Novel glycine transporter type-2 reuptake inhibitors. Part 2: β- and γ-amino acid derivatives

Article abstract of DOI:10.1016/j.bmc.2004.05.043

Several β- and γ-amino acid derivatives were prepared as glycine transport inhibitors and their ability to block the uptake of [ ¹⁴C]-glycine in COS7 cells transfected with human glycine transporter-2 (hGlyT-2) were evaluated. A range of lipoph

Full text of DOI:10.1016/j.bmc.2004.05.043

Bioorganic & Medicinal Chemistry 12 (2004) 4493–4509
Novel glycine transporter type-2 reuptake inhibitors.
Part 2: b- and c-amino acid derivatives
*
ꢀ
Ronald L. Wolin, Alejandro Santillan, Jr., Tristin Barclay, Liu Tang,
Hariharan Venkatesan, Sandy Wilson, Doo Hyun Lee and Timothy W. Lovenberg
Johnson & Johnson Pharmaceutical Research and Development, LLC, 3210 Merryfield Row, San Diego, CA 92121, USA
Received 23 March 2004; accepted 24 May 2004
Available online 6 July 2004
Abstract—Several b- and c-amino acid derivatives were prepared as glycine transport inhibitors and their ability to block the uptake
of [14C]-glycine in COS7 cells transfected with human glycine transporter-2 (hGlyT-2) were evaluated. A range of lipophilic side
chains were tolerated in the b-amino acid series (i.e., Ph, CH2Ph, CH(CH3)2, and CH2CH(CH3)2). In the c-amino acid series,
minimal differences in potency were observed between the a,b-unsaturated analogs and the corresponding saturated derivatives. In
both series, a 4-biphenyl or 4-phenoxyphenyl substituent appended to the urea or cyanogunaidine moiety was necessary for in vitro
activity.
ꢀ 2004 Elsevier Ltd. All rights reserved.
Ar
1. Introduction
R
N
O
R
O
1
3
R
N
H
N
H
N
H
2
The amino acid glycine is an important inhibitory neu-
rotransmitter in the central nervous system (CNS) of
vertebrates and exerts its action post-synaptically at the
strychnine-sensitive glycinergic receptor.1 When glycine
binds to its specific receptor it induces the opening of a
ligand-gated chloride channel, which results in an influx
of chloride ion into the post-synaptic neuron. This
process causes the neuron to become hyperpolarized and
ultimately raises the threshold for neuronal signaling.
The physiological effects of glycine are regulated by two
glycine transporters (GlyT-1 and GlyT-2), which pro-
vide a mechanism for the re-uptake of glycine from the
synaptic cleft back into the pre-synaptic neuron and
surrounding glial cells. Inhibiting glycine transport
(specifically GlyT-2 transport) may provide therapeutic
benefits for a variety of ailments including neuropathic
pain, muscle spasticity, tinnitus and epilepsy.2;3 This
paper describes the synthesis and biological activity for
a series of b- and c-amino acids that were shown to be
effective GlyT-2 reuptake inhibitors (Figs. 1–5). The
previous paper in this series describes our results per-
taining to a-amino acid derivatives.4
R1
R2
R3
Compd
Ar
1
2
H
H
H
Ph
Ph
Ph
Ph
CH(CH3)2
CH3
CH3
CH3
CH3
3
Ph
Ph
CH3
CH2Ph
CH2Ph
4
Ph
CH3
5
OPh
Ph
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
Ph-4-CH3
Ph
6
7
Ph
CH(CH3)2
CH(CH3)2
CH2Ph
8
Ph
9
OPh
Ph
10
11
12
13
CH2Ph
OPh
Ph
(CH3)2CHCH2
(CH3)2CHCH2
OPh
Figure 1. b-Amino acid derivatives.
2. Chemistry
Scheme 1 illustrates the two synthetic routes (A and/or
B) that were employed for the preparation of the - and
-b-amino acid analogs used in this study. Route A
D
L
commenced with a carbodimide mediated coupling be-
tween the appropriately substituted N-Boc amino acid
54 and one of the following diamines, 1-(2-amino-
* Corresponding author. Fax: +1-858-784-3116; e-mail: rwolin@
prdus.jnj.com
Present address: One Amgen Center Dr., Mail stop 29-2-B,
Thousand Oaks, CA 91320, USA.
ethyl)pyrrolidine,
N,N-dimethyl
ethylenediamine,
0968-0896/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2004.05.043

4494
R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
CN
Ar
O
R
N
3
CN
Ar
N
N
H
N
H
N
H
N
H
R
N
1
N
R
N
N
H
H
O
2
R3
Compd
14
Ar
R1
R2
Compd
46
Ar
CH3
CH3
CH2CH(CH3)2
Ph
Ph
Ph
Ph
CH2CH3
CH2CH3
H
CH2Ph
CH2Ph
Ph
47
15
CH(CH3)2
48
Ph
16
OPh-4-Cl
Ph
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
49
Ph
17
50
OPh
18
Ph
OPh
51
OPh-4-Cl
OPh-4-F
19
Ph
OPh-4-Cl
OPh-4-CH3
OPh-4-F
52
20
Ph
OPh-4-CH3
53
21
Ph
Figure 2. Cyanoguanidine b-amino acid derivatives.
Figure 5. Cyanoguanidine c-amino acid derivatives.
ing the diamines noted above led to the target analogs
1–13.
Ar
O
H
R
N
1
The cyanoguanidine analogs shown in Scheme 2 were
constructed from the reaction of amines 58 with N-
cyano-N-biphenytiolurea (61) or N-cyano-N-phenoxy-
phenylthiourea (62) in the presence of EDCI, which
provided the desired cyanoguanidine adducts 14–21.6
N
R
N
H
N
H
n
O
2
R1
R2
Compd
n
Ar
22
23
24
25
H
H
H
H
H
H
H
1
1
2
1
Ph
OPh
Ph
CH3
Ph
A general method for the synthesis of both
D- and L-c-
CH3
26
27
28
29
30
31
32
33
34
35
36
H
H
1
1
1
1
2
1
2
1
1
2
2
OPh
Ph
amino acid analogs is illustrated in Scheme 3. Treatment
of (R)-(+)-2-(tert-butoxycarbonylamino)-3-phenylprop-
anal (62) with methyl(triphenylphosphoranylidene)ace-
tate in CH2Cl2 afforded the olefin adduct exclusively as
the trans-isomer in 80% yield.7 Saponification to the
carboxylic acid 63 was accomplished using aqueous 4 N
LiOH in THF. Removal of the N-Boc group with HCl
in dioxane gave the desired amines, which were con-
densed with 4-biphenyl isocyanate or 4-phenoxyphenyl
isocyanate in toluene to afford the corresponding urea
analogs 64. Carbodiimide mediated coupling between 64
and the appropriate amine component8 provided the
a,b-unsaturated-c-amino acids 22–36. The correspond-
ing saturated analogs 37–45 were obtained via hydro-
genation using 10% Pd/C in EtOH.
CH2CH3
CH3
CH3
CH3
CH3
Ph
CH3
OPh
Ph
CH3
CH2CH3
CH2CH3
CH2CH3
CH2CH3
Ph
Ph
(CH2)4
(CH2)4
(CH2)4
(CH2)4
Ph
OPh
Ph
OPh
Figure 3. Unsaturated c-amino acid derivatives.
Ar
O
H
R
N
1
N
R
N
N
n
H
H
O
2
The cis-a,b-unsaturated intermediate 66 was obtained
using the Still–Gennari olefination reaction.9 Sub-
sequent conversion to the cis-a,b-unsaturated c-amino
acid 33b was achieved under Weinreb conditions
(Scheme 4).10
R1
R2
Compd
n
Ar
37
38
39
40
H
H
H
H
H
H
H
1
1
2
1
Ph
OPh
Ph
CH3
Ph
CH2CH3
CH3
41
42
43
44
45
H
1
1
1
1
1
Ph
Ph
CH3
CH2CH3
2.1. Cyanoguanidines
CH2CH3
Ph
In our studies pertaining to a-amino acid derivatives,4
we found that cyanoguanidines were excellent surro-
gates for the urea linkage and often provided an
improvement in potency. Thus, several analogs con-
taining a cyanoguanidine moiety in the c-amino acid
series were synthesized for comparison (Scheme 5).
(CH2)4
(CH2)4
Ph
OPh
Figure 4. Saturated c-amino acid derivatives.
N-isopropyl ethylenediamine, or N-Boc-ethylenediam-
ine to afford adduct 55. Removal of the N-Boc pro-
tecting group, followed by condensation with either
4-phenoxyphenyl or 4-biphenyl isocyanate provided the
urea targets 1–13.
Carbodiimide mediated coupling of carboxylic acid 63
and the appropriate amines11 provided the correspond-
ing a,b-unsaturated amides 67, which were subsequently
reduced to the saturated intermediates 68. Removal of
the N-Boc-group followed by condensation with 60 or
61 as previously described provided the cyanoguanidine
analogs 46–53.
Alternatively, treatment of the requisite amino acid 56
with the appropriate isocyanate afforded the urea
intermediate 57.5 Subsequent amide formation employ-

R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4495
(Route A)
O
R
3
R
N
O
R
3
1
a
b,c,d
HO
NHBoc
R
N
H
NHBoc
2
Ar
55
54
R
N
O
R
O
1
3
R
2
N
H
N
H
N
H
Ar
O
R
O
a
O
R
3
3
1-13
d
HO
N
H
N
H
HO
NH
2
(Route B)
56
57
Scheme 1. Reagents: (a) R1R2NCH2CH2NH2, EDCI, HOBt, DMF; (b) 4 M HCl/dioxane, CH2Cl2; (c) Dowex 550A anion exchange resin, MeOH;
(d) ArPhNCO, Et3N, CH2Cl2.
CN
Ar
R1
N
O
R
N
R1
N
O
R
c
a, b
R2
N
H
N
H
N
H
R2
N
H
NHBoc
Ar
S
NC
N
H
N
H
14-21
55
60, Ar = Ph
61, Ar = OPh
d, e
H2N
Ar
58, Ar = Ph
59, Ar = OPh
Scheme 2. Reagents: (a) 4 M HCl/dioxane, CH2Cl2; (b) Dowex 550A OH anion-exchange resin, MeOH; (c) 60 or 61, EDCI, DMF; (d) Thiocarbonyl
diimidazole, CH2Cl2; (e) NaNHCN, EtOH.
a, b
c, d
e
Ar
O
HO
HO
H
N
N
H
NHBoc
NHBoc
H
O
O
O
63
62
64
Ar
Ar
O
O
f
H
N
n
H
R1
R1
N
N
N
N
H
N
N
N
n
H
H
H
R2
O
R2
O
22-36
37-45
Scheme 3. Reagents: Only the L-enantiomer is shown for clarity. (a) (Ph)3PCHCO2Me, CH2Cl2; (b) LiOH, THF–H2O; (c) 4 M HCl–dioxane; (d)
ArPhNCO, Et3N, PhCH3; (e) R1R2NCH2CH2NH2, EDCI, HOBt, DMF; (f) H2, 10% Pd/C, EtOH.
O
H3CO
O
N
H
O
N
H
a, b
c, d
O
NH2
NHBoc
NH
33b
H
N
65
66
Scheme 4. Reagents: Only the L-enantiomer is shown for clarity. (a) (CF3CH2O)2P(O)CH2CO2Me, KHMDS/18-C-6, THF; (b) 4 M HCl/dioxane,
CH2Cl2; (c) 4-Biphenylisocyanate, Et3N, PhCH3; (d) 2-Pyrrorlidinyl ethylamine, AlMe3, toluene.
3. Results and discussion
glycine in COS7 cells transfected with human glycine
transporter-2 (hGlyT-2).11;12 Three noteworthy obser-
vations from the data presented in Table 1 are that the
The GlyT-2 analogs synthesized in this study were
evaluated for their ability to block the uptake of [14C]-
L
-enantiomers 6b and 7b are substantially more potent

4496
R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
Ar
CN
N
H
N
H
N
R
NH
2
1
R
1
R
N
R
e
a
1
N
R
NHR
N
R
N
H
N
H
2
63
O
O
2
2
67, R = Boc, a,b-unsat
68, R = Boc, a,b-sat
69, R = H, a,b-sat
46-53
b
c,d
Scheme 5. Reagents: Only the L-enantiomer is shown for clarity. (a) EDCI, HOBt, DMF; (b) H2, Pd/C, EtOH; (c) 4 M HCl/dioxane, CH2Cl2;
(d) Dowex 550A OH an ion-exchange resin; (e) 60 or 61, EDCI, DMF.
Table 1. GlyT-2 inhibitory activity for the urea analogs
Ar
R1
N
O
R3
*
O
R2
N
H
N
H
N
H
Compd
R1
R2
H
R3
Ar
ꢀEnant.
GlyT-2 IC50 (lM)
1
H
Ph
Ph
Ph
Ph
( )
( )
( )
L
0.284
0.059
0.184
0.342
0.333
0.034
0.027
0.953
0.052
1.307
0.041
0.770
0.134
0.523
0.073
1.501
2
H
(CH3)2CH
CH3
CH3
3
CH3
CH3
CH3
Ph
CH2Ph
CH2Ph
Ph
Ph
4
5
CH3
OPh
Ph
L
6a
6b
6c
7b
7c
8
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
Ph–4-CH3
Ph–4-CH3
Ph–4-CH3
Ph
( )
L
Ph
Ph
D
Ph
L
Ph
Ph
D
(CH3)2CH
(CH3)2CH
CH2Ph
Ph
L
9
OPh
Ph
L
10
11
12
13
L
CH2Ph
(CH3)2CHCH2
(CH3)2CHCH2
OPh
Ph
L
L
OPh
L
Table 2. GlyT-2 inhibitory activity for the cyanoguanidine analogs
than their corresponding
D-enantiomers 6c and 7c by
25- and 35-fold, respectively. Secondly, the nature of the
substituent(s) attached to the terminal amino group and
the b-position have a significant influence on GlyT-2
inhibitory activity. For example, comparison between
the N,N-dimethyl derivatives 4 and 5 indicate that
having either a 4-biphenyl or 4-phenoxyphenyl sub-
stituent produces compounds with equivalent GlyT-2
inhibitory activity. However, a 4-fold difference in
activity was observed between derivatives 10 and 11
when a pyrrolidine group was present and 21-fold sep-
aration in activity was seen between the isobutyl deriv-
atives 12 and 13. Thirdly, aryl derivatives 6b and 7b
indicate that direct attachment of a phenyl substituent in
the b-position can produce GlyT-2 inhibitory affects
that are equal to or better than the homologous benzyl
derivatives 8 and 10.
CN
Ar
O
R3
*
N
N
N
H
N
H
N
H
Compd
R3
Ar
ꢀEnant. GlyT-2
IC50 (lM)
14
15
16
17
18
19
20
21
CH2CH(CH3)2
Ph
Ph
L
0.368
CH2Ph
CH2Ph
Ph
( )
( )
( )
( )
( )
( )
L
0.103
0.127
0.060
0.062
0.068
0.134
0.031
OPh–4-Cl
Ph
OPh
Ph
Ph
OPh–4-Cl
OPh–4-CH3
OPh–4-F
Ph
Ph
inhibitory activity. For example, the two enantiomeric
pairs listed in Table 3 (24a/24b, and 35a/35b) and the
one pair of enantiomers listed in Table 4 (37a/37b)
reiterate that incorporation of the natural
is preferred over the corresponding
Secondly, only minor differences in potency were ob-
served between derivatives containing the 4-biphenyl or
4-phenoxyphenyl substituent (Tables 3 and 4, 22a vs 23;
28 vs 29; 33a vs 33b; 35 vs 36a and 44 vs 45). Thirdly,
little or no difference in GlyT-2 inhibitory activity was
observed between corresponding saturated and unsatu-
rated analogs. Interestingly, GlyT-2 inhibitory activity
The data in Table 2 illustrate that the urea moiety can be
replaced with a cyanoguanidine unit to afford com-
pounds with similar or improved GlyT-2 inhibitory
activities. For example, the cyanoguanidine analogs 15
and 17 possess comparable activities to their corre-
sponding urea derivatives 10 and 7b, respectively.
L
-amino acid
-enantiomers.
D
Examination of the c-amino acid derivatives in Tables 3
and 4 reveal that the absolute configuration of the c-
substituent also has a pronounced effect on GlyT-2

R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
Table 3. GlyT-2 inhibitory activity for the unsaturated urea analogs
4497
Ar
O
H
N
n
R1
N
N
H
N
H
*
R2
O
Compd
R1
R2
n
Ar
ꢀEnant.
GlyT-2 IC50 (lM)
22
23
H
H
1
1
2
2
1
1
1
1
1
2
1
2
1
1
1
2
2
2
Ph
L
L
L
D
L
L
L
L
L
L
L
L
L
L
L
L
D
L
2.512
0.400
1.000
3.162
0.128
0.049
0.052
0.073
0.072
0.376
0.048
0.134
0.100
0.230
0.158
0.500
1.400
0.700
H
H
OPh
Ph
24a
24b
25
H
H
H
H
Ph
Ph
CH3
CH3
CH2CH3
CH3
CH3
CH3
CH2CH3
CH2CH3
H
26
27
H
OPh
Ph
H
28
29
CH3
CH3
CH3
Ph
OPh
Ph
30
31
CH2CH3
CH2CH3
Ph
Ph
32
33a
33b
34
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
Ph
Ph
OPh
Ph
35a
35b
36
Ph
OPh
Table 4. GlyT-2 inhibitory activity for the saturated urea analogs
Ar
O
H
R1
N
*
N
N
H
N
n
H
O
R2
Compd
R1
R2
n
Ar
ꢀEnant.
GlyT-2 IC50 (lM)
37a
37b
38
39
40
41
42
43
44
45
H
H
1
1
1
2
1
1
1
1
1
1
Ph
Ph
L
D
D
L
L
L
L
L
L
L
0.315
3.500
0.500
1.000
0.180
0.140
0.272
0.103
0.158
0.125
H
H
H
H
OPh
Ph
H
H
CH3
CH2CH3
CH3
CH2CH3
H
Ph
Ph
H
CH3
Ph
Ph
CH2CH3
(CH2)4
(CH2)4
Ph
OPh
was not notably affected by the geometry of the a,b-
unsaturated bond. (i.e., trans-33a vs cis-33b).
that the GlyT-2 inhibitory activities were similar with
less than a 2-fold difference being observed. The 5-fold
difference in potency between the L- and D-enantiomeric
The structure–function differences begin to emerge when
the chain length linking the amide and the terminal
amino functionality was varied. For example, a 2-car-
bon tether (n ¼ 1) was preferred relative to a 3-carbon
tether (n ¼ 2) in all cases examined. Additionally, GlyT-
2 inhibitory activity remained fairly constant among the
2ꢁ- and 3ꢁ-amino analogs, however, the corresponding
1ꢁ-amino derivatives were generally 2–5-fold less potent
(compare 22a with 27, 28, 31 and 33a in Table 3) and
(37a with 40, 41, 43 and 44 in Table 4).
pair, 49a and 49b, respectively, illustrate the preference
for incorporation of the natural amino acid.
In summary, a wide range of substituents were found to
be well tolerated at the b-position in contrast to our
observations from the homologous a-amino acid series3
and the c-series. The optimal substituent in the c-amino
acid series was derived from phenylalanine.
4. Experimental
Lastly, direct comparison between urea derivatives 42,
43, and 44 in Table 4 with the corresponding cyano-
guanidine derivatives 46, 47, and 49a in Table 5 indicate
NMR spectra were obtained on either a Bruker
model DPX400 (400 MHz) or DPX500 (500 MHz)

4498
R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
Table 5. GlyT-2 inhibitory activity for the cyanoguanidine analogs
CN
Ar
N
H
R1
N
N
* N
H
N
H
O
R2
Compd
R1
R2
Ar
ꢀEnant.
GlyT-2 IC50 (lM)
46
47
CH3
CH2CH3
CH(CH3)2
CH3
CH2CH3
H
Ph
Ph
Ph
Ph
Ph
L
L
L
L
D
L
L
L
L
0.448
0.226
0.162
0.093
0.445
0.188
0.140
0.170
0.227
48
49a
49b
50
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
(CH2)4
OPh
51
52
OPh–4-CI
OPh–4-F
OPh–4-CH3
53
spectrometer. The format of the 1H NMR data below is:
chemical shift in ppm down field of the tetramethylsilane
reference (multiplicity, coupling constant J in Hz, inte-
gration). Mass spectra were obtained on an Agilent
series 1100 MSD using electrospray ionization (ESI) in
either positive or negative mode as indicated. The ‘mass
calculated’ for a molecular formula is the monoisotopic
mass of the compound. Flash column chromatography
was accomplished using the ISCO Foxy 200 system and
one of the following commercially available, prepacked
columns: Biotage 40S (SiO2; 40 g), Biotage 40M (SiO2;
90 g), Biotage 40L (SiO2; 120 g), Biotage 65M (SiO2;
300 g) or ISCO Redisep (SiO2; 10, 12, 35, 40, or 120 g).
Preparative TLC was accomplished using PLC plates
(20 · 20 cm silica gel 60 F254, 0.5 mm).
biphenyl-4-yl-ureido)-3-p-tolyl-propionic acid (0.15 g,
0.40 mmol), 2-pyrrolidin-1-yl-ethylamine (0.05 g,
0.40 mmol) and HOBt (0.081 g, 0.60 mmol) in DMF
(4 mL), was added EDCI (0.12 g, 0.60 mmol). The
resulting solution was stirred under N2 at room tem-
perature for 20 h. The solution was diluted with H2O
(20 mL) and extracted with EtOAc (3 · 30 mL). The
combined extracts were washed with brine (40 mL),
dried (Na2SO4), and filtered, and the solvent was re-
moved under reduced pressure. The crude product was
purified by column chromatography on silica gel using a
gradient of 0–20% (MeOH(1% NH4OH)/CH2Cl2) to
afford 0.12 g (63%) of the desired product as a white
solid. Racemic compound: Rf ¼ 0:11 (10% MeOH (1%
NH4OH)/CH2Cl2). MS (electrospray): mass calculated
1
for C29H34N4O2, 470.27; m=z found, 471.3 [M+H]þ. H
NMR (400 MHz, CD3OD) d 7.57–7.50 (m, 4H), 7.43–
7.37 (m, 4H), 7.29–7.25 (m, 3H), 7.16 (d, J ¼ 7:9 Hz,
2H), 5.22 (t, J ¼ 6:9 Hz, 1H), 3.28–3.23 (m, 2H), 2.68 (d,
J ¼ 6:4 Hz, 2H), 2.52–2.48 (m, 6H), 2.31 (s, 3H), 1.77–
1.75 (m, 4H).
4.1. General procedure for the preparation of urea
derivatives 1–13, and exemplified for compound 6
4.1.1. Route A. (R)-3-(3-Biphenyl-4-yl-ureido)-N-(2-pyr-
rolidin-1-yl-ethyl)-3-p-tolyl-propionamide (6). Step A. 3-
(3-Biphenyl-4-yl-ureido)-3-p-tolyl-propionic acid. To a
solution of 3-amino-3-(p-tolyl)propionic acid (0.50 g,
2.79 mmol) and TEA (0.26 g, 2.56 mmol) in CH2Cl2
(28 mL) cooled to 0 ꢁC, was added 4-biphenyl isocyanate
(0.55 g, 2.79 mmol). The mixture was stirred at 0 ꢁC for
30 min and was then brought to room temperature and
stirred for an additional 3 h. The solvent was removed
under reduced pressure, water (20 mL) was added to the
clear residue, and the mixture was then chilled to 0 ꢁC
and acidified using 1 N HCl. The resulting precipitate
was collected by filtration, washed with copious
amounts of H2O, and dried under vacuum to afford
0.87 g (83%) of the desired product as a white solid. MS
(electrospray): mass calculated for C23H22N2O3, 374.16;
m=z found, 413.0 [M+Na]þ. 1H NMR (400 MHz,
DMSO-d6) d 8.74 (s, 1H), 7.65–7.29 (m, 9H), 7.25 (d,
J ¼ 8:1 Hz, 2H), 7.14 (d, J ¼ 7:9 Hz, 2H), 6.64 (d,
J ¼ 8:5 Hz, 1H), 5.11–5.06 (m, 1H), 2.74–2.67 (m, 2H),
2.27 (s, 3H).
Step C. (R)-3-(3-Biphenyl-4-yl-ureido)-N-(2-pyrrolidin-
1-yl-ethyl)-3-p-tolylpropion-amide. The enantiomers
of the product obtained in step B were separated on
a chiral O.D. (0.46 cm · 25 cm) column using 0.1%
DEA/MeOH at a flow rate of 0.5 mL/min. The (S) and
(R) enantiomers had retention times of 10.3 and
32.4 min, respectively. MS (electrospray): mass calcu-
lated for C29H34N4O2, 470.27; m=z found, 471.2
[M+H]þ.
4.2. General procedure for the preparation of urea
derivatives 1–13, and exemplified for compound 8
Route B. Step A. {(R)-2-Methyl-1-[(2-pyrrolidin-1-yl-
ethylcarbamoyl)-methyl]-propyl}-carbamic acid tert-
butyl ester. HOBt (0.351 g, 2.6 mmol) and EDCI (0.5 g,
2.6 mmol) were added to a solution of (R)-3-tert-but-
oxycarbonylamino-4-methyl-pentanoic
acid
(0.4 g,
1.7 mmol) in DMF (8.5 mL). Following the addition of a
solution of 2-pyrrolidin-1-yl-ethylamine (0.3 g, 2.6
mmol) in DMF (2 mL), N-methyl-morpholine (0.26 g,
Step B. 3-(3-Biphenyl-4-yl-ureido)-N-(2-pyrrolidin-1-yl-
ethyl)-3-p-tolyl-propionamide. To a solution of 3-(3-

R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4499
2.6 mmol) was added dropwise. The reaction mixture
was stirred at room temperature overnight. H2O (20 mL)
and EtOAc (30 mL) were then added to the mixture. The
aqueous layer was extracted with EtOAc (3 · 40 mL).
The combined organic layers were washed with 1 N
NaOH (2 · 20 mL) and brine (40 mL), dried (MgSO4),
and concentrated. Purification by column chromato-
graphy [0–20% (1% NH4OH/MeOH)/CH2Cl2] afforded
0.44 g (78%) of the desired product. MS (electrospray):
mass calculated for C17H33N3O3, 327.25; m=z found,
3.31–3.30 (m, 1H), 3.17 (t, J ¼ 6:0 Hz, 2H), 2.72 (dd,
J ¼ 3:0, 7.0 Hz, 2H), 2.59 (t, J ¼ 6:0 Hz, 2H).
4.2.2. 3-(3-Biphenyl-4-yl-ureido)-N-(2-isopropylamino-
ethyl)-3-phenyl-propionamide (2). Route A. 3-(3-Biphen-
yl-4-yl-ureido)-3-phenyl-propionic acid.
MS (electrospray): mass calculated for C22H20N2O3,
1
360.41; m=z found, 361.2 [M+H]þ, 383.2 [M+Na]þ. H
1
328.3 [M+H]þ. H NMR (400 MHz, CDCl3) d 6.22 (s,
NMR (400 MHz, DMSO-d6) d 12.08 (br s, 1H), 8.73 (br
s, 1H), 7.24–7.65 (m, 14H), 6.80 (d, J ¼ 8:4 Hz, 1H),
5.10–5.17 (m, 1H), 2.73–2.79 (m, 2H)
1H), 5.30 (d, J ¼ 6:7 Hz, 1H), 3.66–3.59 (m, 1H), 3.44–
3.36 (m, 1H), 3.35–3.27 (m, 1H), 2.59–2.56 (m, 2H), 2.52
(m, 4H), 2.42–2.40 (m, 2H), 1.87–1.74 (m, 8H), 1.43 (s,
9H), 0.93 (t, J ¼ 6:3, 6H).
3-(3-Biphenyl-4-yl-ureido)-N-(2-isopropylamino-ethyl)-
3-phenyl-propionamide.
Step B. (R)-3-(3-Biphenyl-4-yl-ureido)-4-methyl-penta-
noic acid (2-pyrrolidin-1-yl-ethyl)-amide. To a solution
of {(R)-2-methyl-1-[(2-pyrrolidin-1-yl-ethylcarbamoyl)-
methyl]-propyl}-carbamic acid tert-butyl ester (0.12 g,
0.37 mmol) in CH2Cl2 (4 mL) was added 4 M HCl
solution in 1,4-dioxane (2 mL). The reaction mixture
was stirred at room temperature for 4 h, and then the
solvent was removed under reduced pressure. The resi-
due was redissolved in MeOH (5 mL) and treated with
basic resin (Dowex 550A OH anion-exchange resin) for
2 h. The resin was filtered off, and the solvents were
removed under reduced pressure. 4-Biphenyl isocyanate
(0.134 g, 0.68 mmol) was then added to a solution of
the residue in CH2Cl2 (3 mL). The reaction mixture
was stirred at room temperature overnight, after
which EtOAc (10 mL) and H2O (10 mL) were added.
The aqueous layer was extracted with EtOAc
(3 · 10 mL). The combined organic layers were washed
with brine (20 mL), and dried (MgSO4). The solvent was
removed under reduced pressure. The residue was
purified by column chromatography [0–20% (1%
NH4OH/MeOH)/CH2Cl2] to afford 0.124 g (86%) of the
desired product.
MS (electrospray): mass calculated for C27H32N4O2,
444.25; m=z found, 445.2 [M+H]þ, 467.2 [M+Na]þ,
1
911.5 [2M+Na]þ. H NMR (400 MHz, CDCl3) d 8.70
(br s, 1H), 8.49 (br s, 1H), 7.45–7.43 (m, 3H), 7.39–7.22
(m, 11H), 5.69–5.61 (m, 1H), 3.41–3.30 (m, 2H), 3.10–
3.01 (m, 1H), 2.91–2.82 (m, 1H), 2.67–2.58 (m, 3H), 0.92
(d, J ¼ 2:3 Hz, 3H), 0.90 (d, J ¼ 2:3 Hz, 3H).
4.2.3.
3-(3-Biphenyl-4-yl-ureido)-N-(2-dimethylamino-
ethyl)-3-phenyl-propionamide (3). Route A. 3-(3-Biphen-
yl-4-yl-ureido)-N-(2-dimethylamino-ethyl)-3-phenyl-
propionamide.
MS (electrospray): mass calculated for C26H30N4O2,
430.24; m=z found, 431.2 [M+H]þ, 453.2 [M+Na]þ,
883.5 [2M+Na]þ. 1H NMR (400 MHz, CDCl3) d 7.71 (s,
1H), 7.46–7.34 (m, 14H), 6.90 (br s, 1H), 6.72 (br s, 1H),
5.29–5.23 (m, 1H), 3.34–3.28 (m, 1H), 3.16–3.10 (m,
1H), 2.71 (dd, J ¼ 14:1, 4.2 Hz, 1H), 2.62 (dd, J ¼ 14:1,
8.0 Hz, 1H), 2.42–2.29 (m, 2H), 2.15 (t, J ¼ 7:0 Hz, 6H).
4.2.4. (S)-3-(3-Biphenyl-4-yl-ureido)-N-(2-dimethylam-
ino-ethyl)-4-phenyl-butyramide (4). Route B. [(S)-1-
Benzyl-2-(2-dimethylamino-ethylcarbamoyl)-ethyl]-car-
bamic acid tert-butyl ester.
4.2.1.
N-(2-Amino-ethyl)-3-(3-biphenyl-4-yl-ureido)-3-
phenyl-propionamide (1). Route A. {2-[3-(3-Biphenyl-4-
yl-ureido)-3-phenyl-propionylamino]-ethyl}-carbamic
acid tert-butyl ester.
MS (electrospray): mass calculated for C19H31N3O3,
349.24; m=z found, 350.2 [M+H]þ. 1H NMR (400 MHz,
CDCl3) d 7.23–7.12 (m, 5H), 6.02 (br s, 1H), 5.66 (br s,
1H), 4.05–3.97 (m, 1H), 3.29–3.25 (m, 2H), 2.99–2.86
(m, 1H), 2.75–2.70 (m, 1H), 2.37–2.28 (m, 3H), 2.21–
2.18 (m, 7H), 1.34 (s, 9H).
MS (electrospray): mass calculated for C29H34N4O4,
1
502.26; m=z found, 503.3 [M+H]þ, 525.3 [M+Na]þ. H
NMR (400 MHz, DMSO-d6) d 8.81 (br t, J ¼ 8:9 Hz,
1H), 7.94 (br t, J ¼ 5:6 Hz, 1H), 7.51–7.66 (m, 5H),
7.39–7.47 (m, 4H), 7.30–7.32 (m, 5H), 6.94 (d,
J ¼ 9:2 Hz, 1H), 6.68 (br t, J ¼ 5:6 Hz, 1H), 5.31 (dd,
J ¼ 14:8, 6.8 Hz, 1H), 2.93–3.05 (m, 2H), 2.81–2.90 (m,
2H), 2.58 (d, J ¼ 6:7 Hz, 2H), 1.37 (s, 9H).
(S)-3-(3-Biphenyl-4-yl-ureido)-N-(2-dimethylamino-
ethyl)-4-phenyl-butyramide.
MS (electrospray): mass calculated for C27H32N4O2,
444.57; m=z found, 445.3 [M+H]þ. 1H NMR (400 MHz,
CDCl3) d 7.49–7.42 (m, 4H), 7.36–7.32 (m, 4H), 7.26–
7.14 (m, 6H), 6.32–6.25 (m, 1H), 6.00 (br s, 1H), 4.33–
4.24 (m, 1H), 3.33–3.24 (m, 1H), 3.22–3.17 (m, 1H), 3.04
(dd, J ¼ 13:5, 6.1 Hz, 1H), 2.74 (dd, J ¼ 13:5, 8.6 Hz,
1H), 2.42 (dd, J ¼ 14:8, 4.3 Hz, 1H), 2.35 (t, J ¼ 5:9 Hz,
2H), 2.23 (dd, J ¼ 14:8, 6.7 Hz, 1H), 2.16 (s, 6H).
N-(2-Amino-ethyl)-3-(3-biphenyl-4-yl-ureido)-3-phenyl-
propionamide.
MS (electrospray): mass calculated for C24H26N4O2,
402.21; m=z found, 403.2 [M+H]þ, 425.2 [M+Na]þ,
827.4 [2M+Na]þ. 1H NMR (400 MHz, CD3OD) d 7.55–
7.48 (m, 4H), 7.44–7.32 (m, 8H), 7.28–7.21 (m, 2H),

4500
R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4.2.5. (S)-N-(2-Dimethylamino-ethyl)-3-[3-(4-phenoxy-
phenyl)-ureido]-4-phenyl-butyramide (5). Route B. (S)-
N-(2-Dimethylamino-ethyl)-3-[3-(4-phenoxy-phenyl)-
ureido]-4-phenyl-butyramide. MS (electrospray): mass
calculated for C27H32N4O3, 460.57; m=z found, 461.3
4.2.9. (R)-4-Methyl-3-[3-(4-phenoxyphenyl)-ureido]-pen-
tanoic acid (2-pyrrolidin-1-yl-ethyl)-amide (9). Route B.
MS (electrospray): mass calculated for C25H34N4O3,
438.26; m=z found, 439.21 [M+H]þ. 1H NMR
(400 MHz, CDCl3) d 7.29–7.21 (m, 4H), 7.0–6.96 (m,
1H), 6.90–6.86 (m, 4H), 6.49 (br s, 1H), 3.85–3.78 (m,
1H), 3.34–3.24 (m, 2H), 2.53–2.48 (m, 2H), 2.46–2.43
(m, 4H), 2.31 (dd, J ¼ 14:9, 8.4 Hz, 1H), 1.83–1.76 (m,
4H), 1.74–1.66 (m, 4H), 0.89 (q, J ¼ 3:3 Hz, 6H).
1
[M+H]þ. H NMR (400 MHz, CDCl3) d 7.37–7.28 (m,
6H), 7.25–7.23 (m, 3H), 7.10–7.07 (m, 1H), 6.99–6.94
(m, 4H), 6.55–6.49 (m, 1H), 6.12–6.05 (m, 1H), 4.4-4.32
(m, 1H), 3.51–3.36 (m, 1H), 3.32–3.25 (m, 1H), 3.09 (dd,
J ¼ 13:5, 6.9 Hz, 1H), 2.82 (dd, J ¼ 13:5, 8.4 Hz, 1H),
2.51–2.43 (m, 3H), 2.32 (dd, J ¼ 14:8, 7.1 Hz, 1H), 2.27
(s, 6H).
4.2.10.
(S)-3-(3-Biphenyl-4-yl-ureido)-4-phenyl-N-(2-
pyrrolidin-1-yl-ethyl)-butyramide (10). Route B. MS
(electrospray): mass calculated for C29H34N4O2, 470.27;
m=z found, 471.3 [M+H]þ. 1H NMR (400 MHz,
CD3OD) d 7.57–7.51 (m, 4H), 7.41–7.27 (m, 9H), 7.24–
7.20 (m, 1H), 4.43–4.37 (m, 1H), 3.49–3.37 (m, 2H),
2.95–2.86 (m, 8H), 2.50 (dd, J ¼ 13:9, 4.2 Hz, 1H), 2.31
(dd, J ¼ 13:9, 9.0 Hz, 1H), 1.89–1.79 (m, 4H).
4.2.6. (R)-3-(3-Biphenyl-4-yl-ureido)-3-phenyl-N-(2-pyr-
rolidin-1-yl-ethyl)-propionamide (7b). Route A. (R)-3-
(3-Biphenyl-4-yl-ureido)-3-phenyl-N-(2-pyrrolidin-1-yl-
ethyl)-propionamide.
MS (electrospray): mass calculated for C28H32N4O2,
456.25; m=z found, 457.3 [M+H]þ, 479.2 [M+Na]þ,
935.4 [2M+Na]þ. 1H NMR (400 MHz, CD3OD) d 7.56–
7.49 (m, 4H), 7.43–7.32 (m, 8H), 7.29–7.23 (m, 2H), 5.27
(t, J ¼ 6:9 Hz, 1H), 3.32–3.29 (m, 2H), 2.70 (d,
J ¼ 6:6 Hz, 2H), 2.62–2.57 (m, 6H), 1.79–1.76 (m, 4H).
4.2.11. (S)-3-[3-(4-Phenoxyphenyl)-ureido]-4-phenyl-N-
(2-pyrrolidin-1-yl-ethyl)-butyramide (11). Route B. MS
(electrospray): mass calculated for C14H12ClNO3, 486.3;
m=z found, 487.3 [M+H]þ. 1H NMR (400 MHz,
CD3OD) d 7.33–7.19 (m, 9H), 7.07–7.04 (m, 1H), 6.93–
6.88 (m, 4H), 4.39–4.33 (m, 1H), 3.37 (t, J ¼ 6:62 Hz,
2H), 2.88 (d, J ¼ 7 Hz, 2H), 2.79 (t, J ¼ 6:09, Hz, 6H),
2.46 (dd, J ¼ 4:7, 14.1 Hz, 1H), 2.33 (dd, J ¼ 8:5,
14.1 Hz, 1H), 1.83–1.76 (m, 4H).
4.2.7. (S)-3-(3-Biphenyl-4-yl-ureido)-3-phenyl-N-(2-pyr-
rolidin-1-yl-ethyl)-propionamide (7c). Route A. (S)-3-(3-
Biphenyl-4-yl-ureido)-3-phenyl-N-(2-pyrrolidin-1-yl-
ethyl)-propionamide.
MS (electrospray): mass calculated for C28H32N4O2,
456.25; m=z found, 457.3 [M+H]þ, 479.2 [M+Na]þ,
935.4 [2M+Na]þ. 1H NMR (400 MHz, CD3OD) d 7.56–
7.49 (m, 4H), 7.43–7.32 (m, 8H), 7.29–7.23 (m, 2H), 5.27
(t, J ¼ 6:9 Hz, 1H), 3.32–3.29 (m, 2H), 2.70 (d,
J ¼ 6:6 Hz, 2H), 2.62–2.57 (m, 6H), 1.79–1.76 (m, 4H).
4.2.12. (S)-3-(3-Biphenyl-4-yl-ureido)-5-methylhexanoic
acid (2-pyrrolidin-1-yl-ethyl)-amide (12). Route B. MS
(electrospray): mass calculated for C26H36N4O2, 436;
m=z found, 437.3 [M+H]þ. 1H NMR (400 MHz,
CD3OD) d 7.58–7.51 (m, 4H), 7.44–7.34 (m, 4H), 7.30–
7.26 (m, 1H) 4.23–4.16 (m, 1H), 3.36 (t, J ¼ 6:8 Hz, 2H),
2.70–2.65 (m, 6H), 2.67 (dd, J ¼ 5:45, 13.9 Hz, 1H), 2.34
(dd, J ¼ 7:4, 13.9 Hz, 1H), 1.79–1.76 (m, 4H), 1.74–1.69
(m, 1H), 1.54–1.46 (m, 1H), 1.38–1.31 (m, 1H), 0.96 (d,
J ¼ 6:8, 6H).
4.2.8. (R)-3-(3-Biphenyl-4-yl-ureido)-4-methyl-pentanoic
acid (2-pyrrolidin-1-yl-ethyl)-amide (8). Route A. {(R)-
2-Methyl-1-[(2-pyrrolidin-1-yl-ethylcarbamoyl)-methyl]-
propyl}-carbamic acid tert-butyl ester.
4.2.13. (S)-5-Methyl-3-[3-(4-phenoxyphenyl)-ureido]-hex-
anoic acid (2-pyrrolidin-1-yl-ethyl)-amide (13). Route B.
MS (electrospray): mass calculated for C26H36N4O3,
MS (electrospray): mass calculated for C17H33N3O3,
327.25; m=z found, 328.3 [M+H]þ. 1H NMR (400 MHz,
CDCl3) d 6.22 (s, 1H), 5.30 (d, J ¼ 6:7 Hz, 1H), 3.66–
3.59 (m, 1H), 3.44–3.36 (m, 1H), 3.35–3.27 (m, 1H),
2.59–2.56 (m, 2H), 2.52 (m, 4H), 2.42–2.40 (m, 2H),
1.87–1.74 (m, 8H), 1.43 (s, 9H), 0.93 (t, J ¼ 6:3, 6H).
1
452; m=z found, 453.3 [M+H]þ. H NMR (400 MHz,
CD3OD) d 7.35–7.23 (m, 4H), 7.08–7.03 (m, 1H), 6.96–
6.88 (m, 4H), 4.20–4.13 (m, 1H), 3.44–3.34 (m, 2H),
2.63–2.49 (m, 6H), 2.38–2.37 (m, 2H), 1.80–1.76 (m,
4H), 1.74–1.65 (m, 1H), 1.52–1.45 (m, 1H), 1.37–1.27
(m, 1H), 0.96 (d, J ¼ 1:06 Hz, 3H), 0.94 (d, J ¼ 0:75 Hz,
3H).
(R)-3-(3-Biphenyl-4-yl-ureido)-4-methyl-pentanoic acid
(2-pyrrolidin-1-yl-ethyl)-amide.
MS (electrospray): mass calculated for C25H34N4O2,
422.27; m=z found, 423.3 [M+H]þ. 1H NMR (400 MHz,
CDCl3) d 7.47–7.30 (m, 8H), 7.24–7.22 (1H), 6.57 (s,
1H), 3.89–3.82 (m, 1H), 3.36–3.25 (m, 2H), 2.53 (t,
J ¼ 6:2 Hz, 2H), 2.47 (d, J ¼ 3:8 Hz, 1H), 2.44 (s, 3H),
2.33 (dd, J ¼ 14:8, 8.6, Hz, 1H), 1.86–1.78 (m, 4H),
1.71–1.66 (m, 4H), 0.92 (d, J ¼ 4:4 Hz, 3H), 0.90 (d,
J ¼ 4:3 Hz, 3H).
4.3. General procedure for the preparation of cyanoguan-
idine derivatives 14–21, and exemplified for compound 17
4.3.1. (R)-3-(N0-Biphenyl-4-yl-N00-cyanoguanidino)-3-phen-
yl-N-(2-pyrrolidin-1-yl-ethyl)-propionamide (17). Step A.
[(R)-1-Phenyl-2-(2-pyrrolidin-1-yl-ethylcarbamoyl)-eth-
yl]-carbamic acid tert-butyl ester. To a solution of (R)-3-

R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4501
tert-butoxycarbonylamino-3-phenyl-propionic
acid
4.42 (m, 1H), 3.44–3.28 (m, 2H), 3.11 (dd, J ¼ 13:6,
7.0 Hz, 1H), 2.94–2.8 (m, 1H), 2.60–2.57 (m, 2H), 2.55–
2.4 (m, 6H), 1.84–1.75 (m, 4H).
(0.54 g, 2.04 mmol), 2-pyrrolidin-1-yl-ethylamine (0.35 g,
3.06 mmol), HOBt (0.41 g, 3.06 mmol) and 4-meth-
ylmorpholine (0.41 g, 4.08 mmol) in DMF (10 mL), was
added EDCI (0.59 g, 3.06 mmol), and the resulting
solution was stirred under N2 at room temperature for
20 h. The solution was diluted with H2O (75 mL) and
was extracted with EtOAc (3 · 75 mL). The combined
extracts were washed with brine (100 mL), dried
(Na2SO4) and filtered, and the solvent was removed
under reduced pressure. The crude product was purified
by column chromatography on silica gel using a gradi-
ent of 2–30% (MeOH (1% NH4OH)/CH2Cl2) to afford
0.65 g (88%) of the desired product as a white solid.
Rf ¼ 0:34 (10% MeOH (1% NH4OH)/CH2Cl2). MS
(electrospray): mass calculated for C20H31N3O3, 361.24;
4.3.3. 3-[N0-Cyano-N00-(4-phenoxyphenyl)-guanidino]-3-
phenyl-N-(2-pyrrolidin-1-yl-ethyl)-propionamide (18). 4-
Phenoxy-phenyl isothiocyanate.
1H NMR (400 MHz, CDCl3) d 7.43 (t, J ¼ 8:0 Hz, 2H),
7.19–7.24 (m, 3H), 7.08 (d, J ¼ 8:0 Hz, 2H), 6.99 (d,
J ¼ 9:0 Hz, 2H).
1-Cyano-3-(4-phenoxy-phenyl)-thiourea.
MS (electrospray): mass calculated for C14H11N3OS,
1
m=z found, 362.2 [M+H]þ, 745.4 [2M+Na]þ. H NMR
1
227.04; m=z found, 268.0 [M)H]ꢁ. H NMR (400 MHz,
(400 MHz, CDCl3) d 7.32–7.28 (m, 4H), 7.24–7.20 (m,
1H), 6.37 (br s, 1H), 6.14 (br s, 1H), 5.01 (br s, 1H), 3.21
(dd, J ¼ 11:2, 5.7 Hz, 2H), 2.74–2.67 (m, 1H), 2.59 (dd,
J ¼ 14, 5.9 Hz, 1H), 2.49–2.38 (m, 6H), 1.76–1.67 (m,
4H), 1.41 (s, 9H).
DMSO-d6) d 9.21 (br s, 1H), 7.36 (d, J ¼ 9:0 Hz, 2H),
7.33–7.36 (m, 2H), 7.06 (t, J ¼ 7:4 Hz, 1H), 6.85–6.93
(m, 4H).
3-[N0-Cyano-N00-(4-phenoxy-phenyl)-guanidino]-3-phen-
yl-N-(2-pyrrolidin-1-yl-ethyl)-propion-amide.
Step B. (R)-3-(N0-Biphenyl-4-yl-N00-cyano-guanidino)-3-
phenyl- N-(2-pyrrolidin-1-yl-ethyl)-propionamide. To a
solution of [(R)-1-phenyl-2-(2-pyrrolidin-1-yl-ethylcar-
bamoyl)-ethyl]-carbamic acid tert-butyl ester (0.25 g,
0.69 mmol) in CH2Cl2 (6.9 mL) was added 4 M HCl in
1,4-dioxane (2.4 mL), and the resulting solution was
stirred at room temperature for 1.5 h. The solvent was
removed under reduced pressure, and the resulting res-
idue was dissolved in MeOH (7 mL) and treated with
basic resin (Dowex 550A OH anion-exchange resin).
The resulting suspension was stirred at room tempera-
ture for 30 min. The resin was filtered off and washed
with MeOH (7 mL). The filtrate and washings were
concentrated under reduced pressure, and the resulting
free amine was dried under vacuum. To a solution of the
free amine and 1-biphenyl-4-yl-3-cyanothiourea (0.21 g,
0.83 mmol) in DMF (3.5 mL), was added EDCI (0.2 g,
1.04 mmol). The resulting solution was stirred under N2
at room temperature for 2 h. The solution was diluted
with EtOAc (70 mL) and washed with 1 N NaOH
(2 · 50 mL). The organic layer was dried (Na2SO4) and
filtered, and the solvent was removed under reduced
pressure. The crude product was purified by column
chromatography on silica gel using a gradient of 5–10%
(MeOH (1% NH4OH)/CH2Cl2) to afford 0.23 g (69%) of
the desired product as a white solid. Rf ¼ 0:39 (10%
MeOH (1% NH4OH)/CH2Cl2). MS (electrospray): mass
calculated for C29H32N6O, 480.26; m=z found, 481.2
[M+H]þ. 1H NMR (400 MHz, CD3OD) d 7.67–7.16 (m,
4H), 7.45–7.41 (m, 2H), 7.35–7.24 (m, 8H), 5.38 (t,
J ¼ 6:4 Hz, 1H), 3.23 (t, J ¼ 6:8 Hz, 2H), 2.71 (d,
J ¼ 6:4 Hz, 2H), 2.47–2.42 (m, 6H), 1.77–1.69 (m, 4H).
MS (electrospray): mass calculated for C29H32N6O2,
496.26; m=z found, 497.3 [M+H]þ. 1H NMR (400 MHz,
CDCl3) d 8.04 (br s, 1H), 7.27–7.15 (m, 9H), 7.05–7.01
(m, 1H), 6.97–6.94 (m, 4H), 6.41 (br s, 1H), 5.26–5.21
(m, 1H), 3.12 (d, J ¼ 4:8 Hz, 2H), 2.66–2.52 (m, 2H),
2.44–2.28 (m, 6H), 1.67–1.58 (m, 4H).
4.3.4. 3-{N0-[4-(4-Chlorophenoxy)-phenyl]-N00-cyanogua-
nidino}-3-phenyl-N-(2-pyrrolidin-1-yl-ethyl)-propiona-
mide (19). 1-[4-(4-Chloro-phenoxy)-phenyl]-3-cyano-
thiourea.
1.8 g (98%) of the desired product was obtained. MS
(electrospray): mass calculated for C14H10ClN3OS,
1
303.02; m=z found, 304.0 [M+H]þ, 326.0 [M+Na]þ. H
NMR (400 MHz, DMSO-d6) d 9.27 (s, 1H), 7.66 (d,
J ¼ 8:6 Hz, 2H), 7.36 (d, J ¼ 8:6 Hz, 2H), 6.93 (d,
J ¼ 9:0 Hz, 2H), 6.89 (d, J ¼ 9:0 Hz, 2H).
3-{N0-[4-(4-Chloro-phenoxy)-phenyl]-N00-cyano-guani-
dino}-3-phenyl-N-(2-pyrrolidin-1-yl-ethyl)-propiona-
mide.
MS (electrospray): mass calculated for C29H31ClN6O2,
530.22; m=z found, 531.2 [M+H]þ. 1H NMR (400 MHz,
CDCl3) d 8.42 (br s, 1H), 7.41 (br s, 1H), 7.33–7.23 (m,
9H), 7.02–6.96 (m, 4H), 6.48 (br s, 1H), 5.36–5.32 (m,
1H), 3.19 (d, J ¼ 3:6 Hz, 2H), 2.72–2.68 (m, 2H), 2.50–
2.36 (m, 6H), 1.73–1.67 (m, 4H).
4.3.2. (S)-3-(N0-Biphenyl-4-yl-N00-cyanoguanidino)-4-phen-
yl-N-(2-pyrrolidin-1-yl-ethyl)-butyramide (15). MS (elec-
trospray): mass calculated for C30H34ClN6O, 494.28;
m=z found, 495.3 [M+H]þ. 1H NMR (400 MHz, CDCl3)
d 7.60–7.56 (m, 4H), 7.45 (t, J ¼ 7:6 Hz, 2H), 7.38–7.25
(m, 8H), 6.75 (d, J ¼ 8:2 Hz, 1H), 6.62 (br s, 1H), 4.5–
4.3.5. 3-[N0-Methyl-N00-(4-p-tolyloxyphenyl)-guanidino]-
3-phenyl-N-(2-pyrrolidin-1-yl-ethyl)-propionamide (20).
4-p-Tolyloxy-phenylisothiocyanate.
MS (electrospray): mass calculated for C14H11NOS,
241.06; m/z found, [M+H]þ. 1H NMR (500 MHz,

4502
R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
DMSO-d6) d 7.43–7.40 (m, 2H), 7.22 (d, J ¼ 8:0 Hz,
J ¼ 15:6, 1.6 Hz, 1H), 4.70–4.61 (m, 1H), 2.93 (dd,
J ¼ 13:7, 6.1 Hz, 1H), 2.84 (dd, J ¼ 13:7, 7.9 Hz, 1H).
2H), 6.98–6.95 (m, 4H), 2.30 (s, 3H).
1-Cyano-3-(4-p-tolyloxy-phenyl)-thiourea.
Step B. (E)-(S)-4-[3-(4-Phenoxy-phenyl)-ureido]-5-phen-
yl-pent-2-enoic acid (2-methylamino-ethyl)-amide. To a
solution of (E)-(S)-4-[3-(4-phenoxy-phenyl)-ureido]-5-
phenyl-pent-2-enoic acid (0.20 g, 0.49 mmol), N0-methyl-
ethane-1,2-diamine (0.04 g, 0.54 mmol) and HOBt
(0.01 g, 0.732 mmol) in DMF (4.9 mL), was added EDCI
(0.14 g, 0.732 mmol). The resulting solution was stirred
under N2 at room temperature for 20 h. The solution
was diluted with H2O (30 mL) and extracted with 3:1
EtOAc/iPrOH (3 · 40 mL). The combined organic
extracts were washed with 1 N NaOH (1 · 30 mL), dried
(Na2SO4) and filtered, and the solvent was removed
under reduced pressure. The residue was purified by
column chromatography on silica gel using a gradient of
0–15% (MeOH (1% NH4OH)/CH2Cl2) to obtain 0.04 g
(18%) of the desired product as a clear oil. Rf ¼ 0:20
(10% MeOH (1% NH4OH)/CH2Cl2). MS (electrospray):
mass calculated for C27H30N4O3, 458.23; m=z found,
459.3 [M+H]þ, 481.2 [M+Na]þ, 917.4 [2M+H]þ. 1H
NMR (400 MHz, CDCl3) d 8.10 (br s, 1H), 7.45 (br t,
J ¼ 5:6 Hz, 1H), 7.23–7.06 (m, 9H), 6.98–6.94 (m, 1H),
6.84–6.78 (m, 4H), 6.64 (dd, J ¼ 15:4, 5.5 Hz, 1H), 6.05
(br d, J ¼ 6:4 Hz, 1H), 5.82 (dd, J ¼ 15:4, 1.2 Hz, 1H),
4.67–4.61 (m, 1H), 3.37–2.28 (m, 1H), 3.20–3.14 (m,
1H), 2.79–2.70 (m, 2H), 2.64–2.54 (m, 3H), 2.25 (s, 3H).
MS (electrospray): mass calculated for C15H13N3OS,
283.08; m=z found, 282.1, [M)H]ꢁ. 1H NMR (500 MHz,
DMSO-d6) d 9.18 (s, 1H), 7.61 (d, J ¼ 8:8 Hz, 2H), 7.13
(d, J ¼ 8:3 Hz, 2H), 6.83–6.81 (m, 4H), 2.26 (s, 3H).
3-[N0-Methyl-N00-(4-p-tolyloxy-phenyl)-guanidino]-3-phen-
yl-N-(2-pyrrolidin-1-yl-ethyl)-propionamide.
MS (electrospray): mass calculated for C30H34N6O2,
1
510.27; m=z found, 511.3 [M+H]þ, 533.2 [M+Na]þ. H
NMR (400 MHz, CDCl3) d 8.11 (br s, 1H), 7.34–7.23
(m, 7H), 7.16 (d, J ¼ 8:1 Hz, 2H), 7.01 (d, J ¼ 8:7 Hz,
2H), 6.96 (d, J ¼ 8:4 Hz, 2H), 6.46 (br s, 1H), 5.35–5.30
(m, 1H), 3.22–3.18 (m, 2H), 2.74–2.63 (m, 2H), 2.51–
2.39 (m, 6H), 2.35 (s, 3H), 1.76–1.68 (m, 4H).
4.3.6. 3-{N0-[4-(4-Fluorophenoxy)-phenyl]-N00-cyanogua-
nidino}-3-phenyl-N-(2-pyrrolidin-1-yl-ethyl)-propiona-
mide (21). MS (electrospray): mass calculated for
C29H31FN6O2, 514.25; m=z found, 515.2 [M+H]þ. 1H
NMR (400 MHz, CDCl3) d 7.33–7.24 (m, 7H), 7.06–6.98
(m, 6H), 6.46 (br s, 1H), 5.34–5.30 (m, 1H), 3.19 (d,
J ¼ 4:0 Hz, 2H), 2.72–2.68 (m, 2H), 2.50–2.36 (m, 6H),
1.72–1.66 (m, 4H).
4.4.2. (E)-(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-
enoic acid (2-amino-ethyl)-amide (22b). (E)-(R)-4-
tert-Butoxycarbonylamino-5-phenyl-pent-2-enoic acid
methyl ester.
4.4. General procedure for the preparation of urea
derivatives 22–36, and exemplified for compound 26
MS (electrospray): mass calculated for C17H23NO4,
305.16; m=z found, 328.1 [M+Na]þ. 1H NMR
(400 MHz, CDCl3) d 7.16–7.31 (m, 5H), 6.92 (dd,
J ¼ 15:7, 5.1 Hz, 1H), 5.90 (d, J ¼ 15:7 Hz, 1H), 4.79 (br
s, 1H), 4.61 (br s, 1H), 3.70 (s, 3H), 2.88 (d, J ¼ 6:4 Hz,
2H), 1.39 (s, 9H).
4.4.1. (E)-(S)-4-[3-(4-Phenoxyphenyl)-ureido]-5-phenyl-
pent-2-enoic acid (2-methyl-aminoethyl)-amide (26).
Step A. (E)-(S)-4-[3-(4-Phenoxy-phenyl)-ureido]-5-phen-
yl-pent-2-enoic acid. To
a solution of (E)-(S)-4-
tert-butoxycarbonylamino-5-phenyl-pent-2-enoic acid
(Example 11, step A) (2.12 g, 7.26 mmol) in CH2Cl2
(73 mL) was added 4 M HCl in 1,4-dioxane (25 mL), and
the resulting solution was stirred at room temperature
for 15 min. The solvent was removed under reduced
pressure. To a solution of the resulting residue and TEA
(0.74 g, 7.26 mmol) in THF (73 mL) cooled to 0 ꢁC, was
added 4-phenoxy phenyl isocyanate (1.53 g, 7.26 mmol),
and the mixture was stirred for 30 min. The solution was
brought to room temperature and was stirred for an
additional 3 h. The solvent was removed under reduced
pressure, and the resulting yellow oil was purified by
column chromatography on silica gel using a gradient of
0–35% (MeOH (10% acetic acid)/CH2Cl2). The purified
product was recrystallized from CH2Cl2 and was washed
with hexanes to afford 1.45 g (50%) of the desired
product as a grey solid. Rf ¼ 0:47 (5% MeOH (1%
NH4OH)/CH2Cl2). MS (electrospray): mass calculated
for C24H22N2O4, 402.16; m=z found, 403.1 [M+H]þ,
(E)-(R)-4-tert-Butoxycarbonylamino-5-phenyl-pent-2-
enoic acid.
MS (electrospray): mass calculated for C16H21NO4,
291.15; m=z found, 314.1 [M+Na]þ. 1H NMR
(400 MHz, CDCl3) d 7.22–7.26 (m, 2H), 7.08–7.11 (m,
2H), 6.93 (dd, J ¼ 15:5, 4.7 Hz, 1H), 5.79 (d,
J ¼ 15:5 Hz, 1H), 4.58 (br s, 1H), 4.48 (br s, 1H), 2.84
(d, J ¼ 6:8 Hz, 2H), 1.33 (s, 9H), remaining peak in the
aromatic region was not detected and is believed to
overlap with the solvent peak at 7.56 ppm.
(E)-(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-eno-
ic acid.
MS (electrospray): mass calculated for C24H22N2O3,
1
386.16; m=z found, 387.1 [M+H]þ, 409.1 [M+Na]þ. H
1
425.1 [M+Na]þ, 827.3 [2M+Na]þ. H NMR (400 MHz,
NMR (400 MHz, DMSO-d6) d 12.33 (br s, 1H), 8.59 (br
s, 1H), 7.59–7.62 (m, 2H), 7.52–7.55 (m, 2H), 7.39–7.47
(m, 4H), 7.20–7.34 (m, 6H), 6.89 (dd, J ¼ 15:7, 5.1 Hz,
1H), 6.40 (d, J ¼ 8:4 Hz, 1H), 5.78 (dd, J ¼ 15:7, 1.6 Hz,
DMSO-d6) d 12.34 (br s, 1H), 8.51 (s, 1H), 7.40–7.20 (m,
9H), 7.08–7.05 (m, 1H), 6.93–6.91 (m, 4H), 6.86 (d,
J ¼ 5:0 Hz, 1H), 6.35 (d, J ¼ 8:5 Hz, 1H), 5.77 (dd,

R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4503
1H), 4.66 (br s, 1H), 2.94 (dd, J ¼ 13:7, 6.2 Hz, 1H), 2.86
(dd, J ¼ 13:7, 8.0 Hz, 1H).
5.85 (d, J ¼ 15:3 Hz, 1H), 4.74–4.67 (m, 1H), 3.33–3.22
(m, 2H), 2.89–2.78 (m, 2H), 2.70–2.63 (m, 2H), 1.58 (br
s, 2H), 1.52 (t, J ¼ 6:4 Hz, 2H).
{2-[(E)-(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-
enoylamino]-ethyl}-carbamic acid tert-butyl ester.
4.4.5. (E)-(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-
enoic acid (3-amino-propyl)-amide (24b). {3-[(E)-(R)-
4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-enoylamino]-
propyl}-carbamic acid tert-butyl ester.
MS (electrospray): mass calculated for C31H36N4O4,
1
528.65; m=z found, 529.3 [M+H]þ, 551.1 [M+Na]þ. H
NMR (400 MHz, CD3OD) d 7.49–7.60 (m, 4H), 7.36–
7.40 (m, 4H), 7.21–7.30 (m, 6H), 6.79 (dd, J ¼ 15:4,
5.6 Hz, 1H), 5.99 (d, J ¼ 15:4 Hz, 1H), 4.72 (dd,
J ¼ 12:3, 6.2 Hz, 1H), 3.29 (br t, J ¼ 6:1 Hz, 1H), 3.15
(br t, J ¼ 6:1 Hz, 1H), 2.97 (dd, J ¼ 13:7, 6.5 Hz, 1H),
2.89 (dd, J ¼ 13:7, 7.8 Hz, 1H), 1.36 (s, 9H).
MS (electrospray): mass calculated for C32H38N4O4,
542.29; m=z found, 443.2 [M)BOC]þ. 1H NMR
(400 MHz, CDCl3) d 7.80 (br s, 1H), 7.33–7.39 (m, 4H),
7.26–7.30 (m, 4H), 7.15–7.21 (m, 4H), 7.11–7.13 (m,
2H), 6.86 (t, J ¼ 5:7 Hz, 1H), 6.67 (dd, J ¼ 15:3, 5.1 Hz,
1H), 5.93 (d, J ¼ 8:2 Hz, 1H), 5.83 (d, J ¼ 15:3 Hz, 1H),
4.96 (br s, 1H), 4.71 (br s, 1H), 3.23–3.33 (m, 1H), 2.97–
3.12 (m, 3H), 2.74–2.85 (m, 2H), 1.48–1.55 (b, 2H), 1.34
(s, 9H).
(E)-(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-eno-
ic acid (2-amino-ethyl)-amide.
MS (electrospray): mass calculated for C26H28N4O2,
1
428.22; m=z found, 429.2 [M+H]þ. H NMR (CD3OD,
400 MHz) d 7.40–7.47 (m, 4H), 7.27–7.31 (m, 4H), 7.12–
7.22 (m, 6H), 6.72 (dd, J ¼ 15:4, 5.6 Hz, 1H), 5.92 (dd,
J ¼ 15:4, 1.5 Hz, 1H), 4.62 (dd, J ¼ 12:4, 6.2 Hz, 1H),
3.27 (br t, J ¼ 6:2 Hz, 1H), 2.89 (dd, J ¼ 13:7, 6.7 Hz,
1H), 2.82 (dd, J ¼ 13:7, 7.8 Hz, 1H), 2.59 (br t,
J ¼ 6:2 Hz, 1H).
(E)-(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-eno-
ic acid (3-amino-propyl)-amide.
MS (electrospray): mass calculated for C27H30N4O2,
442.24; m=z found, 443.2 [M+H]+, 465.2 [M+Na]þ,
1
885.5 [2M+H]þ, 907.4 [2M+Na]þ. H NMR (400 MHz,
CDCl3) d 8.04 (s, 1H), 7.38–7.09 (m, 14H), 6.63 (dd,
J ¼ 15:3, 6.0 Hz, 1H), 6.20 (d, J ¼ 7:7 Hz, 1H), 5.87 (d,
J ¼ 15:3 Hz, 1H), 4.71–4.67 (m, 1H), 3.26–3.22 (m, 2H),
2.85–2.76 (m, 2H), 2.62–2.53 (m, 2H), 1.79 (br s, 2H),
1.47 (t, J ¼ 5:6 Hz, 2H).
4.4.3. (E)-(S)-4-[3-(4-Phenoxyphenyl)-ureido]-5-phenyl-
pent-2-enoic acid (2-amino-ethyl)-amide (23). (2-{(E)-
(S)-4-[3-(4-Phenoxy-phenyl)-ureido]-5-phenyl-pent-2-
enoylamino}-ethyl)-carbamic acid tert-butyl ester.
MS (electrospray): mass calculated for C31H26N4O5,
544.27; m=z found, 567.2 [M+Na]þ. 1H NMR
(400 MHz, DMSO-d6) d 8.49 (br s, 1H), 8.05 (br t,
J ¼ 5:9 Hz, 1H), 7.29–7.38 (m, 6H), 7.19–7.25 (m, 3H),
7.04–7.08 (m, 1H), 6.89–6.93 (m, 4H), 6.81 (br t,
J ¼ 5:8 Hz, 1H), 6.66 (dd J ¼ 15:5, 5.4 Hz, 1H), 6.27 (d,
J ¼ 8:4 Hz, 1H), 5.92 (dd, J ¼ 15:5, 1.3 Hz, 1H), 4.58
(br s, 1H), 3.09–3.14 (m, 2H), 2.93–2.99 (m, 2H), 2.91
(dd, J ¼ 13:7, 6.2 Hz, 1H), 2.80 (dd, J ¼ 13:7, 8.1 Hz,
1H), 1.36 (s, 9H).
4.4.6. (E)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-
enoic acid (2-methylamino-ethyl)-amide (25). MS (elec-
trospray): mass calculated for C27H30N4O2, 442.24; m=z
found, 443.2 [M+H]þ, 465.2 [M+Na]þ, 885.4 [2M+H]þ,
1
907.4 [2M+Na]þ. H NMR (400 MHz, CDCl3) d 8.23
(br s, 1H), 7.46 (br t, J ¼ 5:0 Hz, 1H), 7.40–7.26 (m,
9H), 7.21–7.06 (m, 5H), 6.65 (dd, J ¼ 15:3, 5.3 Hz, 1H),
6.19 (d, J ¼ 7:8 Hz, 1H), 5.85 (d, J ¼ 14:9 Hz, 1H),
4.68–4.62 (m, 1H), 3.35–3.30 (m, 1H), 3.19–3.14 (m,
1H), 2.76–2.54 (m, 5H), 2.24 (s, 3H).
(E)-(S)-4-[3-(4-Phenoxy-phenyl)-ureido]-5-phenyl-pent-
2-enoic acid (2-amino-ethyl)-amide. MS (electrospray):
mass calculated for C26H28N4O3, 444.22; m=z found,
445.2 [M+H]þ, 467.2 [M+Na]þ, 889.4 [2M+H]þ, 911.4
4.4.7. (E)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-
enoic acid (2-dimethylamino-ethyl)-amide (28). MS
(electrospray): mass calculated for C28H32N4O2, 456.25;
1
1
[2M+Na]þ. H NMR (400 MHz, CDCl3) d 8.07 (br s,
m=z found, 457.2 [M+H]þ, 479.2 [M+Na]þ. H NMR
1H), 7.45 (br t, J ¼ 5:6 Hz, 1H), 7.20–7.04 (m, 8H),
6.96–6.92 (m, 2H), 6.86–6.76 (m, 4H), 6.66 (dd J ¼ 15:3,
5.5 Hz, 1H), 6.14 (d, J ¼ 7:7 Hz, 1H), 5.88 (d,
J ¼ 15:0 Hz, 1H), 4.65–4.57 (m, 1H), 3.21–3.14 (m, 1H),
3.11–3.03 (m, 1H), 2.75 (d, J ¼ 7:0 Hz, 2H), 2.63–2.59
(m, 2H), (2.08 br s, 2H).
(400 MHz, CDCl3) d 8.29 (s, 1H), 7.37–7.04 (m, 14H),
6.65 (dd, J ¼ 15:3, 5.7 Hz, 1H), 6.28 (d, J ¼ 8:1 Hz, 1H),
5.88 (dd, J ¼ 15:3, 0.8 Hz, 1H), 4.70–4.63 (m, 1H), 3.31–
3.25 (m, 1H), 3.21–3.15 (m, 1H), 2.80–2.69 (m, 2H),
2.37–2.26 (m, 2H), 2.09 (s, 6H).
4.4.8. (E)-(S)-4-[3-(4-Phenoxyphenyl)-ureido]-5-phenyl-
pent-2-enoic acid (2-dimethylamino-ethyl)-amide (29).
MS (electrospray): mass calculated for C28H32N4O3,
4.4.4. (E)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-
enoic acid (3-amino-propyl)-amide (24a). MS (electro-
spray): mass calculated for C27H30N4O2, 442.24; m=z
found, 443.2 [M+H]þ, 885.5 [2M+H]þ. 1H NMR
(400 MHz, CDCl3) d 7.73 (s, 1H), 7.45–7.11 (m, 14H),
6.62 (dd, J ¼ 6:2, 15.3 Hz, 1H), 5.94 (d, J ¼ 7:2 Hz, 1H),
1
472.59; m=z found, 473.2 [M+H]þ, 495.2 [M+Na]þ. H
NMR (400 MHz, CDCl3) d 7.90 (s, 1H), 7.20–7.07 (m,
9H), 6.97–6.92 (m, 1H), 6.84–6.78 (m, 1H), 6.64 (dd,
J ¼ 15:3, 5.7 Hz, 1H), 5.95 (d, J ¼ 8:4 Hz, 1H), 5.85 (dd,

4504
R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
J ¼ 15:3, 1.2 Hz, 1H), 4.71–4.62 (m, 1H), 3.38–3.31 (m,
1H), 3.20–3.15 (m, 1H), 2.80–2.39 (m, 2H), 2.39–2.27
(m, 2H), 2.13 (s, 6H).
(m, 5H), 6.80 (dd, J ¼ 15:3, 5.1 Hz, 1H), 5.97–5.93 (m,
2H), 4.89–4.83 (m, 1H), 4.51–4.45 (m, 1H), 3.63–3.55
(m, 1H), 3.28–3.21 (m, 1H), 2.95 (dd, J ¼ 13:7, 7.3 Hz,
1H), 2.87 (dd, J ¼ 13:7, 7.3 Hz, 1H), 2.72–2.65 (m, 2H),
2.53–2.45 (m, 4H), 1.78–1.69 (m, 4H).
4.4.9. (E)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-
enoic acid (3-dimethylamino-propyl)-amide (30). MS
(electrospray): mass calculated for C29H34N4O2, 470.27;
m=z found, 471.3 [M+H]þ. 1H NMR (400 MHz, CDCl3)
d 8.13 (s, 1H), 7.81 (t, J ¼ 5:0 Hz, 1H), 7.50–7.33 (m,
8H), 7.30–7.19 (m, 6H), 6.67 (dd, J ¼ 15:4, 6.8 Hz, 1H),
6.54 (d, J ¼ 8:6 Hz, 1H), 5.98 (d, J ¼ 17:6 Hz, 1H),
4.88–4.81 (m, 1H), 3.47–3.29 (m, 2H), 2.96 (dd,
J ¼ 13:6, 7.0 Hz, 1H), 2.88 (dd, J ¼ 13:6, 7.0 Hz, 1H),
2.34 (t, J ¼ 6:4 Hz, 2H), 2.17 (s, 6H), 1.69–1.63 (m, 2H).
4.4.13. (Z)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-
2-enoic acid (2-pyrrolidin-1-yl-ethyl)-amide (33a). Step
A. (Z)-(S)-4-tert-Butoxycarbonylamino-5-phenyl-pent-
2-enoic acid methyl ester. To a solution of bis(2,2,2-
trifluoroethyl)(methoxycarbonylmethyl)-phosphonate
(0.32 g, 1.0 mmol) in THF (10 mL) was added 18-crown-
6 (0.265 g, 1.0 mmol), and the resulting solution was
cooled ()78 ꢁC). The solution was treated with potas-
sium bis(trimethylsilyl)amide (0.2 g, 1.0 mmol) and ((S)-
1-benzyl-2-oxo-ethyl)-carbamic acid tert-butyl ester
(0.25 g, 1.0 mmol), and stirred ()78 ꢁC, 0.5 h). The
reaction mixture was quenched with saturated aqueous
NH4Cl (50 mL) and extracted with EtOAc (2 · 50 mL).
The organic layers were washed with brine (50 mL),
dried (Na2SO4), filtered, and concentrated in vacuo. The
resulting residue was purified by column chromatogra-
phy using 0–40% (EtOAc/hexanes) to provide the
desired product as a white solid (0.185 g, 59%): MS
(electrospray): mass calculated for C17H23NO4, 305.37;
m=z found, 328.1 [M+Na]þ. 1H NMR (CDCl3,
400 MHz) d 7.31–7.38 (m, 2H), 7.20–7.26 (m, 3H), 6.23
(br s, 1H), 5.86 (dd, J ¼ 11:6, 1.0 Hz, 1H), 5.36 (br s,
1H), 4.79 (br s, 1H), 3.75 (s, 3H), 2.99–3.04 (m, 1H),
2.91 (br s, 1H), 1.39 (s, 9H).
4.4.10. (E)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-
2-enoic acid (2-diethylamino-ethyl)-amide (31). (E)-(S)-
4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-enoic acid.
MS (electrospray): mass calculated for C24H22N2O3,
1
386.45; m=z found, 387.1 [M+H]þ, 409.1 [M+Na]þ. H
NMR (DMSO-d6, 400 MHz) d 12.32 (br s, 1H), 8.55 (s,
1H), 7.53–7.64 (m, 5H), 7.40–7.48 (m, 4H), 7.16–7.34
(m, 5H), 6.86 (dd, J ¼ 15:6, 5.1 Hz, 1H), 6.41 (d,
J ¼ 8:4 Hz, 1H), 5.78 (dd, J ¼ 15:6, 1.5 Hz, 1H), 4.63–
4.69 (m, 1H), 2.94 (dd, J ¼ 13:7, 6.2 Hz, 1H), 2.86 (dd,
J ¼ 13:7, 7.8 Hz, 1H). 13C NMR (DMSO-d6 100 MHz) d
166.9, 154.2, 148.7, 138.8, 139.6, 137.6, 132.8, 129.2,
128.9, 128.2, 128.3, 128.0, 126.9, 126.1, 120.7, 118.4,
51.6, 51.2 ppm.
Step B. [(Z)-(S)-1-Benzyl-3-(2-pyrrolidin-1-yl-ethylcar-
bamoyl)-allyl]-carbamic acid tert-butyl ester. To a
solution of (Z)-(S)-4-tert-butoxycarbonylamino-5-phe-
nyl-pent-2-enoic acid methyl ester (0.10 g, 0.33 mmol) in
toluene (3.6 mL) was added aminoethylpyrrolidine
(0.041 g, 0.36 mmol) and trimethylaluminum (2 M in
hexanes, 0.026 g, 0.36 mmol), and the solution was stir-
red (25 ꢁC, 4 h). The solvent was removed in vacuo, and
the residue was partitioned with 1 N NaOH and CH2Cl2
(50 mL each). The organic layer was dried (Na2SO4),
filtered, and concentrated in vacuo. The resulting resi-
due was purified by column chromatography using 0–
20% (1% NH4OH/MeOH in CH2Cl2) to provide the
desired product as a clear oil (0.02 g, 16%): MS (elec-
trospray): mass calculated for C22H33N3O3, 387.25; m=z
found, 388.2 [M+H]þ; 410.2 [M+Na]þ. 1H NMR
(CDCl3, 400 MHz) d 7.20–7.25 (m, 2H), 7.13–7.18 (m,
3H), 5.72–5.81 (m, 2H), 5.08 (br s, 1H), 4.94 (br s, 1H),
3.28–3.45 (m, 2H), 2.91 (dd, J ¼ 13:4, 5.6 Hz, 1H), 2.77–
2.86 (m, 1H), 2.51–2.61 (m, 2H), 2.42–2.47 (m, 4H),
1.65–1.71 (m, 4H), 1.32 (s, 9H).
(E)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-2-eno-
ic acid (2-diethylamino-ethyl)-amide. MS (electrospray):
mass calculated for C30H36N4O2, 484.64; m=z found,
1
485.3 [M+H]þ, 507.2 [M+Na]þ. H NMR (400 MHz,
CD3OD) d 8.39 (br s, 1H), 7.36–7.50 (m, 8H), 7.18–7.31
(m, 6H), 7.03 (br t, J ¼ 5:0 Hz, 1H), 6.75 (dd, J ¼ 15:4,
6.3 Hz, 1H), 6.51 (d, J ¼ 8:2 Hz, 1H), 6.03 (dd, J ¼ 15:4,
0.9 Hz, 1H), 4.78–4.85 (m, 1H), 3.28–3.44 (m, 2H), 2.81–
2.95 (m, 2H), 2.53–2.65 (m, 6H), 1.00 (t, J ¼ 8:2 Hz, 6H).
4.4.11. (E)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-
2-enoic acid (3-diethylamino-propyl)-amide (32). MS
(electrospray): mass calculated for C31H38N4O2, 498.30;
m=z found, 499.3 [M+H]þ. 1H NMR (400 MHz, CDCl3)
d 8.29 (s, 1H), 8.29 (t, J ¼ 4:8 Hz, 1H), 7.52–7.36 (m,
8H), 7.31–7.20 (m, 6H), 6.70 (dd, J ¼ 15:4, 6.8 Hz, 1H),
6.66 (d, J ¼ 9:7 Hz, 1H), 5.97 (dd, J ¼ 15:4, 0.9 Hz, 1H),
4.90–4.83 (m, 1H), 3.45–3.31 (m, 2H), 2.99 (dd,
J ¼ 13:7, 6.9 Hz, 1H), 2.89 (dd, J ¼ 13:7, 7.2 Hz, 1H),
2.52–2.44 (m, 6H), 1.71–1.60 (m, 2H), 0.98 (t,
J ¼ 7:1 Hz, 6H).
Step C. (Z)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-
pent-2-enoic acid (2-pyrrolidin-1-yl-ethyl)-amide. Pre-
pared by a route similar to Example 11, step C. MS
(electrospray): mass calculated for C30H34N4O2, 482.62;
m=z found, 483.3 [M+H]þ. 1H NMR (CDCl3, 400 MHz)
d 7.45–7.49 (m, 4H), 7.39–7.42 (m, 2H), 7.33 (t,
J ¼ 7:3 Hz, 2H), 7.18–7.26 (m, 3H), 7.11–7.17 (m, 3H),
5.71–5.77 (m, 2H), 5.45 (br s, 1H), 3.38–3.46 (m, 2H),
3.24–3.35 (m, 1H), 2.87 (dd, J ¼ 13:6, 6.8 Hz, 1H), 2.76
4.4.12. (E)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-
2-enoic acid (2-pyrrolidin-1-yl-ethyl)-amide (33). MS
(electrospray): mass calculated for C30H34N4O2, 482.27;
m=z found, 483.3 [M+H]þ, 505.2 [M+Na]þ, 987.5
1
[2M+H]þ. H NMR (400 MHz, CDCl3) d 7.99 (s, 1H),
7.53 (d, J ¼ 7:4 Hz, 2H), 7.49–7.37 (m, 7H), 7.32–7.20

R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4505
(dd, J ¼ 13:6, 6.8 Hz, 1H), 2.54–2.64 (m, 2H), 2.48 (br s,
4.4.15. (E)-(S)-4-[3-(4-Phenoxyphenyl)-ureido]-5-phenyl-
pent-2-enoic acid (2-pyrrolidin-1-yl-ethyl)-amide (34). MS
(electrospray): mass calculated for C30H34N4O3, 498.26;
4H), 1.71 (br s, 4H).
1
m=z found, 499.2 [M+H]þ, 997.5.4 [2M+H]þ. H NMR
4.4.14. (Z)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-
2-enoic acid (2-pyrrolidin-1-yl-ethyl)-amide (33b). Step
A. (Z)-(S)-4-tert-Butoxycarbonylamino-5-phenyl-pent-
2-enoic acid methyl ester. To a solution of bis(2,2,2-
trifluoroethyl)(methoxycarbonylmethyl)-phosphonate
(0.32 g, 1.0 mmol) in THF (10 mL) was added 18-
crown-6 (0.265 g, 1.0 mmol), and the resulting solu-
tion was cooled ()78 ꢁC). The solution was treated
with potassium bis(trimethylsilyl)amide (0.2 g,
1.0 mmol) and ((S)-1-benzyl-2-oxo-ethyl)-carbamic
acid tert-butyl ester (0.25 g, 1.0 mmol), and stirred
()78 ꢁC, 0.5 h). The reaction mixture was quenched
with saturated aqueous NH4Cl (50 mL) and extracted
with EtOAc (2 · 50 mL). The organic layers were
washed with brine (50 mL), dried (Na2SO4), filtered,
and concentrated in vacuo. The resulting residue was
purified by column chromatography using 0–40%
(EtOAc/hexanes) to provide the desired product as a
white solid (0.185 g, 59%): MS (electrospray): mass
calculated for C17H23NO4, 305.37; m=z found, 328.1
[M+Na]þ. 1H NMR (CDCl3, 400 MHz) d 7.31–7.38
(m, 2H), 7.20–7.26 (m, 3H), 6.23 (br s, 1H), 5.86 (dd,
J ¼ 11:6, 1.0 Hz, 1H), 5.36 (br s, 1H), 4.79 (br s, 1H),
3.75 (s, 3H), 2.99–3.04 (m, 1H), 2.91 (br s, 1H), 1.39
(s, 9H).
(400 MHz, CDCl3) d 8.31 (s, 1H), 7.59 (br t, J ¼ 5:2 Hz,
1H), 7.34–7.31 (m, 2H), 7.30–7.24 (m, 4H), 7.20–7.18
(m, 3H), 7.07–7.03 (m, 1H), 6.93–6.88 (m, 4H), 6.75 (dd,
J ¼ 15:3, 5.2 Hz, 1H), 6.21 (d, J ¼ 8:2 Hz, 1H), 5.95 (dd,
J ¼ 15:3, 1.3 Hz, 1H), 4.78–4.72 (m, 1H), 3.53–3.45 (m,
1H), 3.33–3.25 (m, 1H), 2.88 (dd, J ¼ 13:7, 7.5 Hz, 1H),
2.81 (dd J ¼ 13:7, 7.2 Hz, 1H), 2.76–2.70 (m, 1H), 2.66–
2.58 (m, 5H), 1.82–1.74 (m, 4H).
4.4.16. (E)-(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pent-
2-enoic acid (3-pyrrolidin-1-yl-propyl)-amide (35b). MS
(electrospray): mass calculated for C31H36N4O2, 496.28;
m=z found, 497.3 [M+H]þ. 1H NMR (400 MHz, CDCl3)
d 8.22 (s, 1H), 7.99 (t, J ¼ 5:4 Hz, 1H), 7.50–7.35 (m,
8H), 7.30–7.18 (m, 6H), 6.69 (dd, J ¼ 15:3, 6.5 Hz, 1H),
6.55 (d, J ¼ 8:5 Hz, 1H), 5.94 (dd, J ¼ 15:3, 1.0 Hz, 1H),
4.87–4.80 (m, 1H), 3.45–3.29 (m, 2H), 2.98–2.89 (m,
2H), 2.54 (t, J ¼ 6:6 Hz, 2H), 2.45 (br s, 4H), 1.77–1.67
(m, 6H).
4.4.17. (E)-(S)-4-[3-(4-Phenoxyphenyl)-ureido]-5-phenyl-
pent-2-enoic acid (3-pyrrolidin-1-yl-propyl)-amide (36).
MS (electrospray): mass calculated for C31H36N4O3,
512.28; m=z found, 513.3 [M+H]þ. 1H NMR (400 MHz,
CDCl3) d 8.51 (s, 1H), 7.93 (br t, J ¼ 5:0 Hz, 1H), 7.31–
7.15 (m, 9H), 7.05–7.01 (m, 1H), 6.91–6.85 (m, 4H), 6.69
(dd, J ¼ 15:4, 5.8 Hz, 1H), 6.50 (d, J ¼ 8:0 Hz, 1H), 5.96
(dd, J ¼ 14:6, 0.72 Hz, 1H), 4.77–4.70 (m, 1H), 3.35–
3.21 (m, 2H), 2.91–2.79 (m, 2H), 2.60 (s, 6H), 1.76–1.68
(m, 6H).
Step B. [(Z)-(S)-1-Benzyl-3-(2-pyrrolidin-1-yl-ethylcar-
bamoyl)-allyl]-carbamic acid tert-butyl ester. To a
solution of (Z)-(S)-4-tert-butoxycarbonylamino-5-phen-
yl-pent-2-enoic acid methyl ester (0.10 g, 0.33 mmol) in
toluene (3.6 mL) was added aminoethylpyrrolidine
(0.041 g, 0.36 mmol) and trimethylaluminum (2 M in
hexanes, 0.026 g, 0.36 mmol), and the solution was stir-
red (25 ꢁC, 4 h). The solvent was removed in vacuo, and
the residue was partitioned with 1 N NaOH and CH2Cl2
(50 mL each). The organic layer was dried (Na2SO4),
filtered, and concentrated in vacuo. The resulting resi-
due was purified by column chromatography using 0–
20% (1% NH4OH/MeOH in CH2Cl2) to provide the
desired product as a clear oil (0.02 g, 16%): MS (elec-
trospray): mass calculated for C22H33N3O3, 387.25; m=z
found, 388.2 [M+H]þ; 410.2 [M+Na]þ. 1H NMR
(CDCl3, 400 MHz) d 7.20–7.25 (m, 2H), 7.13–7.18 (m,
3H), 5.72–5.81 (m, 2H), 5.08 (br s, 1H), 4.94 (br s, 1H),
3.28–3.45 (m, 2H), 2.91 (dd, J ¼ 13:4, 5.6 Hz, 1H), 2.77–
2.86 (m, 1H), 2.51–2.61 (m, 2H), 2.42–2.47 (m, 4H),
1.65–1.71 (m, 4H), 1.32 (s, 9H).
4.5. General procedure for the preparation of urea
derivatives 37–45, and exemplified for compound 37
4.5.1. (R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pentanoic
acid (2-amino-ethyl)-amide (37a). Step A. (R)-4-(3-
Biphenyl-4-yl-ureido)-5-phenyl-pentanoic acid.
MS (electrospray): mass calculated for C24H24N2O3,
388.46; m=z found, 389.2 [M+H]þ, 411.1 [M+Na]þ,
1
387.1 [M)H]ꢁ. H NMR (DMSO-d6 400 MHz) d 12.00
(br s, 1H), 8.44 (br s, 1H), 7.52–7.62 (m, 4H), 7.40–7.47
(m, 4H), 7.28–7.32 (m, 4H), 7.18–7.24 (m 2H), 6.06 (d,
J ¼ 8:6 Hz, 1H), 3.85–3.94 (m, 1H), 2.72–2.80 (m, 2H),
2.20–2.38 (m, 2H), 1.71–1.79 (m, 1H), 1.49–1.57 (m,
1H).
Step C. (Z)-(S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-
pent-2-enoic acid (2-pyrrolidin-1-yl-ethyl)-amide. Pre-
pared by a route similar to Example 11, step C. MS
(electrospray): mass calculated for C30H34N4O2, 482.62;
m=z found, 483.3 [M+H]þ. 1H NMR (CDCl3, 400 MHz)
d 7.45–7.49 (m, 4H), 7.39–7.42 (m, 2H), 7.33 (t,
J ¼ 7:3 Hz, 2H), 7.18–7.26 (m, 3H), 7.11–7.17 (m, 3H),
5.71–5.77 (m, 2H), 5.45 (br s, 1H), 3.38–3.46 (m, 2H),
3.24–3.35 (m, 1H), 2.87 (dd, J ¼ 13:6, 6.8 Hz, 1H), 2.76
(dd, J ¼ 13:6, 6.8 Hz, 1H), 2.54–2.64 (m, 2H), 2.48 (br s,
4H), 1.71 (br s, 4H).
Step B. {2-[(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-
pentanoylamino]-ethyl}-carbamic acid tert-butyl ester.
MS (electrospray): mass calculated for C31H38N4O4,
1
530.66; m=z found, 531.3 [M+H]þ, 553.3 [M+Na]þ. H
NMR (DMSO-d6 400 MHz) d 8.64 (br s, 1H), 7.84 (br
s, 1H), 7.60 (d, J ¼ 8:1 Hz, 2H), 7.53 (d, J ¼ 8:5 Hz,
2H), 7.40–7.47 (m, 4H), 7.28–7.32 (m, 3H), 7.18–7.23

4506
R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
(m, 3H), 6.77 (br t, J ¼ 5:4 Hz, 1H), 6.03 (d, J ¼ 8:6 Hz,
1H), 3.86 (br s, 1H), 3.02–3.07 (m, 2H), 2.94–2.99 (m,
2H), 2.74 (d, J ¼ 6:4 Hz, 2H), 2.08–2.19 (m, 2H), 1.70–
1.75 (m, 1H), 1.51–1.56 (m, 1H), 1.36 (s, 9H).
DMSO-d6) d 8.62 (br s, 1H), 8.03 (br t, J ¼ 5:7 Hz, 1H),
7.60–7.66 (m, 5H), 7.42–7.48 (m, 4H), 7.25–7.33 (m,
5H), 6.79 (br t, J ¼ 5:7 Hz, 1H), 6.68 (dd, J ¼ 15:2,
5.2 Hz, 1H), 6.36 (d, J ¼ 8:6 Hz, 1H), 5.95 (dd, J ¼ 15:2,
1.4 Hz, 1H), 4.62 (br s, 1H), 3.05–3.13 (m, 2H), 2.80–
2.95 (m, 4H), 1.47-1.55 (m, 2H), 1.36 (s, 9H).
4.5.2. (S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pentanoic
acid (2-amino-ethyl)-amide (37b). Step A. {2-[(S)-4-(3-
Biphenyl-4-yl-ureido)-5-phenyl-pentanoylamino]-ethyl}-
carbamic acid tert-butyl ester.
{3-[(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pentanoyl-
amino]-propyl}-carbamic acid tert-butyl ester.
MS (electrospray): mass calculated for C32H40N4O4,
1
MS (electrospray): mass calculated for C32H38N4O4,
1
544.69; m=z found, 545.3 [M+H]þ, 567.3 [M+Na]þ. H
530.66; m=z found, 531.3 [M+H]þ, 553.2 [M+Na]þ. H
NMR (400 MHz, CD3OD) d 7.39–7.47 (m, 4H), 7.27–
7.31 (m, 4H), 3.86–3.93 (m, 1H), 3.00–3.10 (m, 2H),
2.90–2.95 (m, 2H), 2.72 (d, J ¼ 6:9 Hz, 2H), 2.14–2.22
(m, 4H), 1.74–1.83 (m, 1H), 1.47–1.63 (m, 3H), 1.31 (s,
9H).
NMR (400 MHz, CD3OD) d 7.44–7.47 (m, 2H), 7.39–
7.42 (m, 2H), 7.27–7.31 (m, 4H), 7.06–7.21 (m, 6H),
3.87–3.94 (m, 2H), 3.14–3.18 (m, 1H), 3.00–3.10 (m,
3H), 2.68–2.77 (m, 2H), 2.18 (t, J ¼ 7:4 Hz, 2H), 1.75–
1.84 (m, 1H), 1.53–1.62 (m, 1H), 1.30 (s, 9H).
(R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pentanoic acid
(3-amino-propyl)-amide.
Step B. (S)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-penta-
noic acid (2-amino-ethyl)-amide.
MS (electrospray): mass calculated for C27H32N4O2,
444.25; m=z found, 445.2 [M+H]þ, 467.2 [M+Na]þ,
911.5 [2M+Na]. 1H NMR (400 MHz, CDCl3) d 8.04 (br
s, 1H), 7.50–7.32 (m, 8H), 7.23–7.10 (m, 6H), 7.05 (t,
J ¼ 5:1 Hz, 1H), 5.64 (br d, J ¼ 7:6 Hz, 1H), 4.06–3.95
(m, 1H), 3.30–3.13 (m, 2H), 2.84 (dd, J ¼ 13:5, 5.9 Hz,
1H), 2.67 (dd, J ¼ 13:5, 5.7 Hz, 1H), 2.60 (t, J ¼ 5:7 Hz,
2H), 2.26–2.11 (m, 2H), 2.00 (br s, 2H), 1.75–1.63 (m,
2H), 1.46 (t, J ¼ 5:9 Hz, 2H).
MS (electrospray): mass calculated for C26H30N4O2,
430.24; m=z found, 431.2 [M+H]þ, 453.2 [M+Na]þ,
1
883.4 [2M+Na]þ. H NMR (400 MHz, CDCl3) d 7.56
(br s, 1H), 7.47–7.13 (m, 14H), 6.70–6.66 (m, 1H), 5.22
(d, J ¼ 5:9 Hz, 1H), 4.08–4.01 (m, 1H), 3.27–3.18 (m,
2H), 2.81 (dd, J ¼ 13:6, 6.1 Hz, 1H), 2.73–2.67 (m, 3H),
2.29–2.12 (m, 2H), 1.79 (br s, 2H), 1.74–1.63 (m, 2H).
4.5.3. (R)-4-[3-(4-Phenoxyphenyl)-ureido]-5-phenyl-pen-
tanoic acid (2-amino-ethyl)-amide (38). (2-{(R)-4-[3-(4-
Phenoxy-phenyl)-ureido]-5-phenyl-pentanoylamino}-
ethyl)-carbamic acid tert-butyl ester.
4.5.5. (R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pentanoic
acid (2-methylamino-ethyl)-amide (40). MS (electro-
spray): mass calculated for C27H32N4O2, 444.25; m=z
found, 445.2 [M+H]þ, 467.2 [M+Na]þ. 1H NMR
(400 MHz, CDCl3) d 8.50 (br s, 1H), 7.71 (s, 1H), 7.40–
7.34 (m, 4H), 7.30–7.19 (m, 6H), 7.15–7.04 (m, 4H), 6.14
(d, J ¼ 8:7 Hz, 1H), 3.94–3.86 (m, 1H), 3.55–3.46 (m,
1H), 3.26–3.18 (m, 1H), 2.98–2.90 (m, 1H), 2.73–2.62
(m, 3H), 2.40 (s, 3H), 2.29–2.11 (m, 2H), 1.91–1.80 (m,
1H), 1.50–1.36 (m, 1H).
MS (electrospray): mass calculated for C31H38N4O5,
1
546.28; m=z found, 547.2 [M+H]þ, 569.3 [M+Na]þ. H
NMR (400 MHz, CDCl3) d 7.54 (br s, 1H), 7.14–7.21
(m, 5H), 7.05–7.11 (m, 6H), 6.96 (t, J ¼ 7:3 Hz, 1H),
6.77–6.85 (m, 4H), 5.55 (br d, J ¼ 7:8 Hz, 1H), 5.30 (br
s, 1H), 3.95 (br s, 1H), 3.03–3.29 (m, 4H), 2.64–2.74 (m,
2H), 2.17 (br t, J ¼ 6:8 Hz, 1H), 1.70–1.79 (m, 1H),
1.54–1.64 (m, 1H), 1.32 (s, 9H).
(R)-4-[3-(4-Phenoxy-phenyl)-ureido]-5-phenyl-pentanoic
acid (2-amino-ethyl)-amide.
4.5.6. (R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pentanoic
acid (2-diethylamino-ethyl)-amide (43). MS (electro-
spray): mass calculated for C30H38N4O2, 486.30; m=z
1
found, 487.3 [M+H]þ. H NMR (400 MHz, CDCl3) d
MS (electrospray): mass calculated for C26H30N4O3,
446.23; m=z found, 447.2 [M+H]þ, 469.2 [M+Na]þ, 915.4
7.89 (s, 1H), 7.44–7.29 (m, 8 H), 7.23–7.09 (m, 6H), 6.74
(br s, 1H), 5.84 (br s, 1H), 4.05–3.96 (m, 1H), 3.30–3.22
(m, 1H), 3.17–3.10 (m, 1H), 2.83 (dd, J ¼ 13:6, 6.0 Hz,
1H), 2.66 (dd, J ¼ 13:6, 7.2 Hz, 1H), 2.47–2.41 (m, 6H),
2.22 (t, J ¼ 7:0 Hz, 2H), 1.79–1.72 (m, 1H), 1.67–1.59
(m, 1H), 0.88 (t, J ¼ 7:2 Hz, 6H).
1
[2M+Na]þ. H NMR (400 MHz, CDCl3) d 7.77 (br s,
1H), 7.24–7.08 (m, 8H), 7.00–6.93 (m, 2H), 6.88–6.79 (m,
4H), 5.49 (d, J ¼ 8:6 Hz, 1H), 4.03–3.94 (m, 1H), 3.20–
3.11 (m, 2H), 2.75 (dd, J ¼ 6:4, 3.6 Hz, 1H), 2.70–2.65
(m, 3H), 2.25–2.13 (m, 2H), 1.80–1.71 (m, 2H).
4.5.4. (R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pentanoic
acid (3-amino-propyl)-amide (39). {3-[(E)-(S)-4-(3-
Biphenyl-4-yl-ureido)-5-phenyl-pent-2-enoylamino]-prop-
yl}-carbamic acid tert-butyl ester.
4.5.7. (S)-4-(N0-Biphenyl-4-yl-N00-cyanoguanidino)-5-phen-
yl-pentanoic acid (2-pyrrolidin-1-yl-ethyl)-amide (44).
[(E)-(R)-1-Benzyl-3-(2-pyrrolidin-1-yl-ethylcarbamoyl)-
allyl]-carbamic acid tert-butyl ester. MS (electrospray):
mass calculated for C22H33N3O3, 387.25; m=z found,
1
MS (electrospray): mass calculated for C32H38N4O4,
542.67; m=z found, 543.2 [M+H]þ. 1H NMR (400 MHz,
388.3 [M+H]þ. H NMR (400 MHz, CD3OD) d 7.33–
7.14 (m, 5H), 6.70 (dd, J ¼ 5:5, 15.3 Hz, 1H), 5.88 (d,

R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4507
J ¼ 15:3 Hz, 1H), 4.43–4.40 (m, 1H), 3.93 (m, 2H), 2.95–
2.83 (m, 2H), 2.77–2.43 (m, 6H), 1.90–1.85 (m, 4H), 1.36
(s, 9H).
400 MHz) d 7.17–7.31 (m, 5H), 6.78 (dd, J ¼ 14:5,
5.2 Hz, 1H), 6.25 (br s, 1H), 5.82 (dd, J ¼ 15:5, 1.6 Hz,
1H), 4.70 (d, J ¼ 8:9 Hz, 1H), 4.59 (br s, 1H), 3.34–3.42
(m, 2H), 2.88–2.93 (m, 2H), 2.40–2.44 (m, 2H), 2.22 (s,
6H), 1.40 (s, 9H).
[(S)-1-Benzyl-3-(2-pyrrolidin-1-yl-ethylcarbamoyl)-prop-
yl]-carbamic acid tert-butyl ester.
[(R)-1-Benzyl-3-(2-dimethylamino-ethylcarbamoyl)-prop-
yl]-carbamic acid tert-butyl ester.
MS (electrospray): mass calculated for C22H35N3O3,
389.27; m=z found, 390.3 [M+H]þ. 1H NMR (400 MHz,
CD3OD) d 7.26–7.13 (m, 5H), 3.70–3.59 (m, 1H), 3.35–
3.27 (m, 2H), 2.71 (d, J ¼ 7:2 Hz, 2H), 2.61–2.56 (m,
6H), 2.29–2.14 (m, 2H), 1.85–1.80 (m, 4H), 1.650–1.58
(m, 1H), 1.37 (s, 9H).
MS (electrospray): mass calculated for C20H33N3O3,
1
363.50; m=z found, 364.2 [M+H]þ, 386.2 [M+Na]þ. H
NMR (CDCl3, 400 MHz) d 7.09–7.22 (m, 5H), 6.15 (br
s, 1H), 4.52 (br d, J ¼ 8:5 Hz, 1H), 3.72 (br s, 1H), 3.21–
3.24 (m, 1H), 2.75 (dd, J ¼ 13:3, 6.1 Hz, 1H), 2.66 (dd,
J ¼ 13:3, 6.7 Hz, 1H), 2.31 (t, J ¼ 6:0 Hz, 1H), 2.13 (s,
6H), 1.32 (s, 9H).
(S)-4-(N0-Biphenyl-4-yl-N00-cyano-guanidino)-5-phenyl-
pentanoic acid (2-pyrrolidin-1-yl-ethyl)-amide.
MS (electrospray): mass calculated for C31H36N6O,
508.30; m=z found, 509.3 [M+H]þ. 1H NMR (400 MHz,
CDCl3) d 7.57–7.51 (m, 4H), 7.43 (t, J ¼ 7:6 Hz, 2H),
7.35–7.21 (m, 8H), 6.81 (br s, 1H), 4.26–4.18 (m, 1H),
3.38–3.29 (m, 2H), 2.88 (d, J ¼ 4:4 Hz, 2H), 2.58 (t,
J ¼ 6:0 Hz, 2H), 2.51 (br s, 4H), 2.37–2.29 (m, 1H),
2.28–2.22 (m, 1H), 1.90–1.82 (m, 2H), 1.76 (br s, 4H).
(R)-4-(N0-Biphenyl-4-yl-N00-cyano-guanidino)-5-phenyl-
pentanoic acid (2-dimethylamino-ethyl)-amide.
MS (electrospray): mass calculated for C29H34N6O,
1
482.62; m=z found, 483.3 [M+H]þ. H NMR (CDCl3,
400 MHz) d 9.63 (br s, 1H), 7.23–7.58 (m, 15H), 6.54 (br
s, 1H), 4.20–4.25 (m, 1H), 3.30 (br s, 2H), 2.86–2.89 (br
s, 2H), 2.32–2.42 (m, 3H), 2.23–2.27 (m, 1H), 2.23 (s,
6H), 1.84–1.88 (br s, 2H).
4.5.8. (R)-4-(3-Biphenyl-4-yl-ureido)-5-phenyl-pentanoic
acid (2-pyrrolidin-1-yl-ethyl)-amide (44). MS (electro-
spray): mass calculated for C30H36N4O2, 484.28; m=z
found, 485.2 [M+H]þ, 507.2 [M+Na]þ, 991.5
[2M+Na]þ. 1H NMR (400 MHz, CDCl3) d 8.23 (s,
1H), 7.52–7.37 (m, 9H), 7.32–7.14 (m, 5H), 6.06 (br d,
J ¼ 6:6 Hz, 1H), 4.13–4.05 (m, 1H), 3.99 (br s, 1H),
3.42–3.36 (m, 1H), 3.33–3.25 (m, 1H), 2.89 (dd,
4.6.2.
(R)-4-(N0-Biphenyl-4-yl-N00-cyanoguanidino)-5-
phenyl-pentanoic acid (2-diethylamino-ethyl)-amide (47).
[(E)-(S)-1-Benzyl-3-(2-diethylamino-ethylcarbamoyl)-al-
lyl]-carbamic acid tert-butyl ester.
MS (electrospray): mass calculated for C22H35N3O3,
1
J ¼ 13:4,
6.2 Hz,
1H),
2.75
(dd,
J ¼ 13:4,
389.53; m=z found, 390.3 [M+H]þ, 412.3 [M+Na]þ. H
7.0 Hz, 1H), 2.61 (t, J ¼ 6:0 Hz, 2H), 2.57–2.51 (m, 4H),
2.31 (t, J ¼ 7:0 Hz, 2H), 1.90–1.83 (m, 1H), 1.77–1.64
(m, 5H).
NMR (CDCl3, 400 MHz) d 7.17–7.31 (m, 5H), 6.75–
6.79 (m, 1H), 6.19 (br s, 1H), 5.80 (d, J ¼ 15:1 Hz, 1H),
4.62 (br s, 2H), 3.32–3.42 (m, 2H), 2.88–2.93 (m,
2H), 2.48–2.56 (m, 6H), 1.40 (s, 9H), 1.00 (t, J ¼ 7:1 Hz,
6H).
4.5.9. (R)-4-[3-(4-Phenoxyphenyl)-ureido]-5-phenyl-pen-
tanoic acid (2-pyrrolidin-1-yl-ethyl)-amide (45). MS
(electrospray): mass calculated for C30H36N4O3, 500.28;
[(R)-1-Benzyl-3-(2-diethylamino-ethylcarbamoyl)-prop-
yl]-carbamic acid tert-butyl ester.
1
m=z found, 501.3 [M+H]þ, 523.2 [M+Na]þ. H NMR
(400 MHz, CDCl3) d 7.74 (br s, 1H), 7.23–7.17 (m, 6H),
7.13–7.09 (m, 3H), 6.97 (t, J ¼ 7:4 Hz, 1H), 6.87–6.82
(m, 4H), 5.68 (br d, J ¼ 4:8 Hz, 1H), 3.99–3.95 (m, 1H),
3.85 (br s, 1H), 3.34–3.30 (m, 1H), 3.23–3.18 (m, 1H),
2.80 (dd, J ¼ 13:6, 6.2 Hz, 1H), 2.66 (dd, J ¼ 13:6,
7.0 Hz, 1H), 2.56 (t, J ¼ 6:0 Hz, 2H), 2.52–2.48 (m, 4H),
2.24–2.19 (m, 2H), 1.78–1.73 (m, 1H), 1.71–1.67 (m,
4H), 1.62–1.55 (m, 1H).
MS (electrospray): mass calculated for C22H37N3O3,
1
391.55; m=z found, 392.3 [M+H]þ, 414.3 [M+Na]þ. H
NMR (CDCl3, 400 MHz) d 7.18–7.32 (m, 5H), 6.28 (br
s, 1H), 4.58 (br d, J ¼ 8:8 Hz, 1H), 3.80–3.83 (br s, 1H),
3.29–3.32 (m, 2H), 2.85 (dd, J ¼ 13:5, 6.0 Hz, 1H), 2.75
(dd, J ¼ 13:5, 6.8 Hz, 1H), 2.49–2.57 (m, 6H), 2.17–2.30
(m, 2H), 1.84–1.89 (m, 1H), 1.62–1.71 (m, 1H), 1.41 (s,
9H), 1.00 (t, J ¼ 7:1 Hz, 6H).
(R)-4-(N0-Biphenyl-4-yl-N00-cyano-guanidino)-5-phenyl-
pentanoic acid (2-diethylamino-ethyl)-amide.
4.6. The procedure for preparing the cyanoguanidine
derivatives 46–53 was analogous to that for compound 17
MS (electrospray): mass calculated for C31H33N6O,
1
4.6.1. (R)-4-(N0-Biphenyl-4-yl-N00-cyanoguanidino)-5-phen-
yl-pentanoic acid (2-dimethylamino-ethyl)-amide (46).
[(E)-(S)-1-Benzyl-3-(2-dimethylamino-ethylcarbamoyl)-
allyl]-carbamic acid tert-butyl ester. MS (electrospray):
mass calculated for C20H31N3O3, 361.48; m=z found,
362.2 [M+H]þ, 384.2 [M+Na]þ. 1H NMR (CDCl3,
510.68; m=z found, 511.3 [M+H]þ. H NMR (CDCl3,
400 MHz) d 9.66 (br s, 1H), 7.24–7.59 (m, 14H), 6.42 (br
s, 1H), 5.60 (br s, 1H), 4.20–4.26 (m, 1H), 2.30 (br s,
2H), 2.86–2.89 (br s, 2H), 2.52–2.57 (m, 6H), 2.37 (br s,
1H), 2.19–2.26 (m, 1H), 2.85–2.88 (br s, 2H), 1.02 (t,
J ¼ 7:1 Hz, 6H).

4508
R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4.6.3. (R)-4-(N0-Biphenyl-4-yl-N00-cyanoguanidino)-5-phe-
nyl-pentanoic acid (2-isopropylamino-ethyl)-amide (48).
[(E)-(S)-1-Benzyl-3-(2-isopropylamino-ethylcarbamoyl)-
allyl]-carbamic acid tert-butyl ester. MS (electrospray):
mass calculated for C21H33N3O3, 375.25; m=z found,
6.82 (m, 4H), 6.39 (br s, 1H), 4.12–4.03 (m, 1H), 3.29–
3.23 (m, 2H), 2.78 (d, J ¼ 5:6 Hz, 2H), 2.50 (t,
J ¼ 6:0 Hz, 2H), 2.47–2.43 (m, 4H), 2.31–2.22 (m, 1H),
2.16–2.09 (m, 1H), 1.76–1.69 (m, 6H).
1
376.3 [M+H]þ, 398.3 [M+Na]þ. H NMR (400 MHz,
CD3OD) d 7.16–7.27 (m, 5H), 6.74 (dd, J ¼ 15:3,
5.6 Hz, 1H), 5.97 (d, J ¼ 15:3 Hz, 1H), 4.43 (br s, 1H),
3.36 (t, J ¼ 6:7 Hz, 2H), 2.75–2.89 (m, 3H), 2.69 (t,
J ¼ 6:7 Hz, 2H), 1.36 (s, 9H), 1.05 (d, J ¼ 6:3 Hz, 6H).
4.6.7. (R)-4-{N0-[4-(4-Fluorophenoxy)-phenyl]-N00-cyano-
guanidino}-5-phenyl-pentanoic acid (2-pyrrolidin-1-yl-
ethyl)-amide (52). MS (electrospray): mass calculated
for C31H35FN6O2, 542.28; m=z found, 543.2 [M+H]þ. 1H
NMR (400 MHz, CDCl3) d 7.22–7.90 (m, 11H), 6.81 (d,
J ¼ 8:6 Hz, 2H), 6.43 (br s, 1H), 4.10–4.03 (m, 1H),
3.29–3.19 (m, 2H), 2.76 (d, J ¼ 4:8 Hz, 2H), 2.51 (t,
J ¼ 6:0 Hz, 2H), 2.47–2.41 (m, 4H), 2.30–2.21 (m, 1H),
2.16–2.11 (m, 1H), 1.75–1.68 (m, 6H).
[(R)-1-Benzyl-3-(2-isopropylamino-ethylcarbamoyl)-prop-
yl]-carbamic acid tert-butyl ester.
MS (electrospray): mass calculated for C21H35N3O3,
1
377.27; m=z found, 376.3 [M)H]ꢁ. H NMR (400 MHz,
CDCl3) d 7.95 (s, 1H), 7.31–7.12 (m, 5H), 6.73 (dd,
J ¼ 15:3, 5.6 Hz, 1H), 5.97 (d, J ¼ 15:3 Hz, 1H), 4.43
(m, 1H), 2.94 (s, 2H), 2.95–2.75 (m, 3H), 2.69 (t,
J ¼ 6:4 Hz, 2H), 1.29 (s, 9H,), 1.04 (d, J ¼ 6:4 Hz, 6H).
(R)-4-(N0-Biphenyl-4-yl-N00-cyano-guanidino)-5-phenyl-
pentanoic acid (2-isopropylamino-ethyl)-amide.
4.6.8. (R)-4-[N0-Cyano-N00-(4-p-tolyloxyphenyl)-guanid-
ino]-5-phenyl-pentanoic acid (2-pyrrolidin-1-yl-ethyl)-
amide (53). MS (electrospray): mass calculated for
C32H38N6O2, 538.31; m=z found, 539.3 [M+H]þ. 1H
NMR (400 MHz, CDCl3) d 7.31–7.02 (m, 9H), 6.94–6.89
(m, 4H), 6.52 (br s, 1H), 4.21–4.08 (m, 1H), 3.42–3.26
(m, 2H), 2.81 (d, J ¼ 5:6 Hz, 2H), 2.60 (t, J ¼ 6:0 Hz,
2H), 2.56–2.50 (m, 4H), 2.35 (s, 3H), 2.34–2.29 (m, 1H),
2.25–2.18 (m, 1H), 1.83–1.78 (m, 6H).
MS (electrospray): mass calculated for C30H36N6O,
1
496.66; m=z found, 497.2 [M+H]þ, 519.2 [M+Na]þ. H
NMR (400 MHz, CDCl3) d 7.51–7.44 (m, 4H), 7.39–7.34
(m, 2H), 7.30–7.11 (m, 8H), 6.40 (br s, 1H), 5.29 (br s,
1H), 4.18–4.08 (m, 1H), 3.30–3.23 (m, 2H), 2.83–2.78
(m, 1H), 2.77–2.70 (m, 2H), 2.67 (t, J ¼ 5:8 Hz, 2H),
2.34–2.23 (m, 1H), 2.19–2.12 (m, 1H), 1.80–1.76 (m,
2H), 0.99 (d, J ¼ 6:4 Hz, 6H).
Acknowledgements
The authors would like to thank Drs. Sandra Chaplan
and Nigel Shankley for stimulating discussions.
4.6.4. (R)-4-(N0-Biphenyl-4-yl-N00-cyanoguanidino)-5-phen-
yl-pentanoic acid (2-pyrrolidin-1-yl-ethyl)-amide (49a).
MS (electrospray): mass calculated for C13H36N6O,
References and notes
1
508.66; m=z found, 509.3 [M+H]þ, 531.2 [M+Na]þ. H
NMR (CDCl3, 400 MHz) d 7.57 (br t, J ¼ 9:5 Hz, 5H),
7.46 (br t, J ¼ 7.6 Hz, 2H), 7.13–7.30 (m, 8H), 6.34 (br
s, 1H), 5.36 (br s, 1H), 4.14 (dt, J ¼ 7:3, 7.0 Hz, 1H),
3.24–3.40 (m, 2H), 2.72–2.84 (m, 2H), 2.62 (t,
J ¼ 6:0 Hz, 1H), 2.25 (br s, 4H), 2.28–2.30 (m, 1H),
2.13–2.18 (m, 1H), 1.68–1.80 (m, 6H).
1. (a) Krnjevic, K. Physiol. Rev. 1974, 54, 418; (b) Zafra, F.;
ꢀ
ꢀ
Aragon, C.; Olivares, L.; Danbolt, N. C.; Gimenez, C.;
Storm-Mathisen, J. J. Neurosci. 1995, 15, 3952; (c) Luque,
J. M.; Nelson, N.; Richards, J. G. Neuroscience 1995, 64,
525; (d) Jursky, F.; Nelson, N. J. Neurochem. 1995, 64,
ꢀ
1026; (e) Friauf, E.; Aragon, C.; Lohrke, S.; Westenfelder,
B.; Zafra, F. J. Comp. Neurol. 1999, 412, 17; (f) Aragon
ꢀ
ꢀ
Carmen; Lopez-Corcuera Beatriz Eur. J. Pharm. 2003,
479, 249.
4.6.5. (R)-4-[N0-Cyano-N00-(4-phenoxyphenyl)-guanidino]-
5-phenyl-pentanoic acid (2-pyrrolidin-1-yl-ethyl)-amide
(50). MS (electrospray): mass calculated for C31H36N6-
O2, 524.29; m=z found, 525.3 [M+H]þ. 1H NMR
(400 MHz, CDCl3) d 7.37–7.10 (m, 10H), 7.02 (d,
J ¼ 7:9 Hz, 2H), 6.94 (d, J ¼ 8:7 Hz, 2H), 6.58 (br s,
1H), 4.21–4.08 (m, 1H), 3.39–3.30 (m, 2H), 2.85 (d,
J ¼ 6:4 Hz, 2H), 2.58 (t, J ¼ 6:0 Hz, 2H), 2.53–2.49 (m,
4H), 2.41–2.30 (m, 1H), 2.25–2.18 (m, 1H), 1.84–1.73
(m, 6H).
2. (a) Simpson, R. K.; Gondo, M.; Robertson, C. S.;
Goodman, J. C. Neurochem. Res. 1996, 21, 1221; (b)
Huang, W.; Simpson, R. K. Neurol. Res. 2000, 22, 160; (c)
Caulfield, W. L.; Collie, I. T.; Dickins, R. S.; Epemolu, O.;
McGuire, R.; Hill, D. R.; McVey, G.; Morphy, J. R.;
Rankovic, Z.; Sundaram, H. J. Med. Chem. 2001, 44,
2679; (d) Gomeza, J.; Ohno, K.; Betz, H. Curr. Opin. Drug
Discovery Dev. 2003, 6, 675.
3. Examples of other GlyT-2 medicinal chemistry programs:
(a) Ho, K. K.; Appell, K. C.; Baldwin, J. J.; Bohnstedt, A.
C.; Dong, G.; Guo, T.; Horlick, R.; Islam, K. R.; Kultgen,
S. G.; Masterson, C. M.; McDonald, E.; McMillan, K.;
Morphy, J. R.; Rankovic, Z.; Sundaram, H.; Webb, M.
Bioorg. Med. Chem. Lett. 2004, 14, 545; (b) Isaac, M.;
Abdelmalik, S.; Da Silva, K.; Arora, J.; MacLean, N.;
Hung, B.; McCallum, K. Bioorg. Med. Chem. Lett. 2001,
11, 1371; (c) Caufield, W. L.; Collie, I. T.; Dickins, R. S.;
Epemolu, O.; McGuire, R.; Hill, D. R.; McVey, G.;
4.6.6. (R)-4-{N0-[4-(4-Chlorophenoxy)-phenyl]-N00-cyano-
guanidino}-5-phenyl-pentanoic acid (2-pyrrolidin-1-yl-
ethyl)-amide (51). MS (electrospray): mass calculated
for C31H35ClN6O2, 558.25; m=z found, 560.3 [M+H]þ.
1H NMR (400 MHz, CDCl3) d 7.23–7.10 (m, 9H), 6.88–

R. L. Wolin et al. / Bioorg. Med. Chem. 12 (2004) 4493–4509
4509
Morphy, R.; Rankovic, Z.; Sundaram, H. J. Med. Chem.
2001, 44, 2679.
C.; Richardson, R. S.; Roberts, E. Eur. J. Med. Chem.
1993, 28, 47.
ꢀ
4. Wolin, R. L.;Venkatesan, H.; Tang, L.; Santillan, A., Jr.;
8. The amines used were: N,N-dimethylethylenediamine,
N,N-diethylethylenediamine, N-isopropylethylenediamine
and 1-(2-aminoethyl)pyrrolidine.
9. Basha, A.; Lipton, M.; Weinreb, S. M. Tetrahedron Lett.
1977, 4171.
10. (a) Still, W. C.; Gennari, C. Tettrahedron Lett. 1983, 24,
4405; (b) Ando, K.; Oishi, T.; Hirama, M.; Ohno, H.;
Ibuka, T. J. Org. Chem. 2000, 65, 4745.
11. Masereel, B.; Wouters, J.; Pochet, L.; Lambert, D. J. Med.
Chem. 1998, 41, 3239.
Barclay, T.; Wilson, S.; Lee, D. H.; Lovenberg, T. W. Part
1 of 2 for this series, Bioorg. Med. Chem. 2004, 12, see
doi:10.1016/j.bmc.2004.05.042.
5. The commercial availability of starting materials dictated,
which route (A or B) was employed.
6. (a) Atwal, K. S.; Grover, G. J.; Ahmed, S. Z.; Sleph,
P. G.; Dzwonczyk, S.; Baird, A. J.; Normandin, D. E.
J. Med. Chem. 1995, 38, 3236; (b) Atwal, K. S.; Ahmed, S.
Z.; O’Reilly, B. C. Tetrahedron Lett. 1989, 30,
7313.
12. Lovenberg, T. W.; Roland, B. L.; Wilson, S. J.; Xiaoxia,
J.; Pyati, J.; Huvar, A.; Jackson, M. R.; Erlander, M. G.
Mol. Pharm. 1999, 55, 1101.
7. Boden, P. R.; Eden, J. M.; Higginbottom, M.; Hill, D. R.;
Horwell, D. C.; Hunter, J. C.; Martin, K.; Pritchard, M.