6 h

for 160 µg compd

+ 80 µg hexarelin

(cumulative food intake

% variation

compds at 6 h for 80 µg hexarelin)

vs hexarelin^b

saline

16

0.19 ( 0.11

0.28 ( 0.12

0.33 ( 0.22

0.48 ( 0.23

0.63 ( 0.20

0.48 ( 0.22

0.79 ( 0.33

0.47 ( 0.41

0.64 ( 0.01

0.02 ( 0.01

0.43 ( 0.20

0.53 ( 0.33

0.85 ( 0.41

0.91 ( 0.36

0.49 ( 0.17

0.56 ( 0.21

0.06 ( 0.03 (0.90 ( 0.38)

0.01 ( 0.0 (0.76 ( 0.20)

0.20 ( 0.19 (0.70 ( 0.21)

0.06 ( 0.02 (0.70 ( 0.21)

0.17 ( 0.17 (1.14 ( 0.11)

0.29 ( 0.18 (1.10 ( 0.40)

0.02 ( 0.01 (0.67 ( 0.26)

0.01 ( 0.00 (0.60 ( 0.17)

0.41 ( 0.37 (0.78 ( 0.22)

0.75 ( 0.35 (0.67 ( 0.26)

0.27 ( 0.17 (1.14 ( 0.11)

0.22 ( 0.20 (0.59 ( 0.30)

0.74 ( 0.31 (1.10 ( 0.22)

0.30 ( 0.13 (1.10 ( 0.22)

-63

-37

-10

-31

-57

-4

-97

-45

-21

-25

+54

-55

-49

18c

19b

19c

19e

20c

21a

21b

24a

25c

29b

29c

30a

30c

Figure 5. Ability of compounds 19c (2) and 19d (O) to inhibit 0.1

µM ghrelin-induced [Ca²⁺]_iaccumulation in CHO cells expressing the

hGHS-R1a. Values are expressed as the percentage of the fluorescence

signal induced by 10 µM ghrelin with no added antagonist. In each

experiment, each value was determined in duplicate, and the results

given are means from at least three separate experiments.

^aResults are expressed as g of food intake per 100 g of body weight

(mean ( SEM). ^b(Cumulative food intake at 6 h for compound minus

cumulative food intake at 6 h for hexarelin)/cumulative food intake at 6 h

for hexarelin.

Table 3. Inhibition of Hexarelin-Stimulated Cumulative Food Intake at

Various sc Doses of Compound 21b (mean ( SEM)^a

food intake at 6 h

compds

(g/100 g bw)

hexarelin 80 µg

1.01 ( 0.19

0.46 ( 0.11

0.25 ( 0.13

0.08 ( 0.05

+20 µg compound 21b

+80 µg compound 21b

+160 µg compound 21b

+320 µg compound 21b

Figure 6. Effects of compound 19b on ghrelin-induced [Ca²⁺

]

i

^aValues are the mean of 7-8 determinations. Experiments have been

accumulation in CHO cells expressing the hGHS-R1a. Cells were

incubated with various concentrations of ghrelin in the absence of

compounds (9) or in the presence of indicated concentrations of

compound 19b at 10^-8(0), 10^-7(b), or 10^-6M (O). Values are

expressed as the percentage of the fluorescence signal induced by 10

µM ghrelin with no added antagonist. In each experiment, each value

was determined in duplicate, and the results given are means from at

least three separate experiments.

repeated three times.

Table 4. Effect of Compound 21b on GH Secretion in the Rat (sc

Injection)^a,b

compd

[GH] ng/mL

solvent

hexarelin (80 µg)

21b (160 µg)

2.2 ( 0.1

170 ( 13

13 ( 2

19c (K_b4 ( 1 nM), and 19d (K_b14 ( 4 nM) were among the

most potent ghrelin receptor antagonists (Figure 5 for com-

pounds 19c and 19d). They were able to antagonize dose

dependently ghrelin-induced [Ca²⁺]_iaccumulation in CHO cells

transiently transfected with the GHS-R1a. Interestingly, in the

presence of various concentrations of compounds 16, 19b, 19c,

hexarelin + 21b (160 µg)

183 ( 17

^aGH concentration was determined as described in the Experimental

Section (mean ( SEM). ^bValues are the mean of 5-7 determinations.

Experiments have been repeated three times.

reported compound 29c, were able to inhibit hexarelin-induced

food intake in the rat with different potencies that were not in

accordance with their in vitro potency or efficacy. Unexpectedly,

the most potent compound in this series (21b) for the inhibition

of hexarelin-stimulated food intake was not the compound

presenting the best affinity for the GHS-1a receptor (IC₅₀33 (

7 nM), nor was it found the most potent in vitro agonist (30 (

4% of the maximal response on [Ca²⁺]_iaccumulation, EC₅₀49

( 14 nM). There was no clear correlation between in vitro and

in vivo results, some very potent partial agonists in recognizing

the GHS-1a receptor having weak effects on food intake (i.e.,

21a), some potent partial agonist on [Ca²⁺]_iaccumulation being

potent antagonist of hexarelin-stimulated food intake (i.e., 20c).

A dose-response study for the most active compound (21b)

that was able to antagonize the effects of hexarelin on food

intake is reported in Table 3. A clear dose-effect could be

found, compound 21b being already active at the dose of 20

µg/kg.

or 19d, the dose-response curves of ghrelin on [Ca²⁺

]

i

accumulation were shifted in a parallel manner indicating a

competitive antagonism (see Figure 6 for compound 19b as an

example).

Some of the compounds were tested for their activity on food

intake (Table 2). Each compound was sc injected (160 µg/kg)

in the rat. We selected some agonist (29c), partial agonists (18c,

20c, 21a, 21b, 24a, 25c, 29b, 30c), and antagonists (16, 19b,

19c, 19e) compounds according to their in vitro activity on the

GHS-1a receptor. Compound 29c that has been reported to be

an in vitro agonist at the GHS-R1a was unable to stimulate food

intake when administered alone. However, when administered

with hexarelin, cumulative food intake at 6 h was increased

with a variation of about 50% when compared with that of

hexarelin alone. As reported in Table 2, when administered

alone, compounds 24a, 25c, and 30a (all in vitro partial agonists)

elicited a significant increase in cumulative food intake, while

all other compounds were found without effect. When admin-

istered with hexarelin, all compounds, with the exception of

compounds 21a which was without any effect and as already

Compound 21b was evaluated for its activity on GH secretion

after sc injection in the rat. As can be seen in Table 4, compound

21b did not have any proper effect on GH release. On the other

1944 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

General Procedure for Hydrazide Preparation. When hy-

drazides were not commercially available, they were synthesized

in two steps via the corresponding esters as described below.

Ester Preparation. An amount of 1.0 equiv of carboxylic acid

was dissolved in acetonitrile (0.5 mol/L). Then 1.2 equiv of DBU

and 5.0 equiv of methyl iodide were added dropwise consecutively

under stirring. After 8 h under reflux, the solvent was removed in

vacuo. The residue was diluted in dichloromethane, washed with

aqueous potassium hydrogen sulfate (1 M), saturated aqueous

sodium hydrogen carbonate, and saturated aqueous sodium chloride.

The organic layer was dried over sodium sulfate, filtered, and the

solvent was removed in vacuo to afford the corresponding ester,

as a colorless oil.

hand, compound 21b (160 µg/kg) was not able to modify

hexarelin-stimulated GH release. Results on GH secretion are

reported in Table 4.

These results indicate that compound 21b works efficiently

on the hexarelin-stimulated food intake (about 90% decrease

in the cumulative 6 h period) and is without effect on GH

secretion. The discrepancies observed between in vivo and in

vitro activity might result from different pharmacokinetic and/

or pharmacodynamic properties of compound 21b.

Conclusion

Methyl 3-Phenylpropanoate: 3.7 g (84%); ¹H NMR (300 MHz,

DMSO-d₆) δ 2.58 (t, 2H, J ) 7 Hz, CH₂-CH₂-phenyl), 2.84 (t,

2H, J ) 7 Hz, CH₂-CH₂-phenyl), 3.55 (s, 3H, OCH₃), 7.21 (m,

5H, CH phenyl); ¹³C NMR (75 MHz, DMSO-d₆) δ 30.7 (CH₂-

CH₂-phenyl), 35.3 (CH₂-CH₂-phenyl), 51.5 (OCH₃), 126.4 (C₄

phenyl), 128.5 (C₂and C₆phenyl), 128.7 (C₃and C₅phenyl), 140.9

(C₁phenyl), 173.0 (CO ester); MS (ES) m/z 165.0 [M + H]⁺; HPLC

t_R, 1.51 min (conditions A).

A novel class of ghrelin receptor (GHS-R1a) ligands was

identified from substituted 1,2,4-triazoles. These compounds

were easily synthesized from commercially available materials.

They contain only one asymmetric center that was selected at

the beginning of the synthesis from the starting amino acid

residue and conserved throughout the synthesis. SAR studies

allowed us to improve in vitro binding affinity and to discover

potent agonists, partial agonists, and antagonists for the GHS-

1a receptor. The best in vitro receptor antagonists of this series

were found to be compounds 19c (JMV2844) (IC₅₀of 6 ( 3

nM, K_bof 4 ( 1 nM) and 19b (JMV2866) (IC₅₀of 11 ( 4 nM,

K_bof 5 ( 1 nM). The most potent compounds in this series

were tested in vivo for their activity on food intake in the rat.

Compound 21b (JMV2810) that was defined in vitro as a partial

agonist at the GHS-R1a was found the most potent compound

in inhibiting hexarelin-stimulated food intake in the rat.

However, it did not show any activity on GH secretion in the

rat. Considering that some of the compounds tested are

antagonists and some partial agonists in vitro at the GHS-1a

receptor, this should infer that the receptor involved in the

modulation of the food intake by the tested compounds depends

on a more complicated mechanism.

1

Methyl 3-(1H-Indol-3-yl)propanoate: 4.0 g (94%); H NMR

(300 MHz, DMSO-d₆) δ 2.64 (t, 2H, J ) 8 Hz, CH₂-CH₂-indole),

2.94 (t, 2H, J ) 8 Hz, CH₂-CH₂-indole), 3.55 (s, 3H, OCH₃),

6.95 (t, 1H, J ) 7 Hz, H₅indole), 7.04 (t, 1H, J ) 7 Hz, H₆indole),

7.08 (s, 1H, H₂indole), 7.32 (d, 1H, J ) 8 Hz, H₄indole), 7.48 (d,

1H, J ) 8 Hz, H₇indole), 10.78 (brs, 1H, NH indole); ¹³C NMR

(75 MHz, DMSO-d₆) δ 20.7 (CH₂-CH₂-indole), 34.7 (CH₂-

CH₂-indole), 51.2 (OCH₃), 111.8 (C₇indole), 113.5 (C₃indole),

118.5 (C₄and C₅indole), 121.3 (C₆indole), 122.7 (C₂indole), 127.3

(C₉indole), 136.6 (C₈indole), 173.5 (CO ester); MS (ES) m/z 204.1

[M + H]⁺; HPLC t_R, 1.50 min (conditions A).

Methyl 4-Phenylbutanoate: 1.1 g (100%); ¹H NMR (300 MHz,

DMSO-d₆) δ 1.79 (m, 2H, CH₂-CH₂-CH₂-phenyl), 2.26 (t, 2H,

J ) 7 Hz, CH₂-CH₂-CH₂-phenyl), 2.54 (t, 2H, J ) 7 Hz, CH₂-

CH₂-CH₂-phenyl), 3.55 (s, 3H, OCH₃), 7.13-7.16 (m, 3H, H₃,

H₄, and H₅phenyl), 7.22-7.27 (m, 2H, H₂, and H₆phenyl); ¹³C

NMR (75 MHz, DMSO-d₆) δ 26.6 (CH₂-CH₂-CH₂-phenyl), 33.1

(CH₂-CH₂-CH₂-phenyl), 34.7 (CH₂-CH₂-CH₂-phenyl), 51.5

(OCH₃), 126.2 (C₄phenyl), 128.6 (C₂, C₃, C₅, and C₆phenyl), 141.7

(C₁phenyl), 173.4 (CO ester); MS (ES) m/z 179.1 [M + H]⁺. HPLC

t_R, 1.68 min (conditions A).

Experimental Section

General Procedures. Ascending TLC was performed on pre-

coated plates of silica gel 60 F₂₅₄(Merck). Peptide derivatives were

located with charring reagent or ninhydrine. Column chromatog-

raphy was performed with silica gel Kieselguhr Merck G 0.04-

0.063 mm. HPLC purifications were run on a Waters 4000

preparative apparatus on a C18 Deltapak column (100 mm × 40

mm, 15 µm, 100 Å), with UV detection at 214 nm, at a flow rate

of 50 mL/min of a mixture of A, water with 0.1% TFA, and B,

acetonitrile with 0.1% TFA in gradient mode. Analytical HPLC

chromatography was performed on a Beckman Gold apparatus

composed of the 126 solvent module, the 168 detector, and the 32

Karat software; runs were performed on a VWR Chromolith column

(50 mm × 3.9 mm) at a flow rate of 5 mL/min from solution A to

solution B in a 3 min gradient (conditions A) or on a Symmetry

Shield C18 column (50 mm × 4.6 mm, 3.5 µm) at a flow rate of

1 mL/min from solution A to solution B in a 15 min gradient

(conditions B). ¹H and ¹³C NMR spectra were recorded in DMSO-

d₆at 300 and 75 MHz or at 400 and 100 MHz, respectively, and

at 300 K. Chemical shifts were reported as δ values (ppm) indirectly

referenced to the solvent signal. Mass spectrum analyses were

recorded on a Quatromicro (Micromass, Manchester, U.K.) triple-

quadrupole mass spectrometer fitted with an electrospray interface.

(L),(D)-Amino acids and derivatives were from Senn Chemicals,

NeoMPS, or Advanced Chemtech. Human ghrelin was purchased

from NeoMPS and iodinated in our laboratory. All reagents were

of analytical grade.

Methyl 2-(1H-Indol-3-yl)acetate: 0.78 g (72%); ¹H NMR (300

MHz, DMSO-d₆) δ 3.58 (s, 3H, OCH₃), 3.73 (s, 2H, CH₂-indole),

6.97 (t, 1H, J ) 8 Hz, H₅indole), 7.07 (t, 1H, J ) 7 Hz, H₆indole),

7.23 (d, 1H, J ) 2 Hz, H₂indole), 7.35 (d, 1H, J ) 8 Hz, H₄

indole), 7.47 (d, 1H, J ) 8 Hz, H₇indole), 10.92 (s, 1H, NH indole);

¹³C NMR (75 MHz, DMSO-d₆) δ 31.0 (CH₂-indole), 51.9 (OCH₃),

107.4 (C₃indole), 111.8 (C₇indole), 118.8 (C₄indole), 118.9 (C₅

indole), 121.5 (C₆indole), 124.5 (C₂indole), 127.5 (C₉indole),

136.5 (C₈indole), 172.5 (CO ester); MS (ES) m/z 190.1 [M + H]⁺;

HPLC t_R, 1.37 min (conditions A).

1

Methyl 4-(1H-Indol-3-yl)butanoate: 0.69 g (52%); H NMR

(300 MHz, DMSO-d₆) δ 1.87 (m, 2H, CH₂-CH₂-CH₂-indole),

2.32 (t, 2H, J ) 7 Hz, CH₂-CH₂-CH₂-indole), 2.67 (t, 2H, J )

7 Hz, CH₂-CH₂-CH₂-indole), 3.55 (s, 3H, OCH₃), 6.94 (t, 1H,

J ) 7 Hz, H₅indole), 7.03 (t, 1H, J ) 7 Hz, H₆indole), 7.07 (d,

1H, J ) 2 Hz, H₂indole), 7.31 (d, 1H, J ) 8 Hz, H₄indole), 7.47

(d, 1H, J ) 8 Hz, H₇indole), 10.74 (s, 1H, NH indole); ¹³C NMR

(75 MHz, DMSO-d₆) δ 24.4 (CH₂-CH₂-CH₂-indole), 25.7

(CH₂-CH₂-CH₂-indole), 33.4 (CH₂-CH₂-CH₂-indole), 51.5

(OCH₃), 111.7 (C₇indole), 114.1 (C₃indole), 118.5 (C₄indole),

118.6 (C₅indole), 121.2 (C₆indole), 122.7 (C₂indole), 127.5 (C₉

indole), 136.5 (C₈indole), 173.8 (CO ester); MS (ES) m/z 218.1

[M + H]⁺; HPLC t_R, 1.64 min (conditions A).

Hydrazide Preparation. An amount of 1.0 equiv of the

corresponding ester and 10.0 equiv of hydrazine monohydrate were

dissolved in ethanol (0.3 mol/L). The mixture was stirred overnight

at reflux. The solvent was then removed in vacuo, and the residue

was washed with diethylether and dried in vacuo to afford the

corresponding hydrazide as a white powder.

All final compounds were purified by reversed-phase HPLC; the

purity assessed by analytical reversed-phase C18 HPLC was found

superior to 95%, and the structure was confirmed by MS (electro-

spray) and ¹H NMR and ¹³C NMR for the most interesting

compounds.

Triazole DeriVatiVes as Ghrelin Receptor Ligands

Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8 1945

3-Phenylpropanehydrazide: 3.3 g (91%); ¹H NMR (300 MHz,

DMSO-d₆) δ 2.28 (t, 2H, J ) 7 Hz, CH₂-CH₂-phenyl), 2.77 (t,

2H, J ) 7 Hz, CH₂-CH₂-phenyl), 3.69 (brs, 2H, NH₂), 7.11-

7.26 (m, 5H, CH aromatic), 8.94 (brs, 1H, NH); ¹³C NMR (75 MHz,

DMSO-d₆) δ 31.4 (CH₂-CH₂-phenyl), 35.5 (CH₂-CH₂-phenyl),

126.3 (C₄phenyl), 128.6 (C₂and C₆phenyl), 128.7 (C₃and C₅

phenyl), 140.1 (C₁phenyl), 173.1 (CO); MS (ES) m/z 165.1 [M +

H]⁺; HPLC t_R, 0.77 min (conditions A).

(dd, 1H, J ) 14 and 8 Hz, CH₂âTrp), 3.11 (dd, 1H, J ) 14 and

5 Hz, CH₂âTrp), 3.75 (m, 2H, CH₂-CH₂-indole), 4.53 (m, 1H,

CH RTrp), 6.68 (d, 1H, J_o) 8 Hz, H₄Trp), 6.95 (t, 1H, J_o) 7

Hz, H₅Trp), 6.96 (t, 1H, J_o) 8 Hz, H₅indole), 7.03 (t, 1H, J_o)

6 Hz, H₆Trp), 7.04 (m, 2H, H₆and H₂indole), 7.10 (d, 1H, J )

2 Hz, H₂Trp), 7.12 (d, 1H, J_o) 8 Hz, H₄indole), 7.30 (d, 2H, J_o

) 8 Hz, H₇indole and H₇Trp), 7.57 (d, 1H, J ) 7 Hz, NH Boc),

9.95 (brs, 1H, NH thioamide), 10.79 (s, 2H, NH indole and NH

indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ 21.2 (CH₂-

CH₂-indole), 28.5 (CH₃Boc), 31.5 (C âTrp), 46.1 (CH₂-CH₂-

indole), 62.0 (C RTrp), 78.6 (Cq Boc), 110.5 (C₃indole and C₃

Trp), 111.7 (C₇indole and C₇Trp), 118.6 (C₄Trp), 118.7 (C₄

indole), 119.0 (C₅indole and C₅Trp), 121.2 (C₆Trp), 121.3 (C₆

indole), 123.1 (C₂indole and C₂Trp), 127.5 (C₉indole), 127.8 (C₉

Trp), 136.5 (C₈Trp), 136.7 (C₈indole), 155.2 (CO Boc), 204.1

(CS thioamide). MS (ES) m/z 363.29 [M + H - 100]⁺, 406.9 [M

+ H - 56]⁺, 463.1 [M + H]⁺, 925.4 [2M + H]⁺. HPLC t_R, 2.01

min (conditions A).

3-(1H-Indol-3-yl)propanehydrazide: 3.1 g (76%); ¹H NMR

(300 MHz, DMSO-d₆) δ 2.41 (m, 2H, CH₂-CH₂-indole), 2.90

(m, 2H, CH₂-CH₂-indole), 5.72 (brs, 2H, NH₂), 6.93 (t, 1H, J )

7 Hz, H₅indole), 7.02 (t, 1H, J ) 8 Hz, H₆indole), 7.07 (s, 1H, H₂

indole), 7.31 (d, 1H, J ) 8 Hz, H₄indole), 7.48 (d, 1H, J ) 8 Hz,

H₇indole), 9.03 (brs, 1H, NH hydrazide), 10.79 (brs, 1H, NH

indole); ¹³C NMR (75 MHz, DMSO-d₆) δ 21.4 (CH₂-CH₂-indole),

34.7 (CH₂-CH₂-indole), 111.7 (C₇indole), 114.1 (C₃indole),

118.5 (C₄indole), 118.7 (C₅indole), 121.3 (C₆indole), 122.5 (C₂

indole), 127.4 (C₉indole), 136.6 (C₈indole), 171.9 (CO); MS (ES)

m/z 204.1 [M + H]⁺; HPLC t_R, 0.85 min (conditions A).

4-Phenylbutanehydrazide: 1.1 g (100%); ¹H NMR (300 MHz,

DMSO-d₆) δ 1.84 (m, 2H, CH₂-CH₂-CH₂-phenyl), 2.00 (t, 2H,

J ) 7 Hz, CH₂-CH₂-CH₂-phenyl), 2.53 (t, 2H, J ) 8 Hz, CH₂-

CH₂-CH₂-phenyl), 4.40 (brs, 2H, NH₂), 7.09-7.16 (m, 3H, H₂,

H₄, and H₆phenyl), 7.21-7.26 (m, 2H, H₃, and H₅phenyl), 8.90

(s, 1H, NH); ¹³C NMR (75 MHz, DMSO-d₆) δ 27.4 (CH₂-CH₂-

CH₂-phenyl), 33.3 (CH₂-CH₂-CH₂-phenyl), 35.1 (CH₂-CH₂-

CH₂-phenyl), 126.1 (C₄phenyl), 128.7 (C₂, C₃, C₅, and C₆phenyl),

142.1 (C₁phenyl), 171.7 (CO); MS (ES) m/z 179.1 [M + H]⁺;

HPLC t_R, 0.86 min (conditions A).

tert-Butyl (R)-1-(Methylthiocarbamoyl)-2-(1H-indol-3-yl)eth-

ylcarbamate (2b). Obtained from Boc-^D-Trp and methylamine:

1

0.3 g (69%). H NMR (300 MHz, DMSO-d₆, 300 K) δ 1.27 (s,

9H, CH₃Boc), 2.91 (d, 3H, J ) 4 Hz, NH-CH₃), 2.97 (m, 1H,

CH₂âTrp), 3.14 (dd, 1H, J ) 14 and 5 Hz, CH₂âTrp), 4.49 (m,

1H, CH RTrp), 6.64 (d, 1H, J_o) 8 Hz, H₄Trp), 6.93 (t, 1H, J_o)

8 Hz, H₅Trp), 7.03 (t, 1H, J_o) 8 Hz, H₆Trp), 7.11 (s, 1H, H₂

Trp), 7.29 (d, 1H, J_o) 8 Hz, H₇Trp), 7.58 (d, 1H, J ) 8 Hz, NH

Boc), 9.86 (d, 1H, J ) 4 Hz, NH thioamide), 10.75 (s, 1H, NH

indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ 28.5 (CH₃

Boc), 31.5 (C âTrp), 32.7 (NH-CH₃), 61.8 (C RTrp), 78.6 (Cq

Boc), 110.5 (C₃Trp), 111.7 (C₇Trp), 118.6 (C₄Trp), 118.9 (C₅

Trp), 121.2 (C₆Trp), 124.1 (C₂Trp), 127.8 (C₉Trp), 136.5 (C₈

Trp), 155.2 (CO Boc), 204.8 (CS thioamide). MS (ES) m/z 234.4

[M + H - 100]⁺, 277.7 [M + H - 56]⁺, 334.2 [M + H]⁺, 667.3

[2M + H]⁺, 689.1 [2M + Na]⁺. HPLC t_R, 1.93 min (conditions

A).

2-(1H-Indol-3-yl)acetohydrazide: 0.5 g (59%); ¹H NMR (300

MHz, DMSO-d₆) δ 3.46 (s, 2H, CH₂-indole), 4.25 (brs, 2H, NH₂),

6.96 (t, 1H, J ) 7 Hz, H₅indole), 7.05 (t, 1H, J ) 8 Hz, H₆indole),

7.18 (s, 1H, H₂indole), 7.33 (d, 1H, J ) 8 Hz, H₄indole), 7.57 (d,

1H, J ) 8 Hz, H₇indole), 9.20 (brs, 1H, NH hydrazide), 10.86 (s,

1H, NH indole); ¹³C NMR (75 MHz, DMSO-d₆) δ 31.2 (CH₂-

indole), 109.1 (C₃indole), 111.7 (C₇indole), 118.7 (C₄indole),

119.2 (C₅indole), 121.3 (C₆indole), 124.2 (C₂indole), 127.6 (C₉

indole), 136.5 (C₈indole), 170.7 (CO); MS (ES) m/z 190.2 [M +

H]⁺; HPLC t_R, 0.78 min (conditions A).

tert-Butyl (R)-1-(2,4-Dimethoxybenzylcarbamoyl)-2-(1H-in-

dol-3-yl)ethylcarbamate (2c). Obtained from Boc-^D-Trp and 2,4-

dimethoxybenzylamine. ¹H NMR (300 MHz, DMSO-d₆, 300 K) δ

3

(ppm) 1.27 (s, 9H, CH₃Boc), 2.97 (dd, 1H, J ) 8 and 14 Hz,

3

4-(1H-Indol-3-yl)butanehydrazide: 1.0 g (90%); ¹H NMR (300

MHz, DMSO-d₆) δ 1.83 (m, 2H, CH₂-CH₂-CH₂-indole), 2.06

(t, 2H, J ) 7 Hz, CH₂-CH₂-CH₂-indole), 2.62 (t, 2H, J ) 8 Hz,

CH₂-CH₂-CH₂-indole), 4.35 (brs, 2H, NH₂), 6.92 (t, 1H, J ) 7

Hz, H₅indole), 7.02 (t, 1H, J ) 7 Hz, H₆indole), 7.06 (s, 1H, H₂

indole), 7.29 (d, 1H, J ) 8 Hz, H₄indole), 7.46 (d, 1H, J ) 8 Hz,

H₇indole), 8.93 (brs, 1H, NH hydrazide), 10.72 (s, 1H, NH indole);

¹³C RMN (75 MHz, DMSO-d₆) δ 24.8 (CH₂-CH₂-CH₂-indole),

26.5 (CH₂-CH₂-CH₂-indole), 33.7 (CH₂-CH₂-CH₂-indole),

111.7 (C₇indole), 114.5 (C₃indole), 118.5 (C₄indole), 118.7 (C₅

indole), 121.2 (C₆indole), 122.6 (C₂indole), 127.6 (C₉indole),

136.7 (C₈indole), 172.0 (CO); MS (ES) m/z 218.1 [M + H]⁺;

HPLC t_R, 0.93 min (conditions A).

General Procedure for Thioamide 2 Preparation. In a solution

of DCM, amine (1.0 equiv), Boc-^D-Trp (1.0 equiv), NMM (2.2

equiv), and BOP (1.0 equiv) were successively added. After 1 h of

stirring at room temperature, the mixture was concentrated in vacuo

and dissolved in AcOEt. The organic layer was successively washed

with aqueous solutions of 1 M KHSO₄, saturated NaHCO₃, and

brine. The organic layer was then dried over Na₂SO₄, filtered, and

concentrated in vacuo to yield amide 1 that was used without

purification. To 1.0 equiv of amide 1 in DME (10 mL/mmol) was

added Lawesson’s reagent (0.5 equiv) under argon. The reaction

mixture was heated to 85 °C for 2 h and then concentrated in vacuo.

The residue was purified by chromatography on silica gel with a

mixture of AcOEt/hexane 3/7 as eluent. The thioamide 2 was

obtained as a white powder (yields between 35% and 70% for the

two steps).

CH₂âTrp), 3.30 (dd, 1H, J ) 4 and 14 Hz, CH₂âTrp), 3.71 (s,

3H, CH₃O), 3.75 (s, 3H, CH₃O), 4.58 (m, 3H, CH₂-o,p-

dimethoxybenzyl and CH RTrp), 6.37 (dd, 1H, J_o) 8 Hz and J_m

) 2 Hz, H₅o,p-dimethoxybenzyl), 6.53 (d, 1H, J_m) 2 Hz, H₃

o,p-dimethoxybenzyl), 6.86 (d, 1H, J_o) 8 Hz, H₄Trp), 6,87 (d,

1H, J_o) 8 Hz, H₆o,p-dimethoxybenzyl), 6.95 (t, 1H, J_o) 7 Hz,

H₅Trp), 7.03 (t, 1H, J_o) 7 Hz, H₆Trp), 7.11 (s, 1H, H₂Trp),

7.30 (d, 1H, J_o) 8 Hz, H₇Trp), 7.60 (m, 1H, NH Trp), 9.97 (t,

1H, J ) 6 Hz, NH-thioamide), 10.78 (s, 1H, NH indole Trp). ¹³

C

NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 28.5 (CH₃Boc), 31.3

(CH₂âTrp), 44.2 (CH₂-o,p-dimethoxybenzyl), 55.6 (OCH₃), 55.9

(OCH₃), 61.9 (CH RTrp), 78.6 (Cq Boc), 98.7 (C₃o,p-dimethoxy-

benzyl), 104.8 (C₅o,p-dimethoxybenzyl), 110.4 (C₃Trp), 111.7

(C₇Trp), 116.7 (C₁o,p-dimethoxybenzyl), 118.6 (C₄Trp), 118.9

(C₅Trp), 121.2 (C₆Trp), 124.4 (C₂Trp), 127.8 (C₉Trp), 130.1

(C₆o,p-dimethoxybenzyl), 136.5 (C₈Trp), 155.5 (CO Boc), 158.6

(C₂o,p-dimethoxybenzyl), 161.1 (C₄o,p-dimethoxybenzyl), 210.4

(CS thioamide). MS (ES) m/z 470.0 [M + H]⁺. HPLC t_R, 1.97

min (conditions A).

General Procedure for Preparation of Triazole 3. To a

solution of 1.0 equiv of thioamide 2 of tetrahydrofuran (10 mL/

mmol) was added 2.0 equiv of hydrazide and then 1.1 equiv of

mercury(II) acetate at room temperature. After 2 days, the mixture

was filtered on Celite and the filtrate was concentrated in vacuo.

The residue was purified by chromatography on silica gel with a

mixture of AcOEt/MeOH 96/4 as eluent. The desired compounds

were obtained as a white powder (yield ranging between 40% and

60%).

tert-Butyl (R)-1-(2-(1H-Indol-3-yl)ethylthiocarbamoyl)-2-(1H-

indol-3-yl)ethylcarbamate (2a). Obtained from Boc-^D-Trp and

tryptamine: 1.1 g (67%). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ 1.27 (s, 9H, CH₃Boc), 2.86 (m, 2H, CH₂-CH₂-indole), 2.95

tert-Butyl (R)-1-(4-(2-(1H-Indol-3-yl)ethyl)-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3yl)ethylcarbamate (3a). Obtained from 2a and

formic hydrazide. H NMR (400 MHz, DMSO-d₆) δ 1.28 (s, 9H,

Boc), 2.84 (m, 2H, CH₂-CH₂-indole), 3.29 (m, 2H, CH₂âTrp),

1

1946 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

4.05 (m, 2H, CH₂-CH₂-indole), 4.95 (m, 1H, CH RTrp), 6.83

(brs, 1H, H indole), 6.88-6.97 (m, 2H, H indole), 6.98-7.10 (m,

3H, H indole), 7.31 (d, 1H, J ) 8 Hz, H indole), 7.32 (d, 1H, J )

8 Hz, H indole), 7.40 (d, 1H, J ) 8 Hz, H indole), 7.48 (d, 1H, J

) 8 Hz, H indole), 7.63 (d, 1H, J ) 8 Hz, NH Trp), 8.21 (brs, 1H,

H triazole), 10.80 (brs, 1H, NH indole), 10.85 (brs, 1H, NH indole).

MS (ES) m/z 415.0 [M + H - 56]⁺, 471.3 [M + H]⁺, 941.3 [2M

+ H]⁺.

tert-Butyl (R)-1-(5-((1H-Indol-3-yl)methyl)-4-methyl-4H-1,2,4-

triazol-3-yl)-2-(1H-indol-3-yl)ethylcarbamate (3b). Obtained from

2b and 2-(1H-indol-3-yl)acetohydrazide. ¹H NMR (400 MHz,

DMSO-d₆) δ 1.21 (s, 9H, CH₃Boc), 3.10-3.30 (m, 5H, 3H N-CH₃

and 2H CH₂â), 4.15 (m, 2H, CH₂-indole), 4.90 (m, 1H, CH RTrp),

6.90-7.10 (m, 6H, H indole), 7.33 (d, 1H, J ) 8 Hz, H indole),

7.35 (d, 1H, J ) 8 Hz, H indole), 7.41-7.58 (3H, 2H indole, NH

Trp), 10.75 (1H, s, NH indole), 10.90 (1H, s, NH indole). MS (ES)

m/z 471.4 [M + H]⁺, 941.3 [2M + H]⁺.

(R)-N-(1-(4-(2-(1H-Indol-3-yl)ethyl)-4H-1,2,4-triazol-3-yl)-2-

(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Trifluo-

roacetate Salt (11). Obtained from 3a. ¹H NMR (400 MHz,

DMSO-d₆) δ 1.29 (s, 3H, CH₃Aib), 1.35 (s, 3H, CH₃Aib), 2.85

(m, 1H, 1H N-CH₂-CH₂-indole), 2.89 (m, 1H, 1H, N-CH₂-

CH₂-indole), 3.28 (dd, 1H, J ) 14 Hz, J ) 7 Hz, CH₂âTrp),

3.40 (dd, 1H, J ) 14 Hz and J ) 8 Hz, CH₂âTrp), 4.10 (m, 2H,N-

CH₂-CH₂-In), 5.25 (m, 1H, CH RTrp), 6.85 (d, 1H, J ) 2 Hz,

H₂indole), 6.90-6.98 (m, 2H, H₅indole), 7.01 (d, 1H, J ) 2 Hz,

H₂indole), 7.02-7.12 (m, 2H, H₆indole), 7.30 (d, 1H, J ) 8.2

Hz, H₇indole), 7.33 (d, 1H, J ) 8 Hz, H₇indole), 7.40 (d, 1H, J

) 8 Hz, H₄indole), 7.47 (d, 1H, J ) 8 Hz, H₄indole), 8.04 (brs,

3H, NH₂Aib, TFA salt), 8.42 (s, 1H, H triazole), 9.01 (d, 1H, J )

8 Hz, NH Trp), 10.81 (s, 1H, NH indole), 10.90 (s, 1H, NH indole).

(R)-N-(1-(5-((1H-Indol-3-yl)methyl)-4-methyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

1

fluoroacetate Salt (12). Obtained from 3b. H NMR (400 MHz,

DMSO-d₆) δ 1.20 (s, 3H, CH₃Aib), 1.28 (s, 3H, CH₃Aib), 3.32

(d, 3H, N-CH₃), 3.30-3.45 (m, 2H, CH₂âTrp), 4.22 (s, 2H, CH₂-

indole), 5.30 (m, 1H, CH RTrp), 6.91 (t, 1H, J ) 8 Hz, H₅indole),

6.94 (d, 1H, J ) 8 Hz, H₅indole), 7.02 (t, 1H, J ) 8 Hz, H₆indole),

7.05 (t, 1H, J ) 8 Hz, H₆indole), 7.08 (d, 1H, J ) 2 Hz, H₂indole),

7.12 (d, 1H, J ) 2 Hz, H₂indole), 7.29 (d, 1H, J ) 8 Hz, H₇

indole), 7.33 (d, 1H, J ) 8 Hz, H₇indole), 7.48 (d, 1H, J ) 8 Hz,

H₄indole), 7.57 (d, 1H, J ) 8 Hz, H₄indole), 8.00 (brs, 3H, NH₂

Aib, TFA salt), 8.85 (d, 1H, J ) 8 Hz, NH amide), 10.82 (s, 1H,

NH indole), 10.98 (s, 1H, NH indole).

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-methyl-4H-1,2,4-tri-

azol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (13). Obtained from 3c. ¹H NMR (400

MHz, DMSO-d₆) δ 1.30 (s, 3H, CH₃Aib), 1.40 (s, 3H, CH₃Aib),

3.00-3.20 (m, 4H, CH₂-CH₂-indole), 3.36 (s, 3H, N-CH₃),

3.45-3.50 (m, 2H, CH₂âTrp), 5.30 (m, 1H, CH RTrp), 6.95-

7.04 (t, 2H, H₅indole), 7.06-7.13 (m, 2H, H₆indole), 7.18 (brs,

2H, H₂indole), 7.34 (d, 1H, J ) 8 Hz, H₇indole), 7.36 (d, 1H, J

) 8 Hz, H₇indole), 7.48 (d, 1H, J ) 8 Hz, H₄indole), 7.58 (d,

1H, J ) 8 Hz, H₄indole), 8.10 (brs, 3H, NH₂Aib, TFA salt), 8.95

(d, 1H, J ) 8 Hz, NH amide), 10.95 (s, 1H, NH indole), 10.96 (s,

1H, NH indole). ¹³C NMR (100 MHz, DMSO-d₆) 22.9 (CH₂-

CH₂-indole), 24.1 (CH₃Aib), 24.3 (CH₃Aib), 25.9 (CH₂-CH₂-

indole), 28.8 (C âTrp), 30.7 (NCH₃), 46.2 (C RTrp), 57.2 (Cq Aib),

110.2 (C₃indole), 112.3 (2C₇indole), 113.5 (C₃indole), 118.9-

119.2 (2C₅, 2C₄indole), 121.9 (2C₆indole), 123.6 (C₂indole), 125.3

(C₂indole), 127.7 (C₉indole), 128.0 (C₉indole), 136.9 (C₈indole),

137.1 (C₈indole), 155.3 (Cq triazole), 155.8 (Cq triazole), 172.2

(CO Aib).

tert-Butyl (R)-1-(5-(2-(1H-Indol-3-yl)ethyl)-4-methyl-4H-1,2,4-

triazol-3-yl)-2-(1H-indol-3-yl)ethylcarbamate (3c). The title com-

pound was obtained as previously described by reacting thioamide

1

2b with 3-(1H-indol-3-yl)propanehydrazide. H NMR (400 MHz,

DMSO-d₆) δ 1.32 (s, 9H, CH₃Boc), 2.85-3.10 (m, 4H, CH₂-

CH₂-indole), 3.20 (s, 3H, N-CH₃), 3.22-3.40 (m, 2H, CH₂âTrp),

4.92 (m, 1H, CH RTrp), 6.93-7.02 (m, 2H, H indole), 7.04-7.10

(m, 2H, H indole), 7.13 (s, 1H, H indole), 7.16 (s, 1H, H indole),

7.32-7.38 (m, 2H, H indole), 7.42-7.52 (m, 3H, 2H indole and

NH Trp), 10.85 (brs, 2H, NH indole). MS (ES) m/z 485,3 [M +

H]⁺.

tert-Butyl (R)-1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(2,4-dimethoxy-

benzyl)-4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethylcarbamate

(3d). The title compound was obtained as previously described by

reacting thioamide 2c with 3-(1H-indol-3-yl)propanehydrazide: 1.2

1

g (65%). H NMR (300 MHz, DMSO-d₆, 300 K) δ 1.21 (s, 9H,

CH₃Boc), 2.90 (m, 4H, CH₂-CH₂-indole), 3.28 (m, 2H, CH₂

âTrp), 3.59 (s, 3H, OCH₃), 3.66 (s, 3H, OCH₃), 5.01 (m, 3H, CH₂-

o,p-dimethoxybenzyl and CH RTrp), 6.26 (d, 1H, J_o) 8 Hz, H₅

o,p-dimethoxybenzyl), 6.49 (d, 1H, J_o) 8 Hz, H₆o,p-dimethoxy-

benzyl), 6.51 (s, 1H, H₃o,p-dimethoxybenzyl), 6.89 (m, 2H, H₅

Trp and H₅indole), 7.02 (m, 2H, H₆indole and H₆Trp), 7.03 (s,

1H, H₂indole), 7.05 (s, 1H, H₂Trp), 7.26 (d, 1H, J_o) 8 Hz, H₄

Trp), 7.29 (m, 3H, H₄and H₇indole, H₇Trp), 7.57 (d, 1H, J ) 9

Hz, NH Boc), 10.79 (s, 1H, NH indole), 10.81 (s, 1H, NH indole

Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ 22.4 (CH₂-CH₂-

indole), 25.7 (CH₂-CH₂-indole), 28.4 (CH₃Boc), 28.9 (C âTrp),

42.6 (CH₂-o,p-dimethoxybenzyl), 46.8 (C RTrp), 55.6 (OCH₃),

55.8 (OCH₃), 78.8 (Cq Boc), 98.9 (C₃o,p-dimethoxybenzyl), 105.1

(C₅o,p-dimethoxybenzyl), 110.0 (C₃Trp), 111.7 (C₇Trp), 111.8

(C₇indole), 112.9 (C₃indole), 114.8 (C₁o,p-dimethoxybenzyl),

118.4 (C₄indole and C₄Trp), 118.7 (C₅indole and C₅Trp), 121.3

(C₆Trp), 121.4 (C₆indole), 123.0 (C₂indole), 125.1 (C₂Trp), 127.1

(C₉indole), 127.5 (C₉Trp), 128.5 (C₆o,p-dimethoxybenzyl), 136.4

(C₈Trp), 136.6 (C₈indole), 155.5 (Cq triazole and CO Boc), 156.1

(Cq triazole), 157.8 (C₂o,p-dimethoxybenzyl), 161.0 (C₄o,p-

dimethoxybenzyl). MS (ES) m/z 621.0 [M + H]⁺. HPLC t_R, 2.20

min (conditions A).

(R)-N-(1-(5-((1H-Indol-3-yl)methyl)-4H-1,2,4-triazol-3-yl)-2-

(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Trifluo-

roacetate Salt (14). Compound 14 was obtained by treatment of

1

compound 15 with TFA. H NMR (400 MHz, DMSO-d₆) δ 1.31

(s, 3H, CH₃Aib), 1.42 (s, 3H, CH₃Aib), 3.19 (dd, 1H, J ) 15 Hz

and J ) 10 Hz, CH₂âTrp), 3.35 (dd, 1H, J ) 15 Hz, J ) 5 Hz,

CH₂âTrp), 4.15 (s, 2H, CH₂indole), 5.26 (m, 1H, CH RTrp), 6.95

(t, 1H, H₅Trp), 6.96 (t, 1H, H₅indole), 7.05 (t, 1H, H₆Trp), 7.06

(s, 1H, H₂Trp), 7.07 (t, 1H, H₆indole), 7.21 (s, 1H, H₂indole),

7.32 (d, 1H, H₇Trp), 7.37 (d, 1H, H₇indole), 7.51 (d, 1H, J ) 8

Hz, H₄indole), 7.58 (d, 1H, J ) 8 Hz, H₄Trp), 8.00 (s, 3H, NH₂

Aib, TFA salt), 8.64 (d, 1H, J ) 9 Hz, NH amide), 10.77 (s, 1H,

NH indole Trp), 10.92 (s, 1H, NH indole). ¹³C NMR (100 MHz,

DMSO-d₆) δ 22.9 (CH₂-indole), 23.2 (CH₃Aib), 23.3 (CH₃Aib),

29.4 (C âTrp), 48.3 (C RTrp), 56.3 (Cq Aib), 109.7 (C₃indole),

110.3 (C₃Trp), 111.2 (C₇Trp), 111.3 (C₇indole), 118.1 (C₄Trp,

C₅Trp), 118.3 (C₄indole), 118.4 (C₅indole), 120.7 (C₆Trp), 121.0

(C₆indole), 123.4 (C₂indole), 123.6 (C₂Trp), 126.8 (C₉indole),

127.1 (C₉Trp), 136.0 (C₈Trp), 136.2 (C₈indole), 157.5 (Cq

triazole), 161.7 (Cq triazole), 170.8 (CO Aib).

General Procedure for Preparation of Compound 5. The Boc

protecting group of compound 3 was removed at room temperature

for 1 h with a solution of AcOEt/HCl 4 M. The mixture was then

concentrated in vacuo, diluted with MeOH, and concentrated several

times in vacuo. The residue was then coupled with Boc-Aib (1.1

equiv), in the presence of BOP (1.1 equiv) and NMM (2.2 equiv)

for 2 h, in DCM. The mixture was then concentrated in vacuo, and

the residue was dissolved in AcOEt. The organic layer was

successively washed with aqueous solutions of 1 M KHSO₄,

saturated NaHCO₃, and brine. The organic layer was then dried

over Na₂SO₄, filtered, and concentrated in vacuo to yield the desired

compound which was then treated with AcOEt/HCl 4 M as already

described. The final compound was purified by preparative HPLC

on a C18 column using a water/acetonitrile/TFA 0.1% gradient

(yield around 50% for the three steps).

(R)-N-(1-(5-((1H-Indol-3-yl)methyl)-4-(2,4-dimethoxybenzyl)-

4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-meth-

1

ylpropanamide Trifluoroacetate Salt (15). H NMR (400 MHz,

DMSO-d₆) δ 1.27 (s, 3H, CH₃Aib), 1.29 (s, 3H, CH₃Aib), 3.25

(dd, 1H, J ) 14 Hz, J ) 6 Hz, CH₂âTrp), 3.38 (dd, 1H, J ) 14

Triazole DeriVatiVes as Ghrelin Receptor Ligands

Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8 1947

Hz and J ) 9 Hz, CH₂âTrp), 3.68 (s, 3H, OCH₃), 3.72 (s, 3H,

OCH₃), 4.10 (d, 1H, J ) 17 Hz, CH₂-indole), 4.16 (d, 1H, J ) 17

Hz, CH₂-indole), 4.96 (d, 1H, J ) 17 Hz, CH₂o,p-dimethoxy-

benzyl), 5.12 (d, 1H, J ) 17 Hz, CH₂o,p-dimethoxybenzyl), 5.16

(m, 1H, CH RTrp), 6.21 (dd, 1H, J ) 9 Hz and J ) 2 Hz, H₅

o,p-dimethoxybenzyl), 6.27 (d, 1H, J ) 9 Hz, H₆o,p-dimethoxy-

benzyl), 6.57 (d, 1H, J ) 2 Hz, H₃o,p-dimethoxybenzyl), 6.83 (t,

1H, H₅Trp), 6.94 (t, 1H, H₅indole), 7.02 (t, 1H, H₆Trp), 7.05 (s,

1H, H₂indole),7.06 (t, 1H, H₆indole), 7.07 (s, 1H, H₂Trp), 7.07

(d, 1H, H₄Trp), 7.31 (d, 1H, H₇Trp), 7.33 (d, 1H, H₇indole),

7.36 (d, 1H, J ) 8 Hz, H₄indole), 8.00 (brs, 3H, NH₂Aib, TFA

salt), 8.92 (d, 1H, J ) 8 Hz, NH amide), 10.79 (s, 1H, NH indole

Trp), 10.89 (s, 1H, NH indole). ¹³C NMR (100 MHz, DMSO-d₆)

δ 21.2 (CH₂indole), 23.1 (CH₃Aib), 23.2 (CH₃Aib), 28.6 (C âTrp),

41.4 (N-CH₂o,p-dimethoxybenzyl), 45.1 (C RTrp), 55.2 (OCH₃),

55.4 (OCH₃), 56.2 (Cq Aib), 98.5 (C₃o,p-dimethoxybenzyl), 104.6

(C₅o,p-dimethoxybenzyl), 107.9 (C₃indole), 109.5 (C₃Trp), 111.2

(C₇Trp), 111.3 (C₇indole), 115.1 (C₁o,p-dimethoxybenzyl), 117.8

(C₄Trp), 118.1 (C₅Trp), 118.3 (C₄indole), 118.4 (C₅indole), 120.8

(C₆Trp), 121.1 (C₆indole), 123.5 (C₂indole), 124.3 (C₂Trp), 126.6

(C₉indole), 126.8 (C₉Trp), 127.2 (C₆o,p-dimethoxybenzyl), 136.0

(C₈Trp), 136.2 (C₈indole), 157.5 (Cq triazole), 154.9 (Cq triazole),

157.2 (C₂o,p-dimethoxybenzyl), 160.3 (C₄o,p-dimethoxybenzyl),

171.2 (CO Aib).

(Cq Aib), 98.5 (C₃o,p-dimethoxybenzyl), 104.7 (C₅o,p-dimethoxy-

benzyl), 109.5 (C₃Trp), 111.3 (C₇Trp), 115.1 (C₁o,p-dimethoxy-

benzyl), 117.8 (C₄Trp), 118.2 (C₅Trp), 120.8 (C₆Trp), 124.3 (C₂

Trp), 126.5 (C₄benzyl), 126.8 (C₉Trp), 127.3 (C₆o,p-dimethoxy-

benzyl), 128.3 (C₂,C₃, C₅, C₆benzyl), 135.8 (C₁benzyl), 136.0 (C₈

Trp), 153.4 (Cq triazole), 155.0 (Cq triazole), 157.2 (C₂o,p-

dimethoxybenzyl), 160.3 (C₄o,p-dimethoxybenzyl), 171.3 (CO

Aib).

(R)-N-(1-(4-(2,4-Dimethoxybenzyl)-5-phenethyl-4H-1,2,4-tri-

azol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (16c). ¹H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 1.26 (s, 3H, CH₃Aib), 1.30 (s, 3H, CH₃Aib),

2.82 (m, 4H, CH₂-CH₂-phenyl), 3.29 (t, 2H, J ) 8 Hz, CH₂âTrp),

3.61 (s, 3H, OCH₃), 3.68 (s, 3H, OCH₃), 4.85 (d, 1H, J ) 17 Hz,

CH₂-o,p-dimethoxybenzyl), 5.02 (d, 1H, J ) 17 Hz, CH₂-o,p-

dimethoxybenzyl), 5.18 (m, 1H, CH RTrp), 6.29 (dd, 1H, J_o) 8

Hz and J_m) 2 Hz, H₅o,p-dimethoxybenzyl), 6.40 (d, 1H, J_o) 8

Hz, H₆o,p-dimethoxybenzyl), 6.55 (d, 1H, J_m) 2 Hz, H₃o,p-

dimethoxybenzyl), 6.82 (t, 1H, J_o) 8 Hz, H₅Trp), 6.99 (t, 1H, J_o

) 8 Hz, H₆Trp), 7.05 (s, 1H, H₂Trp), 7.09-7.24 (m, 6H, H₄Trp

and CHar phenyl), 7.27 (d, 1H, J_o) 8 Hz, H₇Trp), 7.99 (s3H,

large, NH₂Aib TFA salt), 8.89 (d, 1H, J ) 8 Hz, NH amide),

10.77 (s, 1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300

K) δ (ppm) 23.6 (CH₃Aib), 23.7 (CH₃Aib), 26.5 (CH₂-CH₂-

phenyl), 29.2 (CH₂âTrp), 32.7 (CH₂-CH₂-phenyl), 41.6 (CH₂-

o,p-dimethoxybenzyl), 45.7 (CH RTrp), 55.7 (OCH₃), 55.9 (OCH₃),

56.7 (Cq Aib), 99.1 (C₃o,p-dimethoxybenzyl), 105.2 (C₅o,p-

dimethoxybenzyl), 110.0 (C₃Trp), 111.8 (C₇Trp), 115.7 (C₁o,p-

dimethoxybenzyl), 118.3 (C₄Trp), 118.7 (C₅Trp), 121.3 (C₆Trp),

126.5 (C₂Trp and C₆o,p-dimethoxybenzyl), 127.3 (C₉Trp), 128.1

(C₄phenyl), 128.7 (C₂, C₃, C₅and C₆phenyl), 136.4 (C₈Trp), 140.9

(C₁phenyl), 154.5 (Cq triazole), 155.0 (Cq triazole), 157.8 (C₂o,p-

dimethoxybenzyl), 160.9 (C₄o,p-dimethoxybenzyl), 171.7 (CO

amide).

(R)-N-(1-(4-(3,5-Dimethoxybenzyl)-5-phenethyl-4H-1,2,4-tri-

azol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (17b). ¹H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 1.24 (s, 3H, CH₃Aib), 1.27 (s, 3H, CH₃Aib),

2.83 (s, 4H, CH₂-CH₂-phenyl), 3.32 (m, 2H, CH₂âTrp), 3.61 (s,

6H, OCH₃), 5.02 (m, 2H, CH₂-m-dimethoxybenzyl), 5.18 (m, 1H,

CH RTrp), 6.07 (d, 2H, J_m) 2 Hz, H₂and H₆m-dimethoxybenzyl),

6.42 (brs, 1H, H₄m-dimethoxybenzyl), 6.83 (t, 1H, J_o) 7 Hz, H₅

Trp), 6.99 (t, 1H, J_o) 8 Hz, H₆Trp), 7.08 (d, 1H, J ) 2 Hz, H₂

Trp), 7.13 (t, 3H, J_o) 8 Hz, H₃, H₄and H₅phenyl), 7.20 (d, 3H,

J_o) 7 Hz, H₂and H₆phenyl, H₄Trp), 7.28 (d, 1H, J_o) 8 Hz, H₇

Trp), 7.99 (brs, 3H, NH₂Aib), 8.92 (d, 1H, J ) 8 Hz, NH amide),

10.77 (s, 1H, NH indole). ¹³C NMR (75 MHz, DMSO-d₆, 300 K)

δ (ppm) 23.5 (CH₃Aib), 23.8 (CH₃Aib), 26.5 (CH₂-CH₂-phenyl),

29.2 (CH₂âTrp), 32.7 (CH₂-CH₂-phenyl), 45.6 (CH RTrp), 45.8

(CH₂- m-dimethoxybenzyl), 55.6 (OCH₃), 56.8 (Cq Aib), 99.6 (C₄

m-dimethoxybenzyl), 104.6 (C₂and C₆m-dimethoxybenzyl), 109.9

(C₃Trp), 111.8 (C₇Trp), 118.2 (C₄Trp), 118.7 (C₅Trp), 121.3

(C₆Trp), 124.8 (C₂Trp), 126.5 (C₄phenyl), 127.3 (C₉Trp), 128.7

(C₂, C₃, C₅and C₆phenyl), 136.4 (C₈Trp), 138.6 (C₁m-

dimethoxybenzyl), 140.9 (C₁phenyl), 154.6 (Cq triazole), 154.8

(Cq triazole), 161.4 (C₃and C₅m-dimethoxybenzyl), 171.8 (CO

amide).

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(2,4-dimethoxybenzyl)-

4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-meth-

1

ylpropanamide Trifluoroacetate Salt (16). H NMR (400 MHz,

DMSO-d₆) δ 1.32 (s, 3H, CH₃Aib), 1.36 (s, 3H, CH₃Aib), 2.93

(m, 2H, CH₂-CH₂-indole), 2.97 (m, 2H, CH₂-CH₂-indole), 3.31

(dd, 1H, J ) 15 Hz and J ) 6 Hz, CH₂âTrp), 3.38 (dd, 1H, J )

15 Hz and J ) 9 Hz, CH₂âTrp), 3.66 (s, 3H, o-OCH₃), 3.72 (s,

3H, p-OCH₃), 4.93 (d, 1H, J ) 17 Hz, CH₂o,p-dimethoxybenzyl),

5.10 (d, 1H, J ) 17 Hz, CH₂o,p-dimethoxybenzyl), 5.23 (m, 1H,

CH RTrp), 6.31 (dd, 1H, J ) 9 Hz and J ) 2 Hz, H₅

o,p-dimethoxybenzyl), 6.45 (d, 1H, J ) 9 Hz, H₆o,p-dimethoxy-

benzyl), 6.59 (d, 1H, J ) 2 Hz, H₃o,p-dimethoxybenzyl), 6.88 (t,

1H, J ) 8 Hz, H₅Trp), 6.94 (t, 1H, J ) 8 Hz, H₅indole), 7.04 (t,

1H, H₆Trp), 7.06 (t, 1H, H₆indole), 7.08 (s, 1H, H₂indole), 7.11

(s, 1H, H₂Trp), 7.18 (d, 1H, J ) 8, H₄Trp), 7.33 (3H, H₄, H₇

indole, H₇Trp), 8.05 (s, 3H, NH₂Aib, TFA salt), 8.95 (d, 1H, J )

8 Hz, NH amide), 10.80 (s, 1H, NH indole), 10.82 (s, 1H, NH

indole Trp). ¹³C NMR (100 MHz, DMSO-d₆) δ 22.4 (CH₂-CH₂

indole), 23.2 (CH₃Aib), 23.3 (CH₃Aib), 25.4 (CH₂-CH₂indole),

28.7 (C âTrp), 41.3 (CH₂-o,p-dimethoxybenzyl), 45.3 (C RTrp),

55.2 (p-OCH₃), 55.4 (o-OCH₃), 56.3 (Cq Aib), 98.6 (C₃o,p-

dimethoxybenzyl), 104.7 (C₅o,p-dimethoxybenzyl), 109.5 (C₃Trp),

111.3 (C₇Trp, C₇indole), 112.9 (C₃indole), 115.2 (C₁o,p-

dimethoxybenzyl), 117.8 (C₄indole), 117.9 (C₄Trp), 118.2 (C₅

Trp, C₅indole), 120.9 (C₆Trp, C₆indole), 122.4 (C₂indole), 124.3

(C₂Trp), 126.8 (C₉Indole), 126.9 (C₉Trp), 127.5 (C₆o,p-

dimethoxybenzyl), 136.0 (C₈Trp), 136.2 (C₈indole), 154.6 (2Cq

triazole), 157.3 (C₂o,p-dimethoxybenzyl), 160.4 (C₄o,p-dimethoxy-

benzyl), 171.3 (CO Aib).

(R)-N-(1-(4-(2,4-Dimethoxybenzyl)-5-benzyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

1

fluoroacetate Salt (16a). H NMR (400 MHz, DMSO-d₆) δ 1.30

(s, 3H, CH₃Aib), 1.33 (s, 3H, CH₃Aib), 3.26 (dd, 1H, J ) 14 Hz

and J ) 6 Hz, CH₂âTrp), 3.38 (dd, 1H, J ) 14 Hz and J ) 9 Hz,

CH₂âTrp), 3.69 (s, 3H, OCH₃), 3.72 (s, 3H, OCH₃), 4.02 (s, 2H,

CH₂-benzyl), 4.87 (d, 1H, J ) 17 Hz, CH₂-o,p-dimethoxybenzyl),

5.08 (d, 1H, J ) 17 Hz, CH₂o,p-dimethoxybenzyl), 5.17 (m, 1H,

CH RTrp), 6.24 (dd, 1H, J ) 8 Hz, J ) 2 Hz, H₅o,p-

dimethoxybenzyl), 6.28 (d, 1H, J ) 8 Hz, H₆o,p-dimethoxybenzyl),

6.56 (d, 1H, J ) 2 Hz, H₃o,p-dimethoxybenzyl), 6.85 (t, 1H, J )

8 Hz, H₅Trp), 7.02 (t, 1H, H₆Trp), 7.07 (m, 2H, H₂, H₆benzyl),

7.08 (s, 1H, H₂Trp), 7.09 (d, 1H, H₄Trp), 7.16-7.29 (m, 3H, H₃,

H₄, H₅benzyl), 7.31 (d, 1H, J ) 8 Hz, H₇Trp), 8.01 (s, 3H, NH₂

Aib, TFA salt), 8.92 (d, 1H, J ) 8 Hz, NH amide), 11.79 (s, 1H,

NH indole Trp). ¹³C NMR (100 MHz, DMSO-d₆) δ 23.2 (2CH₃

Aib), 28.7 (C âTrp), 30.2 (CH₂-benzyl), 41.3 (CH₂-o,p-

dimethoxybenzyl), 45.2 (C RTrp), 55.2 (OCH₃), 55.4 (OCH₃), 56.2

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(3-methoxybenzyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpro-

panamide Trifluoroacetate Salt (18a). ¹H NMR (400 MHz,

DMSO-d₆) δ 1.28 (s, 3H, CH₃Aib), 1.30 (s, 3H, CH₃Aib), 2.92

(m, 2H, CH₂-CH₂-indole), 2.98 (m, 2H, CH₂-CH₂-indole), 3.33

(dd, 1H, J ) 15 Hz and J ) 6 Hz, CH₂âTrp), 3.40 (dd, 1H, J )

15 Hz and J ) 9 Hz, CH₂âTrp), 3.66 (s, 3H, OCH₃), 5.09 (m, 2H,

CH₂-m-methoxybenzyl), 5.22 (m, 1H, CH RTrp), 6.38 (d, 1H, J

) 8 Hz, H₆m-methoxybenzyl), 6.59 (s, 1H, H₂m-methoxybenzyl),

6.86 (t, 1H, H₅Trp), 6.87 (d, 1H, H₄m-methoxybenzyl), 6.92 (t,

1H, J ) 7.5 Hz, H₅indole), 7.03 (t, 1H, J ) 7.9 Hz, H₆Trp), 7.05

(t, 1H, H₆indole), 7.07 (s, 1H, H₂indole), 7.11 (s, 1H, H₂Trp),

7.18 (t, 1H, H₅m-methoxybenzyl), 7.19 (d, 1H, H₄Trp), 7.31 (1H,

H₄indole), 7.32 (2H, H₇Trp, H₇indole), 8.00 (s, 3H, NH₂Aib,

1948 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

TFA salt), 8.96 (d, 1H, J ) 8 Hz, NH amide), 10.78 (s, 1H, NH

indole), 10.80 (s, 1H, NH indole Trp). ¹³C NMR (100 MHz, DMSO-

d₆) δ 22.4 (CH₂-CH₂-indole), 23.1 (CH₃Aib), 23.3 (CH₃Aib),

25.4 (CH₂-CH₂indole), 28.7 (C âTrp), 45.3 (CH₂m-methoxy-

benzyl), 45.4 (C RTrp), 55.0 (OCH₃), 56.3 (Cq Aib), 109.5 (C₃

Trp), 111.3 (C₇Trp, C₇indole), 112.0 (C₂m-methoxybenzyl), 113.0

(C₄m-methoxybenzyl, C₃indole), 117.8 (C₄Trp, C₆m-methoxy-

benzyl), 118.0 (C₄indole), 118.2 (C₅indole), 118.3 (C₅Trp), 120.8

(C₆indole), 120.9 (C₆Trp), 122.4 (C₂indole), 124.3 (C₂Trp), 126.7

(C₉indole), 126.9 (C₉Trp), 130.0 (C₅m-methoxybenzyl), 136.0

(C₈indole), 136.1 (C₈Trp), 137.2 (C₁m-methoxybenzyl), 154.3

(2Cq triazole), 159.6 (C₃m-methoxybenzyl), 171.4 (CO amide).

(R)-N-(1-(5-(3-(1H-Indol-3-yl)propyl)-4-(3-methoxybenzyl)-

4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-meth-

ylpropanamide Trifluoroacetate Salt (18b). ¹H NMR (400 MHz,

DMSO-d₆) δ 1.27 (s, 3H, CH₃Aib), 1.30 (s, 3H, CH₃Aib), 1.92

(m, 2H, CH₂-CH₂-CH₂-indole), 2.62 (m, 2H, CH₂-CH₂-CH₂-

indole), 2.68 (m, 2H, CH₂-CH₂-CH₂-indole), 3.24 (dd, 1H, J )

14.5, J ) 5.8, CH₂âTrp), 3.39 (dd, 1H, J ) 14.5, J ) 9.0, CH₂

âTrp), 3.66 (s, 3H, m-OCH₃), 5.07 (s, 2H, CH₂m-methoxybenzyl),

5.18 (m, 1H, CH R Trp), 6.35 (d, 1H, J ) 7.5, H₆m-methoxyben-

zyl), 6.54 (brs, 1H, H₂m-methoxybenzyl), 6.84 (t, 1H, J ) 7.5, H₅

Trp), 6.87 (dd, 1H, J ) 8.0, J ) 2.1, H₄m-methoxybenzyl), 6.94

(t, 1H, J ) 7.3, H₅indole), 7.02 (t, 1H, H₆Trp), 7.02 (s, 1H, H₂

indole), 7.05 (t, 1H, J ) 7.8, H₆indole), 7.08 (d, 1H, J ) 2.1, H₂

Trp), 7.13 (d, 1H, J ) 8.1, H₄Trp), 7.17 (t, 1H, J ) 8.1, H₅

m-methoxybenzyl), 7.30 (d, 1H, H₇Trp), 7.32 (d, 1H, J ) 8, H₇

indole), 7.42 (d, 1H, J ) 7.6, H₄indole), 7.98 (brs, 3H, NH₂Aib,

TFA salt), 8.93 (d, 1H, J ) 8.2, NH amide), 10.71 (s, 1H, NH

indole), 10.77 (s, 1H, NH indole Trp). ¹³C NMR (100 MHz,DMSO-

d₆) δ 23.1 (CH₃Aib), 23.3 (CH₃Aib), 23.9 (CH₂-CH₂-CH₂-

indole), 24.3 (CH₂-CH₂-CH₂-indole), 27.4 (CH₂-CH₂-CH₂

indole), 28.8 (C âTrp), 45.2 (CH₂- m-methoxybenzyl), 45.4 (C

RTrp), 55.1 (m-OCH₃), 56.3 (Cq Aib), 109.5 (C₃Trp), 111.3 (C₇

Trp, C₇indole), 111.8 (C₂m-methoxybenzyl), 113.0 (C₄m-

methoxybenzyl), 113.8 (C₃indole), 117.8 (C₆m-methoxybenzyl),

117.9 (C₄Trp), 118.1 (C₅indole), 118.2 (C₅Trp, C₄indole), 120.8

(C₆Trp), 120.9 (C₆indole), 122.2 (C₂indole), 124.3 (C₂Trp), 126.8

(C₉Trp), 127.0 (C₉indole), 130.0 (C₅m-methoxybenzyl), 136.0

(C₈Trp), 136.2 (C₈indole), 137.4 (C₁m-methoxybenzyl), 154.3

(Cq triazole), 154.6 (Cq triazole), 159.7 (C₃m-methoxybenzyl),

171.4 (CO amide).

3.61 (s, 3H, m-OCH₃), 4.04 (m, 2H, CH₂benzyl), 5.07 (d, 1H, J )

17.4, CH₂m-methoxybenzyl), 5.13 (d, 1H, J ) 17.4, CH₂

m-methoxybenzyl), 5.14 (m, 1H, CH RTrp), 6.32 (d, 1H, J ) 7.8,

H₆m-methoxybenzyl), 6.40 (m, 1H, H₂m-methoxybenzyl), 6.82

(t, 1H, H₅Trp), 6.83 (d, 1H, J ) 7.8, H₄m-methoxybenzyl), 7.01

(t, 1H, J ) 8.2, H₆Trp), 7.04 (d, 1H, J ) 8.2, H₄Trp), 7.06 (d,

1H, J ) 2.0, H₂Trp), 7.12 (m, 2H, H₂, H₆benzyl), 7.13 (t, 1H, J

) 7.9, H₅m-methoxybenzyl), 7.20 (m, 1H, H₄benzyl), 7.24 (m,

2H, H₃, H₅benzyl), 7.29 (d, 1H, J ) 8.2, H₇Trp), 7.99 (brs, 3H,

NH₂Aib, TFA salt), 8.92 (d, 1H, J ) 8.2, NH amide), 10.77 (s,

1H, NH indole Trp). ¹³C NMR (100 MHz, DMSO-d₆) δ 23.0 (CH₃

Aib), 23.3 (CH₃Aib), 28.6 (Câ Trp), 30.1 (CH₂benzyl), 45.2 (CR

Trp), 45.6 (CH₂- m-methoxybenzyl), 54.9 (m-OCH₃), 56.2 (Cq

Aib), 109.4 (C₃Trp), 111.2 (C₇Trp), 111.7 (C₂m-methoxybenzyl),

113.1 (C₄m-methoxybenzyl), 117.9 (C₄Trp, C₆m-methoxybenzyl),

118.2 (C₅Trp), 120.8 (C₆Trp), 124.3 (C₂Trp), 126.6 (C₄benzyl),

126.8 (C₉Trp), 128.3 (C₃, C₅benzyl), 128.4 (C₂, C₆benzyl), 129.9

(C₅m-methoxybenzyl), 135.9 (C₁benzyl, C₈Trp), 137.0 (C₁

m-methoxybenzyl), 153.5 (Cq triazole), 154.8 (Cq triazole), 159.5

(C₃m-methoxybenzyl), 171.3 (CO amide).

(R)-N-(1-(5-((1H-Indol-3-yl)methyl)-4-(4-methoxybenzyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpro-

panamide Trifluoroacetate Salt (19a). ¹H NMR (300 MHz,

DMSO-d₆) δ (ppm) 1.22 (s, 3H, CH₃Aib), 1.25 (s, 3H, CH₃Aib),

3.22 (dd, 1H, J ) 14 and 6 Hz, CH₂âTrp), 3.34 (dd, 1H, J ) 14

and 9 Hz, CH₂âTrp), 3.68 (s, 3H, OCH₃), 4.11 (m, 2H, CH₂-

indole), 5.09 (m, 3H, CH RTrp and CH₂-p-methoxybenzyl), 6.70

(s, 4H, CHar p-methoxybenzyl), 6.78 (m, 2H, H₅indole and H₅

Trp), 6.93 (m, 2H, H₆indole and H₆Trp), 7.01-7,06 (m, 3H, H₂

indole, H₂and H₄Trp), 7.31 (m, 3H, H₄and H₇indole, H₇Trp),

7.98 (brs, 3H, NH₂Aib, TFA salt), 8.92 (d, 1H, J ) 8 Hz, NH

amide), 10.77 (s, 1H, NH indole), 10.89 (s, 1H, NH indole Trp).

¹³C NMR (75 MHz, DMSO-d₆) δ (ppm) 21.7 (CH₂-indole), 23.5

(CH₃Aib), 23.7 (CH₃Aib), 28.9 (C âTrp), 45.6 (C RTrp), 45.8

(CH₂-p-methoxybenzyl), 55.5 (OCH₃), 56.7 (Cq Aib), 108.1 (C₃

indole), 109.7 (C₃Trp), 111.7 (C₇Trp), 111.9 (C₇indole), 114.5

(C₃and C₅p-methoxybenzyl), 118.3 (C₄Trp), 118.7 (C₄indole),

118.8 (C₅indole), 118.9 (C₅Trp), 121.3 (C₆indole), 121.6 (C₆

Trp), 124.2 (C₂indole), 125.3 (C₂Trp), 127.1 (C₉indole), 127.2

(C₉Trp), 127.6 (C₁p-methoxybenzyl), 127.8 (C₂and C₆p-

methoxybenzyl), 136.4 (C₈Trp), 136.7 (C₈indole), 154.2 (Cq

triazole), 155.2 (Cq triazole), 159.2 (C₄p-methoxybenzyl), 171.9

(CO amide).

(R)-N-(1-(4-(3-Methoxybenzyl)-5-phenethyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (18c). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.24 (s, 3H, CH₃Aib), 1.27 (s, 3H, CH₃Aib), 2.82 (m,

4H, CH₂-CH₂-phenyl), 3.32 (m, 2H, CH₂âTrp), 3.63 (s, 3H,

OCH₃), 5.08 (m, 2H, CH₂-m-methoxybenzyl), 5.18 (m, 1H, CH

RTrp), 6.35 (d, 1H, J_o) 8 Hz, H₆m-methoxybenzyl), 6.57 (s, 1H,

H₂m-methoxybenzyl), 6.82 (t, 1H, J_o) 8 Hz, H₅Trp), 6.84 (d,

1H, J_o) 8 Hz, H₄m-methoxybenzyl), 6.99 (t, 1H, J_o) 8 Hz, H₆

Trp), 7.08 (m, 1H, H₄phenyl), 7.11-7,16 (m, 5H, H₂and H₄Trp,

H₂and H₆phenyl, H₅m-methoxybenzyl), 7.20 (m, 2H, H₃and H₅

phenyl), 7.27 (d, 1H, J_o) 8 Hz, H₇Trp), 8.01 (brs, 3H, NH₂Aib,

TFA salt), 8.96 (d, 1H, J ) 8 Hz, NH amide), 10.81 (d, 1H, J )

2 Hz, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ

(ppm) 23.5 (CH₃Aib), 23.8 (CH₃Aib), 26.4 (CH₂-CH₂-phenyl),

29.1 (CH₂âTrp), 32.7 (CH₂-CH₂-phenyl), 45.7 (CH RTrp), 45.8

(CH₂-m-methoxybenzyl), 55.5 (OCH₃), 56.7 (Cq Aib), 109.8 (C₃

Trp), 111.8 (C₇Trp), 112.5 (C₂m-methoxybenzyl), 113.5 (C₄

m-methoxybenzyl), 118.2 (C₄Trp), 118.4 (C₆m-methoxybenzyl),

118.7 (C₅Trp), 121.3 (C₆Trp), 124.8 (C₂Trp), 126.5 (C₄phenyl),

127.3 (C₉Trp), 128.7 (C₂, C₃, C₅, and C₆phenyl), 130.5 (C₅

m-methoxybenzyl), 136.4 (C₈Trp), 137.7 (C₁m-methoxybenzyl),

140.9 (C₁phenyl), 154.6 (Cq triazole), 154.9 (Cq triazole), 160.1

(C₃m-methoxybenzyl), 171.9 (CO amide).

(R)-N-(1-(4-(4-Methoxybenzyl)-5-phenethyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (19b). ¹H NMR (300 MHz, DMSO-d₆) δ (ppm)

1.28 (s, 3H, CH₃Aib), 1.32 (s, 3H, CH₃Aib), 2.46 (m, 2H, CH₂-

CH₂-phenyl), 2.82 (m, 2H, CH₂-CH₂-phenyl), 3.35 (d, 2H, J )

7 Hz, CH₂âTrp), 3.68 (s, 3H, OCH₃), 5.02 (s, 2H, CH₂-p-

methoxybenzyl), 5.22 (m, 1H, CH RTrp), 6.73-6.81 (s, 4H, CHar

p-methoxybenzyl), 6.84 (t, 1H, J_o) 7 Hz, H₅Trp), 7.00 (t, 1H, J_o

) 7 Hz, H₆Trp), 7.05-7.11 (m, 4H, H₂and H₆phenyl, H₂and H₄

Trp), 7.14-7.22 (m, 3H, H₃, H₄and H₅phenyl), 7.29 (d, 1H, J_o)

8 Hz, H₇Trp), 8.09 (brs, 3H, NH₂Aib, TFA salt), 8.99 (d, 1H, J

) 8 Hz, NH amide), 10.83 (s, 1H, NH indole Trp). ¹³C NMR (75

MHz, DMSO-d₆) δ (ppm) 23.5 (CH₃Aib), 23.8 (CH₃Aib), 26.5

(CH₂-CH₂-phenyl), 29.1 (C âTrp), 32.6 (CH₂-CH₂-phenyl),

45.5 (CH₂-p-methoxybenzyl), 45.7 (C RTrp), 55.5 (OCH₃), 56.8

(Cq Aib), 109.7 (C₃Trp), 111.8 (C₇Trp), 114.6 (C₃and C₅

p-methoxybenzyl), 118.3 (C₄Trp), 118.7 (C₅Trp), 121.3 (C₆Trp),

124.9 (C₂Trp), 126.6 (C₄phenyl), 127.3 (C₉Trp), 127.6 (C₁

p-methoxybenzyl), 128.0 (C₂and C₆p-methoxybenzyl), 128.7 (C₂,

C₃, C₅, and C₆phenyl), 136.4 (C₈Trp), 140.8 (C₁phenyl), 154.5

(Cq triazole), 154.8 (Cq triazole), 159.2 (C₄p-methoxybenzyl),

172.0 (CO amide).

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(4-methoxybenzyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpro-

panamide Trifluoroacetate Salt (19c). ¹H NMR (400 MHz,

DMSO-d₆) δ 1.30 (s, 3H, CH₃Aib), 1.33 (s, 3H, CH₃Aib), 2.91

(m, 2H, CH₂-CH₂-indole), 2.97 (m, 2H, CH₂-CH₂-indole), 3.37

(d, 2H, CH₂âTrp), 3.71 (s, 3H, OCH₃), 5.02 (s, 2H, CH₂-p-

(R)-N-(1-(4-(3-Methoxybenzyl)-5-benzyl-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

1

fluoroacetate Salt (18d). H NMR (400 MHz, DMSO-d₆) δ 1.25

(s, 3H, CH₃Aib), 1.29 (s, 3H, CH₃Aib), 3.24 (dd, 1H, J ) 14.3,

J ) 5.8, CH₂âTrp), 3.38 (dd, 1H, J ) 14.3, J ) 9.1, CH₂âTrp),

Triazole DeriVatiVes as Ghrelin Receptor Ligands

Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8 1949

methoxybenzyl), 5.23 (m, 1H, CH RTrp), 6.78 (s, 4H, CHar

p-methoxybenzyl), 6.87 (t, 1H, J ) 8 Hz, H₅Trp), 6.93 (t, 1H, J

) 8 Hz, H₅indole), 7.03 (t, 1H, H₆Trp), 7.05 (t, 1H, H₆indole),

7.07 (s, 1H, H₂indole), 7.09 (s, 1H, H₂Trp), 7.21 (d, 1H, J ) 8

Hz, H₄Trp), 7.32 (3H, H₄, H₇indole, H₇Trp), 8.02 (brs, 3H, NH₂

Aib, TFA salt), 8.97 (d, 1H, J ) 8 Hz, NH amide), 10.77 (s, 1H,

NH indole), 10.80 (s, 1H, NH indole Trp). ¹³C NMR (100 MHz,

DMSO-d₆) δ 22.4 (CH₂-CH₂indole), 23.1 (CH₃Aib), 23.4 (CH₃

Aib), 25.5 (CH₂-CH₂indole), 28.9 (C âTrp), 44.9 (CH₂p-

methoxybenzyl), 45.3 (C RTrp), 55.0 (OCH₃), 56.3 (Cq Aib), 109.5

(C₃Trp), 111.3 (C₇Trp, C₇indole), 113.0 (C₃indole), 114.1 (C₃,

C₅p-methoxybenzyl), 117.9 (C₄Trp), 118.0 (C₄indole), 118.2 (C₅

indole), 118.3 (C₅Trp), 120.9 (C₆indole, C₆Trp), 122.0 (C₂indole),

124.4 (C₂Trp), 126.7 (C₉indole), 126.9 (C₉Trp), 127.3 (C₂, C₆

p-methoxybenzyl), 127.4 (C₁p-methoxybenzyl), 135.9 (C₈Trp),

136.1 (C₈indole), 154.2 (Cq triazole), 154.5 (Cq triazole), 158.4

C₄p-methoxybenzyl), 171.4 (CO amide).

)7 Hz, H₅indole), 6.96 (m, 2H, H₆indole, H₆Trp), 7.02 (s, 1H,

H₂indole), 7.05 (s, 1H, H₂Trp), 7.14 (d, 1H, J_o) 8 Hz, H₄Trp),

7.33 (m, 3H, H₄indole, H₇Trp, H₇indole), 7.90 (d, 1H, J ) 8 Hz,

NH amide), 8.02 (brs, 3H, NH₂Aib, TFA salt), 10.73 (s, 1H, NH

indole), 10.79 (s, 1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-

d₆, 300 K) δ (ppm) 23.6 (CH₃Aib), 23.8 (CH₃Aib), 24.3 (CH₂-

CH₂CH₂-indole), 24.8 (CH₂CH₂CH₂-indole), 27.7 (CH₂CH₂CH₂-

indole), 29.1 (C âTrp), 45.5 (CH₂-p-methoxybenzyl), 45.8 (C

RTrp), 55.5 (OCH₃), 56.8 (Cq Aib), 109.8 (C₃Trp), 111.7 (C₇Trp,

C₇indole), 114.0 (C₃indole), 114.5 (C₃, C₅p-methoxybenzyl),

118.3 (C₄indole, C₄Trp), 118.5 (C₅indole), 118.8 (C₅Trp), 121.3

(C₆indole, C₆Trp), 127.3 (C₉indole), 127.4 (C₉Trp), 127.6 (C₁

p-methoxybenzyl), 127.9 (C₂, C₆p-methoxybenzyl, C₂Trp, C₂

indole), 136.1 (C₈indole), 136.4 (C₈Trp), 154.7 (Cq triazole), 155.1

(Cq triazole), 159.2 (C₄p-methoxybenzyl), 171.9 (CO amide).

(R)-N-(1-(4-(2-Methoxybenzyl)-5-benzyl-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (20a). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.24 (s, 3H, CH₃Aib), 1.27 (s, 3H, CH₃Aib), 3.20 (dd,

1H, J ) 14 and 5 Hz, CH₂âTrp), 3.33 (dd, 1H, J ) 14 and 9 Hz,

CH₂âTrp), 3.68 (s, 3H, OCH₃), 4.00 (s, 2H, CH₂-phenyl), 4.95

(d, 1H, J ) 17 Hz, CH₂-o-methoxybenzyl), 5.07 (m, 1H, CH

RTrp), 5.18 (d, 1H, J ) 17 Hz, CH₂-o-methoxybenzyl), 6.27 (d,

1H, J_o) 8 Hz, H₃o-methoxybenzyl), 6.67 (t, 1H, J_o) 7 Hz, H₅

Trp), 6.77 (t, 1H, J_o) 6 Hz, H₆Trp), 6.92-7.05 (m, 6H, H₂Trp,

H₂and H₆phenyl, H₄, H₅, and H₆o-methoxybenzyl), 7.14-7.26

(m, 5H, H₄and H₇Trp, H₃, H₄, and H₅phenyl), 8.03 (brs, 3H,

NH₂Aib, TFA salt), 8.91 (d, 1H, J ) 8 Hz, NH amide), 10.78 (s,

1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ

(ppm) 23.5 (CH₃Aib), 23.6 (CH₃Aib), 29.1 (C âTrp), 30.5 (CH₂-

phenyl), 42.1 (CH₂-o-methoxybenzyl), 45.7 (CH R Trp), 55.9

(OCH₃), 56.7 (Cq Aib), 109.8 (C₃Trp), 111.3 (C₃o-methoxyben-

zyl), 111.7 (C₇Trp), 118.2 (C₄Trp), 118.7 (C₅Trp), 120.9 (C₅

o-methoxybenzyl), 121.2 (C₆Trp), 123.3 (C₁o-methoxybenzyl),

124.8 (C₂Trp), 126.6 (C₄phenyl), 127.1 (C₄o-methoxybenzyl),

127.2 (C₉Trp), 128.8 (C₂, C₃, C₅and C₆phenyl), 129.5 (C₆

o-methoxybenzyl), 136.0 (C₁phenyl), 136.4 (C₈Trp), 154.0 (Cq

triazole), 155.6 (Cq triazole), 156.5 (C₂o-methoxybenzyl), 171.8

(CO amide).

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(2-methoxy)benzyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpro-

panamide Trifluoroacetate Salt (20b). ¹H NMR (300 MHz,

DMSO-d₆, 300 K) δ (ppm) 1.27 (s, 3H, CH₃Aib), 1.29 (s, 3H,

CH₃Aib), 2.90 (m, 2H, CH₂-CH₂-indole), 2.96 (m, 2H, CH₂-

CH₂-indole), 3.29 (m, 2H, CH₂âTrp), 3.65 (s, 3H, OCH₃), 5.09

(m, 3H, CH₂-o-methoxybenzyl and CH RTrp), 6.49 (d, 1H, J_o)

8 Hz, H₃o-methoxybenzyl), 6.76 (t, 1H, J_o) 8 Hz, H₅Trp), 6.81

(t, 1H, J_o) 8 Hz, H₅indole), 6.89 (t, 1H, J_o) 7 Hz, H₆Trp), 6.96

(t, 1H, J_o) 8 Hz, H₆indole), 6.98 (s, 1H, H₂indole), 7.02 (m, 3H,

H₄, H₅, and H₆o-methoxybenzyl), 7.07 (d, 1H, J_o) 6 Hz, H₄Trp),

7.18 (d, 1H, H₄indole), 7.29 (m, 2H, H₇indole and H₇Trp), 8.07

(brs, 3H, NH₂Aib, TFA salt), 8.97 (d, 1H, J ) 8 Hz, NH amide),

10.80 (s, 1H, NH indole), 10.82 (s, 1H, NH indole Trp). ¹³C NMR

(75 MHz, DMSO-d₆, 300 K) δ (ppm) 22.8 (CH₂-CH₂-indole),

23.6 (CH₃Aib), 23.7 (CH₃Aib), 25.8 (CH₂-CH₂-indole), 29.1

(C âTrp), 42.3 (CH₂-o-methoxybenzyl), 45.7 (C RTrp), 55.8

(OCH₃), 56.7 (Cq Aib), 109.8 (C₃Trp), 111.5 (C₃o-methoxyben-

zyl), 111.8 (C₇indole and C₇Trp), 113.2 (C₃indole), 118.2 (C₄

Trp), 118.4 (C₄indole), 118.7 (C₅indole and C₅Trp), 121.0 (C₆

indole), 121.3 (C₆Trp), 121.4 (C₅o-methoxybenzyl), 123.0 (C₂

indole and C₂Trp), 123.3 (C₁o-methoxybenzyl), 127.0 (C₄

o-methoxybenzyl), 127.1 (C₉indole), 127.3 (C₉Trp), 129.8 (C₆

o-methoxybenzyl), 136.4 (C₈indole), 136.6 (C₈Trp), 155.2 (2Cq

triazole), 156.6 (C2 o-methoxybenzyl), 171.9 (CO amide).

(R)-N-(1-(4-(2-Methoxybenzyl)-5-phenethyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (20c). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.26 (s, 3H, CH₃Aib), 1.29 (s, 3H, CH₃Aib), 2.78-2.92

(m, 4H, CH₂-CH₂-phenyl), 3.29 (m, 2H, CH₂âTrp), 3.65 (s, 3H,

OCH₃), 4.97-5.21 (m, 3H, CH RTrp and CH₂-o-methoxybenzyl),

6.52 (d, 1H, J_o) 7 Hz, H₃o-methoxybenzyl), 6.78 (t, 1H, J_o) 7

(R)-N-(1-(4-(4-Methoxybenzyl)-5-(3-phenylpropyl)-4H-1,2,4-

triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (19d). ¹H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 1.27 (s, 3H, CH₃Aib), 1.31 (s, 3H, CH₃Aib),

1.73 (m, 2H, CH₂-CH₂-CH₂-phenyl), 2.47 (m, 2H, CH₂-CH₂-

3

CH₂-phenyl), 2.52 (t, 2H, J ) 7 Hz, CH₂-CH₂-CH₂-phenyl),

3.35 (d, 2H, J ) 7 Hz, CH₂âTrp), 3.68 (s, 3H, OCH₃), 4.98 (s,

2H, CH₂-p-methoxybenzyl), 5.20 (m, 1H, CH RTrp), 6.75 (s, 4H,

CHar p-methoxybenzyl), 6.82 (t, 1H, J_o) 7 Hz, H₅Trp), 6.99 (t,

1H, J_o) 7 Hz, H₆Trp), 7.04-7.07 (m, 4H, H₂and H₆phenyl, H₂

and H₄Trp), 7.13-7.24 (m, 3H, H₃, H₄, and H₅phenyl), 7.29 (d,

1H, J_o) 8 Hz, H₇Trp), 8.03 (brs, 3H, NH₂Aib, TFA salt), 8.96

(d, 1H, J ) 8 Hz, NH amide), 10.80 (d, 1H, J ) 2 Hz, NH indole

Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.6 (CH₃

Aib), 23.6 (CH₃Aib), 24.06 (CH₂-CH₂-CH₂-phenyl), 28.5

(CH₂-CH₂-CH₂-phenyl), 29.2 (CH₂âTrp), 34.7 (CH₂-CH₂-

CH₂-phenyl), 45.5 (CH₂-p-methoxybenzyl), 45.8 (CH RTrp), 55.5

(OCH₃), 56.8 (Cq Aib), 109.8 (C₃Trp), 111.8 (C₇Trp), 114.6 (C₃

and C₅p-methoxybenzyl), 118.3 (C₄Trp), 118.7 (C₅Trp), 121.3

(C₆Trp), 124.9 (C₂Trp), 126.2 (C₄phenyl), 127.3 (C₉Trp), 127.8

(C₁p-methoxybenzyl), 127.9 (C₂and C₆p-methoxybenzyl), 128.7

(C₂, C₃, C₅, and C₆phenyl), 136.4 (C₈Trp), 141.7 (C₁phenyl),

154.8 (2Cq triazole), 159.2 (C₄p-methoxybenzyl), 171.9 (CO

amide).

(R)-N-(1-(4-(4-Methoxybenzyl)-5-benzyl-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (19e). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.24 (s, 3H, CH₃Aib), 1.28 (s, 3H, CH₃Aib), 3.26 (dd,

1H, ³J ) 14 and 6 Hz, CH₂âTrp), 3.31 (dd, 1H, ³J ) 14 and 9 Hz,

CH₂âTrp), 3.67 (s, 3H, OCH₃), 3.99 (s, 2H, CH₂benzyl), 4.99 (s,

2H, CH₂-p-methoxybenzyl), 5.12 (m, 1H, CH RTrp), 6.67 (s, 4H,

CHar p-methoxybenzyl), 6.80 (t, 1H, J_o) 8 Hz, H₅Trp), 6.98 (t,

1H, J_o) 8 Hz, H₆Trp), 7.02-7.06 (m, 4H, H₂and H₆benzyl, H₂

and H₄Trp), 7.12-7.25 (m, 3H, H₃, H₄, and H₅benzyl), 7.26 (d,

1H, J_o) 8 Hz, H₇Trp), 8.01 (brs, 3H, NH₂Aib, TFA salt), 8.92

(d, 1H, J ) 8 Hz, NH amide), 10.77 (s, 1H, NH indole Trp). ¹³C

NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.5 (CH₃Aib), 23.7

(CH₃Aib), 29.1 (CH₂âTrp), 30.6 (CH₂-benzyl), 45.7 (CH₂-

p-methoxybenzyl), 45.7 (CH RTrp), 55.5 (OCH₃), 56.7 (Cq Aib),

109.8 (C₃Trp), 111.7 (C₇Trp), 114.5 (C₃and C₅p-methoxybenzyl),

118.3 (C₄Trp), 118.7 (C₅Trp), 121.3 (C₆Trp), 124.8 (C₂Trp),

127.1 (C₂and C₆benzyl), 127.3 (C₉Trp), 127.6 (C₁p-methoxy-

benzyl), 127.8 (C₂and C₆p-methoxybenzyl), 128.8 (C₃, C₄, and

C₅benzyl), 136.3 (C₁benzyl), 136.4 (C₈Trp), 153.8 (Cq triazole),

155.2 (Cq triazole), 159.1 (C₄p-methoxybenzyl), 171.9 (CO amide).

(R)-N-(1-(5-(3-(1H-Indol-3-yl)propyl)-4-(4-methoxybenzyl)-

4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-meth-

ylpropanamide Trifluoroacetate Salt (19f). ¹H NMR (300 MHz,

DMSO-d₆, 300 K) δ (ppm) 1.27 (s, 3H, CH₃Aib), 1.30 (s, 3H,

CH₃Aib), 1.84 (m, 2H, CH₂CH₂CH₂-indole), 2.58 (m, 2H, CH₂-

CH₂CH₂-indole), 2.65 (m, 2H, CH₂CH₂CH₂-indole), 3.34 (d, 2H,

³J ) 7 Hz, CH₂âTrp), 3.67 (s, 3H, OCH₃), 4.96 (s, 2H, CH₂-p-

methoxybenzyl), 5.19 (m, 1H, CH RTrp), 6.71 (s, 4H, CH ar

p-methoxybenzyl), 6.89 (t, 1H, J_o)7 Hz, H₅Trp), 6.92 (t, 1H, J_o

1950 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

Hz, H₅Trp), 6.82 (t, 1H, J_o) 8 Hz, H₆Trp), 6.84-7.04 (m, 3H,

H₂and H₆phenyl, H₂Trp), 7.04-7.10 (m, 3H, H₄, H₅, and H₆

o-methoxybenzyl), 7.15 (d, 1H, J_o) 7 Hz, H₄Trp), 7.19-7.29

(m, 4H, H₃, H₄and H₅phenyl, H₇Trp), 8.03 (brs, 3H, NH₂Aib,

TFA salt), 8.94 (d, 1H, J ) 8 Hz, NH amide), 10.82 (s, 1H, NH

indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.6

(CH₃Aib), 23.7 (CH₃Aib), 26.3 (CH₂-CH₂-phenyl), 29.0 (C

âTrp), 32.5 (CH₂-CH₂-phenyl), 42.3 (CH₂-o-methoxybenzyl),

45.7 (C RTrp), 55.8 (OCH₃), 56.7 (Cq Aib), 109.7 (C₃Trp), 111.5

(C₇Trp), 111.8 (C₃o-methoxybenzyl), 118.2 (C₄Trp), 118.7 (C₅

Trp), 121.0 (C₆Trp), 121.3 (C₅o-methoxybenzyl), 123.2 (C₁

o-methoxybenzyl), 124.9 (C₂Trp), 126.6 (C₄phenyl), 127.2 (C₉

Trp and C₄o-methoxybenzyl), 128.7 (C₂, C₃, C₅and C₆phenyl),

129.9 (C₆o-methoxybenzyl), 136.4 (C₈Trp), 140.6 (C₁phenyl),

154.8 (Cq triazole), 155.2 (Cq triazole), 156.7 (C₂o-methoxyben-

zyl), 171.9 (CO amide).

H₅phenyl from N-CH₂-phenyl and from C-CH₂-phenyl), 7.25

(d, 1H, J ) 8 Hz, H₇Trp), 8.01 (brs, 3H, NH₂Aib, TFA salt),

8,91 (d, 1H, J ) 8 Hz, NH amide), 10.78 (s, 1H, NH indole Trp).

¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.5 (CH₃Aib),

23.7 (CH₃Aib), 29.0 (C âTrp), 30.6 (C-CH₂-phenyl), 45.7 (C

RTrp), 46.1 (N-CH₂-phenyl), 56.7 (Cq Aib), 109.8 (C₃Trp), 111.7

(C₇Trp), 118.3 (C₄Trp), 118.7 (C₅Trp), 121.2 (C₆Trp), 124.8

(C₂Trp), 126.3 (C₄phenyl from N-CH₂-phenyl), 127.0 (C₄phenyl

from C-CH₂-phenyl), 127.2 (C₉Trp), 128.0 (C₂, C₆phenyl from

N-CH₂-phenyl), 128.8 (C₂, C₃, C₅, and C₆from C-CH₂-phenyl),

128.9 (C₃and C₅phenyl from N-CH₂-phenyl), 135.8 (C₁phenyl

from N-CH₂-phenyl), 136.2 (C₁phenyl from C-CH₂-phenyl),

136.4 (C₈Trp), 153.9 (Cq triazole), 155.3 (Cq triazole), 171.9 (CO

amide).

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(4-bromobenzyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpro-

panamide Trifluoroacetate Salt (22a). ¹H NMR (400 MHz,

DMSO-d₆) δ 1.28 (s, 3H, CH₃Aib), 1.30 (s, 3H, CH₃Aib), 2.90

(m, 2H, CH₂-CH₂-indole), 3.00 (m, 2H, CH₂-CH₂-indole), 3.37

(m, 2H, CH₂âTrp), 5.10 (s, 2H, CH₂p-bromobenzyl), 5.13 (m,

1H, CH RTrp), 6.75 (d, 2H, J ) 8.1, H₂, H₆p-bromobenzyl), 6.88

(t, 1H, J ) 7.3, H₅Trp), 6.93 (t, 1H, J ) 7.5, H₅indole), 7.03 (t,

1H, J ) 7.0, H₆Trp), 7.05 (m, 1H, H₆indole), 7.07 (d, 1H, J )

1.7, H₂indole), 7.09 (d, 1H, J ) 1.8, H₂Trp), 7.12 (d, 1H, J )

8.2, H₄Trp), 7.28 (d, 1H, J ) 7.9, H₄indole), 7.32 (d, 2H, J )

8.2, H₇Trp, H₇indole), 7.41 (d, 2H, J ) 8.1, H₃, H₅p-

bromobenzyl), 8.01 (brs, 3H, NH₂Aib, TFA salt), 8.95 (d, 1H, J

) 7.9, NH amide), 10.77 (brs, 1H, NH indole), 10.80 (brs, 1H,

NH indole Trp). ¹³C NMR (100 MHz, DMSO-d₆) δ 22.4 (CH₂-

CH₂indole), 23.1 (CH₃Aib), 23.4 (CH₃Aib), 25.4 (CH₂-CH₂

indole), 28.7 (C âTrp), 44.8 (CH₂p-bromobenzyl), 45.2 (C RTrp,),

56.3 (Cq Aib), 109.4 (C₃Trp), 111.3 (C₇Trp, C₇indole), 113.0

(C₃indole), 117.8 (C₄Trp), 118.0 (C₄indole), 118.2 (C₅indole),

118.3 (C₅Trp), 120.8 (C₄p-bromobenzyl), 120.9 (C₆Trp, C₆

indole), 122.5 (C₂indole), 124.4 (C₂Trp), 126.7 (C₉indole), 126.8

(C₉Trp), 128.0 (C₂, C₆p-bromobenzyl), 131.6 (C₃, C₅p-

bromobenzyl), 135.1 (C₁p-bromobenzyl), 136.1 (C₈Trp, C₈indole),

154.2 (Cq triazole), 154.5 (Cq triazole), 171.4 (CO amide).

N-((R)-1-(4-(4-Bromobenzyl)-5-benzyl-4H-1,2,4-triazol-3-yl)-

2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Trifluo-

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-benzyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

1

fluoroacetate Salt (21a). H NMR (400 MHz, DMSO-d₆) δ 1.29

(s, 3H, CH₃Aib), 1.30 (s, 3H, CH₃Aib), 2.88 (m, 2H, CH₂-CH₂-

indole), 2.97 (m, 2H, CH₂-CH₂-indole), 3.37 (m, 2H, CH₂âTrp),

5.11 (s, 2H, CH₂-benzyl), 5.21 (m, 1H, CH RTrp), 6.86 (t, 1H, J

) 7 Hz, H₅Trp), 6.88 (2H, H₂, H₆benzyl), 6.92 (t, 1H, J ) 8 Hz,

H₅indole), 7.03 (t, 1H, J ) 8 Hz, H₆Trp), 7.05 (2H, H₆indole, H₂

indole), 7.09 (d, 1H, J ) 2 Hz, H₂Trp), 7.17 (d, 1H, J ) 8 Hz, H₄

Trp), 7.26 (2H, H₃, H₅benzyl), 7.27 (1H, H₄benzyl), 7.30 (1H, H₄

indole), 7.32 (2H, H₇Trp, H₇indole), 8.03 (brs, 3H, NH₂Aib, TFA

salt), 8.95 (d, 1H, J ) 8 Hz, NH amide), 10.77 (s, 1H, NH indole),

10.81 (s, 1H, NH indole Trp). ¹³C NMR (100 MHz, DMSO-d₆) δ

22.4 (CH₂-CH₂indole), 23.1 (CH₃Aib), 23.3 (CH₃Aib), 25.4

(CH₂-CH₂indole), 28.7 (C âTrp), 45.3 (C RTrp, CH₂-benzyl),

56.3 (Cq Aib), 109.5 (C₃Trp), 111.3 (C₇Trp, C₇indole), 113.0

(C₃indole), 117.8 (C₄Trp), 118.0 (C₄indole), 118.2 (C₅indole),

118.3 (C₅Trp), 120.9 (C₆Trp, C₆indole), 122.4 (C₂indole), 124.3

(C₂Trp), 125.9 (C₄benzyl), 126.7 (C₉indole), 126.9 (C₉Trp), 127.6

(C₂, C₆benzyl), 128.8 (C₃, C₅benzyl), 135.7 (C₁benzyl), 136.0

(C₈Trp), 136.1 (C₈indole), 154.3 (Cq triazole), 154.5 (Cq triazole),

171.4 (CO amide).

(R)-N-(1-(5-(3-(1H-Indol-3-yl)propyl)-4-benzyl-4H-1,2,4-tri-

azol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (21b). ¹H NMR (400 MHz, DMSO-

d₆) δ 1.29 (s, 3H, CH₃Aib), 1.31 (s, 3H, CH₃Aib), 1.90 (m, 2H,

CH₂-CH₂-CH₂-indole), 2.61 (m, 2H, CH₂-CH₂-CH₂-indole),

2.69 (m, 2H, CH₂-CH₂-CH₂-indole), 3.37 (m, 2H, CH₂âTrp),

5.09 (s, 2H, CH₂Bzl), 5.20 (m, 1H, CH RTrp), 6.85 (m, 3H, H₂,

H₆Bzl, H₅Trp), 6.94 (t, 1H, J ) 7.5, H₅indole), 7.01 (s, 1H, H₂

indole), 7.02 (t, 1H, J ) 7.8, H₆Trp), 7.05 (t, 1H, J ) 8, H₆indole),

7.08 (d, 1H, J ) 2.0, H₂Trp), 7.14 (d, 1H, J ) 8.0, H₄Trp), 7.25

(m, 3H, H₃, H₄, H₅benzyl), 7.31 (d, 1H, J ) 8.0, H₇Trp), 7.32 (d,

1H, J ) 8.0, H₇indole), 7.42 (d, 1H, J ) 7.8, H₄indole), 8.03

(brs, 3H, NH₂Aib, TFA salt), 8.95 (d, 1H, J ) 8.1, NH Trp), 10.73

(s, 1H, NH indole), 10.80 (d, 1H, J ) 2.0, NH indole Trp). ¹³C

NMR (100 MHz, DMSO-d₆) δ 23.1 (CH₃Aib), 23.3 (CH₃Aib),

23.8 (CH₂-CH₂-CH₂-indole), 24.1 (CH₂-CH₂-CH₂-indole),

27.2 (CH₂-CH₂-CH₂-indole), 28.7 (C âTrp), 45.4 (C RTrp), 45.5

(CH₂benzyl), 56.3 (Cq Aib), 109.4 (C₃Trp), 111.3 (C₇Trp, C₇

indole), 113.6 (C₃indole), 117.8 (C₄Trp), 118.0 (C₅indole), 118.2

(C₄indole), 118.3 (C₅Trp), 120.8 (C₆indole, C₆Trp), 122.2 (C₂

indole), 124.3 (C₂Trp), 125.9 (C₄benzyl), 126.8 (C₉Trp), 127.0

(C₉indole), 127.7 (C₂, C₆benzyl), 128.7 (C₃, C₅benzyl), 135.5

(C₁benzyl), 136.0 (C₈Trp), 136.2 (C₈indole), 154.3 (Cq triazole),

154.7 (Cq triazole), 171.4 (CO amide).

1

roacetate Salt (22c). H NMR (300 MHz, DMSO-d₆, 300 K) δ

(ppm)1.23 (s, 3H, CH₃Aib), 1.25 (s, 3H, CH₃Aib), 3.26 (dd, 1H,

³J ) 14 and 6 Hz, CH₂Trp), 3.34 (dd, 1H, ³J ) 14 and 9 Hz, CH₂

âTrp), 4.01 (m, 2H, CH₂-benzyl), 5.01 (m, 1H, CH RTrp), 5.08

(s, 2H, CH₂-p-bromobenzyl), 6.59 (d, 2H, J_o) 8 Hz, H₂and H₆

p-bromobenzyl), 6.81 (t, 1H, J_o) 7 Hz, H₅Trp), 6.94 (s, 1H, H₂

Trp), 6.98 (t, 1H, J_o) 7 Hz, H₆Trp), 7.06 (m, 2H, H₂and H₆

benzyl), 7.12 (d, 1H, J_o) 7 Hz, H₄Trp), 7.16-7.20 (m, 3H, H₃,

H₄, and H₅benzyl), 7.26 (d, 1H, J_o) 8 Hz, H₇Trp), 7.29 (d, 2H,

J_o) 8 Hz, H₃and H₅p-bromobenzyl), 8.00 (brs, 3H, NH₂Aib,

TFA salt), 8.92 (d, 1H, J ) 8 Hz, NH amide), 10.78 (s, 1H, NH

indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.5

(CH₃Aib), 23.8 (CH₃Aib), 29.0 (C âTrp), 30.5 (CH₂-benzyl),

45.6 (CH₂- p-bromobenzyl), 45.7 (C RTrp), 56.7 (Cq Aib), 109.7

(C₃Trp), 111.8 (C₇Trp), 118.2 (C₄Trp), 118.7 (C₅Trp), 121.2

(C₄p-bromobenzyl), 121.3 (C₆Trp), 124.9 (C₂Trp), 127.0 (C₂and

C₆benzyl), 127.2 (C₉Trp), 128.4 (C₂and C₆p-bromobenzyl), 128.9

(C₃, C₄and C₅benzyl), 131.9 (C₃and C₅p-bromobenzyl), 135.2

(C₁p-bromobenzyl), 136.2 (C₈Trp), 136.4 (C₁benzyl), 153.9 (Cq

triazole), 155.3 (Cq triazole), 171.9 (CO amide).

(R)-N-(1-(4-(4-Fluorobenzyl)-5-benzyl-4H-1,2,4-triazol-3-yl)-

2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Trifluo-

1

2-Amino-N-((R)-1-(4,5-dibenzyl-4H-1,2,4-triazol-3-yl)-2-(1H-

indol-3-yl)ethyl)-2-methylpropanamide Trifluoroacetate Salt

roacetate Salt (23b). H NMR (300 MHz, DMSO-d₆, 300 K) δ

(ppm) 1.27 (s, 3H, CH₃Aib), 1.29 (s, 3H, CH₃Aib), 3.33 (m, 2H,

CH₂âTrp), 4.02 (s, 2H, CH₂-benzyl), 5.10 (m, 3H, CH₂-p-

fluorobenzyl and CH RTrp), 6.71 (m, 2H, H₃and H₅p-fluoroben-

zyl), 6.80 (t, 1H, J_o) 8 Hz, H₅Trp), 6.90 (d, 2H, J_o) 8 Hz, H₂

and H₆p-fluorobenzyl), 6.94 (t, 1H, J_o) 8 Hz, H₆Trp), 6.99-

7.10 (m, 4H, H₂and H₄Trp, H₂and H₆benzyl), 7.20 (m, 3H, H₃,

H₄and H₅benzyl), 7.27 (d, 1H, J_o) 8 Hz, H₇Trp), 8.09 (brs, 3H,

NH₂Aib, TFA salt), 8.97 (d, 1H, J ) 8 Hz, NH amide), 10.79 (s,

1

(21c). H NMR (300 MHz, DMSO-d₆, 300 K) δ (ppm) 1.23 (s,

3H, CH₃Aib), 1.26 (s, 3H, CH₃Aib), 3.23 (dd, 1H, J ) 14 and 6

Hz, CH₂âTrp), 3.35 (dd, 1H, J ) 14 and 9 Hz, CH₂âTrp), 3.99

(s, 2H, C-CH₂-phenyl), 5.10 (m, 3H, N-CH₂-phenyl and CH

RTrp), 6.77 (m, 3H, H₅Trp, H₂and H₆phenyl from N-CH₂-

phenyl), 6.99 (m, 2H, H₂and H₆Trp), 7.01-7.07 (m, 3H, H₄Trp,

H₂and H₆from C-CH₂-phenyl), 7.15-7.23 (m, 6H, H₃, H₄, and

Triazole DeriVatiVes as Ghrelin Receptor Ligands

Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8 1951

1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ

(ppm) 23.5 (CH₃Aib), 23.8 (CH₃Aib), 29.0 (C âTrp), 31.1 (CH₂-

benzyl), 45.7 (CH₂- p-fluorobenzyl), 45.8 (C RTrp), 56.8 (Cq Aib),

109.6 (C₃Trp), 111.8 (C₇Trp), 115.6 and 115.9 (C₃and C₅

p-fluorobenzyl), 118.2 (C₄Trp), 118.7 (C₅Trp), 121.3 (C₆Trp),

124.8 (C₂Trp), 127.1 (C₄benzyl), 127.2 (C₉Trp), 128.8 and 128.9

(C₂and C₆p-fluorobenzyl), 129.4 (C₂, C₃, C₅, and C₆benzyl), 131.6

(C₁p-fluorobenzyl), 135.9 (C₁benzyl), 136.4 (C₈Trp), 154.0 (C₄

p-fluorobenzyl), 155.3 (2Cq triazole), 172.0 (CO amide).

124.9 (C₂Trp), 126.4 (C₆m,p-dichlorobenzyl and C₄benzyl), 127.0

(C₂m,p-dichlorobenzyl), 127.2 (C₉Trp), 128.4 (C₂, C₃, C₅and C₆

benzyl), 130.7 (C₄and C₅m,p-dichlorobenzyl), 131.8 (C₃m,p-

dichlorobenzyl), 136.0 (C₁benzyl), 136.4 (C₈Trp), 136.7 (C₁m,p-

dichlorobenzyl), 154.1 (Cq triazole), 155.2 (Cq triazole), 172.0 (CO

amide).

N-((R)-1-(4-(3,4-Dichlorobenzyl)-5-phenethyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (24c). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.25 (s, 3H, CH₃Aib), 1.26 (s, 3H, CH₃Aib), 2.84 (m,

4H, CH₂-CH₂-phenyl), 3.34 (d, 2H, J ) 7 Hz, CH₂âTrp), 5.11

(m, 3H, CH RTrp and CH₂-m,p-dichlorobenzyl), 6.63 (dd, 1H, J_o

) 8 Hz and J_m) 2 Hz, H₆m,p-dichlorobenzyl), 6.83 (t, 1H, J_o)

8 Hz, H₅Trp), 6.99 (t, 1H, J_o) 8 Hz, H₆Trp), 7.05 (d, 1H, J )

2 Hz, H₂Trp), 7.12 (m, 5H, CHar phenyl), 7.17 (d, 1H, J_o) 8 Hz,

H₄Trp), 7.21 (s, 1H, H₂m,p-dichlorobenzyl), 7.27 (d, 1H, J_o) 8

Hz, H₅m,p-dichlorobenzyl), 7.39 (d, 1H, J_o) 8 Hz, H₇Trp), 8.02

(brs, 3H, NH₂Aib, TFA salt), 8.94 (d, 1H, J ) 8 Hz, NH amide),

10.78 (s, 1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300

K) δ (ppm) 23.5 (CH₃Aib), 23.8 (CH₃Aib), 26.4 (CH₂-CH₂-

phenyl), 29.1 (C âTrp), 32.6 (CH₂-CH₂-phenyl), 44.7 (CH₂-

m,p-dichlorobenzyl), 45.6 (C RTrp), 56.7 (Cq Aib), 109.7 (C₃Trp),

111.8 (C₇Trp), 118.1 (C₄Trp), 118.7 (C₅Trp), 121.3 (C₆Trp),

124.9 (C₂Trp), 126.5 (C₄phenyl and C₆m,p-dichlorobenzyl), 127.2

(C₉Trp), 128.7 (C₂, C₃, C₅, and C₆phenyl, C₂m,p-dichlorobenzyl),

130.9 (C₄m,p-dichlorobenzyl), 131.4 (C₅m,p-dichlorobenzyl),

132.0 (C₃m,p-dichlorobenzyl), 136.4 (C₈Trp), 137.2 (C₁m,p-

dichlorobenzyl), 140.8 (C₁phenyl), 154.5 (Cq triazole), 154.7 (Cq

triazole), 171.9 (CO amide).

N-((R)-1-(4-(4-Fluorobenzyl)-5-phenethyl-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

1

fluoroacetate Salt (23c). H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.27 (s, 3H, CH₃Aib), 1.28 (s, 3H, CH₃Aib), 2.82 (m,

4H, CH₂-CH₂-phenyl), 3.34 (m, 2H, CH₂âTrp), 5.06 (s, 2H,

CH₂-p-fluorobenzyl), 5.16 (m, 1H, CH RTrp), 6.85 (m, 3H, H₅

Trp, H₃and H₅p-fluorobenzyl), 6.98-7.04 (m, 4H, H₂and H₆Trp,

H₂and H₆phenyl), 7.09-7.11 (m, 2H, H₂and H₆p-fluorobenzyl),

7.15 (d, 1H, J_o) 6 Hz, H₄Trp), 7.19 (t, 3H, J_o) 8 Hz, H₃, H₄

and H₅phenyl), 7.29 (d, 1H, J_o) 8 Hz, H₇Trp), 8.01 (brs, 3H,

NH₂Aib, TFA salt), 8.94 (d, 1H, J ) 8 Hz, NH amide), 10.78 (s,

1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ

(ppm) 23.5 (CH₃Aib), 23.8 (CH₃Aib), 26.5 (CH₂-CH₂-phenyl),

29.2 (C âTrp), 32.7 (CH₂-CH₂-phenyl), 45.4 (CH₂-p-fluoroben-

zyl), 45.7 (C RTrp), 56.8 (Cq Aib), 109.8 (C₃Trp), 111.8 (C₇Trp),

115.9 and 116.2 (C₃and C₅p-fluorobenzyl), 118.3 (C₄Trp), 118.7

(C₅Trp), 121.3 (C₆Trp), 124.8 (C₂Trp), 126.5 (C₄phenyl), 127.3

(C₉Trp), 128.5 (C₂and C₆p-fluorobenzyl), 128.7 (C₂, C₃, C₅and

C₆phenyl), 132.2 (C₁p-fluorobenzyl), 136.4 (C₈Trp), 140.9 (C₁

phenyl), 154.5 (Cq triazole), 154.7 (Cq triazole), 160.3 (C₄

p-fluorobenzyl), 171.9 (CO amide).

N-((R)-1-(5-((1H-Indol-3-yl)methyl)-4-phenethyl-4H-1,2,4-

triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (25b). ¹H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 1.27 (s, 3H, CH₃Aib), 1.29 (s, 3H, CH₃Aib),

2.39-2.53 (m, 4H, CH₂-CH₂-phenyl), 3.74 (m, 1H, CH₂âTrp),

3.92 (m, 1H, CH₂âTrp), 3.99 (s, 2H, CH₂-indole), 5.21 (m, 1H,

CH RTrp), 6.74 (m, 2H, H₅indole and H₅Trp), 6.90 (t, 1H, J_o)

8 Hz, H₆Trp), 6.92 (t, 1H, J_o) 8 Hz, H₆indole), 7.01-7.06 (m,

4H, H₂and H₆phenyl, H₂indole and H₂Trp), 7.16 (m, 3H, H₃, H₄

and H₅phenyl), 7.27 (d, 1H, J_o) 8 Hz, H₄Trp), 7.32 (d, 1H, J_o

) 8 Hz, H₇Trp), 7.36 (d, 1H, J_o) 8 Hz, H₇indole), 7.50 (d, 1H,

J_o) 8 Hz, H₄indole), 7.99 (brs, 3H, NH₂Aib, TFA salt), 9.02 (s,

1H, J ) 8 Hz, NH amide), 10.79 (s, 1H, NH indole Trp), 10.94 (s,

1H, NH indole). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm)

21.4 (CH₂-indole), 23.5 (CH₃Aib), 23.8 (CH₃Aib), 29.5 (C âTrp),

35.8 (CH₂-CH₂-phenyl), 44.5 (CH₂-CH₂-phenyl), 45.8 (C

RTrp), 56.7 (Cq Aib), 108.5 (C₃indole), 109.9 (C₃Trp), 114.0 (C₇

indole and C₇Trp), 118.4 (C₄Trp), 118.8 (C₄indole and C₅Trp),

119.0 (C₅indole), 121.4 (C₆Trp), 121.7 (C₆indole), 124.0 (C₂

indole and C₂Trp), 127.1 (C₄phenyl), 127.7 (C₉indole and C₉

Trp), 128.8 (C₂and C₆phenyl), 129.1 (C₃and C₅phenyl), 136.5

(C₈Trp), 136.6 (C₈indole), 137.5 (C₁phenyl), 153.6 (Cq triazole),

155.0 (Cq triazole), 171.8 (CO amide).

(R)-N-(1-(5-(3-(1H-Indol-3-yl)propyl)-4-phenethyl-4H-1,2,4-

triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (25c). ¹H NMR (300 MHz, DMSO-

d₆) δ (ppm) 1.32 (s, 3H, CH₃Aib), 1.37 (s, 3H, CH₃Aib), 1.86

(m, 2H, CH₂-CH₂-CH₂-indole), 2.38 (m, 2H, CH₂-CH₂-CH₂-

indole), 2.65 (m, 4H, CH₂-CH₂-CH₂-indole and CH₂-CH₂-

phenyl), 3.38 (m, 2H, CH₂-CH₂-phenyl), 3.74 (m, 1H, CH₂âTrp),

3.92 (m, 1H, CH₂âTrp), 5.23 (m, 1H, CH RTrp), 6.78 (m, 2H, H₅

indole and H₅Trp), 6.93 (t, 1H, J_o) 8 Hz, H₆Trp), 7.01 (m, 3H,

H₆indole, H₂and H₆phenyl), 7.05 (d, 1H, J ) 2 Hz, H₂Trp),

7.08 (d, 1H, J ) 2 Hz, H₂indole), 7.15 (m, 3H, H₃, H₄and H₅

phenyl), 7.29 (d, 1H, J_o) 8 Hz, H₄Trp), 7.31 (d, 1H, J_o) 8 Hz,

H₇Trp), 7.44 (d, 1H, J_o) 8 Hz, H₇indole), 7.46 (d, 1H, J_o) 8

Hz, H₄indole), 8.06 (brs, 3H, NH₂Aib, TFA salt), 9.05 (d, 1H, 8

Hz, NH amide), 10.76 (s, 1H, NH indole), 10.85 (d, 1H, J ) 2 Hz,

NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆) δ (ppm) 23.5 (CH₃

Aib), 23.6 (CH₂-CH₂-CH₂-indole), 23.9 (CH₃Aib), 24.5 (CH₂-

CH₂-CH₂-indole), 27.3 (CH₂-CH₂-CH₂-indole), 29.4 (C âTrp),

35.7 (CH₂-CH₂-phenyl), 44.5 (CH₂-CH₂-phenyl), 46.1 (C

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(3,4-dichlorobenzyl)-

4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-meth-

ylpropanamide Trifluoroacetate Salt (24a). ¹H NMR (300 MHz,

DMSO-d₆, 300 K) δ (ppm) 1.26 (s, 6H, CH₃Aib), 2.87 (m, 2H,

CH₂-CH₂-indole), 2.96 (m, 2H, CH₂-CH₂-indole), 3.32 (m, 2H,

CH₂âTrp), 5.13 (m, 3H, CH RTrp and CH₂-m,p-dichlorobenzyl),

6.58 (d, 1H, J_o) 8 Hz, H₆m,p-dichlorobenzyl), 6.85 (t, 1H, J_o)

7 Hz, H₅Trp), 6.96 (t, 1H, J_o) 7 Hz, H₅indole), 7.01 (m, 2H, H₆

indole and H₆Trp), 7.04 (s, 1H, H₂Trp), 7.08 (s, 1H, H₂indole),

7.13 (d, 1H, J_o) 8 Hz, H₅m,p-dichlorobenzyl), 7.20-7.30 (m,

4H, H₄and H₇indole, H₇Trp and H₂m,p-dichlorobenzyl), 7.36

(d, 1H, J_o) 8 Hz, H₄Trp), 8.08 (brs, 3H, NH₂Aib, TFA salt),

8.98 (d, 1H, J ) 8 Hz, NH amide), 10.80 (s, 1H, NH indole), 10.82

(s, 1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ

(ppm) 22.8 (CH₂-CH₂-indole), 23.4 (CH₃Aib), 23.8 (CH₃Aib),

25.8 (CH₂-CH₂-indole), 29.0 (C âTrp), 44.8 (CH₂-m,p-dichlo-

robenzyl), 45.6 (C RTrp), 56.8 (Cq Aib), 109.7 (C₃indole), 111.8

(C₇indole and C₇Trp), 113.3 (C₃Trp), 118.1 (C₄Trp), 118.4 (C₅

indole), 118.6 (C₄indole and C₅Trp), 121.3 (C₆indole and C₆

Trp), 123.0 (C₂indole and C₂Trp), 126.4 (C₆m,p-dichlorobenzyl),

127.1 (C₉Trp), 127.3 (C₉indole), 128.6 (C₂m,p-dichlorobenzyl),

130.9 (C₄m,p-dichlorobenzyl),131.3 (C₅m,p-dichlorobenzyl), 132.0

(C₃m,p-dichlorobenzyl), 136.4 (C₈Trp), 136.6 (C₈indole), 137.2

(C₁m,p-dichlorobenzyl), 154.7 (Cq triazole), 155.1 (Cq triazole),

172.0 (CO amide).

N-((R)-1-(4-(3,4-Dichlorobenzyl)-5-benzyl-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (24b). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.24 (s, 3H, CH₃Aib), 1.25 (s, 3H, CH₃Aib), 3.33 (m,

2H, CH₂âTrp), 4.04 (s, 2H, CH₂-benzyl), 5.05 (m, 1H, CH RTrp),

5.12 (s, 2H, CH₂-m,p-dichlorobenzyl), 6.49 (dd, 1H, J_o) 8 Hz

and J_m) 2 Hz, H₆m,p-dichlorobenzyl), 6.80 (t, 1H, J_o) 8 Hz, H₅

Trp), 6.87 (d, 1H, J_m) 2 Hz, H₂Trp), 6.98 (t, 1H, J_o) 7 Hz, H₆

Trp), 7.02-7.10 (m, 3H, H₂and H₆benzyl, H₅m,p-dichlorobenzyl),

7.18 (m, 4H, H₃, H₄and H₅benzyl, H₂m,p-dichlorobenzyl), 7.26

(m, 2H, H₄and H₇Trp), 8.04 (brs, 3H, NH₂Aib, TFA salt), 8.94

(d, 1H, J ) 9 Hz, NH amide), 10.81 (s, 1H, NH indole Trp). ¹³C

NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.4 (CH₃Aib), 23.8

(CH₃Aib), 29.0 (C âTrp), 30.4 (CH₂-benzyl), 45.1 (CH₂- m,p-

dichlorobenzyl), 45.6 (C RTrp), 56.7 (Cq Aib), 109.6 (C₃Trp),

111.8 (C₇Trp), 118.1 (C₄Trp), 118.6 (C₅Trp), 121.3 (C₆Trp),

1952 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

RTrp), 56.8 (Cq Aib), 109.6 (C₃Trp), 111.8 (C₇Trp), 111.9 (C₇

indole), 113.9 (C₃indole), 118.3 (C₄Trp), 118.6 (C₅indole), 118.7

(C₄indole), 118.9 (C₅Trp), 121.3 (C₆Trp), 121.4 (C₆indole), 122.8

(C₂indole and C₂Trp), 127.1 (C₄phenyl), 127.3 (C₉Trp), 127.5

(C₉indole), 128.8 (C₂and C₆phenyl), 129.1 (C₃and C₅phenyl),

136.5 (C₁phenyl), 136.8 (C₈Trp), 137.2 (C₈indole), 154.7 (2Cq

triazole), 172.0 (CO amide).

indole), 10.96 (s, 1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-

d₆, 300 K) δ (ppm) 22.4 (CH₂-CH₂-indole), 23.6 (CH₃Aib), 23.8

(CH₃Aib), 24.9 (CH₂-CH₂-indole), 29.6 (C âTrp), 46.1 (C RTrp),

47.5 (CH₂-CH(Phe)₂), 51.5 (CH₂-CH(Phe)₂), 56.8 (Cq Aib), 109.8

(C₃Trp), 111.8 (C₇Trp), 112.1 (C₇indole), 113.5 (C₃indole), 118.4

(C₄Trp), 118.7 (C₄and C₅indole), 119.0 (C₅Trp), 121.4 (C₆indole

and C₆Trp), 122.8 (C₂indole), 125.0 (C₂Trp), 127.2 (C₉indole

and C₉Trp), 127.3 (C₄phenyl), 128.2 (C₂and C₆phenyl), 128.7

(C₃and C₅phenyl), 136.6 (C₈indole and C₈Trp), 141.0 (C₁phenyl),

154.6 (2 Cq triazole), 172.0 (CO amide).

N-((R)-2-(1H-Indol-3-yl)-1-(4,5-diphenethyl-4H-1,2,4-triazol-

3-yl)ethyl)-2-amino-2-methylpropanamide Trifluoroacetate Salt

1

(25e). H NMR (300 MHz, DMSO-d₆, 300 K) δ (ppm) 1.32 (s,

3H, CH₃Aib), 1.37 (s, 3H, CH₃Aib), 2.59 (m, 4H, C-CH₂-CH₂-

phenyl), 2.83 (t, 2H, J ) 8 Hz, N-CH₂-CH₂-phenyl), 3.38 (m,

2H, N-CH₂-CH₂-phenyl), 3.84 (m, 1H, CH₂âTrp), 3.94 (m, 1H,

CH₂âTrp), 5.23 (m, 1H, CH RTrp), 6.84 (m, 2H, H₄phenyl from

C-CH₂-CH₂-phenyl and H₄phenyl from N-CH₂-CH₂-phenyl),

6.93 (t, 1H, J_o) 8 Hz, H₅Trp), 7.00 (t, 1H, J_o) 8 Hz, H₆Trp),

7.07 (d, 1H, J ) 2 Hz, H₂Trp), 7.11-7.27 (m, 9H, H₂, H₃, H₅and

H₆phenyl from C-CH₂-CH₂-phenyl, H₂, H₃, H₅and H₆phenyl

from N-CH₂-CH₂-phenyl and H₄Trp), 7.50 (d, 1H, J_o) 8 Hz,

H₇Trp), 8.07 (brs, 3H, NH₂Aib, TFA salt), 9.04 (d, 1H, J ) 8

Hz, NH amide), 10.85 (s, 1H, NH indole Trp). ¹³C NMR (75 MHz,

DMSO-d₆, 300 K) δ (ppm) 23.5 (CH₃Aib), 23.8 (CH₃Aib), 25.9

(C-CH₂-CH₂-phenyl), 29.5 (C âTrp), 32.4 (C-CH₂-CH₂-

phenyl), 35.8 (N-CH₂-CH₂-phenyl), 44.2 (N-CH₂-CH₂-phen-

yl), 45.9 (C RTrp), 56.8 (Cq Aib), 109.7 (C₃Trp), 111.9 (C₇Trp),

118.4 (C₄Trp), 118.9 (C₅Trp), 121.4 (C₆Trp), 124.8 (C₂Trp),

126.6 (C₄phenyl from C-CH₂-CH₂-phenyl), 127.2 (C₄phenyl

from N-CH₂-CH₂-phenyl), 127.4 (C₉Trp), 128.7 (C₂and C₆

phenyl from C-CH₂-CH₂-phenyl, C₂and C₆phenyl from

N-CH₂-CH₂-phenyl), 128.8 (C₃and C₅phenyl from C-CH₂-

CH₂-phenyl, C₃and C₅phenyl from N-CH₂-CH₂-phenyl), 136.5

(C₁phenyl from N-CH₂-CH₂-phenyl), 137.5 (C₁phenyl from

C-CH₂-CH₂-phenyl), 140.8 (C₈Trp), 154.1 (Cq triazole), 154.7

(Cq triazole), 171.9 (CO amide).

2-Amino-N-((R)-1-(5-benzyl-4-(2,2-diphenylethyl)-4H-1,2,4-

triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-methylpropanamide Tri-

fluoroacetate Salt (26a). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.29 (s, 3H, CH₃Aib), 1.34 (s, 3H, CH₃Aib), 3.37 (m,

4H, CH₂âTrp and CH₂-benzyl), 3.74 (t, 1H, J ) 7 Hz, CH₂-

CH(Phe)₂), 4.21 (dd, 1H, J ) 14 and 8 Hz, CH₂-CH(Phe)₂), 4.51

(dd, 1H, J ) 14 and 8 Hz, CH₂-CH(Phe)₂), 5.08 (m, 1H, CH RTrp),

6.72 (m, 2H, H₂and H₆benzyl), 6.86-6.93 (m, 5H, H₃, H₄and H₅

benzyl, H₅and H₆Trp), 7.03 (s, 1H, H₂Trp), 7.06-7.25 (m, 10H,

CHar phenyl from CH(Phe)₂), 7.33 (d, 1H, J_o) 8 Hz, H₄Trp),

7.47 (d, 1H, J_o) 8 Hz, H₇indole), 8.10 (brs, 3H, NH₂Aib, TFA

salt), 8.98 (d, 1H, J ) 8 Hz, NH amide), 10.94 (s, 1H, NH indole

Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.5 (CH₃

Aib), 23.7 (CH₃Aib), 29.4 (C âTrp), 30.1 (CH₂-benzyl), 46.0 (C

RTrp), 47.7 (CH₂-CH(Phe)₂), 51.3 (CH(Phe)₂), 56.8 (Cq Aib),

109.8 (C₃Trp), 112.0 (C₇Trp), 118.5 (C₄Trp), 119.0 (C₅Trp),

121.5 (C₆Trp), 124.8 (C₂Trp), 127.1 (C₄phenyl from CH(Phe)₂),

127.4 (C₉Trp, C₄benzyl), 128.3 (C₂and C₆phenyl from CH(Phe)₂),

128.8-129.1 (C₃and C₅phenyl from CH(Phe)₂, C₂, C₃, C₅, and

C₆benzyl), 136.2 (C₁benzyl), 136.5 (C₈Trp), 141.0 (C₁phenyl

from CH(Phe)₂), 153.5 (Cq triazole), 155.1 (Cq triazole), 172.0 (CO

amide).

(R)-2-Amino-N-(1-(5-benzyl-4-(naphthalen-1-ylmethyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-methylpropan-

amide Trifluoroacetate Salt (27a). ¹H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 1.18 (s, 3H, CH₃Aib), 1.24 (s, 3H, CH₃Aib),

3.17 (dd, 1H, J ) 14 and 5 Hz, CH₂âTrp), 3.36 (dd, 1H, J ) 14

and 9 Hz, CH₂âTrp), 4.05 (m, 2H, CH₂-benzyl), 4.90 (m, 1H,

CH RTrp), 5.65 (d, 1H, J ) 18 Hz, CH₂-naphtyl), 5.81 (d, 1H, J

) 18 Hz, CH₂-naphtyl), 6.12 (d, 1H, J_o) 7 Hz, H₂naphtyl),

6.38 (t, 1H, J_o) 7 Hz, H₅Trp), 6.47 (d, 1H, J_o) 8 Hz, H₄Trp),

6.85 (t, 1H, J_o) 8 Hz, H₆Trp), 7.03 (d, 1H, J ) 2 Hz, H₂Trp),

7.05-7.12 (m, 5H, CHar benzyl), 7.15 (d, 1H, J_o) 8 Hz, H₇Trp),

7.19 (d, 1H, J_o) 8 Hz, H₃naphtyl), 7.58 (m, 2H, H₆and H₇

naphtyl), 7.81 (d, 1H, J_o) 8 Hz, H₄naphtyl), 7.89-8.01 (m, 5H,

NH₂Aib TFA salt, H₅and H₈naphtyl), 8.92 (d, 1H, J ) 8 Hz, NH

amide), 10.73 (s, 1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-

d₆, 300 K) δ (ppm) 23.5 (CH₃Aib), 23.6 (CH₃Aib), 29.2 (C âTrp),

30.5 (CH₂-benzyl), 44.0 (CH₂-naphtyl), 45.6 (C RTrp), 56.6 (Cq

Aib), 109.7 (C₃Trp), 111.7 (C₇Trp), 117.9 (C₄Trp), 118.4 (C₅

Trp), 121.1 (C₆Trp), 122.1 (C₂naphtyl), 122.8 (C₈naphtyl), 124.9

(C₂Trp), 125.7 (C₃naphtyl), 126.7 (C₆naphtyl), 126.9 (C₉Trp),

127.0 (C₇naphtyl), 128.2 (C₄benzyl), 128.7-129.1 (C₂, C₃, C₅,

and C₆benzyl, C₄and C₅naphtyl), 129.9 (C₉naphtyl), 131.5 (C₁

naphtyl), 133.5 (C₁₀naphtyl), 136.2 (C₁benzyl), 136.4 (C₈Trp),

154.2 (Cq triazole), 155.7 (Cq triazole), 171.9 (CO amide).

(R)-N-(1-(5-(3-(1H-Indol-3-yl)propyl)-4-(naphthalen-1-yl-

methyl)-4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-

2-methylpropanamide Trifluoroacetate Salt (27b). ¹H NMR (300

MHz, DMSO-d₆, 300 K) δ (ppm) 1.20 (s, 3H, CH₃Aib), 1.25 (s,

3H, CH₃Aib), 1.93 (m, 2H, CH₂-CH₂-CH₂-indole), 2.66 (m,

4H, CH₂-CH₂-CH₂-indole), 3.25 (dd, 1H, J ) 14 and 5 Hz, CH₂

âTrp), 3.40 (dd, 1H, J ) 14 and 9 Hz, CH₂âTrp), 4.95 (m, 1H,

CH RTrp), 5.66 (d, 1H, J ) 18 Hz, CH₂-naphtyl), 5.81 (d, 1H, J

) 18 Hz, CH₂-naphtyl), 6.37 (d, 1H, J_o) 7 Hz, H₂naphtyl),

6.43 (t, 1H, J_o) 7 Hz, H₅Trp), 6.59 (d, 1H, J_o) 8 Hz, H₄Trp),

6.86 (m, 3H, H₅and H₆indole, H₆Trp), 6.95 (d, 1H, J ) 2 Hz, H₂

indole), 7.00 (d, 1H, J_o) 8 Hz, H₄indole), 7.06 (d, 1H, J ) 2 Hz,

H₂Trp), 7.20-7.33 (m, 3H, H₇indole, H₇Trp, H₃naphtyl), 7.60

(m, 2H, H₆and H₇naphtyl), 7.87 (d, 1H, J_o) 8 Hz, H₄naphtyl),

7.99 (m, 5H, NH₂Aib TFA salt, H₅and H₈naphtyl), 8.95 (d, 1H,

J ) 8 Hz, NH amide), 10.70 (s, 1H, NH indole), 10.77 (s, 1H, NH

indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.5

(CH₃Aib), 23.6 (CH₃Aib), 24.1 (CH₂-CH₂-CH₂-indole), 24.5

(CH₂-CH₂-CH₂-indole), 27.6 (CH₂-CH₂-CH₂-indole), 29.1 (C

âTrp), 44.1 (CH₂-naphtyl), 45.7 (C RTrp), 56.7 (Cq Aib), 109.7

(C₃Trp), 111.7 (C₇indole and C₇Trp), 113.9 (C₃indole), 117.9

(C₄Trp), 118.5 (C₄indole, C₅Trp), 118.6 (C₅indole), 121.1 (C₆

Trp), 121.2 (C₆indole), 122.1 (C₂naphtyl), 122.7 (C₂indole), 122.9

(C₈naphtyl), 125.0 (C₂Trp), 125.9 (C₃naphtyl), 126.8 (C₆naphtyl),

127.0 (C₉indole), 127.1 (C₇naphtyl), 127.4 (C₉Trp), 128.5 (C₄

naphtyl), 129.2 (C₅naphtyl), 129.9 (C₉naphtyl), 131.6 (C₁naphtyl),

133.6 (C₁₀naphtyl), 136.4 (C₈Trp), 136.7 (C₈indole), 155.4 (2Cq

triazole), 171.9 (CO amide).

N-((R)-1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(2,2-diphenylethyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpro-

panamide Trifluoroacetate Salt (26b). ¹H NMR (300 MHz,

DMSO-d₆, 300 K) δ (ppm) 1.34 (s, 3H, CH₃Aib), 1.38 (s, 3H,

CH₃Aib), 2.06 (m, 1H, CH₂-CH₂-indole), 2.30 (m, 1H, CH₂-

CH₂-indole), 2.78 (m, 2H, CH₂-CH₂-indole), 3.35 (dd, 1H, J )

14 and 7 Hz, CH₂âTrp), 3.46 (dd, 1H, J ) 14 and 9 Hz, CH₂

âTrp), 3.58 (t, 1H, J ) 7 Hz, CH₂-CH(Phe)₂), 4.14 (dd, 1H, J )

14 and 8 Hz, CH₂-CH(Phe)₂), 4.39 (dd, 1H, J ) 14 and 7 Hz,

CH₂-CH(Phe)₂), 5.12 (m, 1H, CH RTrp), 6.50 (m, 2H, H₅indole

and H₅Trp), 6.76 (m, 2H, H₆indole and H₆Trp), 6.87 (m, 2H, H₂

indole and H₂Trp), 6.89-6.96 (m, 2H, H₄phenyl), 7.03-7,15 (m,

8H, H₂, H₃, H₅and H₆phenyl), 7.33 (m, 3H, H₄indole, H₄and H₇

Trp), 7.47 (d, 1H, J ) 8 Hz, H₇indole), 8.11 (brs, 3H, NH₂Aib,

TFA salt), 9.04 (d, 1H, J ) 8 Hz, NH amide), 10.76 (s, 1H, NH

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-(naphthalen-1-ylmethyl)-

4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-meth-

ylpropanamide Trifluoroacetate Salt (27c). ¹H NMR (400 MHz,

DMSO-d₆) δ 1.25 (s, 3H, CH₃Aib), 1.28 (s, 3H, CH₃Aib), 2.93

(m, 2H, CH₂-CH₂-indole), 3.01 (m, 2H, CH₂-CH₂-indole), 3.30

(dd, 1H, J ) 14.3, J ) 5.8, CH₂âTrp), 3.40 (dd, 1H, J ) 14.3, J

) 8.8, CH₂âTrp), 5.03 (m, 1H, CRH Trp), 5.62 (d, 1H, J ) 18.0,

CH₂-naphtyl), 5.76 (d, 1H, J ) 18.0, CH₂-naphtyl), 6.36 (d, 1H,

J ) 7.2, H₂naphtyl), 6.51 (t, 1H, J ) 7.4, H₅Trp), 6.72 (d, 1H, J

Triazole DeriVatiVes as Ghrelin Receptor Ligands

Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8 1953

) 7.9, H₄Trp), 6.76 (t, 1H, J ) 7.5, H₅indole), 6.92 (t, 1H, J )

7.5, H₆Trp), 7.0 (t, 1H, J ) 7.5, H₆indole), 7.02 (d, 1H, J ) 2.0,

H₂indole), 7.09 (d, 1H, J ) 2.0, H₂Trp), 7.13 (d, 1H, J ) 7.9, H₄

indole), 7.26 (d, 1H, J ) 7.9, H₇Trp), 7.27 (t, 1H, J ) 8.2, H₃

naphtyl), 7.29 (d, 1H, H₇indole), 7.58-7.64 (m, 2H, H₆, H₇

naphtyl), 7.88 (d, 1H, J ) 8.2, H₄naphtyl), 7.93 (d, 1H, J ) 7.9,

H₈naphtyl), 7.98 (brs, 2H, NH₂Aib, TFA salt), 8.03 (d, 1H, J )

8.2, H₅naphtyl), 8.96 (d, 1H, J ) 7.9, NH Trp), 10.75 (brs, 1H,

NH indole), 10.77 (brs, 1H, NH indole Trp). ¹³C NMR (100 MHz,

DMSO-d₆) δ 22.6 (CH₂-CH₂indole), 23.1 (CH₃Aib), 23.2 (CH₃

Aib), 25.3 (CH₂-CH₂indole), 28.8 (C âTrp), 43.3 (CH₂-naphtyl),

45.3 (C RTrp), 56.2 (Cq Aib), 109.4 (C₃Trp), 111.2 (C₇Trp, C₇

indole), 112.9 (C₃indole), 117.5 (C₄Trp), 117.8 (C₄indole), 118.0

(C₅Trp), 118.1 (C₅indole), 120.7 (C₆Trp), 120.8 (C₆indole), 121.6

(C₂naphtyl), 122.5 (C₂indole, C₈naphtyl), 124.4 (C₂Trp), 125.4

(C₃naphtyl), 126.3 (C₆naphtyl), 126.6 (C₉Indole, C₉Trp, C₇

naphtyl), 127.9 (C₄naphtyl), 128.6 (C₅naphtyl), 129.5 (C₉naphtyl),

131.4 (C₁naphtyl), 133.1 (C₁₀naphtyl), 135.9 (C₈Trp), 136.1 (C₈

indole), 154.7 (2Cq triazole), 171.4 (CO amide).

CH₂-CH₂-indole), 3.10 (m, 2H, CH₂-CH₂-indole), 3.37 (dd, 1H,

J ) 14.2, J ) 7.6, CH₂âTrp), 3.44 (dd, 1H, J ) 14.2, J ) 7.6,

CH₂âTrp), 3.58 (m, 1H, 1H N-CH₂), 3.71 (m, 1H, N-CH₂), 5.21

(m, 1H, CH RTrp), 6.96 (t, 1H, H₅Trp), 6.97 (t, 1H, H₅indole),

7.06 (t, 2H, H₆Trp, H₆indole), 7.09 (s, 1H, H₂Trp), 7.13 (s, 1H,

H₂indole), 7.34 (d, 2H, H₇Trp, H₇indole),7.48 (d, 1H, d, H₄

indole), 7.50 (d, 1H, H₄Trp), 8.14 (brs, 3H, NH₂Aib, TFA salt),

9.08 (d, 1H, J ) 7.8, NH amide), 10.84 (s, 1H, NH indole), 10.88

(s, 1H, NH indole Trp). ¹³C NMR (100 MHz, DMSO-d₆) δ 13.7

(CH₂)₅-CH₃), 21.7 (CH₂-CH₃), 22.4 (CH₂-CH₂indole), 23.1

(CH₃Aib), 23.3 (CH₃Aib), 25.1 (CH₂-CH₂indole), 25.5 (CH₃-

CH₂-CH₂-CH₂), 29.1 (C âTrp), 29.3 (N-CH₂-CH₂), 30.4 (CH₃-

CH₂-CH₂), 42.6 (N-CH₂-CH₂), 45.6 (C RTrp), 56.3 (Cq Aib),

109.2 (C₃Trp), 111.4 (C₇Trp, C₇indole), 112.8 (C₃indole), 117.7

(C₄Trp), 118.0 (C₅indole), 118.2 (C₄indole), 118.4 (C₅Trp), 120.9

(C₆indole, C₆Trp), 122.6 (C₂indole), 124.3 (C₂Trp), 126.8 (C₉

Trp), 126.9 (C₉indole), 136.0 (C₈Trp), 136.2 (C₈indole), 154.0

(Cq triazole), 154.1 (Cq triazole), 171.4 (CO amide).

(R)-N-(1-(5-(3-(1H-Indol-3-yl)propyl)-4-hexyl-4H-1,2,4-tri-

azol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (28c). ¹H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 0.74 (t, 3H, J ) 6 Hz, CH₃-CH₂-CH₂-CH₂-

CH₂-CH₂), 0.95 (brs, 4H, CH₃-CH₂-CH₂-CH₂-CH₂-CH₂),

1.06 (m, 3H, CH₃-CH₂-CH₂-CH₂-CH₂-CH₂and N-CH₂-

CH₂), 1.38 (s, 7H, CH₃Aib and N-CH₂-CH₂), 1.97 (m, 2H, CH₂-

CH₂-CH₂-indole), 2.71 (m, 4H, CH₂-CH₂-CH₂-indole), 3.37

(m, 2H, CH₂âTrp), 3.56 (m, 2H, N-CH₂), 5.15 (m, 1H, CH RTrp),

6.91 (m, 2H, H₅indole and H₅Trp), 7.00 (m, 2H, H₆indole and

H₆Trp), 7.07 (s, 2H, H₂indole and H₂Trp), 7.29 (d, 2H, J_o) 8

Hz, H₇indole and H₇Trp), 7.45 (d, 2H, J ) 7 Hz, H₄indole and

H₄Trp), 8.15 (brs, 3H, NH₂Aib, TFA salt), 9.10 (d, 1H, J ) 6

Hz, NH amide), 10.77 (s, 1H, NH indole), 10.85 (s, 1H, NH indole

Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 14.2 (CH₃-

CH₂-CH₂-CH₂-CH₂-CH₂), 22.2 (CH₃-CH₂-CH₂-CH₂-CH₂-

CH₂and CH₂-CH₂-CH₂-indole), 23.6 (CH₃Aib), 23.7 (CH₃

Aib), 24.5 (CH₂-CH₂-CH₂-indole), 25.9 (CH₃-CH₂-CH₂-

CH₂-CH₂-CH₂), 27.5 (C âTrp and CH₂-CH₂-CH₂-indole), 29.7

(N-CH₂-CH₂), 30.8 (CH₃-CH₂-CH₂-CH₂-CH₂-CH₂), 43.2

(N-CH₂), 46.1 (C RTrp), 56.8 (Cq Aib), 109.5 (C₃Trp), 111.8

(C₇Trp), 111.9 (C₇indole), 113.9 (C₃indole), 118.1 (C₄Trp), 118.5

(C₅indole), 118.6 (C₄indole), 118.9 (C₅Trp), 121.3 (C₆indole

and C₆Trp), 122.8 (C₂indole and C₂Trp), 127.3 (C₉Trp), 127.4

(C₉indole), 136.5 (C₈Trp), 136.8 (C₈indole), 154.7 (2Cq triazole),

172.0 (CO amide).

N-((R)-1-(4-(2-(1H-Indol-3-yl)ethyl)-5-benzyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (29a). ¹H NMR (400 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.31 (s, 3H, CH₃Aib), 1.35 (s, 3H, CH₃Aib), 2.51 (m,

2H, CH₂-CH₂-indole), 3.37 (m, 2H, CH₂âTrp), 3.76-3.90 (m,

4H, CH₂-benzyl and CH₂-CH₂-indole), 5.25 (m, 1H, CH RTrp),

6.88 (t, 2H, J_o) 7 Hz, H₅indole and H₅Trp), 6.95 (t, 2H, J_o) 7

Hz, H₆indole and H₆Trp), 7.03 (m, 4H, H₂Trp, H₂indole, H₂and

H₆benzyl), 7.16 (d, 2H, J_o) 8 Hz, H₄indole and H₄Trp), 7.20-

7,30 (m, 4H, H₇indole, H₃, H₄and H₅benzyl), 7.47 (d, 1H, J_o)

8 Hz, H₇Trp), 8.05 (brs, 3H, NH₂Aib, TFA salt), 9.05 (d, 1H, J

) 8 Hz, NH amide), 10.83 (s, 1H, NH indole), 10.88 (s, 1H, NH

indole Trp). ¹³C NMR (100 MHz, DMSO-d₆, 300 K) δ (ppm) 23.5

(CH₃Aib), 23.7 (CH₃Aib), 29.6 (C âTrp), 30.3 (CH₂-benzyl and

CH₂-CH₂-indole), 44.1 (CH₂-CH₂-indole), 46.1 (C RTrp), 56.8

(Cq Aib), 109.8 (C₃Trp), 109.9 (C₃indole), 111.9 (C₇indole and

C₇Trp), 118.3 (C₄Trp), 118.4 (C₄indole), 118.9 (C₅indole and

C₅Trp), 121.3 (C₆Trp), 121.5 (C₆indole), 123.7 (C₂indole), 124.7

(C₂Trp), 127.0 (C₉indole), 127.2 (C₄benzyl), 127.4 (C₉Trp), 128.8

(C₃and C₅benzyl), 129.0 (C₂and C₆benzyl), 136.3 (C₁benzyl),

136.4 (C₈indole and C₈Trp), 153.1 (Cq triazole), 155.3 (Cq

triazole), 171.8 (CO amide).

(R)-N-(2-(1H-Indol-3-yl)-1-(4-(naphthalen-1-ylmethyl)-5-phen-

ethyl-4H-1,2,4-triazol-3-yl)ethyl)-2-amino-2-methylpropan-

amide Trifluoroacetate Salt (27d). ¹H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 1.21 (s, 3H, CH₃Aib), 1.25 (s, 3H, CH₃Aib),

2.46 (m, 2H, CH₂-CH₂-phenyl), 2.88 (m, 2H, CH₂-CH₂-

phenyl), 3.26 (dd, 2H, ³J ) 14 and 6 Hz, CH₂âTrp), 3.36 (dd, 2H,

³J ) 14 and 9 Hz, CH₂âTrp), 4.99 (m, 1H, CH RTrp), 5.65 (d,

3

1H, J ) 18 Hz, CH₂-naphtyl), 5.78 (d, 1H, J ) 18 Hz, CH₂-

naphtyl), 6.29 (d, 1H, J_o) 7 Hz, H₂naphtyl), 6.45 (t, 1H, J_o) 7

Hz, H₅Trp), 6.62 (d, 1H, J_o) 8 Hz, H₄Trp), 6.88 (t, 1H, J_o) 8

Hz, H₆Trp), 7.04-7.06 (m, 4H, H₂and H₇Trp, H₂and H₆phenyl),

7.07-7.25 (m, 4H, H₃naphtyl, H₃, H₄and H₅phenyl), 7.57-7.60

(m, 2H, H₆and H₇naphtyl), 7.86 (d, 1H, J_o) 8 Hz, H₄naphtyl),

7.98-8.00 (m, 5H, H₅and H₈naphtyl, NH₂Aib, TFA salt), 8.96

(d, 1H, J ) 8 Hz, NH amide), 10.77 (s, 1H, NH indole Trp). ¹³C

NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.5 (CH₃Aib), 23.6

(CH₃Aib), 26.3 (CH₂CH₂-phenyl), 29.2 (C âTrp), 32.6 (CH₂-

CH₂-phenyl), 43.8 (CH₂-naphtyl), 45.6 (C RTrp), 56.7 (Cq Aib),

109.7 (C₃Trp), 111.7 (C₇Trp), 117.9 (C₄Trp), 118.4 (C₅Trp),

121.1 (C₆Trp), 122.1 (C₂naphtyl), 123.0 (C₈naphtyl), 124.9 (C₂

Trp), 125.9 (C₃naphtyl), 126.5 (C₆naphtyl), 126.9 (C₄phenyl),

127.0 (C₉Trp and C₇naphtyl), 127.1 (C₄naphtyl), 128.4 (C₅

naphtyl), 128.7 (C₂, C₃, C₅, and C₆phenyl), 130.0 (C₉naphtyl),

131.7 (C₁naphtyl), 133.6 (C₁₀naphtyl), 136.4 (C₈Trp), 140.8 (C₁

phenyl), 154.8 (Cq triazole), 155.3 (Cq triazole), 171.9 (CO amide).

2-Amino-N-((R)-1-(5-benzyl-4-hexyl-4H-1,2,4-triazol-3-yl)-2-

(1H-indol-3-yl)ethyl)-2-methylpropanamide Trifluoroacetate Salt

1

(28a). H NMR (300 MHz, DMSO-d₆, 300 K) δ (ppm) 0.71 (t,

3

3H, J ) 7 Hz, (CH₂)₅-CH₃), 0.87 (m, 4H, 2 CH₂), 0.95 (m, 2H,

CH₂-CH₃), 1.00 (m, 2H, N-CH₂-CH₂), 1.36 (s, 6H, CH₃Aib),

3.36 (dd, 1H, ³J ) 14 and 7 Hz, CH₂âTrp), 3.41 (dd, 1H, ³J ) 14

and 7 Hz, CH₂âTrp), 3.50 (m, 1H, N-CH₂), 3.65 (m, 1H, N-CH₂),

4.11 (s, 2H, CH₂-benzyl), 5.14 (m, 1H, CH RTrp), 6.90 (t, 1H, J_o

) 7 Hz, H₅Trp), 7.01 (t, 1H, J_o) 7 Hz, H₆Trp), 7.04 (s, 1H, H₂

Trp), 7.09 (m, 2H, H₂and H₆benzyl), 7.17-7.29 (m, 4H, H₄Trp,

H₃, H₄and H₅benzyl), 7.47 (d, 1H, J_o) 8 Hz, H₇Trp), 8.10 (brs,

3H, NH₂Aib, TFA salt), 9.05 (d, 1H, J ) 7 Hz, NH amide), 10.84

(s, 1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ

(ppm) 14.1 ((CH₂)₅-CH₃), 22.1 (CH₂-CH₃), 23.8 (CH₃Aib), 23.5

(CH₃Aib), 25.8 (CH₃-CH₂-CH₂-CH₂), 29.5 (C âTrp), 30.3 (N-

CH₂-CH₂), 30.8 (CH₂-benzyl and CH₃-CH₂-CH₂), 43.3 (N-

CH₂-CH₂), 46.1 (C RTrp), 56.8 (Cq Aib), 109.6 (C₃Trp), 111.9

(C₇Trp), 118.2 (C₄Trp), 118.8 (C₅Trp), 121.4 (C₆Trp), 124.7

(C₂Trp), 127.2 (C₄benzyl), 127.3 (C₉Trp), 128.8 (C₂, C₃, C₅and

C₆benzyl), 136.2 (C₁benzyl), 136.5 (C₈Trp), 153.1 (Cq triazole),

155.1 (Cq triazole), 171.9 (CO amide).

(R)-N-(1-(5-(2-(1H-Indol-3-yl)ethyl)-4-hexyl-4H-1,2,4-triazol-

3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

(R)-N-(1-(4,5-bis(2-(1H-Indol-3-yl)ethyl)-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (29b). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.30 (s, 3H, CH₃Aib), 1.37 (s, 3H, CH₃Aib), 2.50 (m,

2H, N-CH₂-CH₂-indole), 2.68 (t, 2H, J_o) 8 Hz, C-CH₂-CH₂-

1

fluoroacetate Salt (28b). H NMR (400 MHz, DMSO-d₆) δ 0.77

(t, 3H, J ) 7.2 (CH₂)₅-CH₃), 1.01 (m, 4H, 2CH₂), 1.11 (m, 2H,

CH₂-CH₃), 1.14 (m, 1H, N-CH₂-CH₂), 1.33 (m, 1H, N-CH₂-

CH₂), 1.40 (s, 3H, CH₃Aib), 1.42 (s, 3H, CH₃Aib), 3.05 (m, 2H,

1954 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

indole), 2.91 (t, 2H, J_o) 8 Hz, C-CH₂-CH₂-indole), 3.34 (m,

2H, N-CH₂-CH₂-indole), 3.93 (m, 2H, CH₂âTrp), 5.25 (m, 1H,

CH RTrp), 6.72-6.94 (m, 4H, H₅and H₆Trp, H₅indole from

C-CH₂-CH₂-indole and H₅indole from N-CH₂-CH₂-indole),

6.98-7.04 (m, 4H, H₂Trp, H₆indole from C-CH₂-CH₂-indole,

H₂and H₆indole from N-CH₂-CH₂-indole), 7.11 (s, 1H, H₂

indole from C-CH₂-CH₂-indole), 7.19 (d, 1H, J_o) 8 Hz, H₄

indole from N-CH₂-CH₂-indole), 7.28 (m, 3H, H₄and H₇Trp,

H₇indole from N-CH₂-CH₂-indole), 7.40 (d, 1H, J_o) 8 Hz, H₇

indole from C-CH₂-CH₂-indole), 7.44 (d, 1H, J_o) 8 Hz, H₄

indole from C-CH₂-CH₂-indole), 8.04 (brs, 3H, NH₂Aib, TFA

salt), 9.69 (d, 1H, J ) 8 Hz, NH amide), 10.73 (s, 1H, NH indole

from C-CH₂-CH₂-indole), 10.82 (d, 1H, J ) 2 Hz, NH indole

Trp), 10.84 (s, 1H, NH indole from N-CH₂-CH₂-indole). ¹³C

NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 22.7 (C-CH₂-CH₂-

indole), 23.6 (CH₃Aib), 23.8 (CH₃Aib), 25.4 (C-CH₂-CH₂-

indole), 26.0 (N-CH₂-CH₂-indole), 29.6 (C âTrp), 43.9 (N-

CH₂-CH₂-indole), 46.0 (C RTrp), 56.8 (Cq Aib), 109.5 (C₃indole

from N-CH₂-CH₂-indole), 109.9 (C₃Trp), 111.7 (C₇Trp), 111.9

(C₇indole from N-CH₂-CH₂-indole and C₇indole from C-CH₂-

CH₂-indole), 113.5 (C₃indole from C-CH₂-CH₂-indole), 118.3

(C₄indole from N-CH₂-CH₂-indole), 118.4 (C₄Trp), 118.5 (C₅

indole from C-CH₂-CH₂-indole), 118.7 (C₄indole from C-CH₂-

CH₂-indole), 118.9 (C₅Trp), 119.0 (C₅indole from N-CH₂-

CH₂-indole), 121.3 (C₆Trp), 121.5 (C₆indole from C-CH₂-

CH₂-indole and C₆indole from N-CH₂-CH₂-indole), 122.8 (C₂

Trp, C₂indole from C-CH₂-CH₂-indole and C₂indole from

N-CH₂-CH₂-indole), 127.1 (C₉Trp), 127.2 (C₉indole from

C-CH₂-CH₂-indole), 127.4 (C₉indole from N-CH₂-CH₂-

indole), 136.5 (C₈Trp and C₈indole from C-CH₂-CH₂-indole),

136.6 (C₈indole from N-CH₂-CH₂-indole), 154.5 (Cq triazole),

154.8 (Cq triazole), 171.8 (CO amide).

amide Trifluoroacetate Salt (30a). ¹H NMR (300 MHz, DMSO-

d₆) δ (ppm) 1.25 (s, 3H, CH₃Aib), 1.28 (s, 3H, CH₃Aib), 1.73

(m, 2H, CH₂-CH₂-CH₂-phenyl), 2.23 (s, 3H, CH₃p-methylben-

zyl), 2.49-2.54 (m, 4H, CH₂-CH₂-CH₂-phenyl), 3.33 (m, 2H,

CH₂âTrp), 5.04 (s, 2H, CH₂-p-methylbenzyl), 5.16 (m, 1H, CH

RTrp), 6.74 (d, 2H, J_o) 8 Hz, H₃and H₅p-methylbenzyl), 6.80

(t, 1H, J_o) 7 Hz, H₅Trp), 6.98 (t, 1H, J_o) 7 Hz, H₆Trp), 7.03

(d, 1H, J ) 2 Hz, H₂Trp), 7.06 (m, 5H, CHar phenyl), 7.14 (d,

1H, J_o) 7 Hz, H₄Trp), 7.20 (d, 2H, J_o) 7 Hz, H₂and H₆

p-methylbenzyl), 7.27 (d, 1H, J_o) 8 Hz, H₇Trp), 8.01 (brs, 3H,

NH₂Aib, TFA salt), 8.95 (d, 1H, J ) 8 Hz, NH amide), 10.80 (d,

1H, J ) 2 Hz, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆) δ

(ppm) 21.0 (CH₃p-methylbenzyl), 23.5 (CH₃Aib), 23.8 (CH₃Aib),

24.0 (CH₂-CH₂-CH₂-phenyl), 28.5 (CH₂-CH₂-CH₂-phenyl),

29.1 (C âTrp), 34.7 (CH₂-CH₂-CH₂-phenyl), 45.7 (C RTrp), 45.8

(CH₂-p-methylbenzyl), 56.8 (Cq Aib), 109.8 (C₃Trp), 111.8 (C₇

Trp), 118.3 (C₄Trp), 118.7 (C₅Trp), 121.3 (C₆Trp), 124.9 (C₂

Trp), 126.2 (C₄phenyl), 126.4 (C₃and C₅p-methylbenzyl), 127.3

(C₉Trp), 128.7 (C₂, C₃, C₅and C₆phenyl), 129.8 (C₂and C₆

p-methylbenzyl), 133.0 (C₁p-methylbenzyl), 136.4 (C₈Trp), 137.5

(C₄p-methylbenzyl), 141.7 (C₁phenyl), 154.8 (2Cq triazole), 171.9

(CO amide).

(R)-N-(1-(4-(4-Methylbenzyl)-5-(3-benzyl)-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (30b). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.22 (s, 3H, CH₃Aib), 1.27 (s, 3H, CH₃Aib), 2.22 (s,

3H, CH₃p-methylbenzyl), 3.22 (dd, 1H, J ) 14 and 6 Hz, CH₂

âTrp), 3.33 (dd, 1H, J ) 14 and 9 Hz, CH₂âTrp), 3.99 (s, 2H,

CH₂-benzyl), 5.04 (s, 2H, CH₂-p-methylbenzyl), 5.09 (m, 1H,

CH RTrp), 6.64 (d, 2H, J_o) 8 Hz, H₃and H₅p-methylbenzyl),

6.78 (t, 1H, J_o) 7 Hz, H₅Trp), 6.98 (t, 4H, J_o) 7 Hz, H₆Trp,

H₃, H₄and H₅benzyl), 7.01 (d, 1H, J ) 2 Hz, H₂Trp), 7.07 (d,

2H, J_o) 7 Hz, H₂and H₆p-methylbenzyl), 7.20 (m, 3H, H₄Trp,

H₂and H₆benzyl), 7.26 (d, 1H, J_o) 8 Hz, H₇Trp), 7.98 (brs, 3H,

NH₂Aib, TFA salt), 8.89 (d, 1H, J ) 8 Hz, NH amide), 10.74 (s,

1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ

(ppm) 21.0 (CH₃p-methylbenzyl), 23.5 (CH₃Aib), 23.7 (CH₃Aib),

29.1 (C âTrp), 30.6 (CH₂-benzyl), 45.7 (C RTrp), 46.0 (CH₂-p-

methylbenzyl), 56.7 (Cq Aib), 109.8 (C₃Trp), 111.7 (C₇Trp), 118.3

(C₄Trp), 118.6 (C₅Trp), 121.2 (C₆Trp), 124.8 (C₂Trp), 126.3

(C₃and C₅p-methylbenzyl), 127.0 (C₄benzyl), 127.2 (C₉Trp),

128.9 (C₂, C₃, C₅, and C₆benzyl), 129.7 (C₂and C₆p-methylben-

zyl), 132.9 (C₁p-methylbenzyl), 136.3 (C₄p-methylbenzyl), 136.4

(C₈Trp), 137.4 (C₁benzyl), 153.9 (Cq triazole), 155.3 (Cq triazole),

171.8 (CO amide).

(R)-N-(1-(5-(2-(1H-Indol-2-yl)ethyl)-4-(4-methylbenzyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpro-

panamide Trifluoroacetate Salt (30c). ¹H NMR (300 MHz,

DMSO-d₆, 300 K) δ (ppm) 1.25 (s, 3H, CH₃Aib), 1.28 (s, 3H,

CH₃Aib), 2.23 (s, 3H, CH₃-p-methylbenzyl), 2.84-2.97 (m, 4H,

CH₂-CH₂-indole), 3.32 (m, 2H, CH₂âTrp), 5.04 (s, 2H, CH₂-

p-methylbenzyl), 5.16 (m, 1H, CH RTrp), 6.79-6.86 (m, 4H, CH

ar p-methylbenzyl), 6.99-7.05 (m, 4H, H₅and H₆indole, H₅and

H₆Trp), 7.08 (m, 3H, H₂indole, H₂and H₄Trp), 7.25-7.30 (m,

3H, H₄and H₇indole, H₇Trp), 8.00 (brs, 3H, NH₂Aib, TFA salt),

8.94 (d, 1H, J ) 8 Hz, NH amide), 10.76 (s, 1H, NH indole), 10.78

(s, 1H, NH indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ

(ppm) 21.0 (CH₃- p-methylbenzyl), 22.8 (CH₂-CH₂-indole), 23.8

(CH₃Aib), 23.9 (CH₃Aib), 25.9 (CH₂-CH₂-indole), 28.5 (C

âTrp), 45.7 (CH₂- p-methylbenzyl and C RTrp), 56.7 (Cq Aib),

109.9 (C₃Trp), 111.8 (C₇indole and C₇Trp), 113.4 (C₃indole),

118.1 (C₄Trp), 118.3 (C₄indole), 118.5 (C₅indole), 118.7 (C₅

Trp), 120.9 (C₆indole and C₆Trp), 121.3 (C₂indole and C₂Trp),

126.3 (C₃and C₅p-methylbenzyl), 127.2 (C₉indole), 127.3 (C₉

Trp), 129.8 (C₂and C₆p-methylbenzyl), 133.1 (C₁p-methylbenzyl),

135.8 (C₈indole, C₈Trp), 136.4 (C₄p-methylbenzyl), 154.8 (Cq

triazole), 155.0 (Cq triazole), 171.9 (CO amide).

(R)-N-(1-(4-(2-(1H-Indol-3-yl)ethyl)-5-(3-(1H-indol-3-yl)pro-

pyl)-4H-1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-

1

methylpropanamide Trifluoroacetate Salt (29c). H NMR (300

MHz, DMSO-d₆) δ (ppm) 1.29 (s, 3H, CH₃Aib), 1.35 (s, 3H, CH₃

Aib), 1.78 (m, 2H, CH₂-CH₂-CH₂-indole), 2.34 (m, 2H, CH₂-

CH₂-CH₂-indole), 2.48 (m, 2H, N-CH₂-CH₂-indole), 2.80 (m,

2H, CH₂-CH₂-CH₂-indole), 3.34 (m, 2H, N-CH₂-CH₂-indole),

3.94 (m, 2H, CH₂âTrp), 5.27 (m, 1H, CH RTrp), 6.73-6.94 (m,

4H, H₅and H₆Trp, H₅indole from N-CH₂-CH₂-indole and H₅

indole from CH₂-CH₂-CH₂-indole), 6.99-7.04 (m, 5H, H₂Trp,

H₂and H₆indole from N-CH₂-CH₂-indole, H₂and H₆indole

from CH₂-CH₂-CH₂-indole), 7.20 (d, 1H, J_o) 8 Hz, H₄indole

from N-CH₂-CH₂-indole), 7.29 (m, 3H, H₄and H₇Trp, H₇indole

from N-CH₂-CH₂-indole), 7.40 (d, 1H, J_o) 8 Hz, H₇indole

from CH₂-CH₂-CH₂-indole), 7.44 (d, 1H, J_o) 8 Hz, H₄indole

from CH₂-CH₂-CH₂-indole), 8.05 (brs, 3H, NH₂Aib, TFA salt),

9.07 (d, 1H, J ) 8 Hz, NH amide), 10.75 (s, 1H, NH indole from

CH₂-CH₂-CH₂-indole), 10.86 (s, 1H, NH indole Trp), 10.90 (s,

1H, NH indole from N-CH₂-CH₂-indole). ¹³C NMR (75 MHz,

DMSO-d₆) δ (ppm) 23.6 (CH₃Aib), 23.8 (CH₃Aib), 24.5 (CH₂-

CH₂-CH₂-indole), 25.8 (CH₂-CH₂-CH₂-indole), 27.2 (CH₂-

CH₂-CH₂-indole), 29.4 (C âTrp), 44.1 (N-CH₂-CH₂-indole),

46.0 (C RTrp), 52.9 (N-CH₂-CH₂-indole), 56.8 (Cq Aib), 109.7

(C₃Trp and C₃indole from N-CH₂-CH₂-indole), 111.8 (C₇Trp),

111.9 (C₇indole from N-CH₂-CH₂-indole and C₇indole from

CH₂-CH₂-CH₂-indole), 114.0 (C₃indole from CH₂-CH₂-CH₂-

indole), 118.2 (C₄indole from N-CH₂-CH₂-indole), 118.3 (C₄

Trp), 118.5 (C₅indole from CH₂-CH₂-CH₂-indole), 118.6 (C₄

indole from CH₂-CH₂-CH₂-indole), 118.9 (C₅Trp), 119.0 (C₅

indole from N-CH₂-CH₂-indole), 121.3 (C₆Trp), 121.4 (C₆

indole from CH₂-CH₂-CH₂-indole), 121.6 (C₆indole from

N-CH₂-CH₂-indole), 122.7 (C₂Trp, C₂indole from N-CH₂-

CH₂-indole and C₂indole from CH₂-CH₂-CH₂-indole), 127.1

(C₉Trp), 127.4 (C₉indole from N-CH₂-CH₂-indole and C₉

indole from CH₂-CH₂-CH₂-indole), 136.4 (C₈Trp), 136.5 (C₈

indole from CH₂-CH₂-CH₂-indole), 136.7 (C₈indole from

N-CH₂-CH₂-indole), 154.7 (2 Cq triazole), 171.9 (CO amide).

(R)-N-(1-(4-(4-Methylbenzyl)-5-(3-phenylpropyl)-4H-1,2,4-

triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

(R)-N-(1-(4-(4-Methylbenzyl)-5-phenethyl-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (30d). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.25 (s, 3H, CH₃Aib), 1.28 (s, 3H, CH₃Aib), 2.23 (s,

Triazole DeriVatiVes as Ghrelin Receptor Ligands

Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8 1955

3H, CH₃p-methylbenzyl), 2.83 (m, 4H, CH₂-CH₂-phenyl), 3.32

(m, 2H, CH₂âTrp), 5.05 (s, 2H, CH₂-p-methylbenzyl), 5.18 (m,

1H, CH RTrp), 6.75 (d, 2H, J_o) 8 Hz, H₃and H₅p-methylbenzyl),

6.82 (t, 1H, J_o) 8 Hz, H₅Trp), 6.99 (t, 1H, J_o) 8 Hz, H₆Trp),

7.02-7.11 (m, 6H, H₂Trp and CHar phenyl), 7.15 (d, 1H, J_o) 7

Hz, H₄Trp), 7.20 (d, 2H, J_o) 7 Hz, H₂and H₆p-methylbenzyl),

7.28 (d, 1H, J_o) 8 Hz, H₇Trp), 8.01 (brs, 3H, NH₂Aib, TFA

salt), 8.93 (d, 1H, J ) 8 Hz, NH amide), 10.77 (s, 1H, NH indole

Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 21.0 (CH₃

p-methylbenzyl), 23.6 (CH₃Aib), 23.8 (CH₃Aib), 26.5 (CH₂-

CH₂-phenyl), 29.1 (C âTrp), 32.7 (CH₂-CH₂-phenyl), 45.7 (C

RTrp and CH₂-p-methylbenzyl), 56.8 (Cq Aib), 109.8 (C₃Trp),

111.8 (C₇Trp), 118.3 (C₄Trp), 118.7 (C₅Trp), 121.3 (C₆Trp),

124.8 (C₂Trp), 126.4 (C₃and C₅p-methylbenzyl), 126.6 (C₄

phenyl), 127.3 (C₉Trp), 128.7 (C₂, C₃, C₅, and C₆phenyl), 129.8

(C₂and C₆p-methylbenzyl), 133.0 (C₁p-methylbenzyl), 136.4 (C₈

Trp), 137.5 (C₄p-methylbenzyl), 140.9 (C₁phenyl), 154.5 (Cq

triazole), 154.9 (Cq triazole), 171.9 (CO amide).

(R)-N-(1-(4-(4-Ethylbenzyl)-5-phenethyl-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (31). ¹H NMR (300 MHz, DMSO-d₆, 300 K) δ

(ppm) 1.10 (t, 3H, J ) 8 Hz, CH₃-CH₂p- ethylbenzyl), 1.25 (s,

3H, CH₃Aib), 1.28 (s, 3H, CH₃Aib), 2.53 (q, 2H, J ) 8 Hz, CH₃-

CH₂p-ethylbenzyl), 2.83 (m, 4H, CH₂-CH₂-phenyl), 3.34 (m,

2H, CH₂âTrp), 5.07 (s, 2H, CH₂-p-ethylbenzyl), 5.19 (m, 1H,

CH RTrp), 6.77 (d, 2H, J_o) 8 Hz, H₃and H₅p-ethylbenzyl), 6.81

(t, 1H, J_o) 7 Hz, H₅Trp), 6.99 (t, 1H, J_o) 8 Hz, H₆Trp), 7.05-

7.10 (m, 7H, CHar phenyl, H₂and H₆p-ethylbenzyl), 7.13 (d, 1H,

J ) 2 Hz, H₂Trp), 7.20 (d, 1H, J_o) 7 Hz, H₄Trp), 7.28 (d, 1H,

J_o) 8 Hz, H₇Trp), 8.03 (brs, 3H, NH₂Aib, TFA salt), 8.94 (d,

1H, J ) 8 Hz, NH amide), 10.79 (s, 1H, NH indole Trp). ¹³C NMR

(75 MHz, DMSO-d₆, 300 K) δ (ppm) 15.9 (CH₃-CH₂p-

ethylbenzyl), 23.5 (CH₃Aib), 23.8 (CH₃Aib), 26.5 (CH₂-CH₂-

phenyl), 28.1 (CH₃-CH₂p-ethylbenzyl), 29.1 (C âTrp), 32.7

(CH₂-CH₂-phenyl), 45.7 (C RTrp), 45.8 (CH₂-p-ethylbenzyl),

56.8 (Cq Aib), 109.8 (C₃Trp), 111.8 (C₇Trp), 118.3 (C₄Trp),

118.7 (C₅Trp), 121.3 (C₆Trp), 124.9 (C₂Trp), 126.5 (C₃and C₅

p-ethylbenzyl), 126.6 (C₄phenyl), 127.3 (C₉Trp), 128.6 (C₂and

C₆p-ethylbenzyl, C₂, C₃, C₅, and C₆phenyl), 133.1 (C₁p-

ethylbenzyl), 136.5 (C₈Trp), 140.8 (C₁phenyl), 143.8 (C₄p-

ethylbenzyl), 154.6 (Cq triazole), 154.9 (Cq triazole), 171.9 (CO

amide).

(s, 2H, CH₂-o-pyridyl), 6.80 (t, 1H, J_o) 8 Hz, H₅Trp), 6.92 (t,

1H, J_o) 8 Hz, H₅pyridyl), 6.97 (t, 1H, J_o) 8 Hz, H₆Trp), 7.04

(d, 1H, J_o) 8 Hz, H₄Trp), 7.07 (d, 1H, J ) 2 Hz, H₂Trp), 7.10-

7.16 (m, 5H, CHar benzyl), 7.19 (s, 1H, H₃o-pyridyl), 7.26 (d,

1H, J_o) 8 Hz, H₇Trp), 7.57 (t, 1H, J_o) 9 Hz, H₄o-pyridyl),

8.16 (brs, 3H, NH₂Aib, TFA salt), 8.36 (d, 1H, J_Râ) 5 Hz, H₆

o-pyridyl), 9.01 (d, 1H, J ) 8 Hz, NH amide), 10.85 (s, 1H, NH

indole Trp). ¹³C NMR (75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.4

(CH₃Aib), 23.7 (CH₃Aib), 28.6 (C âTrp), 30.4 (CH₂-benzyl),

45.7 (C RTrp), 47.7 (CH₂- o-pyridyl), 56.7 (Cq Aib), 109.8 (C₃

Trp), 111.8 (C₇Trp), 118.3 (C₄Trp), 118.6 (C₅Trp), 121.2 (C₆

Trp), 121.7 (C₃o-pyridyl), 123.3 (C₅o-pyridyl), 124.8 (C₂Trp),

127.1 (C₄benzyl), 127.3 (C₉Trp), 128.8 (C₂and C₆benzyl), 129.0

(C₃and C₅benzyl), 135.6 (C₁benzyl), 136.4 (C₈Trp), 137.5 (C₄

o-pyridyl), 149.5 (C₆o-pyridyl), 154.1 (Cq triazole), 154.2 (Cq

triazole), 155.7 (C₂o-pyridyl), 172.0 (CO amide).

(R)-2-Amino-N-(1-(5-phenethyl-4-(pyridin-2-ylmethyl)-4H-

1,2,4-triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-methylpropan-

amide Trifluoroacetate Salt (33b). ¹H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 1.26 (s, 3H, CH₃Aib), 1.29 (s, 3H, CH₃Aib),

2.95 (m, 4H, CH₂-CH₂-phenyl), 3.40 (m, 2H, CH₂âTrp), 5.26

(m, 1H, CH RTrp), 5.37 (s, 2H, CH₂-o-pyridyl), 6.83 (t, 1H, J_o)

7 Hz, H₅Trp), 6.98 (t, 1H, J_o) 8 Hz, H₆Trp), 7.11-7.30 (m,

10H, H₂, H₄and H₇Trp, CHar phenyl, H₃and H₅o-pyridyl), 7.71

(t, 1H, J_o) 7 Hz, H₄o-pyridyl), 8.22 (brs, 3H, NH₂Aib, TFA

salt), 8.42 (d, 1H, J_Râ) 4 Hz, H₆o-pyridyl), 9.05 (d, 1H, J ) 8

Hz, NH amide), 10.87 (s, 1H, NH indole Trp). ¹³C NMR (75 MHz,

DMSO-d₆, 300 K) δ (ppm) 23.4 (CH₃Aib), 23.7 (CH₃Aib), 26.4

(CH₂-CH₂-phenyl), 28.6 (C âTrp), 32.5 (CH₂-CH₂-phenyl),

45.7 (C RTrp), 47.6 (CH₂o-pyridyl), 56.8 (Cq Aib), 109.8 (C₃Trp),

111.8 (C₇Trp), 118.3 (C₄Trp), 118.6 (C₅Trp), 121.2 (C₆Trp),

122.0 (C₃o-pyridyl), 123.6 (C₅o-pyridyl), 126.3 (C₂Trp), 126.6

(C₄phenyl), 127.3 (C₉Trp), 128.7 (C₂, C₃, C₅, and C₆phenyl),

136.4 (C₈trypophane), 137.7 (C₄o-pyridyl), 140.7 (C₁phenyl),

150.1 (C₆o-pyridyl), 154.9 (Cq triazole), 155.2 (Cq triazole), 158.7

(C₂o-pyridyl), 172.0 (CO amide).

N-((R)-1-(4-(4-Methoxyphenethyl)-5-phenethyl-4H-1,2,4-tri-

azol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropan-

1

amide Trifluoroacetate Salt (34). H NMR (300 MHz, DMSO-

d₆, 300 K) δ (ppm) 1.30 (s, 3H, CH₃Aib), 1.35 (s, 3H, CH₃Aib),

2.55 (m, 4H, CH₂-CH₂-phenyl and CH₂-CH₂-p-methoxyben-

zyl), 2.83 (t, 2H, J ) 8 Hz, CH₂-CH₂-phenyl), 3.37 (m, 2H, CH₂-

CH₂-p-methoxybenzyl), 3.65 (s, 3H, OCH₃), 3.77 (m, 1H, CH₂

âTrp), 3.89 (m, 1H, CH₂âTrp), 5.20 (m, 1H, CH RTrp), 6.72 (s,

4H, CHar p-methoxybenzyl), 6.94 (t, 1H, J_o) 7 Hz, H₅Trp), 7.02

(t, 1H, J_o) 8 Hz, H₆Trp), 7.05 (d, 1H, J ) 2 Hz, H₂Trp), 7.11

(d, 2H, J_o) 7 Hz, H₂and H₆phenyl), 7.16 (d, 1H, J_o) 7 Hz, H₄

Trp), 7.25 (m, 3H, H₃, H₄, H₅phenyl), 7.50 (d, 1H, J_o) 8 Hz, H₇

Trp), 8.05 (brs, 3H, NH₂Aib, TFA salt), 9.02 (d, 1H, J ) 8 Hz,

NH amide), 10.83 (d, 1H, J ) 2 Hz, NH indole Trp). ¹³C NMR

(75 MHz, DMSO-d₆, 300 K) δ (ppm) 23.5 (CH₃Aib), 23.8 (CH₃

Aib), 26.0 (CH₂-CH₂-phenyl), 29.5 (C âTrp), 32.5 (CH₂-CH₂-

phenyl), 35.0 (CH₂-CH₂-p- methoxybenzyl), 44.4 (CH₂-CH₂-

p-methoxybenzyl), 45.8 (C RTrp), 55.4 (OCH₃), 56.8 (Cq Aib),

109.9 (C₃Trp), 111.9 (C₇Trp), 114.2 (C₃and C₅p-methoxybenzyl),

118.4 (C₄Trp), 118.9 (C₅Trp), 121.4 (C₆Trp), 124.7 (C₂Trp),

126.5 (C₄phenyl), 127.4 (C₉Trp), 128.7 (C₂, C₃, C₅, and C₆phenyl),

129.4 (C₁p-methoxybenzyl), 130.3 (C₂and C₆p-methoxybenzyl),

136.5 (C₈Trp), 141.0 (C₁phenyl), 154.0 (Cq triazole), 154.5 (Cq

triazole), 158.6 (C₄p-methoxybenzyl), 171.8 (CO amide).

In Vitro hGHSR-1a Evaluation. Transient transfection of LLC

PK-1 cells and membrane preparation were performed as previously

described.³¹LLC PK-1 cells were grown at 37 °C, 5% CO₂in

Dulbecco’s modified eagle’s medium (DMEM) supplemented with

10% FCS (v/v), glutamine (2 mM), and antibiotics (50 units/mL

penicillin and 50 µg/mL streptomycin). LLC PK-1 cells were

transiently transfected with 1 µg of hGHS-R1a using electroporation

(Easyject Optima apparatus, Equibio) according to the manufac-

turer’s protocol (Equibio). Electroporation was carried out at room

temperature according to the manufacturer’s instructions with the

following parameters: 250 V, 1500 µF, and infinite internal

N-((R)-1-(4-(4-Nitrobenzyl)-5-phenethyl-4H-1,2,4-triazol-3-

yl)-2-(1H-indol-3-yl)ethyl)-2-amino-2-methylpropanamide Tri-

fluoroacetate Salt (32). ¹H NMR (300 MHz, DMSO-d₆, 300 K) δ

(ppm) 1.28 (s, 3H, CH₃Aib), 1.29 (s, 3H, CH₃Aib), 2.77-2.94

(m, 4H, CH₂-CH₂-phenyl), 3.28 (dd, 1H, ³J ) 14 and 8 Hz, CH₂

3

âTrp), 3.43 (dd, 1H, J ) 14 and 7 Hz, CH₂âTrp), 5.05 (m, 1H,

CH RTrp), 5.25 (d, 2H, J ) 7 Hz, CH₂-p-nitrobenzyl), 6.72 (t,

1H, J_o) 7 Hz, H₅Trp), 6.89 (d, 2H, J_o) 9 Hz, H₂and H₆

p-nitrobenzyl), 6.92 (t, 1H, J_o) 7 Hz, H₆Trp), 7.00 (d, 1H, J_m

)

2 Hz, H₂Trp), 7.08-7.15 (m, 4H, H₄and H₇Trp, H₂and H₆

phenyl), 7.17 (t, 2H, J_o) 7 Hz, H₃and H₅phenyl), 7.24 (t, 1H, J_o

) 8 Hz, H₄phenyl), 7.92 (d, 2H, J_o) 9 Hz, H₃and H₅

p-nitrobenzyl), 8.06 (brs, 3H, NH₂Aib, TFA salt), 8.98 (d, 1H, J

) 8 Hz, NH amide), 10.79 (s, 1H, NH indole Trp). ¹³C NMR (75

MHz, DMSO-d₆, 300 K) δ (ppm) 23.5 (CH₃Aib), 23.8 (CH₃Aib),

26.4 (CH₂-CH₂-phenyl), 29.1 (C âTrp), 32.6 (CH₂-CH₂-

phenyl), 45.3 (CH₂-p-nitrobenzyl), 45.7 (C RTrp), 56.8 (Cq Aib),

109.6 (C₃Trp), 111.8 (C₇Trp), 118.1 (C₄Trp), 118.5 (C₅Trp),

121.2 (C₆Trp), 124.1 (C₂and C₆p-nitrobenzyl), 124.8 (C₂Trp),

126.5 (C₄phenyl), 127.2 (C₉Trp, C₃and C₅p-nitrobenzyl), 128.7

(C₂, C₃, C₅, and C₆phenyl), 136.4 (C₈Trp), 140.8 (C₁phenyl),

143.5 (C₁p-nitrobenzyl), 147.1 (C₄p-nitrobenzyl), 154.5 (Cq

triazole), 154.8 (Cq triazole), 172.0 (CO amide).

(R)-2-Amino-N-(1-(5-benzyl-4-(pyridin-2-ylmethyl)-4H-1,2,4-

triazol-3-yl)-2-(1H-indol-3-yl)ethyl)-2-methylpropanamide Tri-

fluoroacetate Salt (33a). ¹H NMR (300 MHz, DMSO-d₆, 300 K)

δ (ppm) 1.23 (s, 3H, CH₃Aib), 1.27 (s, 3H, CH₃Aib), 3.34 (dd,

1H, J ) 14 and 6 Hz, CH₂âTrp), 3.43 (dd, 1H, J ) 14 and 9 Hz,

CH₂âTrp), 4.13 (s, 2H, CH₂-benzyl), 5.22 (s, 1H, CH RTrp), 5.35

1956 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 8

Demange et al.

resistance. Transfected cells were plated in 10 cm culture dishes

containing complete growth medium without phenol red. Ap-

proximately 48 h post-transfection, cells were washed three times

with phosphate-buffered saline, pH 6.95, once with 10 mL of

homogenization buffer (HB) containing 50 mM Tris (pH 7.3), 5

mM MgCl₂, 2.5 mM EDTA, and 30 µg/mL bacitracin, and were

then collected by scrapping. The cells underwent two cycles of

freeze/thawing and were then centrifuged at 10 000g for 20 min at

4 °C. The membrane pellet was resuspended in a minimal volume

of HB, aliquoted, and stored at -80 °C until use. Membrane protein

concentration was determined by the Bradford method using the

Bio-Rad protein assay kit.

Cheng-Prusoff equation.³²Schild analysis³³was also used to

determine the EC₅₀of ghrelin in the presence of different

concentrations of antagonist, and from this the pA₂and the exact

K_bwere determined.

In Vivo Experiments in the Rat. A. Growth Hormone Assay.

Compounds were dissolved in DMSO (10^-2M) and brought to

the final volume with saline. Animals, male 10-day-old Sprague-

Dawley rats weighing about 25 g (Charles River, Calco, Italy), were

used. Rat pups were received on the fifth day after birth and were

housed in our facilities under controlled conditions (22 ( 2 °C,

65% humidity, and artificial light from 06:00 to 20:00 h). A standard

dry diet and water were available ad libitum to the dams. One hour

before the experiments, pups were separated from their respective

dams and were divided randomly into groups of eight each. All

the experiments were performed in accordance with the Italian

Guidelines for the Use of Animals in Medical Research.

Pups were acutely challenged with solvent (DMSO, final dilution

1:300), hexarelin (80 µg/kg sc), or the compound to be tested (160

µg/kg sc). For combined treatments (test compounds plus hexarelin),

test compounds were administered 10 min before hexarelin. Pups

were killed by decapitation 15 min later. Trunk blood was collected

and centrifuged immediately. Plasma samples were stored at -20

°C until assayed for the determination of plasma GH concentrations.

GH was assayed in plasma using a commercial rat GH enzyme

immunoassay kit (Spibio, Montigny le Bretonneux, France). Values

are expressed in terms of NIDDK-rat-GHRP-2 standard (potency

2 IU/mg) as ng/mL plasma. The minimum detectable value of rat

GH was about 1.0 ng/mL, and intra-assay variability was about

6%.

B. Experiments on Food Intake. Young adult male Sprague-

Dawley rats (Charles River Laboratories, Calco, Italy) weighing

125-150 g were used. All rats were housed in single cages under

controlled conditions (22 ( 2 °C, 65% humidity, artificial light

from 08:00 to 20:00 h) with ad libitum access to standard rat chow

and water. Rats had 1 week of acclimation in individual home cages

and animal room conditions. The following week, they were trained

daily to mimic the experimental procedure. At the end of training,

rats were administered sc (around 10:00-11:00 a.m.) with graded

doses of the compounds to test (0, 20, 80, 160, 320 µg/kg) at time

-10 min and hexarelin (80 µg/kg) at time 0 to stimulate the feeding

behavior. Immediately after, the animals were returned to their home

cages, which contained a known amount of standard rat chow and

ad libitum water. The remaining food was carefully collected and

weighed to the nearest 0.1 g every hour for the following 6 h. In

all the experiments hexarelin stimulated the intake of about 1 g of

standard dry pellet food per 100 g of body weight of rats. Food

intake was normalized for the body weight of the animals and

expressed as g of food eaten for 100 g of body weight. Statistical

analysis of food intake eaten in the first 2 h and in the total period

of observation of 6 h was performed by one-way ANOVA followed

by Dunnett’s t test for multiple comparisons. A P value less than

0.05 was considered significant.

Receptor Binding Studies. Isolated plasma membranes from

LLC PK-1 cells (10 µg of protein) were incubated in HB for 60

min at 25 °C (steady-state conditions) with 60 pM ¹²⁵I-His⁹-

ghrelin (Amersham) in the presence or absence of competing

compounds. Nonspecific binding was defined using an excess (1

µM) of ghrelin and was always less than 20% of total binding.

The binding reaction was stopped by addition of 4 mL of ice-cold

HB followed by rapid filtration over Whatman GF/C filters

presoaked with 0.5% polyethyleneimine to prevent excessive

binding of radioligand to the filters. Filters were rinsed three times

with 3 mL of ice-cold wash buffer (50 mM Tris (pH 7.3), 10 mM

MgCl₂, 2.5 mM EDTA, and 0.015% (w/v) Triton X-100), and the

radioactivity bound to membranes was measured in a γ counter.

Intracellular Calcium Mobilization Assay. The calcium experi-

ments were performed using the benchtop scanning fluorometer

FlexStation II machine (pharmacologie and screening plateform of

the Institut Fe´de´ratif de Recherche 3, Montpellier, France). CHO

cells were transiently transfected with the hGHS-1a receptor, using

electroporation, and were then plated into 96-well black-bottom

plates (80 000 cells/well). Twenty-four hours later the cells were

washed with 150 µL buffer A (Hanks’ balanced salt solution, 0.5%

BSA, 20 mM CaCl₂, 2.5 mM probenecid, pH 7.4) and were then

loaded with 1 µM of the fluorescent calcium indicator Fluo-4AM

prepared in buffer A, containing 0.06% pluronic acid (a mild ionic

detergent which facilitates Fluo-4AM ester loading). The cells were

left to incubate for 1 h in the dark at 37 °C. Following the

incubation, excess Fluo-4AM was removed from the cells by

washing twice with 100 µL of buffer A, and 50 µL of the same

buffer was then added to each well. The cells were left at room

temperature for 30 min to allow complete de-esterification of

intracellular Fluo-4AM esters. The black-bottom plate containing

the cells, as well as the plate containing the compounds to be tested,

was then placed into the temperature-regulated FlexStation machine.

The machine records the fluorescence output over a period of 60

s, with the compounds being automatically distributed into the wells

containing the cells after 15 s. The Fluo-4AM exhibits a large

fluorescence intensity increase on binding of calcium, and therefore

the fluorescence output is used directly as a measure of intracellular

calcium mobilization. The excitation and emission wavelengths

were 485 and 525 nm, respectively. The basal fluorescence intensity

of dye-loaded cells was 800-1200 arbitrary units, and the

fluorescence peak upon maximal response was 5000-7000 units.

To assess the ability of each of the compounds to induce calcium

mobilization, they were tested at a concentration of 10 µM in

triplicate, in at least two independent experiments. In each case,

the change in fluorescence upon addition of the compound was

compared with the basal fluorescence output measured with the

control (addition of buffer A only). The maximum fluorescent

output was equivalent to that achieved when the cells where

stimulated with 1 µM ghrelin. For the compounds behaving as

agonists and displaying a high affinity binding for hGHS-R1a in

radiolabeled binding experiments, the EC₅₀(the molar concentration

of the agonist producing 50% of the maximal possible effect of

that agonist) was determined using a dose-response curve. In the

case of high affinity antagonists, the IC₅₀and K_bwere determined

using antagonist inhibition curves in the presence of 0.1 µM ghrelin

(submaximal concentration). The IC₅₀was calculated as the molar

concentration of antagonist that reduced the maximal response of

ghrelin by 50%, and an estimation of the K_bwas made using the

Acknowledgment. We gratefully acknowledge Mr. Pierre

Sanchez for providing MS analytical data. The authors thank

Aeterna-Zentaris and the CNRS for the financial support of this

work and for providing a Research Grant for the Ph.D. Thesis

of A.M. (BDI 752776/01).

Supporting Information Available: Displacement curves of

¹²⁵I-His⁹-ghrelin for compounds 18a, 19d, 21a, and 29c; inhibition

curves of ghrelin-induced [Ca²⁺]_iaccumulation by compounds 16

and 19b; [Ca²⁺]_iaccumulation dose-response curves of ghrelin in

the presence of increasing concentrations of compounds 16, 19c,

and 19d; physicochemical properties of all final compounds. This

material is available free of charge via the Internet at http://

pubs.acs.org.

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JM070024H

Article Doi

Synthesis and pharmacological in vitro and in vivo evaluations of novel triazole derivatives as ligands of the ghrelin receptor. 1

DOI: 10.1021/jm070024h

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Article abstract of DOI:10.1021/jm070024h

Full text of DOI:10.1021/jm070024h

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