Discovery of novel N-phenylglycine derivatives as potent and selective β3-adrenoceptor agonists for the treatment of frequent urination and urinary incontinence

Article abstract of DOI:10.1021/jm000455z

With a novel assay using isolated ferret detrusor to estimate β₃-adrenoceptor agonistic activity, we found that a series of glycine derivatives of ritodrine, a β₂-adrenoceptor agonist, are potent β₃-adrenoceptor agonists,

Full text of DOI:10.1021/jm000455z

1436
J . Med. Chem. 2001, 44, 1436-1445
Discover y of Novel N-P h en ylglycin e Der iva tives a s P oten t a n d Selective
â3-Ad r en ocep tor Agon ists for th e Tr ea tm en t of F r equ en t Ur in a tion a n d Ur in a r y
In con tin en ce
Nobuyuki Tanaka,* Tetsuro Tamai, Harunobu Mukaiyama, Akihito Hirabayashi, Hideyuki Muranaka,
Satoshi Akahane, Hiroshi Miyata, and Masuo Akahane
Central Research Laboratory, Kissei Pharmaceutical Company Ltd., 4365-1, Hotaka, Nagano 399-8304, J apan
Received October 24, 2000
With a novel assay using isolated ferret detrusor to estimate â3-adrenoceptor agonistic activity,
we found that a series of glycine derivatives of ritodrine, a â2-adrenoceptor agonist, are potent
â3-adrenoceptor agonists, with excellent selectivity versus â1 and â2 subtypes. Substitution of
halogens in the phenyl ring increased potency and selectivity for the â3-adrenoceptor, and this
was dependent upon the position of the halogens. The chlorine-substituted derivatives 3f-i
exhibited potent â3-adrenoceptor-mediated relaxation of ferret detrusor (EC50 ) 0.93, 11, 14,
and 160 nM) and higher potency at â3-adrenoceptors than at â1 or â2. The intravenous
administration of 3h significantly reduced the urinary bladder pressure in anesthetized male
rats (ED50 ) 48 µg/kg) without cardiovascular side effects. This article is the first report of
structure-activity relationships (SAR) concerning â3-adrenoceptor agonists as agents for the
treatment of urinary frequency and incontinence.
In tr od u ction
In 1984, â3-adrernergic receptors (AR) were proposed
as a third group of â-ARs in addition to the â1- and â2-
ARs found in rat adipose tissue utilizing various
â-agonists.1-4 In 1989, the primary structure of the â3-
AR was identified and characterized using cloning and
molecular pharmacological techniques.5-7 â3-ARs are
G-protein-linked receptors. Like other â-ARs, it has a
seven transmembrane-spanning structure and plays a
significant role in regulating lipolysis and thermogen-
esis in rodent and human adipose tissue. Moreover,
studies of â3-AR mRNA demonstrated that â3-ARs exist
in the human heart, gall bladder, gastrointestinal (GI)
tract, and prostate in addition to adipocytes.8 These
F igu r e 1. â2- and â3-AR agonists for clinical or research use.
aThe R* and S* in parentheses indicate the relative configu-
findings encouraged us to look for potent â3-AR agonists
to treat various metabolic and gastrointestinal diseases,
such as obesity, diabetes, and irritable bowel syndrome.2
Recently, it has been suggested that â3-ARs exist in the
human detrusor and its relaxation is mediated mainly
via â3-ARs.9-12 In the urinary bladder, urine storage on
a peripheral receptor level is controlled by â3-ARs, which
accept signals from sympathetic nerves in the human
detrusor. Therefore, we thought that potent, selective
â3-AR agonists might provide a new approach for the
treatment of urinary bladder dysfunction, such as
urinary frequency and incontinence. Although a number
of antimuscarinic drugs are widely prescribed for such
diseases,13 their antimuscarinic activity has unaccept-
able side effects, such as dry mouth and constipation.
In addition, antimuscarinic drugs are contraindicated
in patients with urinary retention, because they inhibit
the micturation pressure. It is noteworthy that â3-AR
agonists do not possess such adverse effects. However,
if â3-AR activity cannot be separated from â1- and â2-
b
ration of the hydroxy and methyl groups. The R in parenthe-
ses indicates the absolute configuration of the hydroxy and
methyl groups.
AR activity, â3-AR agonists would have unfavorable
effects, such as tachycardia or tremor. To find drugs
without such adverse effects, this study evaluated the
â3-AR activity of compounds using the ferret detrusor
in a novel assay.14 We also examined â1- and â2-AR
agonistic activity using rat atria and uteri.
First, we evaluated some â-AR agonists that are used
clinically or preclinically. As shown in Table 2, isopro-
terenol (a nonselective â-AR agonist), ritodrine15 (a â2-
AR agonist), and CL31624316 (a â3-AR agonist) relax the
ferret detrusor via â3-AR activation.14 BRL373443,17 (a
â3-AR agonist) produced the greatest relaxation and full
agonistic activity. In comparison, the N-phenylglycine
derivatives (3) produced sufficient detrusor-relaxation
mediated via â3-AR and exhibited â3-AR selectivity
against effects mediated via â1- and â2-AR. Moreover,
most of them behaved as full agonists (80-100% maxi-
mum response relative to isoproterenol). Thus, the
N-phenylglycine derivatives 3 appear to be a new class
* To whom correspondence should be addressed. Tel:
+81-263-82-8820. Fax: +81-263-82-8827. E-mail: nobuyuki•tanaka@
pharm.kissei.co.jp.
10.1021/jm000455z CCC: $20.00 © 2001 American Chemical Society
Published on Web 04/03/2001

Novel N-Phenylglycine Derivatives
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9 1437
Sch em e 1. General Method for Compounds 3a
ethyl alcohols described above were substituted by
bromine using Ph3P and CBr4 to give the phenethyl
bromide intermediates.
As mentioned above, N-(2-chlorophenyl)glycine de-
rivatives 2f,g cannot be synthesized in the same manner
as the others, since selective N-monoalkylation of the
2-chloroaniline derivatives 919 with ethyl 2-bromo-
acetate was not possible. This failure was assumed to
be caused by similar alkylation rates for N-monoalky-
lation and N,N-dialkylation leading to N,N-dialkylation.
In fact, this reaction consumed few 2-chloroaniline
derivatives while using ethyl 2-bromoacetate in an
amount equivalent to 9 and afforded only N,N-dialky-
lated aniline derivatives when using ethyl 2-bromo-
acetate in an amount exceeding twice the equivalent to
9. Nagaraj et al. reported that 2-substituted anilines,
particularly 2-chloro or 2-nitroaniline, are more liable
to undergo N,N-diacetylation to give the N-phenyldi-
acetamide derivative than unsubstituted ones.20 They
assumed that the facility of N,N-dialkylation is deter-
mined by the inductive and steric effects of the substit-
uents at the ortho-position on the aniline. This hypoth-
esis might also hold in our case of N-alkylation, although
the reaction type is quite distinct from N-acylation.
Therefore, we planned to improve the N-monoalkylation
via trifluoroacetoanilide (10) as shown in Scheme 3.
Acidic protection of the hydroxy group of 9 with dihydro-
2H-pyran (DHP) followed by regioselective acylation
with trifluoroacetoanhydride gave the trifluoroaceto-
anilide (10). N-Alkylation via a metal salt of the amide
10 with sodium hydride gave 11. Cleavage of the
trifluoroacetyl group under alkaline conditions and
cleavage of the THP group with p-TsOH followed this.
The hydroxy group was finally replaced by bromine
using Ph3P and CBr4 to give the desired intermediates
2f,g.
a
Reagents: (a) DIPEA; (b) aq NaOH.
of â3-AR agonist that might be useful for the treatment
of urinary diseases, such as urinary frequency and
incontinence, without undesirable side effects. The
synthesis of these compounds (3) and the results of in
vitro and in vivo assays are described in detail in the
following sections.
Ch em istr y
The N-phenylglycine derivatives 3 described herein
(Table 1) were prepared from 4′-hydroxynorephedrine
(1) and the correctly substituted aminophenethyl bro-
mide (2) via the corresponding esters, followed by
saponification, as illustrated in Scheme 1. Optically
active 4′-hydroxynorephedrine (1) was obtained by opti-
cal resolution of its commercially available racemate
using L-tartaric acid.18
The aminophenethyl bromide (2) incorporated glycine
moieties were generally synthesized as shown in Scheme
2 except for the N-(2-chlorophenyl)glycine derivatives
2f,g. The 4′-aminophenethyl derivatives 4a -c were
converted into the corresponding glycine ester analogues
2a and 5b,c by N-alkylation using ethyl 2-bromoacetate.
These were then halogenated using N-halosuccinimide
or hypochlorite esters to give the dichloroaniline deriva-
tives (6 from 5b; 2j,k from 2e following bromination of
5c), mono- and dibromo derivatives (2l,m from 2a ), and
monoiodo derivative (2n from 2a ). N-Phenylglycine
analogues (7, 8b-d ) bearing methyl or benzyl groups,
or acetate on nitrogen, were derived using alkylating
agents, such as iodomethane, benzyl bromide, and ethyl
2-bromoacetate. The hydroxy groups of all of the phen-
The synthesis of the isobutyrate intermediates 2o,p
was investigated in a manner similar to the preparation
of 2-phenoxyisobutyrate such as fibrates,21 which are
agents used to treat hyperlipidemia (Scheme 4). Fol-
lowing protection of the hydroxyl group of the nitroben-
zene derivatives 13a ,b, the O-protected compounds
14a ,b were obtained by reduction with zinc followed by
treatment with 1,1,1-trichloro-2-methyl-2-propanol (Chlo-
reton) to carry out the conversion to N-phenylamino-
isobutyric acid.22 Esterification with simultaneous cleav-
Sch em e 2. Synthesis of Intermediates 2a
a
Reagents: (a) ethyl 2-bromoacetate, K2CO3; (b) NCS; (c) MeI, K2CO3; (d) alkyl halide, K2CO3; (e) Ph3P, CBr4; (f) NBS or NIS; (g)
tert-butyl hypochlorite.

1438 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9
Tanaka et al.
Ta ble 1. Structures and Physical Data of the N-Phenylglycine Derivatives 3
compd
R1
R2
R3
R
n
formula
MW
anal.a
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
3o
3p
H
H
H
H
Cl
H
H
H
H
Cl
Cl
H
H
H
H
Cl
H
H
H
H
H
H
H
Cl
Cl
Cl
H
Br
H
H
H
H
H
H
H
H
H
CH3
1
1
2
1
1
1
1
1
1
1
1
1
1
1
0
0
C19H24N2O4‚1.3H2O
C20H26N2O4‚0.3H2O
367.8
363.8
406.1
443.5
405.9
378.9
436.1
431.3
454.4
413.3
422.3
529.2
450.3
488.3
390.5
406.9
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
b, d
C, H, N
C, H, N
c, d
C, H, N
C, H, N
C, H, N
C, H, N
C, H, N
c, d
C
C
C
C
21H26N2O6‚0.2H2O
26H30N2O4‚0.5H2O
19H23ClN2O4‚1.5H2O
19H23ClN2O4
Bn
H
H
CH3
H
CH3
H
H
H
H
H
H
Cl
Cl
Cl
Cl
H
Cl
Br
Br
I
C20H25ClN2O4‚2.4H2O
C
19H22Cl2N2O4‚H2O
C20H24Cl2N2O4‚1.5H2O
C
C
C
19H22Cl2N2O4
19H22Cl2N2O4‚0.5H2O
19H22Br2N2O4‚1.5H2O
C19H23BrN2O4‚1.5H2O
C19H23IN2O4‚H2O
H
H
C(CH3)2CO2H
C(CH3)2CO2H
C21H28N2O4‚H2O
C21H27ClN2O4
a
b
Elemental analyses were within (0.4% of the theoretical values. Anal. C, N; H: found 6.31, calcd 6.89. c Elemental analysis not
d
performed. The chemical purity determined by HPLC was more than 96%.
Sch em e 3. Synthesis of Intermediates 2a
detrusor is mediated via â3-AR, as in the human
detrusor.14 Therefore, in this study, we used a ferret
detrusor preparation to estimate the â3-AR agonistic
activity. The activities of â1- and â2-AR were evaluated
using rat atria or uteri, respectively, according to the
usual method. Table 2 summarizes the results of the in
vitro assays of all of our compounds.
The glycine derivative 3a of ritodrine possessed potent
â3-AR agonistic activity (EC50 ) 24 nM) and selectivity
over the â1- and â2-AR agonist activity (â1/â3 ) 54-fold
and â2/â3 ) 27-fold). Introduction of a methyl group on
the nitrogen of the glycine moiety of 3a slightly de-
creased the efficacy for all â-ARs (3b) and also slightly
altered the selectivity for â3-AR (â1/â3 ) 65-fold and â2/
â3 ) 31-fold), even though the â3 potency was reduced.
In contrast, the N-benzylglycine derivative 3d had
marked enhancement of all â-AR agonistic activity.
Thus, 3d had twice the â3-AR agonistic activity of 3a
(EC50 ) 13 nM) but had low selectivity over the â1- and
â2-AR agonistic activity (â1/â3 ) 12-fold and â2/â3 ) 19-
fold). However, replacement of the N-benzyl group with
a carboxymethyl group (3c) significantly lowered all
â-AR agonistic activity. The 2-aminoisobutyric acid
derivative 3o, with a geminal methyl group on the R
carbon atom of the glycine moiety, had similar â3-AR
potency (23 nM) and higher selectivity (â1/â3 and â2/â3
) 478-fold) in comparison with 3a . These initial studies
suggested that substitution of methyl groups on the
glycine moiety significantly increased the selectivity for
â3-AR, due to a decrease in the â1- and â2-AR agonistic
activity, even when these compounds produced a modest
agonistic effect on â3-AR.
a
Reagents: (a) TFAA, TEA; (b) DHP, PPTS; (c) ethyl 2-bro-
moacetate, NaH; (d) TsOH; (e) K2CO3; (f) MeI, K2CO3; (g) Ph3P,
CBr4.
Sch em e 4. Synthesis of Intermediates 2a
a
Reagents: (a) MOMCl, DIPEA; (b) 3% Pt-C, H2; (c) chloretone,
KOH; (d) SOCl2, EtOH; (e) Ph3P, CBr4.
age of the protective group, and further bromination of
15a ,b as described above, gave the phenethyl bromide
bearing the aminoisobutyrate moiety (2o,p ).
Next, we investigated the effect of halogen substitu-
tion on the phenyl ring for â3-AR agonistic activity and
selectivity. The substitution of halogens, electron-
withdrawing groups, changed the potency and selectiv-
ity significantly. These changes were dependent upon
the position of the halogen substituents in the phenyl
ring, i.e., ortho- or meta-sites or both. The best rationale
for the SAR for the halogen substituent position is found
Resu lts a n d Discu ssion
â3-AR agonists are reported to produce concentration-
dependent relaxation of rat, canine, and human detru-
sor.23 Moreover, we found that relaxation of the ferret

Novel N-Phenylglycine Derivatives
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9 1439
Ta ble 2. â-AR Agonistic Activity and Selectivity of the N-Phenylglycine Derivatives 3
â1 â2
-log EC20 ( SE (EC20: nM)a -log IC50 ( SE (IC50: nM)b -log EC50 ( SE (EC50: nM)c IAd
â3
â3-AR selectivitye
compd
â1/â3
â2/â3
3a
3b
3c
3d
3e
3f
5.89 ( 0.21
(1300)
5.47 ( 0.14
(3400)
4.57 ( 0.11
(27000)
6.82 ( 0.06
(150)
6.96 ( 0.06
(110)
5.57 ( 0.05
(2700)
4.60 ( 0.19
(25000)
4.54 ( 0.13
(29000)
6.19 ( 0.14
(650)
5.80 ( 0.23
(1600)
6.55 ( 0.19
(280)
6.60 ( 0.02
(250)
7.21 ( 0.16
(62)
5.48 ( 0.13
(3300)
7.62 ( 0.23
(24)
7.28 ( 0.22
(52)
6.08 ( 0.12
(840)
7.89 ( 0.25
(13)
8.14 ( 0.20
(7.2)
9.03 ( 0.13
(0.93)
7.96 ( 0.18
(11)
7.85 ( 0.10
(14)
6.80 ( 0.23
(160)
6.34 ( 1.04
(460)
7.21 ( 0.17
(62)
7.09 ( 0.35
(81)
6.24 ( 0.14
(570)
6.09 ( 0.15
(820)
7.64 ( 0.10
(23)
8.25 ( 0.13
(5.6)
0.82
0.88
0.79
0.92
0.97
54
27
65
32
12
15
31
0.33
19
8.6
0.88 2903
0.99 2273
0.85 2071
0.84 >625
3548
>9091
1000
3g
3h
3i
4 >
(>100000)
4.85( 0.20
(14000)
4 >
4 >
>625
(>100000)
6.82 ( 0.05
(150)
(>100000)
5.77 ( 0.33
(1700)
3j
0.84
0.83
0.83
0.76
0.70
0.74
0.95
0.83
0.77
0.96
0.99
0.33
3.7
3k
3l
5.89 ( 0.03
(1300)
4.72 ( 0.06
(19000)
5.10 ( 0.09
(8000)
5.27 ( 0.19
(5400)
4.96 ( 0.16
(11000)
6.59 ( 0.0.06
(260)
6.80 ( 0.10
(160)
4.77 ( 0.07
(17000)
5.89 ( 0.20
(1300)
5.59 ( 0.06
(2600)
5.85 ( 0.06
(1400)
5.66 ( 0.15
(2200)
4.96 ( 0.01
(11000)
5.85 ( 0.20
(1400)
7.62 ( 0.07
(24)
5.01 ( 0.09
(9700)
21
235
14
21
32
3m
3n
3o
3p
2.5
2.7
478
250
0.13
388
4.14
6.6
478
46
ritodrine
6.72 ( 0.10
(190)
7.60 ( 0.17
(25)
8.66 ( 0.08
(2.2)
7.06 ( 0.11
(87)
0.84
CL316243
BRL37344
isoproterenol
680
55
6.92 ( 0.04
(120)
9.82 ( 0.08
(0.15)
8.04 ( 0.10
(9.1)
10.0 ( 0.03
(0.1)
0.002
0.001
a
b
In parentheses is the EC20 value (nM), the mean concentration required to increase 20 beats/minute in the rat atria (n g 3). In
parentheses is the IC50 value (nM), the mean concentration required to produce 50% inhibition of uterine contraction in the rat uterus
(n g 3). c In parentheses is the EC50 value (nM), the mean concentration required to produce 50% relaxation of detrusor before the addition
of the compound in the ferret detrusor (n g 3). Intrinsic activity (IA) given as a ratio of the maximum stimulation with forskolin (10-5
d
M). e The selectivity is the concentration ratio of â3 (EC50) to â1 (EC20) or â2 (IC50) for each drug.
in the chlorine-substituted compounds. Ortho-substitu-
tion of chlorine in 3a (3f) enhanced the â3-AR potency
(EC50 ) 0.93 nM) and selectivity (â1/â3 ) 2900-fold and
â2/â3 ) 3540-fold). On the other hand, the meta-
substituted compound 3e was less selective for â3-AR
than the ortho-chloride 3f, since meta-substitution
enhanced the agonistic activities for all the â-ARs.
Substitution of chlorine into the phenyl ring of 3a at
both ortho-positions (3h ), i.e., 2,6-dichloro substitution,
also increased the potency and selectivity, while 3h had
a 15-fold lower â3-AR potency (EC50 ) 14 nM) and lower
selectivity over the â1- and â2-AR agonistic activity by
1.4- and 3.6-fold, respectively, than the monochloride
3f. In contrast, the 2,5-dichloro substitution (3k ) only
slightly altered the â-AR agonistic activity of 3a ,
presumably due to the counteracting effect of the
chlorine at each position. In fact, the selectivity of 3k
was similar to that of 3a . The 2,3-dichloro substitution
(3j) unexpectedly increased the â1-AR agonistic activity
rather than that of â2- or â3-AR. The results of substi-
tuting chlorines in the phenyl ring indicated that to
improve the potency and selectivity of a â3-AR agonist
requires mono- or disubstitution of a halogen at the
ortho-position rather than at the meta-position.
The bromine- and iodine-substituted compounds 3l-n
were also â3-AR agonists that reduced the â1- and â2-
AR agonistic activities of 3a . It should be noted that
the dibromo-substituted compound 3l retained a high
selectivity (â1/â3 ) 235-fold and â2/â3 ) 32-fold) for â3-
AR. Thus, their profiles had a similar trend to those of
the chlorine-substituted compounds. The rank order of
â3-AR agonistic potency of monohalogen-substituted
compounds was chlorine 3f (EC50 ) 0.93 nM) > bromine
3m (EC50 ) 570 nM) > iodine 3n (EC50 ) 820 nM). This
suggested that the larger the atomic nucleus of the
halogen substituted in the phenyl ring of 3a , the less
potent the â3-AR agonistic activity induced.
Based on this evidence, particularly the enhancement
of the â3-AR agonistic activity by appropriate chlorine
substitution and of â3-AR selectivity by methyl substitu-
tion on the glycine moiety, further optimization was
carried out by introducing chlorine into the methyl-
substituted glycine analogues (3b,o). Mono- and dichloro
substituents at the ortho-positions (3g,i) altered the â3-

1440 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9
Tanaka et al.
Ta ble 3. Comparing 3h and Isoproterenol Application in the
Rat
in vitro
rat detrusor ferret detrusor
in vivo
rat (iv)
compd
-log EC50 ( SEa -log EC50 ( SEa ED50 (µg/kg)b
3h
6.72 ( 0.02 (190) 7.85 ( 0.10 (14)
7.06 ( 0.11 (87)
48
0.60
isoproterenol 8.00 ( 0.01 (10)
a
b
See footnote c in Table 2. ED50 is the mean dose required to
lower the intrabladder pressure of an anesthetized rat by 50% over
that before drug administration (n g 3). Since the ED50 value was
read from a plot of the dose-response curve that is multiplicate,
it is not meaningful to assign standard error to it.
AR agonist activity of 3b 2.2- and 0.15-fold, respectively.
Interestingly, both compounds showed weak potency for
both â1- and â2-ARs. Therefore, the selectivity for â3-
AR was greatly improved by the chloro substituent as
compared to 3b. Second, monochloro substituents at the
meta-position (3p ) increased the agonistic activities of
all the â-ARs (â3: EC50 ) 5.6 nM) as compared to 3o,
so that there was little improvement in selectivity for
â3-AR activity over â1- and â2-AR activity. Simple
monochloro substitution at the ortho-position improved
both â3-AR activity and selectivity.
Next, we attempted to evaluate the effect of these
compounds on intrabladder pressure in anesthetized
rats. Compound 3h , which had one of the best profiles
overall, was selected for this examination, because the
synthesis of 3h was comparatively facile. Relaxation of
the rat urinary bladder is mediated via both â2- and â3-
ARs.23 Therefore, we confirmed the potency of compound
3h in isolated rat detrusor preparations before conduct-
ing in vivo experiments. As shown in Table 3 and Figure
2a, the EC50 of 3h in rat detrusor was 190 nM, and
isoproterenol exhibited 19 times more potent relaxing
activity than 3h . In vivo, 3h sufficiently lowered the
intrabladder pressure (ED50 ) 48 µg/kg) and the potency
of isoproterenol was 80 times higher than that of 3h .
On the other hand, 3h had no effects on heart rate or
blood pressure, while isoproterenol elicited a significant
increase in heart rate and lowering of blood pressure,
as shown in Figure 2b,c. These results were due to high
selectivity for â3-AR, indicating that 3h was a potent,
selective â3-AR agonist that reduced the urinary bladder
pressure without cardiovascular side effects, which are
mediated by â1- and â2-AR.
In conclusion, a series of glycine-modified ritodrine
was synthesized, and their â3-AR activity was estimated
in a novel functional assay using the ferret detrusor.
Replacement of the phenolic hydroxy group on ritodrine
with glycine enhanced both â3-AR potency for ferret
detrusor relaxation and selectivity over â1- and â2-AR.
Additionally, mono- or disubstitution of chlorine at the
ortho-position improved both the â3-AR activity and
selectivity. In vitro results demonstrated that ortho-
chloro-substituted compounds with or without N-methyl
substituents (3f-i) exhibited the best full agonistic
activity and selectivity for â3-AR. The in vivo result for
the glycine analogue 3h , a representative of this series,
reflected the in vitro result; namely, 3h lowered the
intrabladder pressure of anesthetized rats without
cardiovascular side effects due to â1- or â2-AR mediation.
Moreover, 3h showed nearly full agonistic activity to
Chinese hamster ovary cells expressing the cloned
human â3-AR (data not shown). The discovery of these
F igu r e 2. Time course of intravesical pressure (a), heart rate
(b), and blood pressure (c) in anesthetized rats after admin-
istration of iv saline (1 mL/kg), isoproterenol (10 µg/g), and
3h (1 µg, 10 µg, 0.1 mg, 1.0 mg) (n ) 3). Intravesical pressure
(a) is expressed as a percentage of the maximal relaxation with
isoproterenol at 2 min. Heart rate (b) is expressed as the
difference from the value before drug administration. Blood
pressure (c) is expressed as a percentage of the value before
drug administration.
compounds (3), which are novel selective â3-AR agonists,
is expected to provide impetus for developing a new
approach in the field of urology. Encouraged by these
findings, we are continuing to examine the toxicology,
pharmacodynamics, and pharmacokinetics of these
compounds in several species in the hope of finding
useful drugs for the treatment of frequent urination and
urinary incontinence.
Exp er im en ta l Section
Gen er a l Meth od s. Melting points were taken on a Yanaco
MP-3S Micro melting point apparatus and are uncorrected.
Infrared spectra were measured on a Nicolet 510 FT-IR
spectrophotometer and are reported in reciprocal centimeters.
Proton NMR spectra were recorded at 400 or 500 MHz with a
Bruker AMX 400 or DRX 500 instrument, and chemical shifts
are reported in parts per million (δ) downfield from tetram-
ethylsilane as the internal standard. The peak patterns are
shown as the following abbreviations: br ) broad, d ) doublet,
m ) multiplet, s ) singlet, t ) triplet, q ) quartet. The mass
spectra (MS) and high-resolution mass spectra (HRMS) were
carried out with a J EOL J MS-SX102A mass spectrometer with
capabilities for fast atom bombardment. Elemental analyses

Novel N-Phenylglycine Derivatives
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9 1441
were performed by the Yanaco CHN corder MT-5 analyzer.
The analytical results obtained were within (0.4% of the
theoretical values, unless otherwise stated. Silica gel 60 F254
precoated plates on glass from Merck KGaA or aminopropyl
silica gel (APS) precoated NH TLC from Fuji Silysia Chemical
Ltd. was used for thin-layer chromatography (TLC). Flash or
medium-pressure liquid column chromatography (MPLC) was
performed on silica gel BW-350 (particle size 25-44 µm) from
Fuji Silysia Chemical Ltd. or APS Daisogel IR-60 (particle size
25-40 µm) from Daiso Co., Ltd. Analytical HPLC was run on
a Shimadzu LC-VP instrument, equipped with an Inertsil
ODS-3, 5 µm, 4.6 × 250 mm column under two elution
conditions: (a) a gradient (MeCN in 0.02 M H3PO4): 10 min
(17.0%), 10-30 min (17-50%), 30-40 min (50%); (b) an
isocratic condition in 0.02 M H3PO4 containing a specified
concentration of MeCN, flow rate ) 1.0 mL/min, λ ) 225 nm.
The column temperature was maintained at 40 °C. All of the
reported purities were over 96%, unless otherwise stated. All
reagents and solvents were commercially available unless
otherwise indicated. Yields were not optimized.
4-(2-Br om oeth yl)a n ilin e Hyd r obr om id e (4a ). 4-Amino-
phenethyl alcohol (4b) (25 g, 0.18 mol) was dissolved in 48%
HBr (250 mL), and the mixture was heated under reflux for 4
h with stirring. After cooling, collection of the resulting
precipitates by filtration gave 30.3 g (59%) of 4a as a white
solid: mp 204-206 °C; IR (KBr) 2849, 2564, 1916, 1614, 1570,
1503; 1H NMR (DMSO-d6) δ 3.15 (2H, t, J ) 7.0 Hz), 3.74 (2H,
t, J ) 7.0 Hz), 7.25 (2H, d, J ) 8.0 Hz), 7.38 (2H, d, J ) 8.0
Hz), 9.70 (2H, br).
Eth yl N-[3-Ch lor o-4-(2-h yd r oxyeth yl)p h en yl]a m in oa c-
eta te (5c). The title compound was prepared from 4c by
similar method described in 5b and purification by MPLC on
silica gel (eluent: hexane/EtOAc ) 2/1) to give 5c as a white
solid: mp 69-71 °C; IR (KBr) 3384, 3331, 2936, 1730, 1614,
1515; 1H NMR (CDCl3) δ 1.30 (3H, t, J ) 7.2 Hz), 1.40 (1H, t,
J ) 6.3 Hz), 2.90 (2H, t, J ) 6.3 Hz), 3.81 (2H, q, J ) 6.3 Hz),
3.86 (2H, d, J ) 5.2 Hz), 4.25 (2H, q, J ) 7.2 Hz), 4.28-4.32
(1H, m), 6.47 (1H, dd, J ) 8.1, 2.5 Hz), 6.62 (1H, d, J ) 2.5
Hz), 7.06 (1H, d, J ) 8.1 Hz).
E t h yl N-[2,6-Dib r om o-4-(2-b r om oet h yl)p h en yl]a m i-
n oa ceta te (2l). To a stirred solution of 2a (515 mg, 1.80 mmol)
in MeCN (3.6 mL) were added concentrated HCl (150 µL) and
N-bromosuccinimide (641 mg, 3.60 mmol) under ice-cooling,
and the mixture was stirred for 1 h. EtOH (3.6 mL) was added
to the reaction mixture, and the mixture was stirred for 30
min under ice-cooling. 0.4 M aqueous Na2S2O3 (9.0 mL) was
added, and the mixture was stirred for 1 h under ice-cooling.
The reaction mixture was diluted with water and extracted
with EtOAc. The extract was washed with brine and dried over
anhydrous MgSO4, and the solvent was removed in vacuo.
Purification of the residue by MPLC on silica gel (eluent:
hexane/EtOAc ) 6/1) gave 799 mg (100%) of 2l as a pale yellow
oil: 1H NMR (CDCl3) δ 1.29 (3H, t, J ) 7.1 Hz), 3.03 (2H, t, J
) 7.4 Hz), 3.50 (2H, t, J ) 7.4 Hz), 4.12 (2H, d, J ) 5.7 Hz),
4.24 (2H, q, J ) 7.1 Hz), 4.78 (1H, t, J ) 5.7 Hz), 7.32 (2H, s).
Eth yl N-[2-Br om o-4-(2-br om oeth yl)p h en yl]a m in oa c-
eta te (2m ). The title compound was prepared by similar
method described in 2l using a molar equivalent of N-
bromosuccinimide to 2a and purification by MPLC on silica
gel (eluent: hexane/EtOAc ) 6/1) as a pale yellow oil: 1H NMR
(CDCl3) δ 1.30 (3H, t, J ) 7.1 Hz), 3.03 (2H, t, J ) 7.6 Hz),
3.49 (2H, t, J ) 7.6 Hz), 3.93 (2H, s), 4.26 (2H, q, J ) 7.1 Hz),
4.90 (1H, br s), 6.46 (1H, d, J ) 8.2 Hz), 7.03 (1H, dd, J ) 2.0,
8.2 Hz), 7.31 (1H, d, J ) 2.0 Hz).
Eth yl N-[4-(2-Br om oeth yl)-2-iod op h en yl]a m in oa ceta te
(2n ). The title compound was prepared by similar method
described in 2l using a molar equivalent of N-iodosuccinimide
to 2a and purification by MPLC on silica gel (eluent: hexane/
EtOAc ) 9/1) as a white solid: mp 70-72 °C; 1H NMR (CDCl3)
δ 1.31 (3H, t, J ) 7.1 Hz), 3.01 (2H, t, J ) 7.6 Hz), 3.48 (2H,
t, J ) 7.6 Hz), 3.92 (2H, d, J ) 5.3 Hz), 4.26 (2H, q, J ) 7.1
Hz), 4.75-4.85 (1H, m), 6.39 (1H, d, J ) 8.2 Hz), 7.06 (1H, dd,
J ) 1.9, 8.2 Hz), 7.54 (1H, d, J ) 1.9 Hz).
4′-Am in o-2′-ch lor op h en eth yl Alcoh ol (4c). To a solution
of 2-chloro-4-nitrophenethyl alcohol24 (770 mg, 3.82 mmol) in
HOAc (40 mL) was added concentrated HCl (0.67 mL, 8.0
mmol) at room temperature. While the mixture was vigorously
stirred, zinc powder (2.62 g, 40.0 mmol) was added. The
resulting suspension was stirred for 5min and diluted with
water (40 mL) followed by filtration to remove the zinc powder.
The filtrate was concentrated in vacuo and the residue was
basified with saturated aqueous NaHCO3, and extracted with
EtOAc. The extract was washed with brine, dried over
anhydrous MgSO4, and concentrated in vacuo to give 530 mg
(81%) of 4c as a light brown oil: IR (neat) 3343, 2953, 2884,
1
1724, 1620, 1501; H NMR (CDCl3) δ 1.36 (1H, br), 2.90 (2H,
t, J ) 6.7 Hz), 3.64 (2H, br), 3.82 (2H, t, J ) 6.7 Hz), 6.53 (1H,
dd, J ) 8.1, 2.5 Hz), 6.71 (1H, d, J ) 2.5 Hz), 7.03 (1H, d, J )
8.1 Hz).
Eth yl N-[2,6-Dich lor o-4-(2-h yd r oxyeth yl)p h en yl]a m i-
n oa ceta te (6). The title compound was prepared from 5b
instead of 2a by similar method described in 2l using tert-
butyl hypochlorite instead of N-bromosuccinimide and puri-
fication by MPLC on silica gel (eluent: hexane/EtOAc ) 3/1)
Eth yl N-[4-(2-Br om oeth yl)p h en yl]a m in oa ceta te (2a ).
To a solution of 4a (9.15 g, 32.6 mmol) in DMF (65 mL) were
added K2CO3 (4.95 g, 35.8 mmol) and ethyl bromoacetate (3.97
mL, 35.8 mmol), and the mixture was stirred for 36 h at room
temperature. The reaction mixture was poured into ice water,
and collection of the resulting precipitates by filtration gave
8.39 g (90%) of 2a as a yellow solid: mp 66-68 °C; IR (KBr)
1
as an oil: IR (neat) 3356, 2937, 1736, 1562; H NMR (CDCl3)
δ 1.28 (3H, t, J ) 7.1 Hz), 2.74 (2H, t, J ) 6.4 Hz), 3.82 (2H,
t, J ) 6.4 Hz), 4.14 (2H, s), 4.23 (2H, q, J ) 7.1 Hz), 7.12 (2H,
1
s).
3384, 2983, 1727, 1611, 1521; H NMR (CDCl3) δ 1.29 (3H, t,
J ) 7.1 Hz), 3.04 (2H, t, J ) 7.8 Hz), 3.49 (2H, t, J ) 7.8 Hz),
3.88 (2H, s), 4.15-4.35 (3H, m), 6.56 (2H, d, J ) 8.5 Hz), 7.02
(2H, d, J ) 8.5 Hz).
Eth yl N-Eth yloxyca r bon ylm eth yl-N-[4-(2-h yd r oxyeth -
yl)p h en yl]a m in oa ceta te (8c). A mixture of 4b (1.37 g, 10.0
mmol), ethyl bromoacetate (11.1 mL, 0.10 mol), and K2CO3
(3.46 g, 25.0 mmol) in DMF (30 mL) was stirred overnight at
room temperature and then for 1 h at 70 °C. EtOH (30 mL)
was added and the mixture was stirred for 1 h at 70 °C
followed by cooling to room temperature. After addition of
diethylamine (20.7 mL, 0.20 mol) at 10 °C and stirring for 1
h, the reaction mixture was concentrated to remove EtOH and
diethylamine, diluted with diethyl ether, and washed with
water. The organic layer was washed with 1 N HCl, saturated
aqueous NaHCO3, and brine successively, and dried over
anhydrous MgSO4. The solvent was removed in vacuo to give
3.05 g (99%) of 8c as an oil: IR (neat) 3448, 2983, 2936, 1744,
Eth yl N-[4-(2-Hyd r oxyeth yl)p h en yl]a m in oa ceta te (5b).
To a solution of 4b (25 g, 0.18 mol) in DMF (500 mL) were
added K2CO3 (30.0 g, 0.22 mol) and ethyl bromoacetate (24.0
mL, 0.22 mol), and the mixture was stirred for 16 h at room
temperature. Et2NH (38.0 mL, 0.37 mol) was added to the
reaction mixture, and the resulting mixture was stirred for 1
h. The insoluble material was filtered off and the filtrate was
concentrated in vacuo. The residue was diluted with diethyl
ether, and the resulting insoluble material was filtered off. The
filtrate was washed with 10% aqueous citric acid solution,
saturated aqueous NaHCO3 and brine subsequently, and dried
over anhydrous MgSO4. Removal of the solvent in vacuo gave
35.5 g (87%) of 5b as an off-white solid: mp 54-55 °C; IR (KBr)
1
1617, 1524; H NMR (CDCl3) δ 1.28 (6H, t, J ) 7.2 Hz), 1.35
(1H, t, J ) 6.4 Hz), 2.76 (2H, t, J ) 6.4 Hz), 3.79 (2H, q, J )
6.4 Hz), 4.12 (4H, s), 4.21 (4H, q, J ) 7.2 Hz), 6.58 (2H, d, J )
8.9 Hz), 7.08 (2H, d, J ) 8.9 Hz).
1
3413, 3378, 2953, 1730, 1617, 1521; H NMR (CDCl3) δ 1.29
(3H, t, J ) 7.2 Hz), 1.42 (1H, t, J ) 6.3 Hz), 2.76 (2H, t, J )
6.3 Hz), 2.76 (2H, q, J ) 6.3 Hz), 3.88 (2H, s), 4.22 (1H, br),
4.24 (2H, q, J ) 7.2 Hz), 6.58 (2H, d, J ) 8.4 Hz), 7.05 (2H, d,
J ) 8.4 Hz).
2′-Ch lor o-4′-[2-((RS)-t et r a h yd r op yr a n -2-yloxy)et h yl]-
2,2,2-tr iflu or oa ceta n ilid e (10). To a stirred solution of 9 (950
mg, 5.54 mmol) and Et3N (2.3 mL, 16.5 mmol) in THF (5.5

1442 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9
Tanaka et al.
1
mL) was added a solution of trifluoroacetic anhydride (1.6 mL,
11.3 mmol) in THF (2.0 mL) under ice-cooling, and the mixture
was stirred for 10 min. To the reaction mixture was added
MeOH (2.0 mL), and the resulting mixture was stirred for 5
min. 1 N HCl (10 mL) was added to the stirred mixture, and
the resulting mixture was extracted with EtOAc. The extract
was washed with a saturated aqueous NaHCO3 and brine
subsequently, and dried over anhydrous MgSO4. Removal of
the solvent in vacuo gave 1.4 g (94%) of 2′-chloro-4′-(2-
hydroxyethyl)-2,2,2-trifluoroacetanilide as a white solid: mp
74-76 °C; IR (KBr) 3436, 3279, 2948, 1724, 1611, 1553; 1H
NMR (CDCl3) δ 2.86 (2H, t, J ) 6.4 Hz), 3.87 (2H, t, J ) 6.4
Hz), 7.22 (1H, dd, J ) 8.4, 2.0 Hz), 7.35 (1H, d, J ) 2.0 Hz),
8.24 (1H, d, J ) 8.4 Hz), 8.36 (1H, br).
To a solution of 2′-chloro-4′-(2-hydroxyethyl)-2,2,2-trifluo-
roacetanilide (1.4 g, 5.23 mmol) and 3,4-dihydro-2H-pyran (1.4
mL, 15.4 mmol) in CH2Cl2 (15 mL) was added pyridinium
p-toluenesulfonate (14 mg, 0.06 mmol), and the mixture was
heated under reflux for 1 h with stirring. After concentration
of the reaction mixture in vacuo, the residue was dissolved in
EtOAc, washed with a saturated aqueous NaHCO3 and brine.
The organic layer was dried over anhydrous MgSO4, and the
solvent was removed in vacuo. Purification of the residue by
MPLC on silica gel (eluent: hexane/diethyl ether ) 3/1) gave
1.4 g (76%) of 10 as a brown oil: IR (neat) 3407, 3262, 2948,
1736, 1588, 1535; 1H NMR (CDCl3) δ 1.40-1.90 (6H, m), 2.88
(2H, t, J ) 6.7 Hz), 3.40-3.50 (1H, m), 3.60 (1H, dt, J ) 9.8,
6.7 Hz), 3.65-3.80 (1H, m), 3.94 (1H, dt, J ) 9.8, 6.7 Hz), 4.55-
4.60 (1H, m), 7.23 (1H, dd, J ) 8.4, 1.9 Hz), 7.36 (1H, d, J )
1.9 Hz), 8.22 (1H, d, J ) 8.4 Hz), 8.36 (1H, br).
E t h yl N-[2-Ch lor o-4-[2-((RS)-t et r a h yd r op yr a n -2-yl-
oxy)eth yl]p h en yl]-N-tr iflu or oa cetyla m in oa ceta te (11).
To a stirred solution of 10 (352 mg, 1.0 mmol) in DMF (3 mL)
was added 60% NaH in mineral oil (48 mg, 2.0 mmol) under
ice-cooling, and the mixture was stirred for 30 min at room
temperature. Ethyl bromoacetate (133 µL, 1.2 mmol) was
added to the reaction mixture, and the mixture was stirred
for 16 h. The reaction mixture was diluted with EtOAc, washed
with brine, and dried over anhydrous MgSO4. After the solvent
was removed in vacuo, purification of the residue by MPLC
on silica gel (eluent: hexane/diethyl ether ) 2/1) gave 250 mg
(57%) of 11 as a clear oil: IR (neat) 2948, 1750, 1710, 1498;
1H NMR (CDCl3) δ 1.28 (3H, t, J ) 7.1 Hz), 1.40-1.85 (6H,
m), 2.91 (2H, t, J ) 6.6 Hz), 3.40-3.50 (1H, m), 3.55-3.70 (2H,
m), 3.72 (1H, d, J ) 17.2 Hz), 3.90-4.00 (1H, m), 4.15-4.30
(2H, m), 4.55-4.65 (1H, m), 4.98 (1H, d, J ) 17.2 Hz), 7.15-
7.25 (1H, m), 7.35-7.45 (1H, m), 7.56 (1H, d, J ) 8.1 Hz).
Eth yl N-[2-Ch lor o-4-(2-h yd r oxyeth yl)p h en yl]a m in oa c-
eta te (12a ; R ) H). A solution of 11 (830 mg, 1.90 mmol) and
p-TsOH monohydrate (80 mg, 0.42 mmol) in EtOH (9.0 mL)
was stirred for 2 h at 40 °C. K2CO3 (314 mg, 2.27 mmol) was
added, and the mixture was heated under reflux for 5 h with
stirring. The insoluble material was filtered off, the filtrate
was concentrated in vacuo, and the residue was dissolved in
EtOAc. The solution was washed with saturated aqueous
NaHCO3 and brine, and dried over anhydrous MgSO4, and the
solvent was removed in vacuo. Purification of the residue by
MPLC on silica gel (eluent: hexane/EtOAc ) 2/1) gave 315
mg (65%) of 12 as an oil: IR (neat) 3407, 2942, 1739, 1614,
1521; 1H NMR (CDCl3) δ 1.30 (3H, t, J ) 7.1 Hz), 1.37 (1H, br
s), 2.74 (2H, t, J ) 6.5 Hz), 3.75-3.85 (2H, m), 3.93 (2H, d, J
) 5.5 Hz), 4.26 (2H, q, J ) 7.1 Hz), 4.80-4.90 (1H, m), 6.49
(1H, d, J ) 8.2 Hz), 7.00 (1H, dd, J ) 8.2, 2.0 Hz), 7.17 (1H,
d, J ) 2.0 Hz).
1617, 1521; H NMR (CDCl3) δ 1.25 (3H, t, J ) 7.1 Hz), 1.51
(1H, br), 2.77 (2H, t, J ) 6.5 Hz), 3.05 (3H, s), 3.80 (2H, t, J )
6.5 Hz), 4.04 (2H, s), 4.18 (2H, q, J ) 7.1 Hz), 6.65 (2H, d, J )
8.8 Hz), 7.09 (2H, d, J ) 8.8 Hz).
The following compounds (7, 8d , and 12b) were prepared
from the corresponding compounds (6, 5b, and 12) and an alkyl
halide such as iodomethane or benzyl bromide by a similar
method as described above.
E t h yl N-[2,6-d ich lor o-4-(2-h yd r oxyet h yl)p h en yl]-N-
m eth yla m in oa ceta te (7): H NMR (CDCl3) δ 1.26 (3H, t, J
) 7.1 Hz), 1.41 (1H, br), 2.70-2.80 (2H, m), 2.94 (3H, s), 3.80-
3.90 (4H, m), 4.17 (2H, q, J ) 7.1 Hz), 7.10-7.20 (2H, m).
Eth yl N-ben zyl-N-[4-(2-h yd r oxyeth yl)p h en yl]a m in oa c-
eta te (8d ; R ) Bn ): IR (neat) 3404, 2935, 1743, 1616, 1522;
1H NMR (CDCl3) δ 1.26 (3H, t, J ) 7.1 Hz), 1.36 (1H, t, J )
6.3 Hz), 2.76 (2H, t, J ) 6.3 Hz), 3.79 (2H, q, J ) 6.3 Hz), 4.06
(2H, s), 4.20 (2H, q, J ) 7.1 Hz), 4.63 (2H, s), 6.64 (2H, d, J )
8.8 Hz), 7.06 (2H, d, J ) 8.8 Hz), 7.20-7.40 (5H, m).
1
Eth yl N-[2-ch lor o-4-(2-h ydr oxyeth yl)ph en yl]-N-m eth yl-
a m in oa ceta te (12b; R ) Me): IR (neat) 3413, 2942, 1742,
1501; H NMR (CDCl3) δ 1.24 (3H, t, J ) 7.1 Hz), 1.35-1.50
1
(1H, m), 2.78 (2H, t, J ) 6.5 Hz), 2.97 (3H, s), 3.75-3.90 (2H,
m), 3.96 (2H, s), 4.15 (2H, q, J ) 7.1 Hz), 7.07 (1H, dd, J )
8.2, 1.9 Hz), 7.14 (1H, d, J ) 8.2 Hz), 7.21 (1H, d, J ) 1.9 Hz).
4-[2-(Meth oxym eth oxy)eth yl]a n ilin e (14a ; R1 ) H). To
a solution of 4-nitrophenethyl alcohol (5.0 g, 29.9 mmol) and
N,N-diisopropylethylamine (DIPEA) (6.3 mL, 35.9 mmol) in
THF (100 mL) was added chloromethyl methyl ether (MOMCl)
(2.7 mL, 35.9 mmol) at room temperature and the mixture was
stirred for 5 h. DIPEA (6.3 mL) and MOMCl (2.7 mL) were
added to the reaction mixture, and the mixture was stirred
overnight. Moreover, DIPEA (6.3 mL) and MOMCl (2.7 mL)
were added to the reaction mixture. After stirred for 6 h, 28%
aqueous ammonia solution (7.3 mL, 0.12 mol) was added at
room temperature and the mixture was stirred for 3 h. The
resulting mixture was diluted with hexane and vigorously
stirred for 15 min. The organic layer was separated and
washed successively with water, 10% aqueous citric acid
solution, saturated aqueous NaHCO3, and brine. The hexane
layer was dried over anhydrous MgSO4 and concentrated in
vacuo to give 6.0 g (96%) of methoxymethyl 4′-nitrophenethyl
ether as a light yellow oil: IR (neat) 3076, 2948, 2878, 2459,
1927, 1602, 1518; 1H NMR (CDCl3) δ 3.01 (2H, t, J ) 6.5 Hz),
3.27 (3H, s), 3.80 (2H, t, J ) 6.5 Hz), 4.60 (2H, s), 7.41 (2H, d,
J ) 8.7 Hz), 8.16 (2H, d, J ) 8.7 Hz).
3% Platinum on carbon, sulfided and moistened with water
(63%), was suspended in the solution of methoxymethyl 4′-
nitrophenethyl ether (1.0 g, 4.74 mmol) in MeOH (10 mL) and
stirred for 18 h at room temperature under hydrogen. The
reaction mixture was filtrated to remove the catalyst and
concentrated in vacuo to give 850 mg (99%) of 14a as a
colorless oil: IR (neat) 3444, 3363, 2935, 2885, 1628, 1520; 1H
NMR (CDCl3) δ 2.80 (2H, t, J ) 7.2 Hz), 3.31 (3H, s), 3.56
(2H, br), 3.70 (2H, t, J ) 7.2 Hz), 4.61 (2H, s), 6.63 (2H, d, J
) 8.2 Hz), 7.19 (2H, d, J ) 8.2 Hz).
3-Ch lor o-4-[2-(m eth oxym eth oxy)eth yl]a n ilin e (14b; R 1
) Cl). The title compound as an oil was prepared from 2′-
chloro-4′-nitrophenethyl alcohol21 by similar method described
in 14a : 1H NMR (CDCl3) δ 2.92 (2H, t, J ) 7.1 Hz), 3.31 (3H,
s), 3.71 (2H, t, J ) 7.1 Hz), 3.70-3.90 (2H, m), 4.61 (2H, s),
6.54 (1H, dd, J ) 8.2, 2.4 Hz), 6.72 (1H, d, J ) 2.4 Hz), 7.04
(1H, d, J ) 8.2 Hz).
Eth yl 2-[[4-(2-Hyd r oxyeth yl)p h en yl]a m in o]-2-m eth yl-
p r op ion a te (15a ; R1 ) H). To the mixture of 14a (725 mg,
4.0 mmol) and 1,1,1-trichloro-2-methyl-2-propanol 0.5 hydrate
(1.47 g, 4.0 mmol) in acetone (12 mL) was added potassium
hydroxide (6.40 g, 114 mmol) at 0 °C, and the mixture was
stirred for 1 h at 0 °C and overnight at room temperature.
The reaction mixture was concentrated in vacuo, diluted with
water, and washed with diethyl ether. Ammonium chloride
(3.57 g, 66.7 mmol) was dissolved in the aqueous solution, and
the mixture was acidified with 10% aqueous citric acid solution
and extracted with EtOAc. The organic layer was washed with
brine, dried over anhydrous MgSO4, and concentrated in vacuo.
Eth yl N-[4-(2-Hydr oxyeth yl)ph en yl]-N-m eth ylam in oac-
eta te (8b; R ) Me). To a solution of 5b (1.15 g, 5.15 mmol) in
DMF (10 mL) were added K2CO3 (1.17 g, 8.47 mmol) and
iodomethane (420 µL, 6.75 mmol), and the mixture was stirred
for 9 h at room temperature. The reaction mixture was poured
into water and extracted with EtOAc. The extract was washed
with brine, dried over anhydrous MgSO4, and concentrated in
vacuo. Purification of the residue by flash column chromatog-
raphy on silica gel (eluent: CH2Cl2/diethyl ether ) 10/1) gave
820 mg (67%) of 8b as a brown oil: IR (neat) 3395, 2936, 1742,

Novel N-Phenylglycine Derivatives
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9 1443
The residue was dissolved in EtOH (40 mL), and thionyl
chloride (875 µL, 12.0 mmol) was carefully added dropwise to
the solution at 0 °C. The mixture was heated under reflux for
5 h and concentrated to remove the solvent. The residual oil
was dissolved in EtOAc, basified with saturated aqueous
NaHCO3, and washed with brine. The organic layer was dried
over anhydrous MgSO4 and concentrated in vacuo. The residue
was purified by MPLC on silica gel (eluent: hexane/EtOAc )
1/1) to give 155 mg (15.4%) of 15a as a dark brown oil: IR
(neat) 3419, 2988, 2936, 1733, 1620, 1521; 1H NMR (CDCl3) δ
1.19 (3H, t, J ) 7.2 Hz), 1.34 (1H, br), 1.54 (6H, s), 2.75 (2H,
t, J ) 6.7 Hz), 3.76-3.82 (2H, m), 4.00 (1H, br), 4.17 (2H, q, J
) 7.2 Hz), 6.56 (2H, d, J ) 8.6 Hz), 7.00 (2H, d, J ) 8.6 Hz).
Eth yl 2-[[3-Ch lor o-4-(2-h yd r oxyeth yl)p h en yl]a m in o]-
2-m eth ylp r op ion a te (15b). The title compound as an oil was
prepared from 14b by similar method described in 15a : 1H
NMR (CDCl3) δ 1.21 (3H, t, J ) 7.1 Hz), 1.54 (6H, s), 2.89
(2H, t, J ) 6.7 Hz), 3.81 (2H, t, J ) 6.7 Hz), 4.19 (2H, q, J )
7.1 Hz), 6.43 (1H, dd, J ) 8.3, 2.5 Hz), 6.61 (1H, d, J ) 2.5
Hz), 7.01 (1H, d, J ) 8.3 Hz).
E t h yl N-[4-(2-Br om oet h yl)-2,6-d ich lor op h en yl]a m i-
n oa ceta te (2h ). To a stirred solution of 6 (650 mg, 2.23 mmol)
and triphenylphosphine (700 mg, 2.67 mmol) in CH2Cl2 (10
mL) was added carbon tetrabromide (886 mg, 2.67 mmol)
under ice-cooling, and the mixture was stirred for 1 h. Simply
purification of the reaction mixture by flash column chroma-
tography on silica gel (eluent: hexane/EtOAc ) 3/1) and
further purification of the fraction by MPLC on silica gel
(eluent: hexane/CH2Cl2 ) 1/1) gave 708 mg (89%) of 2h as an
oil: 1H NMR (CDCl3) δ 1.28 (3H, t, J ) 7.2 Hz), 3.03 (2H, t, J
) 7.4 Hz), 3.50 (2H, t, J ) 7.4 Hz), 4.16 (2H, d, J ) 5.7 Hz),
4.23 (2H, q, J ) 7.2 Hz), 4.80-4.90 (1H, m), 7.10 (2H, s).
The following phenethyl bromide analogues were prepared
by a similar method as described here using the corresponding
phenethyl alcohol derivatives. All of the compounds were
obtained as an oil except 2e.
Eth yl N-[4-(2-br om oeth yl)p h en yl]-N-m eth yla m in oa c-
eta te (2b): 1H NMR (CDCl3) δ 1.24 (3H, t, J ) 7.1 Hz), 3.05
(3H, s), 3.05 (2H, t, J ) 7.9 Hz), 3.50 (2H, t, J ) 7.9 Hz), 4.04
(2H, s), 4.17 (2H, q, J ) 7.1 Hz), 6.64 (2H, d, J ) 8.8 Hz), 7.07
(2H, d, J ) 8.8 Hz).
Eth yl N-[4-(2-br om oeth yl)p h en yl]-N-eth yloxyca r bon -
ylm eth yla m in oa ceta te (2c): 1H NMR (CDCl3) δ 1.27 (3H, t,
J ) 7.1 Hz), 3.05 (2H, t, J ) 7.8 Hz), 3.48 (2H, t, J ) 7.8 Hz),
4.12 (2H, s), 4.21 (2H, q, J ) 7.1 Hz), 6.57 (2H, d, J ) 8.6 Hz),
7.05 (2H, d, J ) 8.6 Hz).
Eth yl N-ben zyl-N-[4-(2-br om oeth yl)p h en yl]a m in oa c-
eta te (2d ): 1H NMR (CDCl3) δ 1.26 (3H, t, J ) 7.1 Hz), 3.04
(2H, t, J ) 7.8 Hz), 3.48 (2H, t, J ) 7.8 Hz), 4.06 (2H, s), 4.20
(2H, q, J ) 7.1 Hz), 4.63 (2H, s), 6.63 (2H, d, J ) 8.5 Hz), 7.03
(2H, d, J ) 8.5 Hz), 7.20-7.40 (5H, m).
E t h yl N-[4-(2-b r om oet h yl)-3-ch lor op h en yl]a m in oa c-
eta te (2e): mp 85-86 °C; 1H NMR (CDCl3) δ 1.31 (3H, t, J )
7.1 Hz), 3.00-3.20 (2H, m), 3.45-3.7 (2H, m), 3.86 (2H, d, J
) 5.3 Hz), 4.25 (2H, q, J ) 7.1 Hz), 4.34 (1H, br), 6.45-6.50
(1H, m), 6.60 (1H, d, J ) 1.6 Hz), 7.00-7.10 (1H, m).
E t h yl N-[4-(2-b r om oet h yl)-2-ch lor op h en yl]a m in oa c-
eta te (2f): 1H NMR (CDCl3) δ 1.30 (3H, t, J ) 7.1 Hz), 3.03
(2H, t, J ) 7.6 Hz), 3.49 (2H, t, J ) 7.6 Hz), 3.93 (2H, d, J )
5.5 Hz), 4.26 (2H, q, J ) 7.1 Hz), 4.85-4.95 (1H, m), 6.49 (1H,
d, J ) 8.3 Hz), 6.98 (1H, dd, J ) 8.3, 2.0 Hz), 7.14 (1H, d, J )
2.0 Hz).
4.04 (1H, br), 4.16 (2H, q, J ) 7.1 Hz), 6.54 (2H, d, J ) 8.6
Hz), 6.98 (2H, d, J ) 8.6 Hz).
Eth yl 2-[[4-(2-br om oeth yl)-3-ch lor op h en yl]a m in o]-2-
m eth ylp r op ion a te (2p ): 1H NMR (CDCl3) δ 1.20 (3H, t, J )
7.1 Hz), 1.55 (6H, s), 3.14 (2H, t, J ) 7.8 Hz), 3.51 (2H, t, J )
7.8 Hz), 4.13 (1H, br s), 4.18 (2H, q, J ) 7.1 Hz), 6.42 (1H, dd,
J ) 8.3, 2.5 Hz), 6.58 (1H, d, J ) 2.5 Hz), 7.00 (1H, d, J ) 8.3
Hz).
E t h yl N-[4-(2-Br om oet h yl)-2,3-d ich lor op h en yl]a m i-
n oa cet a t e (2j), E t h yl N-[4-(2-Br om oet h yl)-2,5-d ich lo-
r op h en yl]a m in oa ceta te (2k ). To a stirred solution of 2e (79
mg, 0.25 mmol) in CH2Cl2 (2.0 mL) was added tert-butyl
hypochlorite (31 µL, 0.27 mmol) under ice-cooling, and the
mixture was stirred for 6 h at room temperature. The solvent
was removed in vacuo, and purification of the residue by flash
column chromatography on silica gel (eluent: hexane/EtOAc
) 15/1) gave 31 mg (36%) of 2j as a high-polar regioisomer
and 34 mg (39%) of 2k as a low-polar regioisomer. 2j: 1H NMR
(CDCl3) δ 1.30 (3H, t, J ) 7.1 Hz), 3.05-3.25 (2H, m), 3.50-
3.70 (2H, m), 3.94 (2H, d, J ) 5.4 Hz), 4.26 (2H, q, J ) 7.1
Hz), 5.04 (1H, br), 6.41 (1H, d, J ) 8.4 Hz), 7.05 (1H, d, J )
8.4 Hz). 2k : 1H NMR (CDCl3) δ 1.31 (3H, t, J ) 7.1 Hz), 3.00-
3.20 (2H, m), 3.45-3.70 (2H, m), 3.90 (2H, d, J ) 5.3 Hz), 4.27
(2H, q, J ) 7.1 Hz), 4.95 (1H, br), 6.53 (1H, s), 7.17 (1H, s).
N-[2,6-Dich lor o-4-[2-[[(1S,2R)-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m eth yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic
Acid (3h ). To a solution of 1 (495 mg, 2.96 mmol) and 2h (700
mg, 1.97 mmol) in DMF (6 mL) was added N,N-diisopropyl-
ethylamine (343 µL, 1.97 mmol), and the mixture was stirred
for 7 h at 70 °C. The reaction mixture was concentrated in
vacuo, and purification of the residue by MPLC on APS
(eluent: CH2Cl2/EtOH ) 20/1) gave 510 mg (64%) of ethyl
N-[2,6-dichloro-4-[2-[[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-
1-methylethyl]amino]ethyl]phenyl]aminoacetate as a glassy
oil: 1H NMR (CDCl3) δ 0.95 (3H, d, J ) 6.4 Hz), 1.30 (3H, t,
J ) 7.2 Hz), 2.55-3.05 (5H, m), 4.16 (2H, d, J ) 6.0 Hz), 4.25
(2H, q, J ) 7.2 Hz), 4.51 (1H, d, J ) 5.3 Hz), 4.78 (1H, t, J )
6.0 Hz), 6.75 (2H, d, J ) 8.5 Hz), 7.00 (2H, s), 7.10 (2H, d, J
) 8.5 Hz).
Ethyl N-[2,6-dichloro-4-[2-[[(1S,2R)-2-hydroxy-2-(4-hydroxy-
phenyl)-1-methylethyl]amino]ethyl]phenyl]aminoacetate (500
mg, 1.13 mmol) was dissolved in 1 N NaOH (5.0 mL), and the
solution was stirred for 1 h at room temperature. To the
reaction mixture was added 1 N HCl (5.0 mL) under ice-cooling
with stirring, and collection of the resulting precipitates by
filtration gave 464 mg (99%) of 3h as a solid: mp 175-180 °C
dec; [R]D30 ) -3.5° (c ) 1.00, HOAc); IR (KBr) 3358, 3017, 1618,
1
1575, 1516; H NMR (DMSO-d6) δ 0.90 (3H, d, J ) 6.6 Hz),
2.65-2.80 (2H, m), 2.95-3.20 (3H, m), 3.76 (2H, s), 4.93 (1H,
br s), 5.55 (1H, br), 6.72 (2H, d, J ) 8.5 Hz), 7.13 (2H, d, J )
8.5 Hz), 7.16 (2H, s); MS m/z (relative intensity) 415 (0.75),
413 (M + H)+, 289 (1.1), 246 (3.8). Anal. (C19H22Cl2N2O4‚H2O)
431.32: C, H, N.
The following compounds were prepared from the corre-
sponding phenethyl bromide derivatives (2a -p ) by a similar
method as described here.
N-[4-[2-[[(1S,2R)-2-Hyd r oxy-2-(4-h yd r oxyp h en yl)-1-m e-
th yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic a cid (3a ): mp
25
186-188 °C dec; [R]D ) -6.7° (c ) 0.75, HOAc); IR (KBr)
3411, 3017, 1615, 1572, 1523; 1H NMR (DMSO-d6) δ 0.87 (3H,
d, J ) 6.4 Hz), 2.50-3.20 (5H, m), 3.51 (2H, s), 4.86 (1H, br
s), 6.45 (2H, d, J ) 8.1 Hz), 6.70 (2H, d, J ) 8.4 Hz), 6.83 (2H,
d, J ) 8.1 Hz), 7.11 (2H, d, J ) 8.4 Hz); MS m/z (relative
intensity) 345 (M + H)+, 221 (0.18), 178 (0.51). Anal.
(C19H24N2O4‚1.3H2O) 367.8: C, H, N.
Eth yl N-[4-(2-br om oeth yl)-2-ch lor op h en yl]-N-m eth yl-
1
a m in oa ceta te (2g): H NMR (CDCl3) δ 1.24 (3H, t, J ) 7.1
Hz), 2.97 (3H, s), 3.07 (2H, t, J ) 7.6 Hz), 3.52 (2H, t, J ) 7.6
Hz), 3.97 (2H, s), 4.15 (2H, q, J ) 7.1 Hz), 7.04 (1H, dd, J )
8.2, 2.0 Hz), 7.13 (1H, d, J ) 8.2 Hz), 7.18 (1H, d, J ) 2.0 Hz).
Eth yl N-[4-(2-br om oeth yl)-2,6-d ich lor op h en yl]-N-m e-
N-[4-[2-[[(1S,2R)-2-Hyd r oxy-2-(4-h yd r oxyp h en yl)-1-m e-
th yleth yl]am in o]eth yl]ph en yl]-N-m eth ylam in oacetic acid
1
25
th yla m in oa ceta te (2i): H NMR (CDCl3) δ 1.26 (3H, t, J )
(3b): amorphous; [R]D ) -6.9° (c ) 0.96, HOAc); IR (KBr)
1
7.1 Hz), 2.95 (3H, s), 3.06 (2H, t, J ) 7.3 Hz), 3.52 (2H, t, J )
7.3 Hz), 3.88 (2H, s), 4.17 (2H, q, J ) 7.1 Hz), 7.14 (2H, s).
Eth yl 2-[[4-(2-br om oeth yl)p h en yl]a m in o]-2-m eth ylp r o-
p ion a te (2o): 1H NMR (CDCl3) δ 1.18 (3H, t, J ) 7.1 Hz),
1.54 (6H, s), 3.03 (2H, t, J ) 7.9 Hz), 3.48 (2H, t, J ) 7.9 Hz),
3377, 2958, 1618, 1579, 1519; H NMR (CD3OD) δ 1.07 (3H,
d, J ) 6.7 Hz), 2.84 (2H, t, J ) 8.1 Hz), 3.03 (3H, s), 3.10-
3.25 (2H, m), 3.30-3.40 (1H, m), 3.86 (2H, s), 4.99 (1H, d, J )
3.4 Hz), 6.64 (2H, d, J ) 8.8 Hz), 6.78 (2H, d, J ) 8.6 Hz),
7.02 (2H, d, J ) 8.8 Hz), 7.17 (2H, d, J ) 8.6 Hz); MS m/z

1444 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9
Tanaka et al.
(relative intensity) 359 (M + H)+, 192 (0.76). Anal. (C20H26N2O4‚
0.3H2O) 363.8: C, H, N.
a cid (3k ): mp 191-195 °C dec; [R]D25 ) -3.4° (c ) 0.83, HOAc);
IR (KBr) 3360, 3023, 1608, 1573, 1512; 1H NMR (DMSO-d6) δ
0.89 (3H, d, J ) 6.5 Hz), 2.65-3.25 (5H, m), 3.55 (2H, s), 4.93
(1H, br s), 5.58 (1H, br s), 6.53 (1H, s), 6.71 (2H, d, J ) 8.4
Hz), 7.13 (2H, d, J ) 8.4 Hz), 7.19 (1H, s), 9.30 (1H, br); MS
N -Ca r b oxym e t h yl-N -[4-[2-[[(1S ,2R )-2-h yd r oxy-2-(4-
hydroxyphenyl)-1-methylethyl]amino]ethyl]phenyl]amino-
a cetic a cid (3c): mp 228-230 °C dec; [R]D25 ) -6.9° (c ) 0.96,
HOAc); IR (KBr) 3198, 2930, 1695, 1614, 1573, 1524; 1H NMR
(DMSO-d6) δ 0.94 (3H, d, J ) 6.7 Hz), 2.83 (2H, t, J ) 8.4 Hz),
3.05-3.17 (2H, m), 3.30-3.37 (2H, m), 3.97 (4H, s), 5.01 (1H,
br s), 5.96 (1H, br), 6.41 (2H, d, J ) 8.9 Hz), 6.74 (2H, d, J )
8.5 Hz), 7.03 (2H, d, J ) 8.9 Hz), 7.15 (2H, d, J ) 8.5 Hz),
8.71 (2H, br), 9.39 (1H, br); MS m/z (relative intensity) 403
(M + H)+, 236 (0.99), 176 (0.81). Anal. (C21H26N2O6‚0.2H2O)
406.1: C, H, N.
m/z (relative intensity) 413 (M + H)+, 246 (0.18). Anal. (C19H22
Cl2N2O4‚0.5H2O) 422.3: C, H, N.
-
N-[2,6-Dibr om o-4-[2-[[(1S,2R)-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m eth yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic
a cid (3l): mp 188-192 °C dec; [R]D29 ) -3.4° (c ) 1.29, HOAc);
1
IR (KBr) 3327, 3188, 1593, 1516; H NMR (DMSO-d6) δ 0.89
(3H, d, J ) 6.6 Hz), 2.65-3.20 (5H, m), 3.75 (2H, s), 4.75-
4.90 (1H, m), 5.40 (1H, br), 6.71 (2H, d, J ) 8.3 Hz), 7.11 (2H,
d, J ) 8.3 Hz), 7.38 (2H, s); MS m/z (relative intensity) 505
(0.45), 503 (M + H)+, 501 (0.53). Anal. (C19H22Br2N2O4‚1.5H2O)
529.23: C, H, N.
N -Be n zyl-N -[4-[2-[[(1S ,2R )-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m eth yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic
30
a cid (3d ): amorphous; [R]D ) -6.8° (c ) 0.62, DMSO); IR
(KBr) 3429, 2513, 1616, 1576, 1520; 1H NMR (DMSO-d6) δ 0.90
(3H, d, J ) 6.6 Hz), 2.60-2.80 (2H, m), 2.90-3.05 (2H, m),
3.15-3.25 (1H, m), 3.98 (2H, s), 4.59 (2H, s), 4.95-5.05 (1H,
m), 6.51 (2H, d, J ) 8.6 Hz), 6.72 (2H, d, J ) 8.5 Hz), 6.88
(2H, d, J ) 8.6 Hz), 7.13 (2H, d, J ) 8.5 Hz), 7.15-7.35 (5H,
m), 9.35 (2H, br); MS m/z (relative intensity) 435 (M + H)+,
268 (0.61). Anal. (C26H30N2O4‚0.5H2O) 443.5: C, H, N.
N -[3-Ch lor o-4-[2-[[(1S ,2R )-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m eth yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic
N-[2-Br om o-4-[2-[[(1S,2R)-2-h ydr oxy-2-(4-h ydr oxyph en -
yl)-1-m eth yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic a cid
27
(3m ): amorphous; [R]D ) -4.7° (c ) 0.51, HOAc); IR (KBr)
3392, 3191, 1615, 1560, 1519; 1H NMR (DMSO-d6) δ 0.92 (3H,
d, J ) 6.5 Hz), 2.70-2.90 (2H, m), 3.00-3.40 (3H, m), 3.75
(2H, s), 4.93 (1H, br s), 5.36 (1H, br), 6.50 (1H, d, J ) 8.3 Hz),
6.74 (2H, d, J ) 8.5 Hz), 7.04 (1H, dd, J ) 8.3, 1.8 Hz), 7.14
(2H, d, J ) 8.5 Hz), 7.34 (1H, d, J ) 1.8 Hz); MS m/z (relative
intensity) 425 (0.99), 423 (M + H)+, 258 (0.32), 256 (0.38). Anal.
(C19H23BrN2O4‚1.5H2O) 450.3: C, H, N.
25
a cid (3e): amorphous; [R]D ) -1.6° (c ) 0.25, 1 N HCl); IR
(KBr) 3413, 1614, 1562, 1512; 1H NMR (DMSO-d6) δ 0.86 (3H,
d, J ) 6.4 Hz), 2.55-2.85 (5H, m), 3.35 (2H, s), 4.55 (1H, br
s), 6.40 (1H, dd, J ) 8.3, 2.2 Hz), 6.51 (1H, d, J ) 2.2 Hz),
6.68 (2H, d, J ) 8.4 Hz), 6.87 (1H, d, J ) 8.3 Hz), 7.06 (2H, d,
J ) 8.4 Hz); MS m/z 379 (M + H)+. Anal. (C19H23ClN2O4‚
1.5H2O) 405.9: C, H, N.
N-[4-[2-[[(1S,2R)-2-Hyd r oxy-2-(4-h yd r oxyp h en yl)-1-m e-
th yleth yl]a m in o]eth yl]-2-iod op h en yl]a m in oa cetic a cid
27
(3n ): mp 151-155 °C dec; [R]D ) -4.7° (c ) 0.51, HOAc); IR
(KBr) 3367, 3200, 1603, 1516; 1H NMR (DMSO-d6) δ 0.92 (3H,
d, J ) 6.6 Hz), 2.70-2.80 (2H, m), 3.00-3.25 (3H, m), 3.68
(2H, s), 4.93 (1H, br s), 5.15 (1H, br), 6.39 (1H, d, J ) 8.3 Hz),
6.73 (2H, d, J ) 8.6 Hz), 7.00-7.10 (1H, m), 7.14 (2H, d, J )
8.6 Hz), 7.53 (1H, d, J ) 1.8 Hz); MS m/z (relative intensity)
471 (M + H)+, 347 (0.18), 304 (0.51). Anal. (C19H23IN2O4‚H2O)
488.3: C, H, N.
N -[2-Ch lor o-4-[2-[[(1S ,2R )-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m eth yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic
a cid (3f): mp 193-195 °C dec; [R]D30 ) -6.7° (c ) 1.00, HOAc);
1
IR (KBr) 3367, 3029, 1615, 2360,1618, 1575, 1519; H NMR
(DMSO-d6) δ 0.90 (3H, d, J ) 6.4 Hz), 2.60-2.80 (2H, m), 2.90-
3.20 (3H, m), 3.52 (2H, s), 4.95 (1H, br s), 5.35 (1H, br), 6.46
(1H, d, J ) 8.4 Hz), 6.72 (2H, d, J ) 8.6 Hz), 6.91 (1H, dd, J
) 8.4, 1.8 Hz), 7.05-7.20 (3H, m); MS m/z (relative intensity)
379 (M + H)+, 212 (6.29). Anal. (C19H23ClN2O4) 378.9: C, H,
N.
2-[[4-[2-[[(1S,2R)-2-Hyd r oxy-2-(4-h ydr oxyp h en yl)-1-m e-
th yleth yl]a m in o]eth yl]p h en yl]a m in o]-2-m eth ylp r op ion -
29
ic a cid (3o): mp 193-200 °C dec; [R]D ) -8.2° (c ) 1.00,
HOAc); IR (KBr) 3392, 3147, 1618, 1557, 1519; 1H NMR
(DMSO-d6 + D2O) δ 0.91 (3H, d, J ) 6.6 Hz), 1.37 (6H, s),
2.55-2.75 (2H, m), 2.85-3.00 (2H, m), 3.10-3.20 (1H, m), 4.92
(1H, d, J ) 2.2 Hz), 6.47 (2H, d, J ) 8.5 Hz), 6.70-6.80 (4H,
m), 7.13 (2H, d, J ) 8.5 Hz); MS m/z (relative intensity) 373
(M + H)+, 249 (0.04), 206 (0.19). Anal. (C21H28N2O4‚H2O)
390.48: C, H, N.
N -[2-Ch lor o-4-[2-[[(1S ,2R )-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m et h ylet h yl]a m in o]et h yl]p h en yl]-N-m et h yl-
25
a m in oa cetic a cid (3g): amorphous; [R]D ) -4.5° (c ) 0.75,
HOAc); IR (KBr) 3209, 1597, 1516; 1H NMR (DMSO-d6) δ 0.87
(3H, d, J ) 6.4 Hz), 2.65-2.90 (5H, m), 2.89 (3H, s), 3.60-
3.70 (2H, m), 4.56 (1H, br), 6.65 (2H, d, J ) 8.5 Hz), 6.81 (1H,
dd, J ) 8.3, 1.9 Hz), 6.95-7.05 (4H, m); MS m/z (relative
intensity) 393 (M + H)+; HPLC tR ) 14.3 min (gradient), 7.8
min (20% MeCN, isocratic). Anal. Calcd (C20H25ClN2O4‚
2.4H2O) 436.1: C, 55.08; H, 6.89; N, 6.42. Found: C, 54.76;
H, 6.31; N, 6.21.
2-[[3-Ch lor o-4-[2-[[(1S,2R)-2-h ydr oxy-2-(4-h ydr oxyph en -
yl)-1-methylethyl]amino]ethyl]phenyl]amino]-2-methylpropionic
28
a cid (3p ): mp 170-173 °C dec; [R]D ) -4.0° (c ) 1.00, 1 N
HCl); IR (KBr) 3197, 1615, 1557, 1522; 1H NMR (DMSO-d6) δ
0.88 (3H, d, J ) 6.6 Hz), 1.37 (6H, s), 2.60-2.90 (4H, m), 3.00-
3.10 (1H, m), 4.83 (1H, br s), 6.40 (1H, dd, J ) 8.3, 2.4 Hz),
6.54 (1H, d, J ) 2.4 Hz), 6.71 (2H, d, J ) 8.6 Hz), 6.76 (1H, d,
N-[2,6-Dich lor o-4-[2-[[(1S,2R)-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m et h ylet h yl]a m in o]et h yl]p h en yl]-N-m et h yl-
J
) 8.3 Hz), 7.11 (2H, d, J ) 8.6 Hz); MS m/z (relative
intensity) 407 (M + H)+, 361 (0.28), 240 (0.43), 194 (0.62);
HPLC tR ) 19.4 min (gradient), 5.8 min (25% MeCN, isocratic).
32
a m in oa cetic a cid (3i): mp 135-138 °C; [R]D ) -5.9° (c )
0.54, MeOH); IR (KBr) 3382, 3193, 1615, 1575, 1516; 1H NMR
(DMSO-d6) δ 0.84 (3H, d, J ) 6.6 Hz), 2.30-2.95 (8H, m), 3.76
(2H, s), 4.64 (1H, br s), 6.69 (2H, d, J ) 8.5 Hz), 7.09 (2H, d,
J ) 8.5 Hz), 7.22 (2H, s); MS m/z (relative intensity) 429 (0.64),
427 (M + H)+, 303 (0.31), 260 (0.23). Anal. (C20H24Cl2N2O4‚
1.5H2O) 454.4: C, H, N.
In Vitr o Assa y for â3-Ad r en ocep tor -Stim u la tin g Ef-
fects. Urinary bladders of male ferrets (1100-1400 g in body
weight) and male rats (200-380 g in body weight) were
isolated and longitudinal detrusor strips, approximately 10
mm in length and approximately 2 mm in width were
prepared. The experiment was performed according to the
organ bath method. The preparations were suspended in a
Krebs solution maintained at 37 °C and continuously gassed
with a mixture of 95% oxygen and 5% carbon dioxide under 1
g of tension. Detrusor tension were measured isometrically
with a force-displacement transducer (SB-1T; Nihon-Kohdan,
Tokyo, J apan) and recorded on a rectigram (Rectigraph 8K;
NEC San-ei, Tokyo, J apan). The drug was added cumulatively
to the organ bath every about 5 min. The drug efficacy was
evaluated as the molar concentration of the drug required to
produce 50% of detrusor relaxation before the addition of the
drug. In this experiment, tension of detrusor before the
addition of the drug was expressed as 100% and tension of
N-[2,3-Dich lor o-4-[2-[[(1S,2R)-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m eth yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic
a cid (3j): mp 199-208 °C dec; [R]D25 ) -4.3° (c ) 0.47, HOAc);
IR (KBr) 3355, 3017, 1603, 1578, 1519; 1H NMR (DMSO-d6) δ
0.89 (3H, d, J ) 6.5 Hz), 2.75-3.25 (5H, m), 3.53 (2H, s), 4.90
(1H, br s), 5.62 (1H, br s), 6.45 (1H, d, J ) 8.5 Hz), 6.71 (2H,
d, J ) 8.4 Hz), 7.01 (1H, d, J ) 8.5 Hz), 7.13 (2H, d, J ) 8.4
Hz); MS m/z (relative intensity) 413 (M + H)+, 247 (0.98),
HRMS C19H23Cl2N2O4; HPLC tR ) 21.3 min (gradient), 6.2 min
(25% MeCN, isocratic).
N-[2,5-Dich lor o-4-[2-[[(1S,2R)-2-h yd r oxy-2-(4-h yd r oxy-
p h en yl)-1-m eth yleth yl]a m in o]eth yl]p h en yl]a m in oa cetic

Novel N-Phenylglycine Derivatives
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9 1445
maximal relaxation after the addition of 10-5 M concentration
of forskolin was expressed as 0%.
(4) Wilson, C.; Wilson, S.; Piercy, V.; Sennitt, M. V.; Arch, J . R. The
rat lipolytic â-adrenoceptor: studies using novel â-adrenoceptor
agonists. Eur. J . Pharmacol. 1984, 100, 309-319.
(5) Emorine, L. J .; Marullo, S.; Briend-Sutren, M.-M.; Patey, G.;
Tate, K.; Delavier-Klutchko, C.; Strosberg, A. D. Molecular
characterization of the human â3-adrenergic receptor. Science
1989, 245, 1118-1121.
(6) Emorine, L. J .; Feve, B.; Pairault, J .; Briend-Sutren, M.-M.;
Nahmias, C.; Marullo, S.; Delavier-Klutchko, C.; Strosberg, D.
A. The human â3-adrenergic receptor: relationship with atypical
receptors. Am. J . Clin. Nutr. 1992, 55, 215S-218S.
(7) Tate, K. M.; Briend-Sutren, M.-M.; Emorine, L. J .; Delavier-
Klutchko, C.; Marullo, S.; Strosberg, A. D. Expression of three
â-adrenergic-receptor subtypes in transfected Chinese hamster
ovary cells. Eur. J . Biochem. 1991, 196, 357-361.
(8) Berkowitz, D. E.; Nardone, N. A.; Smiley, R. M.; Price, D. T.;
Kreutter, D. K.; Fremeau, R. T.; Schwinn, D. A. Distribution of
â3-adrenoceptor mRNA in human tissues. Eur. J . Pharmacol.
1995, 289, 223-228.
(9) (a) Igawa, Y.; Yamazaki, Y.; Takeda, H.; Akahane, M.; Ajisawa,
Y.; Yoneyama, T.; Nishizawa, O. Possible â3-adrenoceptor-
mediated relaxation of the human detrusor. Acta Physiol. Scand.
1998, 164, 117-118. (b) Igawa, Y.; Yamazaki, Y.; Takeda, H.;
Hayakawa, K.; Akahane, M.; Ajisawa, Y.; Yoneyama, T.; Nish-
izawa, O.; Anderrson, K.-E. Functional and molecular biological
evidence for a possible â3-adrenoceptor in the human detrusor
muscle. Br. J . Pharmacol. 1999, 126, 819-825.
(10) Takeda, M.; Obara, K.; Mizusawa, T.; Tomita, Y.; Arai, K.;
Tsutsui, T.; Hatano, A.; Takahashi, K.; Nomura, S. Evidence for
â3-adrenoceptor subtypes in relaxation of the human urinary
bladder detrusor: analysis by molecular biological and phar-
macological methods. J . Pharmacol. Exp. Ther. 1999, 288, 1367-
1373.
(11) Fujimura, T.; Tamura, K.; Tsutsumi, T.; Yamamoto, T.; Naka-
mura, K.; Koibuchi, Y.; Kobayashi, M.; Yamaguchi, O. Expres-
sion and possible functional role of the â3-adrenoceptor in human
and rat detrusor muscle. J . Urol. 1999, 161, 680-685.
(12) Anderrson, K.-E. Advances in the pharmacological control of the
bladder. Exp. Physiol. 1999, 84, 195-213.
In Vitr o Assa y for â1-Ad r en ocep tor -Stim u la tin g Ef-
fects. Atria of male SD rats (250-400 g in body weight) were
isolated and the experiment was performed according to the
organ bath method. The preparations were exposed to Krebs
solution maintained at 37 °C and gassed with a mixture of
95% oxygen and 5% carbon dioxide under 0.5 g of tension. The
cardiac contractility was measured isometrically with a force-
displacement transducer (SB-1T; Nihon-Kohdan), and heart
rate was recorded on a rectigram via a tachometer (Rectigraph
8K; NEC San-ei). The drug was added cumulatively to the
Magnus bath every 3 min. The drug efficacy was evaluated
as the molar concentration of the drug required to increase
20 beats/minute.
In Vitr o Assa y for â2-Ad r en ocep tor -Stim u la tin g Ef-
fects. Uteri of pregnant SD rats (pregnancy day 21, 200-380
g in body weight) were isolated and longitudinal uterine
muscle strips of approximately 15 mm in length and 5 mm in
width were prepared. The experiment was performed accord-
ing to the Magnus method. The preparations were exposed to
Locke-Ringer solution maintained at 37 °C and continuously
gassed with a mixture of 95% oxygen and 5% carbon dioxide
under 0.5 g of tension. Spontaneous contractions of myo-
metrium were measured isometrically with a force-displace-
ment transducer (SB-1T; Nihon-Kohdan) and recorded on a
rectigram (Rectigraph 8K; NEC San-ei). The drug was added
cumulatively to the organ bath every 5 min. The drug efficacy
was evaluated as the molar concentration of the drug required
to produce 50% of the inhibition of uterine contraction as
comparing the total degree of uterine contraction during 5 min
before the addition of the drug (100%) with the total degree of
uterine contraction during 5 min after the addition of the drug
at various concentrations.
Bla d d er P r essu r e in An esth etized Ra ts. Male rats
(300-350 g in body weight) were anesthetized with urethane
(1.5 g kg-1, sc), and the midline abdomen was incised. The
ureter on each side was ligated and cut proximal to the ligature
so as to allow urine to drain into cotton wads. After the urethra
had been ligated, a polyethylene catheter (PE-50; Nihon Becton
Dickinson, Tokyo, J apan) was inserted into the urinary bladder
via the top of the bladder dome and connected through a three-
way connector to a pressure transducer (SPB-108; NEC San-
ei) and syringe filled with warmed saline. The initial bladder
pressure was adjusted to 6 cm H2O by instillation of warmed
saline (37 °C) in 0.05 mL increments. An arterial catheter was
inserted into the left carotid artery (PE-90; Nihon Becton
Dickinson) and connected to a pressure transducer (SPB-108;
NEC San-ei) for the measurement of blood pressure. Heart
rate was measured via tachometer (132l; NEC San-ei) con-
nected to the transducer amplifier (1829; NEC San-ei). Bladder
pressure, blood pressure, and heart rate were recorded con-
tinuously on a rectigraph (Recti-Horiz-8K; NEC San-ei). Drug
effects on bladder pressure, blood pressure, and heart rate
were quantified by expressing each post-administration value
as a percentage of the value before drug administration. No
animal was exposed to more than one of the test drugs. A
venous catheter was inserted into the left femoral vein (PE-
50; Nihon Becton Dickinson) for drug injection.
(13) (a) Wein, A. J . Pharmacologic options for the overactive bladder.
Urology 1998, 51 (Suppl. 2A), 43-47. (b) Hills, C. J .; Winter, S.
A.; Balfour, J . A. Tolterodine. Drugs 1998, 55, 813-820.
(14) Takeda, H.; Igawa, Y.; Komatsu, Y.; Yamazaki, Y.; Akahane,
M.; Nishizawa, O.; Ajisawa, Y. Characterization of â-adreno-
ceptor subtypes in the ferret urinary bladder in vitro and in vivo.
Eur. J . Pharrmcol. 2000, 403, 147-155.
(15) Travis, B. E.; McCullough, J . M. Pharmacotherapy of preterm
labor. Pharmacotherapy 1993, 13, 28-36.
(16) Bloom, J . D.; Dutia, M. D.; J ohnson, B. D.; et al. Disodium (R,R)-
5-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]-1,3-ben-
zodioxole-2,2-dicarboxylate (CL 316,243). A potent â-adrenergic
agonist virtually specific for â3 receptor. A promising antidiabetic
and antiobesity agent. J . Med. Chem. 1992, 35, 3081-3084.
(17) Oriowo, M. A.; Chapman, H.; Kirkham, D. M.; Sennitt, M. V.;
Ruffolo, R. R., J r.; Cawthorne, M. A. The selectivity in vitro of
the stereoisomers of the beta-3 adrenoceptor agonist BRL 37344.
J . Pharmacol. Exp. Ther. 1996, 277, 22-27.
(18) Sith, H. E.; Burrows, E. P. Agonist effects of â-phenethylamines
on the noradrenergic cyclic adenosine 3′,5′-monophosphate
generating system in rat limbic forebrain. Stereoisomers of
p-Hydroxynorephedrine. J . Med. Chem. 1977, 20, 978-981.
(19) Substituted phenylethyl alcohols: their production and composi-
tion containing same. Patent No. DE1921653 and GB1264892.
(20) (a) Murakami, Y.; Kondo, K.; Miki, K.; Akiyama, Y.; Watanabe,
T.; Yokoyama, Y. The ortho-substituted N,N-diacetylaniline as
a
selective acetylating reagent. Tetrahedron Lett. 1997, 38,
3751-3754. (b) Ayyangar, N. R.; Srinivasan, K. V. Effect of
substituents in the formation of diacetanilides. Can. J . Chem.
1984, 62, 1292-1296.
(21) Staels, B.; Dallongeville, J .; Auwerx, J .; Schoonjans, K.; Leit-
ersdorf, E.; Fruchart, J . C. Mechanism of action of fibrates on
lipid and lipoprotein metabolism. Circulation 1998, 98, 2088-
2093.
(22) Corey, E. J .; Barcza, S.; Klotmann, G. A new method for the
directed conversion of the phenoxy grouping into a variety of
cyclic polyfunctional systems. J . Am. Chem. Soc. 1969, 91, 4782-
4786.
Ackn owledgm en t. We thank Dr.Yoshinobu Yamaza-
ki and Mr. Hiroo Takeda for their scientific contribu-
tions to this work. We also thank Dr. Hiromu Harada
for helpful comments while reviewing the manuscript.
(23) Yamazaki, Y.; Takeda, H.; Akahane, M.; Igawa, Y.; Nishizawa,
O.; Ajisawa, Y. Species differences in the distribution of â-a-
drenoceptor subtypes in bladder smooth muscle. Br. J . Phar-
macol. 1998, 124, 593-599.
(24) This compound was prepared by the method described in the
following literature:. Uhlmann, E.; Pflreiderer, W. Nucleotide.
XIV. Substituted â-phenylethyl groups. New blocking groups for
oligonucleotide syntheses by the phosphotriester approach. Helv.
Chim. Acta 1981, 64, 1688-1703.
Refer en ces
(1) Weyer, C.; Gautier, J . F.; Danforth, E., J r. Development of beta3-
adrenoceptor agonists for the treatment of obesity and diabetes-
an update. Diabetes Metab. 1999, 25, 11-21.
(2) Howe, R. â3-adrenergic agonists. Drugs Future 1993, 18, 529-
549.
(3) Arch, J . R.; Ainsworth, A. T.; Cawthorne, M. A.; Piercy, V.;
Sennitt, M. V.; Thod, V. E.; Wilson, C.; Wilson, S. Atypical
â-adrenoceptors on brown adpocytes as target for anti-obesity
drugs. Nature 1984, 309, 163-165.
J M000455Z