BMS-196085: A potent and selective full agonist of the human β3 adrenergic receptor

Article abstract of DOI:10.1016/S0960-894X(01)00629-1

A series of 4-hydroxy-3-methylsulfonanilido-1,2-diarylethylamines were prepared and evaluated for their human β₃ adrenergic receptor agonist activity. SAR studies led to the identification of BMS-196085 (25), a potent β₃ full agonist (K_i=21 nM, 95% activation) with partial agonist (45%) activity at the β₁ receptor. Based on its desirable in vitro and in vivo properties, BMS-196085 was chosen for clinical evaluation.

Full text of DOI:10.1016/S0960-894X(01)00629-1

Bioorganic & Medicinal Chemistry Letters 11 (2001) 3041–3044
BMS-196085: A Potent and Selective Full Agonist of the
Human ꢀ3 Adrenergic Receptor
A. V. Gavai,* P. M. Sher, A. B. Mikkilineni, K. M. Poss, P. J. McCann,
R. N. Girotra, L. G. Fisher, G. Wu, M. S. Bednarz, A. Mathur, T. C. Wang, C. Q. Sun,
D. A. Slusarchyk, S. Skwish, G. T. Allen, D. E. Hillyer, B. H. Frohlich,
B. E. Abboa-Offei, M. Cap, T. L. Waldron, R. J. George, B. Tesfamariam, T. W. Harper,
C. P. Ciosek, Jr., D. A. Young, K. E. Dickinson, A. A. Seymour, C. M. Arbeeny
and W. N. Washburn
Bristol-Myers Squibb Pharmaceutical Research Institute, PO Box 4000, Princeton, NJ 08543-4000, USA
Received 26 June 2001; accepted 7 September 2001
Abstract—A series of 4-hydroxy-3-methylsulfonanilido-1,2-diarylethylamines were prepared and evaluated for their human b3
adrenergic receptor agonist activity. SAR studies led to the identification of BMS-196085 (25), a potent b3 full agonist (Ki=21 nM,
95% activation) with partial agonist (45%) activity at the b1 receptor. Based on its desirable in vitro and in vivo properties, BMS-
196085 was chosen for clinical evaluation. # 2001 Elsevier Science Ltd. All rights reserved.
Agonist occupancy of the b3 adrenergic receptor (AR)
on the adipose tissue elevates cAMP levels, thereby sti-
mulating lipolysis and upregulating adipose specific
genes. The increased expression of uncoupling protein, a
brown adipose tissue specific mitochondrial protein,
uncouples fatty acid oxidation from oxidative phos-
phorylation. This process increases heat production
with a commensurate boost in energy consumption. b3
AR agonists represent a novel approach to alter energy
utilization and thereby ameliorate obesity and non-
insulin dependent diabetes mellitus.1 The preceding
paper2 described the discovery of hydroxysulfonanilides
as a novel class of potent and selective agonists of the
human b3 AR leading up to the discovery of BMS-194449.
This paper3 describes SAR studies in the 4-hydroxy-3-
methylsulfonanilido-1,2-diarylethylamine series, leading
to the discovery of BMS-196085 (25), a b3 full agonist
with a significantly improved profile over BMS-194449,
that was selected for clinical evaluation.
removal of the triethylsilyl and the benzyl protecting
groups (Scheme 1).4 The requisite 1,2-diarylethylamines
3 were prepared, as illustrated in Scheme 2, by either
sequential treatment of the aldehyde 4 with lithium
hexamethyldisilazide and benzyl magnesium chloride5
or via a two-step sequence utilizing reductive amination
of the 1,2-diarylethanone 6 obtained from acid chloride
5 using zinc mediated palladium-catalyzed coupling6
with benzyl bromide.
Scheme 1. Reagents and conditions: (a) diisopropylethylamine, THF,
140 ꢀC; (b) TFA, aq methanol; (c) H2, Pd/C, methanol.
The b3 AR agonists 1 disclosed in this report were pre-
pared by a convergent route comprising coupling of the
iodide 22 with various 1,2-diarylethylamines 3 in the pre-
sence of diisopropylethylamine followed by sequential
Scheme 2. Reagents and conditions: (a) LiN(SiMe3)2, THF;
PhCH2MgCl, THF; aq NH4Cl; (b) PhCH2Br, Zn, Pd(PPh3)4, DME;
(c) HCO2NH4, 160 ꢀC; concd HCl, MeOH.
*Corresponding author. Fax: +1-609-252-6601; e-mail: ashvinikumar.
gavai@bms.com
0960-894X/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved.
PII: S0960-894X(01)00629-1

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A. V. Gavai et al. / Bioorg. Med. Chem. Lett. 11 (2001) 3041–3044
The synthesis of the optically active amine derivatives 8
is shown in Scheme 3.7 Aldehyde 4 was condensed with
(R)-phenylglycinol and the resulting imine was added to
a solution-suspension of benzylmagnesium chloride and
cerium(III) chloride in THF at À45 ꢀC to provide a 10:1
mixture in favor of the desired R,R-diastereomer 7,
which was obtained in diastereomerically pure form by
recrystallization as an HCl salt. Oxidation of the chiral
auxiliary with lead tetraacetate generated an imine, which
was hydrolyzed to liberate the homochiral amine 8.8
Further SAR in this series established the paradigm that
a sterically less demanding hydrogen bond acceptor,
such as a methoxyl (24) or a benzyloxy group (28), in
the para position of the a aryl ring enhances binding to
the b3 receptor with no significant effect on the affinity
for the b1 or b2 receptor (Table 3). The reduced potency
and selectivity of compound 29 may be attributed to an
increase in steric bulk and, secondarily, to the reduced
basicity of the oxygen attached to the phenyl ring. Pro-
gressive increase in electronegativity of the substituent
attached to the phenolic oxygen ultimately abolished
the enhanced b3 affinity. Compare 24, 25, and 26, where
a methoxyl or a difluoromethoxy group is favored in the
para-position of the a aryl ring while a trifluorometh-
Previous results2 from our laboratories indicated that
the hydroxysulfonanilido-ethanolamine moiety confers
full agonist activity at the human b3 receptor with the
1,2-diarylethylamine promoting high affinity and
greater selectivity for binding to the b3 adrenoceptor
over b1 and b2 receptors. The parent compound 9
showed reasonable potency, selectivity and full agonist
activity for the human b3 receptor (Table 1). Further
SAR studies revealed that R,R diastereomers were pre-
ferred since they provided the most favorable b3
potency and selectivity profile in this series.2 The nature
of the a aryl ring in the 1,2-diarylethylamine was
quite important since replacement with a thiazole or a
thiophene resulted in b2-selective compounds; whereas,
certain heterocycles such as a pyridine or benzo[b]thio-
phene maintained selectivity.
Table 2. Activity of compounds at the cloned human b adrenoceptors9
Compd
R
b3 Binding
Ki (nM)
b3 IA
(% act)
Selectivity
versus b1 versus b2
14a
15a
16
17
18
19
20
21
22
23
F
SO2Me
CN
CO2H
CO2Me
CONMe2
CONHMe
CONH2
CH2CONH2
CONHOH
836
440
210
8600
85
800
120
70
100
129
107
123
98
11
53
30
17
42
25
79
90
17
537
1
3
4
6
5
0.4
3
8
2
The potency of compounds in this series was sig-
nificantly influenced by the para substituent R on the a
phenyl ring in the 1,2-diarylethylamine moiety (Table 2).
A methyl ester (18) or a primary carboxamide (21 and
22) provided substantially increased affinity for the b3
receptor. The b3 binding selectivity of 20, 21, and 23
versus the b1 receptor is noteworthy.
98
102
108
106
106
74
147
4
aMixture of four diastereomers.
Table 3. Activity of compounds at the cloned human b adrenocep-
tors9
Scheme 3. Reagents and conditions: (a) (R)-2-phenylglycinol, CDCl3;
(b) PhCH2MgCl, CeCl3, THF; (c) Pb(OAc)4, methanol; (d) aq HCl,
methanol.
Table 1. Activity of compounds at the cloned humanb adrenoceptors9
Compd
R1
R2
R3 b3 Binding Ki (nM) Selectivity
vs b1 vs b2
24a
25
26b
27b
28b
29b
30
31
32
33
OMe
OCHF2
OCF3
OCH2CF3
OCH2Ph
OPh
OCH2O
OCHF2 OCHF2
OCHF2
OCHF2
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
44
21
210
84
70
990
8
38
69
9
59
36
25
83
58
4
52
37
6
8
5
2
1
2
0.5
8
0.4
0.6
14
Compd
R
b3 Binding
Ki (nM)
b3 IA
(% act)
Selectivitya
vs b1
15
30
4
vs b2
9
Phenyl
4-Pyridyl
2-Thiazolyl
3-Thienyl
5-Benzo[b]thienyl
360
700
2400
129
133
129
45
110
90
3
8
0.6
0.3
2
10
11
12
13
Me
H
1
19
12
230
aMixture of four diastereomers.
bMixture of R,R and R,S diastereomers.
aBinding selectivity is defined as Ki b1/Ki b3 or Ki b2/Ki b3.

A. V. Gavai et al. / Bioorg. Med. Chem. Lett. 11 (2001) 3041–3044
3043
oxyl is not, since the hydrogen bond acceptor ability of
the latter is drastically reduced. The difluoromethoxy
group also provides additional metabolic stability by
minimizing the propensity for the N-dealkylation path-
way to produce 4-hydroxy-3-methylsulfonoanilidoetha-
nolamine.2
(NEFA), free glycerol and potassium were determined
30 min after intravenous (iv) administration. Changes in
heart rate were monitored over the 30 min period.
Compounds 25 and 30 elicited dose-related increases in
NEFA levels (ED50=0.02 mg/kg for both 25 and 30),
achieving the maximal response evoked by iso-
proterenol. The lipolysis was unchanged in the presence
of 0.1 mg/kg of propranolol, a potent b1 and b2
antagonist, thus indicating that it was mediated through
the b3 adrenoceptor. However, despite the greater than
50-fold binding selectivity for the b3 versus b1 receptor,
these compounds produced tachycardia at a dose of
0.1 mg/kg, which was attributed to the activation of
b1 AR. Indeed, the tachycardia was abolished upon
co-administration with 0.1 mg/kg of propranolol.
Substitution at the meta position of the a phenyl ring is
not beneficial since it tends to increase binding to the b2
receptor. For example, difluoromethoxy (31) or a
methyl (32) substitution at the meta-position in the a
phenyl ring reduced the binding selectivity ratio (Ki b2/
Ki b3) of 25 about 10-fold. Although introduction of a
methyl group on the a carbon resulted in a significant
improvement in b3 potency (33), this effect was accom-
panied by an even greater increase in affinity for the b1
receptor.
In vivo selectivity of the most promising b3 agonists,
based on their in vitro profile and metabolic considera-
tions, was measured in African green monkeys by
increasing the dose progressively (0.01, 0.02, 0.1, 0.5,
and 2.5 mg/kg) until the onset of statistically significant
b1- or b2-mediated side effects. Although all the com-
pounds induced maximal lipolysis comparable to that
induced by isoproterenol, the naphthalene containing
compounds 34 and 36 exhibited a 10-fold reduction in
potency relative to the phenyl series, as shown in Table 5.
Compound 25 (BMS-196085) provided the best profile
with about 5-fold and 25-fold in vivo selectivity versus
b1 and b2 adrenergic receptors, respectively.
For compounds with b3 binding selectivity, intrinsic
activity (IA) at the b1 receptor, measured as a percen-
tage of the maximal increase in the beating rate of an
isolated spontaneously beating guinea pig atrium
induced by isoproterenol,10 was found to be a useful in
vitro predictor of tachycardia in primates. Increasing
lipophilicity was beneficial in reducing b1 agonist activ-
ity in this series (Table 4). Replacing the a phenyl ring
with a naphthalene (36 vs 25) provided significant
reduction in the b1 IA with concurrent improvement in
b3 binding and the selectivity profile. Similar substitu-
tions in the closely related 3-pyridine series resulted in
improved b3 potency and selectivity but the reduced
lipophilicity of these compounds contributed to higher
b1 agonist activity.
BMS-196085 emerged as the lead candidate from this
series and was chosen for further evaluation. BMS-
196085 is 190-fold more potent for binding to the
human (Ki=21 nM) versus murine (Ki=4,000 nM) b3
adrenoceptor. It is a partial agonist for the stimulation
of adenylate cyclase activity in CHO cells transfected
with the human b1 (IA=63%) and b2 (IA=45%)
receptors. In addition, this compound is a partial ago-
nist (IA=45%) at the b1 receptor in the guinea pig atria
assay.
Selected compounds were evaluated in vivo in anesthe-
tized African green monkeys to determine the margin of
separation between b3-mediated lipolysis and b1- or b2-
dependent events as measured by the changes in heart
rate and serum potassium levels, respectively. Changes
in plasma concentrations of non-esterified fatty acids
BMS-196085 showed a high volume of distribution
(10Æ5 L/kg), moderate clearance (36Æ9 mL/min/kg)
and a half-life of 7.3Æ1.9 h upon iv administration to
African green monkeys. Extensive glucuronidation
resulted in poor (<5%) oral systemic bioavailabilty. In
vitro studies showed that the phenolic and benzylic
hydroxyls were highly susceptible to glucuronidation.
Table 4. Activity of compounds at the cloned human b adrenocep-
tors9
BMS-196085 was administered via subcutaneous osmo-
tic mini-pumps for 2 weeks in obese hyperglycemic ob/
Compd
Ar
b3 Binding Selectivity b1 IA
(IA) Ki (nM)
(% act)a
(% act) vs b1 vs b2
Table 5. In vivo selectivity in African green monkeys (iv)
30
25
34
35
36
37
38
3,4-Methylenedioxyphenyl
4-Difluoromethoxyphenyl
1-Napthyl
4-Methoxy-1-napthyl
4-Difluoromethoxy-1-napthyl
6-Methoxy-3-pyridyl
8 (94)
21 (95)
43 (105)
26 (85)
2 (100)
25 (101)
15 (94)
52
36
33
46
275
180 30
61 13
8
5
6
9
9
80
45
40
22
23
70
60
Compd
Lipolysis
ED50 (mg/kg)
Margin before onset Margin before onset
of tachycardiaa
of hypokalemiaa
25
30
34
36
0.02
0.02
0.25
0.25
5
1
2
2
25
25
2
2,6-Dimethoxy-3-pyridyl
2
ab1 intrinsic activity is given as a percent of the maximal increase in the
beating rate of an isolated spontaneously beating guinea pig atrium
induced by isoproterenol.
aMargin before onset of tachycardia or hypokalemia was defined as
the lowest dose required to produce statistically significant event
divided by the ED50 for lipolysis.

3044
A. V. Gavai et al. / Bioorg. Med. Chem. Lett. 11 (2001) 3041–3044
ob mice to test its efficacy in a rodent model of obesity
and diabetes. A dose-dependent reduction in plasma
NEFA and free glycerol was observed. In addition, 3.4
mg/kg/day of BMS-196085 significantly reduced plasma
glucose concentrations from 399Æ53 mg/dl in vehicle-
treated mice to 207Æ6 mg/dl. Thus, chronic adminis-
tration of BMS-196085 produced desirable lowering of
plasma glucose and fatty acids in a murine model of
obesity-induced diabetes. This is consistent with pre-
vious studies demonstrating that chronic treatment with
b3 AR agonists results in proliferation of brown adipose
tissue, with an upregulation of the b3 AR, which is
associated with a decrease in plasma glucose, insulin
and NEFA levels.11
References and Notes
1. (a) For recent reviews, see: Weyer, C.; de Souza, C. J. Drug
Dev. Res. 2000, 51, 80. (b) Bray, G. A.; Tartaglia, L. A. Nature
2000, 404, 672. (c) Weyer, C.; Gautier, J. F.; Danforth, E., Jr.
Diabetes Metab. 1999, 25, 11. (d) Kordik, C. P.; Reitz, A. B. J.
Med. Chem. 1999, 42, 181. (e) Weber, A. E. Annu. Rep. Med.
Chem. 1998, 33, 193.
2. Washburn, W. N.; Sher, P. M.; Poss, K. M.; Girotra, R.
N.; McCann, P. J.; Gavai, A. V.; Mikkilineni, A. B.; Mathur,
A.; Cheng, P.; Dejneka, T. C.; Sun, C. Q.; Wang, T. C.; Har-
per, T. W.; Russell, A. D.; Slusarchyk, D. A.; Skwish, S.;
Allen, G. T.; Hillyer, D. E.; Frohlich, B. H.; Abboa-Offei, B.
E.; Cap, M.; Waldron, T. L.; George, R. J.; Tesfamariam, B.;
Ciosek, C. P., Jr.; Ryono, D.; Young, D. A.; Dickinson, K. E.;
Seymour, A. A.; Arbeeny, C. M.; Gregg, R. E. Bioorg. Med.
Chem. Lett. 2001, 11, 3035.
While the low oral bioavailability of BMS-196085 pre-
cluded development as an oral agent, the combination
of potency, low clearance, and moderate (12 mg/cm2/h)
transdermal flux across human cadaver skin suggested
that transdermal delivery might be a viable means to
assess whether long term exposure to a b3 agonist would
increase resting metabolic rate in man.12 In an initial
clinical proof-of-concept study, bolus iv administration
of BMS-196085 resulted in elevation of plasma levels of
free fatty acids at doses that did not produce any b1- or
b2-mediated side effects. However, 2-week continuous iv
infusion of BMS-196085 up to doses resulting in tachy-
cardia failed to produce statistically significant changes
in the resting metabolic rate.13
3. For a preliminary report regarding a portion of this work,
see: Gavai, A. V.; Sher, P. M.; Mathur, A.; Mikkilineni, A. B.;
Poss, K. M.; McCann, P. J.; Girotra, R. N.; Fisher, L. G.;
Wu, G.; Wang, T. C.; Sun, C. Q.; Bednarz, M. S.; Slusarchyk,
D. A.; Skwish, S.; Allen, G. T.; Hillyer, D. E.; Frohlich, B. H.;
Abboa-Offei, B. E.; Cap, M.; Waldron, T. L.; George, R. J.;
Tesfamariam, B.; Ciosek, C. P., Jr.; Young, D. A.; Dickinson,
K. E.; Seymour, A. A.; Arbeeny, C. M.; Washburn, W. N.
Abstract of Papers, 216th National Meeting of the American
Chemical Society, Boston, MA, Aug 23–27, 1998; MEDI-023.
4. Spectral data were fully consistent with the structures
depicted.
5. Hart, D. J.; Kanai, K.; Thomas, D. G.; Yang, T.-K. J. Org.
Chem. 1983, 48, 289.
6. Sato, T.; Naruse, K.; Enokiya, M.; Fujisawa, T. Chem.
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23, 2055.
In summary, this paper describes the study of 4-
hydroxy-3-methylsulfonanilido-1,2-diarylethylamines as
human b3 adrenergic receptor agonists. The study cul-
minated in the discovery of BMS-196085, a potent b3
full agonist with good selectivity for b3 over b1 and b2
receptors. However, efforts to demonstrate clinical
efficacy with this compound were not successful.
9. Receptor binding assays were carried out with membranes
prepared from CHO cells expressing the cloned human receptor
in the presence of 125I-iodocyanopindolol as previously repor-
ted: Sher, P. M.; Fisher, L. G.; Skwish, S.; Michel, I. M.; Seiler,
S. M.; Washburn, W. N.; Dickinson, K. E. Med. Chem. Res.
1997, 7, 109. b3 AR agonist activity was assessed by measure-
ment of cAMP accumulation levels in CHO membranes
expressing human b3 AR. Intrinsic activity (IA) was given as
percent of the maximal stimulation with isoproterenol.
10. Tesfamariam, B.; Allen, G. T. Br. J. Pharmacol. 1994, 112, 55.
11. Arbeeny, C. M.; Meyers, D. S.; Hillyer, D. E.; Bergquist,
K. E. Am. J. Physiol. 1995, 268, E678.
Acknowledgements
We thank Dr. Scott Biller for helpful discussions and
suggestions. We acknowledge the members of the Bris-
tol-Myers Squibb analytical chemistry department for
analytical and spectral determinations.
12. Unpublished work, communicated by T. Yu, Bristol-Myers
Squibb, Princeton, NJ, USA.
13. Unpublished work, communicated by P. Slugg, Bristol-
Myers Squibb, Princeton, NJ, USA.