Optimization of 3-(1H-Indazol-3-ylmethyl)-1,5-benzodiazepines as potent, orally active CCK-A agonists

Article abstract of DOI:10.1021/jm970265x

We previously described a series of 3-(1H-indazol-3-ylmethyl)-1,5- benzodiazepine CCK-A agonists exemplified by compound 1 (GW 5823), which is the first reported binding selective CCK-A full agonist demonstrating oral efficacy in a rat feeding model. In this report we describe analogs of compound 1 designed to explore changes to the CS and N1 pharmacophores and their effect on agonist activity and receptor selectivity. Agonist efficacy in this series was affected by stereoelectronic factors within the C3 moiety. Binding affinity for the CCK-A vs CCK-B receptor showed little dependence on the structure of the C3 moiety but was affected by the nature of the second substituent at CS. Structure-activity relationships at the N1- anilidoacetamide 'trigger' moiety within the C3 indazole series were also investigated. Both agonist efficacy and binding affinity within this series were modulated by variation of substituents on the Nl-anilidoacetamide moiety. Evaluation of several analogs in an in vivo mouse gallbladder emptying assay revealed compound 1 to be the most potent and efficacious of all the analogs tested. The pharmacokinetic and pharmacodynamic profile of 1 in rats is also discussed.

Full text of DOI:10.1021/jm970265x

2706
J . Med. Chem. 1997, 40, 2706-2725
Op tim iza tion of 3-(1H-In d a zol-3-ylm eth yl)-1,5-ben zod ia zep in es a s P oten t, Or a lly
Active CCK-A Agon ists
Brad R. Henke,*,† Christopher J . Aquino,† Larry S. Birkemo,‡ Dallas K. Croom,‡,§ Robert W. Dougherty, J r.,§,|
Gregory N. Ervin,‡, Mary K. Grizzle,‡ Gavin C. Hirst,†,∇ Michael K. J ames,‡,§ Michael F. J ohnson,‡
Kennedy L. Queen,| Ronald G. Sherrill,† Elizabeth E. Sugg,† Edward M. Suh,† J erzy W. Szewczyk,†
Rayomand J . Unwalla,†,# J eff Yingling,| and Timothy M. Willson†
Glaxo Wellcome Research and Development, Five Moore Drive, Research Triangle Park, North Carolina 27709
Received April 22, 1997X
We previously described a series of 3-(1H-indazol-3-ylmethyl)-1,5-benzodiazepine CCK-A
agonists exemplified by compound 1 (GW 5823), which is the first reported binding selective
CCK-A full agonist demonstrating oral efficacy in a rat feeding model. In this report we describe
analogs of compound 1 designed to explore changes to the C3 and N1 pharmacophores and
their effect on agonist activity and receptor selectivity. Agonist efficacy in this series was
affected by stereoelectronic factors within the C3 moiety. Binding affinity for the CCK-A vs
CCK-B receptor showed little dependence on the structure of the C3 moiety but was affected
by the nature of the second substituent at C3. Structure-activity relationships at the N1-
anilidoacetamide “trigger” moiety within the C3 indazole series were also investigated. Both
agonist efficacy and binding affinity within this series were modulated by variation of
substituents on the N1-anilidoacetamide moiety. Evaluation of several analogs in an in vivo
mouse gallbladder emptying assay revealed compound 1 to be the most potent and efficacious
of all the analogs tested. The pharmacokinetic and pharmacodynamic profile of 1 in rats is
also discussed.
Cholecystokinin (CCK) is a gastrointestinal hormone
and neurotransmitter involved in a number of digestive
processes such as contraction of the gall bladder,
stimulation of pancreatic and biliary secretion, and
modulation of gastric emptying.1 In addition, CCK
functions as a satiety signal by direct stimulation of
vagal afferents that signal to feeding centers in the
brain.2 CCK is found in a number of molecular forms
throughout peripheral tissues and the central nervous
system, with the C-terminal octapeptide CCK-8 (Asp-
Tyr(SO3H)-Met-Gly-Trp-Met-Asp-PheNH2) being the
minimal sequence required for bioactivity.1b,c The
physiological actions of CCK are mediated via two
G-protein-coupled seven transmembrane receptors.
CCK-A receptors are localized primarily in peripheral
tissues and appear to be the subtype which mediates
the satiety effect of CCK,3 while CCK-B receptors are
located mainly in the CNS.4 Exogenously administered
CCK has been shown to reduce both duration and size
of meals in several species, including lean5 and obese6
humans. In addition, administration of CCK-8 to
patients on total parenteral nutrition suggests a role
for CCK in the prevention of gallstones.7 An orally
active CCK-A selective agonist might therefore be useful
as a satiety agent and may provide an alternative to
current therapies for the treatment of obesity.8
We recently reported the identification of a series of
3-(indazol-3-ylmethyl)-1,5-benzodiazepines, exemplified
by 1 (Figure 1), which are potent, selective CCK-A
agonists in vitro.9 Compound 1 (GW 5823) is the first
reported CCK-A agonist which has demonstrated sup-
pression of food intake when dosed orally in a rat
feeding model. This paper provides a more complete
account of the design, synthesis, and pharmacological
activity of this series of 3-(indazol-3-ylmethyl)-1,5-
benzodiazepine CCK-A agonists. The structure-activ-
ity relationships of both the C3 substituents and the
N1-anilidoacetamide substituents are discussed. These
substituents appear to be the key pharmacophores
which modulate CCK-A agonist activity of this class of
compounds. In addition, the in vivo pharmacodynamic
and pharmacokinetic evaluation of compound 1 and
several additional analogs is described.
Ch em istr y
The general synthetic route used to prepare most of
the analogs is depicted in Scheme 1. This approach
allows for easy variation of both the N1 and C3 sub-
stituents. Construction of the N1 substituent was
effected via reductive amination10 of a primary aniline
with the appropriate ketone to afford the requisite
secondary aniline, followed by acylation with bro-
moacetyl bromide (Scheme 1). Alkylation of N-phenyl-
1,2-phenylenediamine with the appropriate bromoace-
tamide took place with complete chemoselectivity toward
the primary aniline. Double acylation with malonyl
dichloride then afforded the 1,5-benzodiazepine scaffold
in rapid fashion. This cyclization reaction was effected
simply by stirring the two reagents in a THF solution;
interestingly, addition of an external base to the reac-
tion afforded no cyclized material, possibly due to
decomposition of the malonyl dichloride via ketene
formation. Analogs which contain C3 alkyl substituents
* Address correspondence to: Brad R. Henke, Glaxo Wellcome
Research and Development, N2114, Five Moore Drive, Research
Triangle Park, NC 27709. Tel: (919) 483-1363. FAX: (919) 315-5668.
E-mail: henke∼br@glaxo.com.
† Department of Medicinal Chemistry.
‡ Department of Pharmacology.
§ Current address: Inspire Pharmaceuticals, Durham, NC 27703.
| Department of Receptor Biochemistry.
Current address: Department of Psychology, Brigham Young
University, Provo, UT 84602.
∇ Current address: BASF Bioresearch Corp., Worcester, MA 01605.
# Current address: Wyeth-Ayerst Research, Philadelphia, PA 19101.
X Abstract published in Advance ACS Abstracts, August 1, 1997.
S0022-2623(97)00265-3 CCC: $14.00 © 1997 American Chemical Society

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2707
F igu r e 1.
Sch em e 1a
a
Reagents: (i) NaB(OAc)3H, AcOH, THF, 0 °C to room temperature; (ii) bromoacetyl bromide, Et3N, CH2Cl2, 0 °C to room temperature;
(iii) K2CO3, DMF, 60 °C, 18 h; (iv) malonyl dichloride, THF, 0 °C to room temperature, 18 h; (v) NaH, NaN(TMS)2 or KN(TMS)2, room
temperature, DMF, 15 min and then addition of alkyl halide, DMF, room temperature, 2-5 h; (vi) NaN(TMS)2 or KN(TMS)2, room
temperature, DMF, 15 min and then addition of R3-X, DMF, room temperature, 2-5 h; (vii) deprotection (if necessary).
were synthesized via deprotonation using either NaH,
KN(TMS)2, or NaN(TMS)2 as the base followed by
addition of the requisite heteroaromatic alkyl halide,
followed by deprotection if necessary (Scheme 1). Choice
of base used for the deprotonation had no effect on either
the yield or time course of the reaction; based on
convenience, NaN(TMS)2 was usually employed. For-
mation of the C3 quaternary analogs in which the
second substituent was a methyl group was achieved
by a second deprotonation and quenching with methyl
iodide, again followed by deprotection if necessary. This
sequence of alkylations could also be reversed without
loss of yield; however, usually the alkylations were
carried out in the order described above since it was a
more efficient way to obtain both the C3-hydrogen and
C3-methyl analogs containing a common C3 indazole
derivative.
Alkylation of the N1 amide nitrogen was carried out by
deprotonation of the N1 amide with NaH and addition
of the requisite bromoacetamide (formed as in Scheme
1). Careful monitoring of both the amount of NaH
utilized and the reaction time was needed in order to
avoid byproducts originating from additional alkylation
at the C3 position. Completion of the synthesis pro-
ceeded in a fashion identical to that outlined in Scheme
1. In general the route depicted in Scheme 1 is the
preferred route to these analogs, based on ease of
synthesis and higher yields.
Analogs 21 and 24, which contain a C3 methoxy
group, were synthesized by the route shown in Scheme
3. Dimethyl methoxymalonate was deprotonated using
NaN(TMS)2 and alkylated with the appropriate bro-
mide, followed by saponification to the diacid and
conversion to the diacid chloride. Cyclization of these
disubstituted malonate derivatives with the appropriate
diamine (constructed as in Scheme 1) required refluxing
THF in order to effect cyclization, presumably due to
the increased steric bulk around the acid chlorides.
Deprotection then afforded analogs 21 and 24.
An alternative approach (Scheme 2) was also inves-
tigated and utilized in the synthesis of analogs 38, 42,
44, and 45. In this approach the 1,5-benzodiazepine
ring was formed prior to attachment of the N1 moiety.
Formation of the benzodiazepine ring was accomplished
via a three-step procedure which involved acylation of
2-nitrodiphenylamine with methylmalonyl chloride, re-
duction of the aromatic nitro group with 10% palladium
on carbon, and sodium ethoxide catalyzed ring closure.
The general synthetic route used in preparing several
of the 3-bromoheterocyclic alkylating agents used in
Schemes 1 and 2 is outlined in Scheme 4. The three-
step sequence, starting from the corresponding known

2708 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Henke et al.
Sch em e 2a
a
Reagents: (i) methylmalonyl chloride, toluene, 80 °C, 48 h; (ii) H2, 10% Pd/C, EtOH/EtOAc; (iii) Na/EtOH; (iv) NaH, DMF, 0 °C then
3d ,h -j, room temperature; (v) NaH, NaN(TMS)2 or KN(TMS)2, DMF, room temperature, 15 min and then addition of alkyl halide, DMF
room temperature, 2-5 h; (vi) NaN(TMS)2 or KN(TMS)2, DMF, room temperature, 15 min and then addition of R3-X, DMF, room
temperature, 2-5 h; (vii) deprotection (if necessary).
Sch em e 3a
a
Reagents: (i) NaN(TMS)2, DMF, room temperature, 15 min; (ii) alkyl halide, DMF, room temperature, 2-5 h; (iii) NaOH, EtOH,
room temperature; (iv) oxalyl chloride, cat. DMF, CH2Cl2, 0 °C to room temperature, 1 h; (v) THF, reflux, 4 h; (vi) 10% Pd/C, formic acid,
EtOH, reflux, 6 h (R ) benzyl).
Sch em e 4a
Sch em e 5a
a
Reagents: (i) benzyl bromide or methyl iodide, K2CO3, DMF,
room temperature; (ii) DIBAL-H, CH2Cl2, -78 °C to room tem-
perature; (iii) PPh3Br2, CH3CN or CCl4, 0 °C.
3-carboxylic acid derivatives,11 involves conversion to
the methyl or benzyl ester, reduction of the ester to the
corresponding alcohol using DIBAL-H, and conversion
to the bromide with Ph3PBr2.12 An additional NH
protection step was needed in the indole and indazole
series and was done prior to reduction of the ester.
However, there were several problems with this general
approach. Preparation of the requisite 3-carboxylic
acids11 was often a several-step procedure and tended
to be cumbersome on large scale. In addition, poor
(<50%) yields were also observed in many cases during
attempted conversion of the alcohols to the bromides
using Ph3PBr2 or other brominating agents. Finally,
this synthetic route allowed for little flexibility in choice
of protecting groups for the indazole or indole nitrogen;
benzyl13 was found to be the most robust but was often
difficult to remove, resulting in incomplete conversion
and poor yields in the final deprotection step.
a
Reagents: (i) NaNO2, NaOH, H2O then H2SO4, SnCl2; (ii)
hydrazine, ethylene glycol, 0 °C for 4 h then reflux; (iii) (BOC)2O,
Et3N, DMAP, CH3CN; (iv) N-bromosuccinimide, cat. benzoyl
peroxide, CCl4, reflux.
efficient method for construction of the desired bro-
mides. Diazotization of the requisite o-aminoacetophe-
nones followed by SnCl2-mediated reduction provided
the 3-methylindazole derivatives.14 Protection of the N1
nitrogen by (Boc)2O13 followed by radical bromination
with NBS15 provided the protected indazole bromides
in good yields. The desired bromide was always ac-
companied by unreacted starting material and dibro-
minated products, but fortunately in all cases these
could be easily separated by silica gel chromatography.
Compounds 18 and 28 were also synthesized in an
analogous manner from their corresponding 3-methyl
derivatives.16 In cases where the desired o-aminoac-
etophenone was not readily available, an alternative
procedure starting with the o-fluoroacetophenone analog
An alternative route (Scheme 5) was developed in the
indazole series which provided a shorter and more

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2709
Sch em e 6a
a
Reagents: (i) ethyl propiolate, Et3N, THF, room temperature; (ii) Pd(OAc)2, PPh3, NaHCO3, DMF, 110 °C, 16 h; (iii) DIBAL-H, CH2Cl2,
-78 °C to room temperature; (iv) PPh3Br2, CCl4, 0 °C.
Sch em e 7a
a
Reagents: (i) Tf2O, Et3N, CH2Cl2; (ii) (PPh3)2PdCl2, CuI, 1-ethoxy-1-(trimethylstannyl)ethene, DMF, 75 0 °C; (iii) 2 N HCl, THF; (iv)
H2, 10% Pd/C, EtOH, room temperature.
Ta ble 1. In Vitro Profile of 1,5-Benzodiazepine CCK-A Agonists
structuresa
functional assayb
binding assayc
CCK-B (pIC50
no.
X
Y
ED50 (nM)
%max
CCK-A (pIC50
)
)
A/BSel
CCK-8
15
16
17
1
-
-
2 ( 1 (5)
100
8.88 ( 0.22 (8)
7.96 ( 0.14 (3)
9.46 ( 0.04 (8)
5.28 ( 0.08 (3)
0.3
480
-
CH
CH
CH
N
NH
O
340 (1)
70 (4)
40 (1)
50 (1)
100 (6)
80 (2)
30 (1)
-
-
-
-
S
NH
O
-
-
-
109 ( 60 (4)
130 (1)
-
7.64 ( 0.12 (5)
7.05 ( 0.15 (4)
6.00 ( 0.23 (4)
3.76 ( 1.02 (3)
50
1980
-
18
19
N
N
S
-
-
a
b
See figure. Functional activity in the isolated guinea pig gall bladder following incubation with the test ligand for 30 min at 37 °C;
ED50, concentration at which 50% of the maximal contraction was observed ( SE (number of determinations); -, an ED50 was not
determined; %max (number of determinations), relative efficacy as determined by the maximal contraction observed at 1 µM standardized
to CCK-8 (1 µM) ) 100%, all values ( 5%. c Binding affinity for human CCK-A and CCK-B receptors; pIC50, -log of the concentration
that displaced 50% of [125I]Bolton-Hunter CCK-8 from membrane preparations isolated from CHO-K1 cells stably transfected with cDNA
of human CCK-A and CCK-B receptors ( SE (number of determinations); -, not determined; A/BSel, CCK-A receptor selectivity calculated
from IC50(B)/IC50(A).
was utilized (Scheme 5). Generation of the hydrazone
with hydrazine hydrate followed by refluxing in ethyl-
ene glycol to effect intramolecular nucleophilic aromatic
substitution provided the desired 3-methylindazole
derivative.
vinyl ether afforded no desired product with this sub-
strate. Reduction of the nitro group with H2 and 10%
palladium provided the amino derivative which was
converted into the desired bromide using the four-step
sequence outlined in Scheme 5.
The synthesis of 3-(bromomethyl)benzofuran is shown
in Scheme 6. Michael addition of 2-bromophenol with
ethyl propiolate followed by an intramolecular Heck17
coupling afforded benzofuran-3-carboxylic acid ethyl
ester. This material was then reduced with DIBAL-H
and converted to the desired bromide with Ph3PBr2.
The synthesis of 3-(bromomethyl)-1-(tert-butoxycar-
bonyl)pyrazolo[4,3-b]pyridine, used in the formation of
compound 29, is outlined in Scheme 7. 2-Hydroxy-3-
nitropyridine was converted into the corresponding
triflate ester under standard conditions18 and then
coupled with 1-ethoxy-1-(trimethylstannyl)ethene19 us-
ing methodology described by Stille20 to afford, after
hydrolysis, 1-(3-nitropyridin-2-yl)ethanone. The more
direct approach utilizing a Heck coupling with butyl
Biology
Analogs were initially evaluated for in vitro functional
efficacy in inducing contraction of the isolated guinea
pig gallbladder (GPGB) at a 1 µM concentration (Tables
1-4).21 The activity of all compounds reported was
reversed completely by addition of the CCK-A receptor
selective antagonist MK-32922 (0.5 µM). Full concentra-
tion-response curves on the GPGB and receptor binding
affinities were obtained only for those compounds which
induced g50% of the maximal contraction produced by
CCK-8. Receptor binding affinities were measured on
membrane preparations from CHO-K1 cell lines23 stably
transfected with cDNA from either human CCK-A24 or
CCK-B25 receptors (Tables 1-4). IC50 values were

2710 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Ta ble 2. In Vitro Profile of 1,5-Benzodiazepine CCK-A Agonists
Henke et al.
structuresa
X
functional assayb
binding assayc
CCK-B (pIC50
no.
R
Y
ED50 (nM)
%max
CCK-A (pIC50
)
)
A/BSel
CCK-8
15
-
-
-
2 ( 1 (5)
340 (1)
530 (1)
150 (1)
-
100
8.88 ( 0.22
9.46 ( 0.04 (8)
5.28 ( 0.08 (3)
4.76 ( 0.26 (5)
4.53 ( 0.48 (3)
0.3
H
CH
CH
CH
CH
N
NH
NH
NH
70 (4)
60 (3)
60 (2)
40 (2)
100 (6)
80 (3)
70 (3)
90 (3)
40 (2)
60 (2)
7.96 ( 0.14 (3)
8.08 ( 0.24 (4)
7.86 ( 0.29 (3)
7.75 ( 0.11 (2)
7.64 ( 0.12 (5)
7.88 ( 0.02 (3)
7.84 ( 0.31 (3)
7.37 ( 0.43 (3)
6.51 ( 0.16 (5)
7.41 ( 0.01 (2)
480
2090
2140
-
20
CH3
OCH3
CH3
H
CH3
OCH3
H
21
22
NCH3
NH
NH
NH
NCH3
NCH2Ph
NCH3
-
1
109 ( 60 (4)
320 (1)
70 (1)
6.00 ( 0.23 (4)
4.16 ( 0.23 (3)
5.44 ( 0.17 (3)
5.62 ( 0.20 (3)
4.00 ( 0.01 (2)
50
23
N
5100
250
60
24
N
25
N
70 ( 10 (2)
340 (1)
240 (1)
26
H
CH3
N
320
-
27
N
-
a
b
See figure. Functional activity in the isolated guinea pig gall bladder following incubation with the test ligand for 30 min at 37 °C;
ED50, concentration at which 50% of the maximal contraction was observed (SE (number of determinations); -, an ED50 was not determined;
%max (number of determinations), relative efficacy as determined by the maximal contraction observed at 1 µM standardized to CCK-8
(1 µM) ) 100%, all values ( 5%. c Binding affinity for human CCK-A and CCK-B receptors; pIC50, -log of the concentration that displaced
50% of [125I]Bolton-Hunter CCK-8 from membrane preparations isolated from CHO-K1 cells stably transfected with cDNA of human
CCK-A and CCK-B receptors ( SE (number of determinations); -, not determined; A/BSel, CCK-A receptor selectivity calculated from
IC50(B)/IC50(A).
determined using competitive radioligand binding with
labeled CCK-8.
ing orally active satiety agents by modifying the C3
moiety. The structure-activity relationships of both
phenylurea and amide series of compounds at this C3
position was the focus of two recent reports from our
laboratories.28,29
Selected compounds which induced g50% contraction
of the GPGB relative to CCK-8 were also evaluated for
in vivo activity in the mouse gallbladder emptying26
(MBGE) assay at a single dose (0.1 µmol/kg, ip or 1 µmol/
kg, po). The extent of CCK-A-mediated gallbladder
emptying is measured 30 min after compound admin-
istration, thus providing a rapid measure of CCK-A-
mediated peripheral agonist activity (Table 5). In vivo
satiety effects were assessed following intraperitoneal
(ip) administration in a rat feeding21 model (Table 5).
This model provides measurement of the anorectic
activity of CCK-A agonists taking into account both
vagally-mediated behavioral satiety effects in combina-
tion with effects through inhibition of gastric empty-
ing.27 The ED50 values in Table 5 represent the dose of
test compound which produces a half-maximal response
for that individual compound.
The strategy for modification of the C3 pharmacoph-
ore was suggested by structural analysis of the selective
CCK-A antagonist natural product asperlicin (Figure
1),30 which has been used by others as a template for
the design of subtype-selective antagonists. The pio-
neering work at Merck22,31 and later at Lilly32 demon-
strated that the 3-indolinylmethyl group embedded
within the structure of asperlicin was an important
element for bioactivity. In addition, this moiety is
structurally similar to L-tryptophan, which is a key
amino acid required for agonist activity in the peptide
sequence of CCK and in various peptidomimetics of
CCK.33 The recurrence of the indole moiety in the
reported CCK agonists and antagonists provided us
with some degree of confidence that structure-activity
relationships developed for the 1,4-benzodiazepine CCK-A
and CCK-B receptor antagonists would be applicable to
our 1,5-benzodiazepine CCK-A agonist series.
Resu lts a n d Discu ssion
We had previously disclosed the identification of a
series of 3-(phenylureido)-1,5-benzodiazepine CCK-A
agonists.21 To our knowledge, these compounds (exem-
plified by 2, Figure 1) were the first reported non-
peptide CCK-A agonists. Agonist efficacy within this
series was modulated by variation of substituents on
the N1-anilidoacetamide moiety, with minor structural
modifications providing the “trigger” for interconversion
between antagonist and agonist functional activity.
Structure-activity relationships at this position re-
vealed that a single methyl group confers agonist
activity, with an N-isopropyl substituent providing
optimal efficacy. Given this apparent sensitivity to
agonist/antagonist interconversion at the N1 pharma-
cophore, we decided to focus our effort toward identify-
The structures and in vitro biological data are found
in Tables 1-4 and fall into two broad categories:
analogs in which the N1 substituent is an N-isopropyl-
N-(4-methoxyphenyl)acetamide group while the C3 sub-
stituent is varied (Tables 1-3), and analogs in which
the C3 substituent is a 3-indazol-3-ylmethyl group while
the substituents on the N1-anilido nitrogen atom are
changed (Table 4). Physical data for these compounds
is presented in Table 7.
As the GPGB activity data in Table 1 shows, CCK-A
agonist efficacy was modulated by the 5-membered ring
structure embedded within the C3 heterocycle. Nitro-

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2711
Ta ble 3. In Vitro Profile of 1,5-Benzodiazepine CCK-A Agonists
f
b
CCK-8
a
b
See figure. Functional activity in the isolated guinea pig gall bladder following incubation with the test ligand for 30 min at 37 °C;
ED50, concentration at which 50% of the maximal contraction was observed ( SE (number of determinations); -, an ED50 was not
determined; %max (number of determinations), relative efficacy as determined by the maximal contraction observed at 1 µM standardized
to CCK-8 (1 µM) ) 100%, all values ( 5%. c Binding affinity for human CCK-A and CCK-B receptors; pIC50, -log of the concentration
that displaced 50% of [125I]Bolton-Hunter CCK-8 from membrane preparations isolated from CHO-K1 cells stably transfected with cDNA
of human CCK-A and CCK-B receptors ( SE (number of determinations); -, not determined; A/BSel, CCK-A receptor selectivity calculated
from IC50(B)/IC50(A).
gen is the preferred heteroatom in both the 1- and
2-position of the 5-membered ring. The CCK-A agonist
efficacy within this series increased in the order of
benzothiophene ≈ benzisothiazole ≈ benzofuran < in-
dole ≈ benzisoxazole < indazole, with analog 1 having
efficacy equal to that of CCK-8 in the GPGB assay.
Representation of the electrostatic potential surface
mapped onto the electron density surface using SPAR-
TAN34 (data not shown) provides a qualitative explana-
tion for the observed trend within this series. The
increase in efficacy parallels the increase in negative
electrostatic potential at the 2-position of the indole ring,
suggesting that high electron density at this position is
important for agonist activity. Table 2 shows the effects
on CCK-A activity of altering the remaining C3 sub-
stituent and increasing steric bulk on the N1 nitrogen
within the indole and indazole series. Replacement of
the C3 hydrogen atom with either a methyl or methoxy
substituent resulted in a small decrease in agonist
activity (15 vs 20 and 21, 1 vs 23 and 24). Methylation
of the indole or indazole nitrogen also resulted in a small
decrease in efficacy (20 vs 22, 1 vs 25, 23 vs 27), while
N-benzyl analog 26 had substantially reduced agonist
activity. Importantly, all compounds which showed
g50% contraction in the GPGB assay also displayed
submicromolar potencies ranging from 20 to 500 nM
(Tables 1 and 2). Interpretations on potency differences
within this series are precluded due to the lack of a
significant number of full dose-response experiments
for most entries.

2712 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Ta ble 4. In Vitro Profile of 1,5-Benzodiazepine CCK-A Agonists
Henke et al.
binding assayc
functional assayb
CCK-8
a
b
See figure. Functional activity in the isolated guinea pig gall bladder following incubation with the test ligand for 30 min at 37 °C;
ED50, concentration at which 50% of the maximal contraction was observed ( SE (number of determinations); -, an ED50 was not
determined; %max (number of determinations), relative efficacy as determined by the maximal contraction observed at 1 µM standardized
to CCK-8 (1 µM) ) 100%, all values ( 5%. c Binding affinity for human CCK-A and CCK-B receptors; pIC50, -log of the concentration
that displaced 50% of [125I]Bolton-Hunter CCK-8 from membrane preparations isolated from CHO-K1 cells stably transfected with cDNA
of human CCK-A and CCK-B receptors ( SE (number of determinations); -, not determined; A/BSel, CCK-A receptor selectivity calculated
from IC50(B)/IC50(A).
CCK receptor binding affinity and subtype selectivity
were also modulated by the nature of the other sub-
stituent at C3 and steric bulk around the N1 nitrogen
(Table 2). Replacement of the C3 hydrogen with either
a methyl or methoxy group resulted in a 5-100-fold
improvement in CCK-A/CCK-B binding selectivity (15
vs 20 and 21, 1 vs 23 and 24). This improvement in
selectivity was due primarily to loss of affinity for the
CCK-B receptor, although modest improvement in
CCK-A affinity was also observed. Several of these
compounds displayed A/B selectivities >1000, the high-
est seen to date within the 1,5-benzodiazepine series.
Interestingly, compound 18 (Table 1), which has a
hydrogen at the C3 position, also displayed >1000-fold
selectivity for the CCK-A receptor. The origin of this
marked improvement in binding selectivity vs other
compounds in this series with a C3 hydrogen is unclear.
While methylation of the N1 nitrogen had little effect
on CCK-A binding, N-benzyl analog 26 showed >10-fold
loss in both CCK-A and CCK-B binding affinity, sug-
gesting a lack of tolerance by the receptors for sterically
demanding groups at this site.
The effect of changing both the steric bulk and
stereoelectronics of the 6-membered ring portion of the
C3 heterocycle was briefly examined, with the results
shown in Table 3. On the basis of the efficacy in the
GPGB assay, indazole was chosen as the 5-membered
ring template for this investigation. Incorporation of a
nitrogen in the 7-position to yield the 1H-pyrazolo[4,3-
b]pyridin-7-yl derivative 28 which displayed similar
efficacy to compound 1; however, the 1H-pyrazolo[4,3-
b]pyridin-4-yl analog 29 showed a large decrease in
efficacy. In addition, the pyrazolo[4,3-b]pyridine deriva-
tives showed a small reduction in binding affinity for
the CCK-A receptor. Replacement of hydrogen with
fluorine in the 4, 5, and 6 positions had little or no effect
on either efficacy or affinity for the CCK receptors, while
saturation of the phenyl ring (33) reduced both efficacy
and binding affinity to a modest degree. The 5-meth-
ylpyrazole analog 35 in which the indazole phenyl ring
is essentially removed was inactive, as was the 4-phe-
nylpyrazole analog 36. The drastic reduction in agonist
activity of these two analogs suggests that the C3

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2713
Ta ble 5. In Vivo Activity of Lead 1,5-Benzodiazepines
Ta ble 7. Physical Data for Compounds 1 and 15-45
MGBEa
HRMS molecular ion
anorexiab
ip
ip
po
no.
formula
% puritya
theory
found
analysisb
C,H,N
no.
ED50
%max
ED50
%max
ED50
%max
1
15
C35H33N5O4
99
97
100
97
99
98
100
100
98
96
98
-
-
C
36H34N4O4
586.2587 586.2580 C,H,Nc
CCK-8
1
15
20
21
23
24
25
27
0.03
0.2
3.8
0.8
ND
ND
0.3
0.8
10
95
97
90
91
84
ND
89
83
ND
ND
10
ND
89
74
46
54
28
72
84
75
30
50
95
98
16 C36H33N3O5
588.2503 588.2498
604.2271 604.2270
-
-
-
-
-
17
18
19
20
C
C
C
C
36H33N3O4S
35H32N4O5
35H32N4O4S
37H36N4O4
100
380
ND
ND
100
30
ND
ND
ND
ND
ND
220
ND
ND
ND
ND
ND
52
-
-
-
C,H,N
C,H,N
C,H,Nd
-
21 C37H36N4O5
616.2686 616.2675
615.2968 615.2971
22
23
24
C
C
C
38H38N4O4
36H35N5O4
36H35N5O5
-
98
ND
602.2768 602.2767 C,H,N
450
618.2719 618.2716 C,H,Ne
a
In vivo mouse gall bladder emptying assay. Following over-
night food deprivation, male CD-1 mice (10 animals per dose) were
treated (ip or po) with vehicle (ethanol/propylene glycol/water, 2:3:
5, 1 mL/kg) or test compound dissolved in vehicle (1 mL/kg). 30
min after drug treatment, animals were sacrificed (CO2) and the
gall bladders were dissected out and weighed. Gall bladder wet
weights of the treated animals were normalized to the vehicle
control group; ED50, dose of test compound that produces a half-
maximal response of individual compounds, nmol/kg; %max,
maximal response at 1 nmol/kg, ip for CCK-8, 0.1 µmol/kg, ip or 1
25 C36H35N5O4
100
97
97
95
98
100
95
97
96
97
100
100
98
99
98
97
94
96
96
-
-
C,H,N
-
26
27
28
C
C
C
42H39N5O4
37H37N5O4
34H32N6O4
678.3082 678.3080
616.2920 616.2924
-
-
-
-
-
-
-
C,H,Nf
C,H,Ng
C,H,N
-
29 C34H32N6O4
30 C35H37N5O4
31
32
33
34
35
36
37
C
C
C
C
C
C
C
35H32FN5O4
35H32FN5O4
35H32FN5O4
35H32FN5O4
32H33N5O4
37H35N5O4
34H31N5O3
606.2517 606.2506
606.2517 606.2517
606.2517 606.2516
606.2517 606.2510
-
-
-
b
µmol/kg, po for test compounds. Anorectic potency in rats con-
-
-
-
-
C,H,N
C,H,N
ditioned to a palatable liquid diet and fasted for 2 h; ED50, dose of
test compound that produces a half-maximal response, nmol/kg;
%max, maximal response at 0.5 µmol/kg, ip for CCK-8 and 10
µmol/kg, ip for test compound; ND, not determined.
558.2505 558.2501 C,H,Nh
38 C34H30FN5O3
576.2411 576.2404
-
588.2611 588.2602
588.2611 588.2604
602.2403 602.2410
584.2662 584.2660
-
C,H,N
-
-
-
-
39
40
41
42
43
44
45
C
C
C
C
C
C
C
35H30F3N5O3
35H33N5O4
35H33N5O4
35H31N5O5
36H33N5O3
34H29N5O3
35H33N5O3
-
Ta ble 6. Rat Pharmacokinetic Data for Compounds 1, 23, 24,
and 27
dose
Cmax
T1/2
CLTOT
Vss
no. routea (mg/kg)b (ng/mL)c (h)d (mL/min/kg)e (mL/kg)f %Fg
94
98
556.2349 556.2341 C,H,N
C,H,N
1
iv
po
id
iv
id
iv
po
iv
6.3
6.2
6.6
5.2
5.2
5.5
6.3
6.5
6.5
2105
20
193
3393
30
4900
90
3270
20
2.1
-
-
3.9
-
3.4
-
38
-
-
30
-
35
-
5175
-
-
4313
-
7630
-
NA
8
-
-
a
Purity values were obtained by reverse-phase analytical HPLC
16
NA
15
NA
5
using a Waters 600E system equipped with a Waters 990 diode
array spectrometer (λ range 200-400 nm). The stationary phase
was a Vydac C-18 column (5 µm, 4.6 mm × 200 mm). The mobile
phase employed 0.1% aqueous TFA with acetonitrile as the organic
modifier and the flow rate was 1.0 or 1.5 mL/min (to ) 3 min).
23
24
27
7.5
-
31
-
11050 NA
-
b
Combustion analyses are within (0.4% of the calculated value
po
4
unless otherwise indicated. c C, calc 73.70, found 72.70. C, calc
d
a
b
73.98, found 73.27. e C, calc 70.00, found 69.10. f C, calc 69.37,
IV ) intravenous, po ) oral, id ) intraduodenal. Compound
g
h
dosed as a solution in 5% DMSO/95% Molecusol solution (4:6,
found 68.69. N, calc 14.28, found, 13.73. C, calc 73.23, found
72.78.
Molecusol:pH 7 buffer, w/v). c Maximum detected plasma concen-
d
tration of parent drug in ng/mL. Half-life of parent compound,
h. e Total body clearance of parent compound in mL/min/kg, )
[(dose)iv]/[(AUC)iv]. f Volume of distribution at steady state, mL/
kg. g Oral bioavailability in Long-Evans rats, [(AUC)po]/[(AUC)iv]
× 100.
agonist in vitro but showed a 10-fold reduction in CCK-A
binding affinity vs compound 1. Since previous inves-
tigations21 had revealed the anilido nitrogen to be
extremely sensitive to both steric and stereoelectronic
perturbation, we chose to look at only three modifica-
tions at this site which had not been evaluated earlier.
Replacement of the N-isopropyl group with cyclopentyl
(43) led to a slight loss in efficacy with no change in
binding affinity, while replacement with cyclopropyl (44)
or tert-butyl (45) groups resulted in >10-fold decrease
in CCK-A binding affinity. Overall, none of the modi-
fications at the N1-anilido moiety resulted in compounds
with an in vitro profile superior to that of 1.
pharmacophore must occupy a fairly flat and narrow
but relatively deep pocket within the CCK-A receptor.
Finally, a brief investigation of the N1-anilidoaceta-
mide moiety was carried out within the C3 indazolyl-
methyl series. The results are displayed in Table 4.
Previous work21 in the C3 urea series had shown that
hydrophilic electron-donating groups such as methoxy
at the para position of the anilido ring were optimal for
in vitro efficacy and A/B binding selectivity. Removal
of the p-methoxy group (37) lowered efficacy only
slightly in this series, but reduced A/B binding selectiv-
ity >10-fold. Interestingly, replacement of the p-meth-
oxy group with electron-withdrawing groups (38, 39)
had only a modest reduction in efficacy, in contrast to
the C3 phenylurea series.21 The corresponding o- and
m-methoxy isomers 40 and 41 were not only less
efficacious than the para isomer 1 but also displayed a
reversal in A/B binding selectivity, derived from both
an increase in CCK-B affinity and a decrease in CCK-A
affinity. The 3,4-methylenedioxy analog 42 was a full
A subset of compounds which displayed good in vitro
efficacy and A/B binding selectivity were characterized
further for in vivo potency and efficacy (Table 5). All
compounds tested were fully efficacious relative to
CCK-8 following ip administration in the mouse gall-
bladder emptying (MGBE) assay, with potencies rang-
ing from 10- to 100-fold less than that of CCK-8.
However, only compounds 1, 15, 24, 25, and 27 dis-
played >50% maximal response when dosed orally in
this assay. Of these five compounds, 1 and 25 were the
most potent when dosed orally, with 1 being the most

2714 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Henke et al.
logs also displayed similar in vitro lability in this assay
(Figure 2), suggesting that the metabolic instability
associated with these compounds is more complex than
simple oxidation at the C3 indazole moiety.
CCK is reported to inhibit gastric emptying in a
variety of species through CCK-A receptor-mediated
contraction of the pyloric sphincter.35 Therefore, gastric
retention of drug may also contribute to the low oral
bioavailability observed with 1. Compound 1 was
evaluated for its ability to inhibit gastric emptying in
rats following both ip and po administration.36 In this
assay compound 1 was able to completely inhibit gastric
emptying upon ip and po administration at a concentra-
tion of 0.1 and 1.0 µmol/kg, respectively (data not
shown). Intraduodenal (id) administration of 1, which
bypasses the pyloric sphincter, resulted in a 2-fold
increase in bioavailability over that seen upon oral
dosing (Table 6). In addition, the Cmax after id admin-
istration was 10-fold higher than that obtained via po
administration. Taken together these results suggest
that gastric retention of 1 is partially responsible for
the low oral bioavailability. The clinical implications
of the gastric retention observed with compound 1 are
not well understood since there is considerable species
variation in CCK-A receptor-mediated delayed gastric
emptying, with humans reported to be less sensitive
than rats.37 A more detailed analysis of the pharma-
cokinetic and pharmacodynamic profiles of nonpeptide
CCK-A agonists is the subject of a recent report from
our laboratories.38
F igu r e 2. Test compound was incubated for 3 h with liver
from normal (noninduced) Sprague-Dawley rats at 37 °C
using 4 µM P450 concentrations in 0.1 M potassium phosphate
buffer (pH 7.2) in a final volume of 1 mL. Analysis of the
incubation mixture was carried out by analytical HPLC.
potent and efficacious of the compounds tested inde-
pendent of the route of administration.
The potency and efficacy of analogs 1, 24, and 25 were
also evaluated upon ip administration in the rat con-
ditioned feeder assay (Table 5). Compound 24 was only
a partial agonist in this assay, and an ED50 was not
determined. Benzodiazepine 25, although fully effica-
cious compared to CCK-8, was 10-fold less potent.
Compound 1, however, displayed potency and efficacy
equal to that of CCK-8. The differences in potency and
efficacy among the analogs tested in these two assays
may reflect species differences in pharmacokinetics and/
or pharmacodynamics of the various compounds.
The pharmacokinetic profiles of compound 1 and
analogs in which the C3 substituent (23, 24) and
indazole N1 nitrogen (27) are altered were evaluated
in the rat (Table 6). Compound 1 displayed fairly high
total body clearance (CLTOT ) 38 mL/min/kg) and a
short half-life (t1/2 ) 2.1 h) following iv administration.
The oral bioavailability of a 10 µmol/kg (6 mg/kg) dose
was 8%, with a Cmax of only 20 ng/mL. Analogs 23, 24,
and 27 also displayed similar pharmacokinetic profiles
characterized by high total body clearance and poor oral
bioavailability, although the half-life of these analogs
were all longer than that seen with compound 1.
To investigate the contribution of liver metabolism
to the poor bioavailability and high clearance observed
in these analogs, compound 1 was incubated with rat
liver microsomes (37 °C, 5 µM 1, 1 mg microsomal
protein) for 3 h. The results indicate compound 1 was
rapidly metabolized by rat liver microsomes, with a half-
life of approximately 30 min (Figure 2). The fluorinated
analogs 31-34, which displayed potency and efficacy
equal to that of 1 in vitro, were also incubated with rat
liver microsomes. The fluorine substituents might serve
to protect against any potential oxidative metabolism
occurring in the indazole moiety and thus provide
greater metabolic stability. Unfortunately these ana-
Despite the low oral bioavailability of compound 1,
on the basis of the overall in vitro and in vivo profile,
this analog was evaluated for oral activity in the rat
conditioned feeder model. The results (Figure 3) dem-
onstrate indazole 1 was effective at reducing food intake
to 40% of vehicle controls when given orally at a dose
of 10 µmol/kg, with statistically significant reduction in
food intake occurring at a dose of 1 µmol/kg after 180
min. At the higher dose the reduction in food intake
could be seen up to 24 h after dosing (data not shown).
Compound 1 was even more efficacious as an anorectic
agent when dosed id, with a 10 µmol/kg dose reducing
food intake to 30% of that seen with vehicle controls
after just 30 min postdosing (Figure 3). This increase
in efficacy is not surprising given the higher %F and
Cmax values obtained with id vs po administration (vide
supra). The chronic effectiveness of 1 in this model has
not been evaluated.
The potential for CCK-B agonist-mediated pharma-
cological side effects such as increased gastric acid
secretion or enhanced anxiety would be unacceptable
in a therapeutic agent for the treatment of obesity. The
identification of 1 as an orally active analog in two in
vivo models of CCK-A-mediated activity, coupled with
the modest (50-fold) selectivity for CCK-A vs CCK-B
receptors, prompted us to evaluate the CCK-B func-
tional profile of this compound. The ability of 1 to
mobilize intracellular calcium in stably transfected
CHO-K1 cells expressing the hCCK-A or hCCK-B
receptors and loaded with FURA2-AM was used to
evaluate functional activity.33d CCK-8 was a full agonist
on both human CCK-A (EC50 ) 0.1 nM) and CCK-B
(EC50 ) 0.05 nM) cell lines.29 Indazole 1 profiled as a
potent, full agonist on the CHO cells expressing the

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2715
Su m m a r y
In our initial communication9 we described a synopsis
of the discovery of a series of 3-(1H-indazol-3-ylmethyl)-
1,5-benzodiazepines which are binding-selective CCK-A
full agonists. One of these compounds, 1 (GW 5823) was
the first non-peptide CCK-A agonist to demonstrate
suppression of food intake when given orally in a rat
feeding model. In the present paper we detailed the
design, synthesis, and structure-activity relationships
within this series of 1,5-benzodiazepines. Modulation
of efficacy in this series was dependent on the electronic
nature of the C3 heterocyclic substituent and the steric
bulk of both the second C3 substituent and the N1-
indazolyl substituent. Modulation of receptor subtype
binding affinity was achieved by altering the size of the
second C3 substituent and by changing the N1-anili-
doacetamide substituents. Several additional potent
and selective CCK-A agonists from this series were
discovered to have in vivo activity. None, however,
displayed potency or efficacy equal to that of 1 in these
assays. In addition, data suggests that GW 5823 is a
CCK-B antagonist in vitro. The rat pharmacokinetic
profiles of GW 5823 and several close analogs indicate
these compounds suffer from poor oral bioavailability
and relatively high clearance. This low bioavailability
in the rat appears to be a consequence of both delayed
gastric emptying and rapid metabolism by the liver.
Despite the pharmacokinetic limitations, GW 5823 is a
potent and efficacious anorectic agent when dosed both
orally and intraduodenally in a rat conditioned feeding
model and shows promise as an orally active satiety
agent which may be useful for the treatment of obesity.
It remains to be seen whether the low bioavailability
and inhibition of gastric emptying observed with GW
5823 in rats will translate to humans. Efforts to further
refine the pharmacological profile of this series of
compounds are continuing and will be reported at a later
date.
F igu r e 3. Male Long-Evans rats (225-300 g) were condi-
tioned for 2 weeks to consume a palatable liquid diet (Bio-
Serve F1657, Frenchtown, NJ ) after a 2 h fast. On pretreat-
ment day, rats were fasted (100 min) and injected po with drug
vehicle (propylene glycol, PG, 1 mL/kg) and an oral preload of
saline (0.9% NaCl, 8 mL/kg). Liquid diet access was provided
20 min later, and consumption was measured at 30, 90, and
180 min. To qualify for the drug treatment study, rats had to
consume at least 8 mL of liquid diet within the first 30 min
on the pretreatment day. The next day, following the 100 min
deprivation, rats (8-10 animals per dose) were treated po or
id with vehicle (PG, 1 mL/kg) or various doses (0.1-10 µmol/
kg) of test compound dissolved in PG (1 mL/kg), immediately
followed by the saline oral preload. Food access was again
provided 20 min later and food intake was measured at 30,
90, and 180 min. All food intake data were normalized for each
rat to the respective values from the pretreatment day. *p <
0.05 using Dunnett’s multiple comparison test.
hCCK-A receptor (EC50 ) 145 nM, n ) 1) but was
inactive at concentrations up to 10 µM on the CHO cells
expressing the hCCK-B receptor. Although compound
1 was not tested for CCK-B antagonist activity in this
assay, the lack of CCK-B agonist activity displayed by
1 provides additional evidence for the potential utility
of 1 as a therapeutic agent.
Exp er im en ta l Section
Gen er a l. All commercial chemicals and solvents are re-
agent grade and were used without further purification unless
otherwise specified. The following solvents and reagents have
been abbreviated: tetrahydrofuran (THF), ethyl ether (Et2O),
dimethyl sulfoxide (DMSO), EtOAc (EtOAc), dichloromethane
(DCM), trifluoroacetic acid (TFA), dimethylformamide (DMF),
methanol (MeOH). All reactions except those in aqueous
media were carried out with the use of standard techniques
for the exclusion of moisture. Reactions were monitored by
thin-layer chromatography on 0.25 mm silica gel plates (60F-
254, E. Merck) and visualized with UV light, iodine vapors,
or 5% phosphomolybdic acid in 95% ethanol.
Final compounds were typically purified either by flash
chromatography on silica gel (E. Merck 40-63 mm) as
described by Still40 or by preparative reverse phase high-
pressure liquid chromatography (RP-HPLC) using a Waters
Model 3000 Delta Prep equipped with a Delta-pak radial
compression cartridge (C-18, 300 A, 15 µm, 47 mm × 300 mm)
as the stationary phase. The mobile phase employed 0.1%
aqueous TFA with acetonitrile as the organic modifier. Linear
gradients were used in all cases, and the flow rate was 100
mL/min (to ) 5 min). Analytical purity was assessed by RP-
HPLC using a Waters 600E system equipped with a Waters
990 diode array spectrometer (λ range 200-400 nm). The
stationary phase was a Vydac C-18 column (5 µm, 4.6 mm ×
200 mm). The mobile phase was the same as above and the
flow rate was 1.0 or 1.5 mL/min (to ) 3 min). Analytical data
is reported as retention time, tR, in minutes (% acetonitrile,
time, flow rate).
Compound 1 was also resolved into its optical antipo-
des to evaluate the relationship between bioactivity and
absolute stereochemistry at C3. Absolute stereochem-
istry at this position has been shown to modulate both
CCK-A/CCK-B selectivity and potency in 1,4-benzodi-
azepine CCK antagonists.31 Racemic 1 was separated
on a Chiralpak AD column to afford the two enanti-
omers with >98% ee. The faster-eluting enantiomer
was a potent (ED50 ) 70 nM, n ) 1) full agonist (%max
) 105%, n ) 1) at the CCK-A receptor in vitro (GPGB
assay), while the other enantiomer was less potent (ED50
) 530 nM, n ) 1) and efficacious (%max ) 80%, n ) 1).
Surprisingly, the receptor binding selectivities for the
two enantiomers were similar, with the faster eluting
enantiomer having slightly better affinity for both
receptor subtypes (CCK-A pIC50 ) 7.47 ( 0.46, CCK-B
pIC50 ) 6.45 ( 0.09, n ) 3) than its antipode (CCK-A
pIC50 ) 6.67 ( 0.37, CCK-B pIC50 ) 6.02 ( 0.15, n )
3). It is possible that the N1-anilidoacetamide moiety
overrides any influence on receptor binding selectivities
attributed to the stereochemical disposition of the C3
substituent, as a similar effect has been reported in a
1,4-benzodiazepine CCK-B antagonist series.39

2716 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Henke et al.
1H NMR spectra were recorded on either a Varian VXR-
300, a Varian Unity-400, or a Varian Unity-300 instrument.
Chemical shifts are reported in parts per million (ppm, δ
units). Coupling constants are reported in units of hertz (Hz).
Splitting patterns are designated as s, singlet; d, doublet; t,
triplet; q, quartet; m, multiplet; b, broad. Low-resolution mass
spectra (MS) were recorded on a J EOL J MS-AX505HA, J EOL
SX-102, or a SCIEX-APIiii spectrometers. High-resolution
mass spectra were recorded on a AMD-604 (AMD Electra
GmbH) high-resolution double-focusing mass spectrometer
(Analytical Instrument Group, Raleigh, NC). Mass spectra
were acquired in the positive ion mode under electrospray
ionization (ESI) or fast atom bombardment (FAB) methods.
Combustion analyses were performed by Atlantic Microlabs,
Inc., Norcross, GA. MK-32922 was obtained from Merck & Co.
(Rahway, NJ ). CCK-8 was purchased from Sigma (St. Louis,
MO).
Gen er a l Meth od for Red u ctive Am in a tion of An ilin es
w ith Keton es/Ald eh yd es. Where appropriate secondary
amines could not be procured from commercial sources, a
primary amine was converted to the desired secondary amine
via reductive amination with an appropriate aldehyde or
ketone using the following method: To a stirring solution of
the appropriate aniline in THF at 0 °C is added 1.0 equiv of
the appropriate aldehyde or ketone, 1.0 equiv of acetic acid,
and 1.5 equiv of sodium triacetoxyborohydride. The solution
is stirred at room temperature for 15 h, cooled to 0 °C, and
then quenched by careful addition of H2O. The reaction
mixture warmed to room temperature and is poured into
EtOAc, the organic layer is separated, washed with brine (1
× 200 mL), and dried (MgSO4), and the solvents are removed
in vacuo to afford the crude compounds as yellow to brown
oils which were used without further purification. Spectral
data for representative compounds are as follows:
2-Br om o-N -cyclop e n t yl-N -(4-m e t h oxyp h e n yl)a ce t -
a m id e (3c). Chromatography using EtOAc/hexanes (3/17) as
eluent gave an amber oil (87% yield): 1H NMR (CDCl3, 300
MHz) δ 7.09 (d, 2H, J ) 9.0), 6.90 (d, 2H, J ) 9.0), 4.84 (m,
1H), 3.83 (s, 3H), 3.54 (s, 2H), 1.87 (m, 2H), 1.49 (m, 4H), 1.25
(m, 2H); TLC Rf ) 0.65 (EtOAc/hexanes, 3/17).
2-Br om o-N-cyclop r op yl-N-p h en yla ceta m id e (3d ). Chro-
matography eluted successively with EtOAc/hexanes (1/9, 100
mL; 3/17, 300 mL) gave an amber oil (76% yield): 1H NMR
(CDCl3, 300 MHz) δ 7.39 (m, 3H), 7.15 (m, 2H), 3.62 (s, br,
2H), 3.24 (m, 1H), 0.83 (m, 2H), 0.52 (m, 2H); TLC Rf ) 0.18
(EtOAc/hexanes, 3/17).
2-Br om o-N-(4-(t r iflu or om et h yl)p h en yl)-N-isop r op yl-
a ceta m id e (3e). Chromatography using EtOAc/hexanes (3/
17) as eluent afforded an amber oil (81% yield): 1HNMR
(CDCl3, 300 MHz) δ 7.26-7.09 (m, 4H), 4.85 (m, 1H), 3.51 (s,
2H), 1.05 (d, 6H, J ) 6.9); low-resolution MS (FAB) m/ e 274
(MH+).
N-Isopr opyl-N-(3-m eth oxyph en yl)br om oacetam ide (3f).
Concentrated in vacuo to afford a dark mobile oil: 1H NMR
(300 MHz, CDCl3) δ 7.38 (t, 1H, J ) 8.0), 7.01 (dd, 1H, J )
8.1, 2.2), 6.81 (d, 1H, J ) 7.6), 6.79 (s, 1H), 4.95 (m, 1H, J )
6.8), 3.88 (s, 3H), 3.60 (s, 2H), 1.06 (d, 6H, J ) 6.8).
N-Isopr opyl-N-(2-m eth oxyph en yl)br om oacetam ide (3g).
Concentrated in vacuo to afford a dark mobile oil: 1H NMR
(300 MHz, CDCl3) δ 7.45 (dt, 1H, J ) 7.8, 1.4), 7.20 (dd, 1H,
J ) 7.8, 1.4), 7.04 (m, 2H), 4.90 (m, 1H, J ) 6.8), 3.85 (s, 3H),
3.60 (dd, 2H, J ) 32.9, 11.5), 1.20 (d, 3H, J ) 6.8), 0.97 (d,
3H, J ) 6.8).
N-Isop r op yl-N-(3,4-(m eth ylen ed ioxy)p h en yl)br om oa c-
eta m id e (3h ). Concentrated in vacuo to afford a dark mobile
oil: 1H NMR (300 MHz, CDCl3) δ 6.82 (d, 1H, J ) 8.2), 6.61
(m, 2H), 4.90 (m, 1H, J ) 6.8), 3.58 (s, 2H), 1.07 (m, 6H).
2-Br om o-N-ter t-bu tyl-N-p h en yla ceta m id e (3i). Purifi-
cation via filtration through a pad of silica gel eluted with
DCM: 1H NMR (CDCl3, 300 MHz) δ 7.45-7.21 (m, 12H), 7.08
(t, 1H), 6.90 (m, 1H), 4.30 (d, 1H, J ) 16.4), 3.85 (d, 1H, J )
16.6), 3.59 (d, 1H, J ) 12.0), 3.49 (d, 1H, J ) 11.9), 1.43 (s,
9H); TLC Rf ) 0.24 (EtOAc/hexanes, 1/1).
Gen er a l P r oced u r e for Alk yla tion of N-P h en yl-o-p h e-
n ylen ed ia m in e w ith Br om oa ceta m id es 3a -g. To a stir-
ring solution of N-phenyl-o-phenylenediamine in DMF at room
temperature was added 1.1 equiv of K2CO3 followed by 1.0
equiv of the bromoacetamide. The resulting mixture was
heated to 60 °C for 16 h and then cooled to room temperature.
The mixture was filtered to remove the K2CO3 and then diluted
with 800 mL of EtOAc and 200 mL of Et2O. This solution was
washed successively with H2O (2 × 400 mL), brine (1 × 400
mL), 1 N HCl (2 × 400 mL), and H2O (1 × 400 mL), and the
organics were dried (MgSO4) and concentrated to give a
greenish-black oil. The resultant oil was purified either by
trituration in the appropriate solvent or by silica gel flash
column chromatography using the appropriate eluent and the
combined filtrates evaporated in vacuo to give the correspond-
ing acetamides. Spectral data for representative compounds
are as follows:
N-Isopr opyl-N-ph en yl-2-((2-(ph en ylam in o)ph en yl)am i-
n o)a ceta m id e (7a ). Chromatography using first CHCl3, then
hexane/EtOAc (2/1) as eluents gave a clear oil (62%): 1H NMR
(300 MHz, CDCl3) δ 7.42-6.8 (m, 14H), 6.36 (m, 1H), 4.95 (m,
1H), 3.22 (s, 2H), 1.05 (d, 6H J ) 6.8); MS m/ e 360 (MH+);
TLC Rf ) 0.18 (CHCl3).
N-Isopr opyl-N-(4-m eth oxyph en yl)-2-((2-(ph en ylam in o)-
p h en yl)a m in o)a cet a m id e (7b ). Trituration with Et2O/
petroleum ether (1/4) gave a light gray solid which was dried
under vacuum to afford the title compound (75%): 1H NMR
(CDCl3, 300 MHz) δ 7.24-6.71 (m, 12H), 6.43 (d, 1H, J ) 8.3),
4.96 (m, 1H), 3.92 (s, 3H), 3.44 (s, 2H), 1.05 (d, 6H, J ) 6.9).
N-Cyclop en tyl-N-(4-m eth oxyp h en yl)-2-((6-(p h en yla m i-
n o)cycloh exa -2,4-d ien yl)a m in o)a cet a m id e (7c). Chro-
matograhpy using EtOAc/hexanes (3/17) as eluent afforded a
yellow oil (67%): 1H NMR (acetone-d6, 300 MHz) δ 7.26-6.50
(m, 13H), 6.22 (d, 1H, J ) 7.9), 5.29 (s, br, 1H), 4.82 (m, 1H),
3.87 (s, 3H), 3.41 (d, 2H, J ) 4.4), 1.83 (m, 2H), 1.48 (m, 4H),
1.33 (m, 2H); TLC Rf ) 0.14 (EtOAc/hexanes, 3/17).
N-Isop r op yl-N-(4-m eth oxyp h en yl)a m in e (46a ): 1H NMR
(300 MHz, CDCl3) δ 6.78 (d, 2H, J ) 8.8), 6.57 (d, 2H, J )
9.1), 3.75 (s, 3H), 3.55 (m, 1H), 2.92 (bs, 1H), 1.18 (d, 6H, J )
6.1); TLC (EtOAc/Hex (2:3)) Rf ) 0.72.
N-Isopr opyl-N-(3-m eth oxyph en yl)am in e (46b): 1H NMR
(300 MHz, CDCl3) δ 7.13 (t, 1H, J ) 8.0), 7.01 (dt, 2H, J )
9.7, 1.9), 6.19 (s, 1H), 3.80 (s, 3H), 3.62 (m, 1H, J ) 6.8), 1.06
(d, 6H, J ) 6.8).
N-Isop r op yl-N-(2-m eth oxyp h en yl)a m in e (46c): 1H NMR
(300 MHz, CDCl3) δ 6.91 (t, 1H, J ) 7.6), 7.01 (d, 1H, J )
7.6), 6.68 (t, 2H, J ) 7.9), 3.88 (s, 3H), 3.66 (m, 1H, J ) 6.8),
1.28 (d, 6H, J ) 6.8).
N -Isop r op yl-N -(3,4-(m e t h yle n e d ioxy)p h e n yl)a m in e
(46d ): 1H NMR (300 MHz, CDCl3) δ 6.72 (d, 1H, J ) 8.3), 6.43
(s, 1H), 6.29 (s, br, 1H), 5.91 (s, 2H), 3.53 (m, 1H, J ) 6.8),
1.17 (m, 6H).
Gen er al P r ocedu r e for Acylation of Secon dar y Am in es
To Give 2-Br om oa ceta m id es of Gen er a l F or m u la 3.
A
solution of amine (1.0 equiv) and triethylamine (1.0 equiv) in
CH2Cl2 was cooled to 0 °C. Bromoacetyl bromide (1.0 equiv)
was dissolved in CH2Cl2 and was added dropwise over 45 min
with stirring. The reaction mixture was stirred anywhere from
3 h to overnight at ambient temperature, washed successively
with 0.3 N HCl (300 mL) and brine (300 mL), dried over
sodium sulfate, filtered, and evaporated in vacuo. The result-
ant oil was purified by silica gel flash column chromatography
using the appropriate eluent, and the combined filtrates were
evaporated in vacuo to give the corresponding 2-bromoaceta-
mide in good yield (>85% typical) and high purity. Spectral
data for representative compounds are as follows:
2-Br om o-N-isop r op yl-N-p h en yla ceta m id e (3a ). Chro-
matography eluting with EtOAc/hexane (1/1) afforded a brown
oil which crystallized on standing (76% yield): 1H NMR (300
MHz, CDCl3) δ 7.39 (m, 3H), 7.15 (m, 2H), 4.93 (m, 1H), 3.53
(s, 2H), 1.04 (d, 6H, J ) 6.8).
2-B r o m o -N -is o p r o p y l-N -(4-m e t h o x y p h e n y l)a c e t a -
m id e (3b). Chromatography eluting with EtOAc/hexane (1/
1) afforded a brown oil which crystallized on standing (82%
yield): 1H NMR (300 MHz, CDCl3) δ 7.10 (d, 2H, J ) 9.1),
6.93 (d, 2H, J ) 9.1), 4.93 (m, 1H), 3.84 (s, 3H), 3.53 (s, 2H),
1.04 (d, 6H, J ) 6.8); TLC (EtOAc/hexane (3/17)) Rf ) 0.18.

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2717
N-Isop r op yl-2-((2-(p h en yla m in o)p h en yl)a m in o)-N-(4-
(t r iflu or om et h yl)p h en yl)a cet a m id e (7e). Chromatogra-
phy using hexane/EtOAc (5/1) as eluent afforded a light tan
solid (57%): 1H NMR (CDCl3, 400 MHz) δ 7.72 (d, 2H, J )
8.2), 7.26 (d, 2H, J ) 8.2), 7.15 (m, 3H), 6.95 (dd, 1H, J ) 7.7,
7.7), 6.80 (dd, 1H, J ) 7.1, 7.1), 6.74 (d, 2H, J ) 7.9), 6.68 (dd,
1H, J ) 7.4, 7.4), 6.29 (d, 1H, J ) 7.9), 5.20 (s, 1H), 5.00 (m,
1H), 3.40 (s, 2H), 1.06 (d, 6H, J ) 6.6); low-resolution MS
(FAB) m/ e 427 (MH+); high-resolution MS (C24H24F3N3O) calcd
427.1871, found 427.1871.
N-Isopr opyl-N-(3-m eth oxyph en yl)-2-((2-(ph en ylam in o)-
p h en yl)a m in o)a cet a m id e (7f). Chromatography using
EtOAc/hexane (1/4) as eluent gave a light brown foam (62%):
1H NMR (300 MHz, CDCl3) δ 7.43 (t, 1H, J ) 8.0), 7.3-7.1
(m, 3H), 7.02 (m, 2H), 6.9-6.6 (m, 7H), 6.36 (d, 1H, J ) 7.8),
5.3 (s, br, 1H), 4.95 (m, 1H, J ) 6.8), 3.88 (s, 3H), 3.53 (s, 2H),
1.06 (m, 6H).
N-Isopr opyl-N-(2-m eth oxyph en yl)-2-((2-(ph en ylam in o)-
p h en yl)a m in o)a cet a m id e (7g). Chromatography using
EtOAc/hexane (1/4) as eluent gave a light brown foam (71%):
1H NMR (300 MHz, CDCl3) δ 7.46 (t, 1H, J ) 7.9), 7.030-7.05
(m, 8H), 6.98 (t, 1H, J ) 6.8), 6.84 (m, 2H), 6.70 (t, 1H, J )
7.6), 6.37 (d, 1H, J ) 8.0), 5.4 (s, br, 1H), 4.95 (m, 1H, J )
6.8), 3.84 (s, 3H), 3.45 (dd, 2H, J ) 23.2, 6.6), 1.20 (d, 3H, J )
6.8), 1.01 (d, 3H, J ) 6.8).
Gen er a l P r oced u r e for Cycliza tion To P r ovid e 1,5-
Ben zod ia zep in es of Gen er a l F or m u la 4. To 100 mL of
THF at 0 °C was added dropwise over 20 min simultaneously
a solution of 8.0 g (1.0 equiv) of the requisite diaminoacetamide
in 100 mL of THF and 2.40 mL (1.2 equiv) of malonyl
dichloride in 100 mL of THF. The resulting solution was
stirred at room temperature for 20 h and the solvent removed
in vacuo. The resultant material was purified by silica gel
flash column chromatography using the appropriate eluent,
and the combined filtrates were evaporated in vacuo to give
the corresponding acetamides. Spectral data for representa-
tive compounds are as follows:
2-(2,4-Dioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]-
diazepin -1-yl)-N-isopr opyl-N-ph en ylacetam ide (4a). Chro-
matography (50-75% EtOAc/petroleum ether) followed by
recrystallization from hot EtOAc/petroleum ether gave a white
powder (56%): mp 199-200 °C; 1H NMR (CDCl3, 300 MHz) δ
7.6-7.2 (m, 12H), 7.09 (t, 1H, J ) 8), 6.90 (d, 1H, J ) 8), 5.05
(m, 1H), 4.38 (d, 1H, J ) 17), 4.04 (d, 1H, J ) 17), 3.54 (dd,
2H, J ) 5, 22), 1.10 (d, 6H, J ) 7); low-resolution MS (FAB)
m/ e 428 (MH+).
2-(2,4-Dioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]-
d ia zep in -1-yl)-N-isop r op yl-N-(4-m et h oxyp h en yl)a cet a -
m id e (4b). Chromatography using hexanes/EtOAc (1/1) as
eluent afforded a light tan solid (60%): 1H NMR (CDCl3, 300
MHz) δ 7.44-6.86 (m, 13H), 5.02 (m, 1H), 4.38 (d, 1H, J )
16.6), 4.04 (d, 1H, J ) 16.6), 3.84 (s, 3H), 2.55 (m, 2H), 1.10
(d, 6H, J ) 6.8).
N -Cyclop e n t yl-2-(2,4-d ioxo-5-p h e n yl-2,3,4,5,-t e t r a -
h yd r oben zo[b][1,4]d ia zep in -1-yl)-N-(4-m eth oxyp h en yl)-
a ceta m id e (4c). Chromatography using EtOAc/hexanes (1/
1) as eluent afforded a clear glass (48%): 1H NMR (CDCl3,
300 MHz) δ 7.43-7.20 (m, 8H), 7.09 (m, 2H), 6.97 (m, 3H),
4.95 (m, 1H), 4.38 (d, 1H, J ) 16.4), 4.06 (d, 1H, J ) 16.3),
3.84 (s, 3H), 3.59 (d, 1H, J ) 12.0), 3.49 (d, 1H, J ) 11.9), 1.90
(m, 2H), 1.52 (m, 4H), 1.35 (m, 2H); TLC Rf ) 0.16 (EtOAc/
hexanes, 1/1).
2-(2,4-Dioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]-
d ia zep in -1-yl)-N-isop r op yl-N-(4-(tr iflu or om eth yl)p h en y-
l)a ceta m id e (4e). Chromatography using hexane/EtOAc (3/
2) as eluent afforded a light tan solid (54%): mp 186-188 °C;
1H NMR (CDCl3, 400 MHz) δ 7.74 (d, 2H, J ) 8.1), 7.42 (d,
2H, J ) 8.1), 7.36 (m, 3H), 7.25 (m, 4H), 7.08 (ddd, 1H, J )
1.4, 8.4, 8.4), 6.90 (dd, 1H, J ) 1.2, 8.2), 5.06 (m, 1H), 4.12
(dd, 2H, J ) 14.4, 95.5), 3.52 (dd, 2H, J ) 12.0, 34.5), 1.11 (d,
6H, J ) 6.6); low-resolution MS (FAB) m/ e 496 (MH+), 293,
265. Anal. (C27H24F3N3O3) Calcd: C, 65.45; H, 4.88; N, 8.48;
Found: C, 65.16; H, 4.95; N, 8.33.
eluent afforded an amber foam (46%): 1H NMR (300 MHz,
CDCl3) δ 7.3-7.1 (m, 10H), 7.02 (t, 1H, J ) 7.2), 6.92 (dd 1H,
J ) 8.6, 2.4), 6.83 (d, 1H, J ) 7.2), 4.95 (m, 1H, J ) 6.8), 4.38
(m, 1H), 4.02 (m, 1H), 3.78 (s, 3H), 3.48 (dd, 2H, J ) 39.3,
11.9), 1.06 (m, 6H).
2-(2,4-Dioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]-
d ia zep in -1-yl)-N-isop r op yl-N-(2-m et h oxyp h en yl)a cet a -
m id e (4g). Chromatography using 2% MeOH in DCM as
eluent afforded a cream foam which exists as 3:2 mixture of
rotamers (major rotamer recorded): 1H NMR (300 MHz,
CDCl3) δ 7.60-6.90 (m, 13H), 5.05 (m, 1H, J ) 6.9), 4.60-
3.40 (m, 7H), 1.12 (m, 6H).
1-P h en yl-1,5-d ih yd r o-1H -b en zo[b][1,4]d ia zep in e-2,4-
d ion e (5). 2-Nitrophenylenediamine (100 g, 1.0 equiv, 0.47
mol) is dissolved in 1 L of dry toluene and cooled to 0 °C with
a ice/water bath. Methylmalonyl chloride (55 mL, 1.1 equiv,
0.51 mol) is added dropwise over 20 min. The reaction mixture
is allowed to warm to room temperature and stirred 1 h, and
at 80 °C for 2 days. The solvent is removed in vacuo, and the
resulting solid is recrystallized from Et2
O/CH2Cl2/hexane to
afford 110.6 g of N-(2-nitrophenyl)-N-phenylmalonamic acid
methyl ester. A mixture of 55.6 g (1.0 equiv, 0.17 mol) of the
above product and 5 g of 10% Pd/C is taken up in 4 L of ethanol
and 200 mL of EtOAc, the reaction mixture is stirred under
an atmosphere of hydrogen gas for 7 h and then filtered
through Celite, and the solvent is removed in vacuo to afford
43.7 g of N-(2-aminophenyl)-N-phenylmalonamic acid methyl
ester. The above amine (10 g, 1.0 equiv, 35.0 mmol) is
dissolved in 220 mL of ethanol and cooled to 0 °C, and 1.2 g
(56.0 mmol, 1.6 equiv) of Na dissolved in 180 mL of ethanol is
added. The reaction mixture is warmed slowly to room
temperature and stirred for 1 h followed by the removal of
solvent in vacuo. The residue is acidified with 1 N HCl and
extracted with EtOAc (2 × 500 mL). The organic layer is dried
over MgSO4, and the solvent is removed in vacuo. Trituration
with Et2O afforded 2.75 g of a white solid: 1H NMR (DMSO,
300 MHz) δ 10.60 (s, 1H), 7.64-7.08 (m, 8H), 6.81 (d, J ) 8.0,
1H), 3.61-3.11 (m, 2H); Rf ) 0.44 (hexane/EtOAc, 1/2).
Gen er a l P r oced u r e for Alk yla tion of 1,5-Ben zod ia z-
ep in es w ith Br om oa ceta m id es of F or m u la 2 To P r ovid e
Com p ou n d s of Gen er a l F or m u la 4. To a stirred solution
of 1.0 equiv of 1-phenyl-1,5,5a,9a-tetrahydrobenzo[b][1,4]-
diazepine-2,4-dione in DMF is added 1.3 equiv of 60 wt % NaH
in mineral oil at ambient temperature and the resulting
reaction stirred 0.5 h. To this solution is added 1.0 equiv of
the desired acetamide in 3 mL of DMF, and the resulting
reaction is stirred 18 h at room temperature. The solvent is
removed in vacuo and the residue taken into 50 mL of EtOAc,
washed successively with H2O (30 mL), 1 N HCl (30 mL),
NaHCO3 (30 mL), and brine (30 mL), dried (MgSO4), and
filtered, and solvents are removed in vacuo. The resultant
material was purified by silica gel flash column chromatog-
raphy using the appropriate eluent, and the combined filtrates
were evaporated in vacuo to give the corresponding aceta-
mides. Spectral data for representative compounds are as
follows:
N -Cyclop r op yl-2-(2,4-d ioxo-5-p h e n yl-2,3,4,5-t e t r a -
h yd r oben zo[b][1,4]d ia zep in -1-yl)-N-(4-m eth oxyp h en yl)-
a ceta m id e (4d ). Chromatography using EtOAc/hexanes (1/
1) as eluent afforded a white foam (52%):
1H NMR (CDCl3,
300 MHz) δ 7.50-7.07 (m, 13H), 6.92 (d, 1H, J ) 7.3), 3.60 (d,
1H, J ) 11.9), 3.51 (d, 1H, J ) 12.0), 3.30 (m, 1H), 0.86 (m,
2H), 0.60 (m, 2H); TLC Rf ) 0.35 (EtOAc/hexanes, 2/1).
2-(2,4-Dioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]-
d ia zep in -1-yl)-N-isop r op yl-N-(3,4-(m eth ylen ed ioxy)p h e-
n yl)a ceta m id e (4h ). Concentration of solvent afforded a
brown glass: 1H NMR (300 MHz, CDCl3) δ 8.03 (s, 1H), 7.5-
6.6 (m, 11H), 6.09 (s, 2H), 5.03 (m, 1H, J ) 6.9), 4.46 (dd, 1H,
J ) 27.2, 12.6), 4.16 (dd, 1H, J ) 27.2, 5.6), 3.58 (d, 1H, J )
15.8), 3.48 (d, 1H, J ) 15.8), 1.08 (m, 6H).
N -t er t -B u t y l-2-(2,4-d i o x o -5-p h e n y l-2,3,4,5,5a ,9a -
h exa h yd r ob en zo[b][1,4]d ia zep in -1-yl)-N-p h en yla cet a -
m id e (4i). Chromatography eluted successively with EtOAc/
hexanes (2/3 to 1/1) afforded a white foam: 1H NMR (CDCl3,
300 MHz) δ 7.45-7.21 (m, 12H), 7.08 (t, 1H), 6.90 (m, 1H),
4.30 (d, 1H, J ) 16.4), 3.85 (d, 1H, J ) 16.6), 3.59 (d, 1H, J )
2-(2,4-Dioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]-
d ia zep in -1-yl)-N-isop r op yl-N-(3-m et h oxyp h en yl)a cet a -
m id e (4f). Chromatography using 3% MeOH in DCM as

2718 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Henke et al.
12.0), 3.49 (d, 1H, J ) 11.9), 1.43 (s, 9H); TLC Rf ) 0.24
(d, 1H, J ) 16.6), 4.17 (d, 1H, J ) 16.6), 3.80 (s, 3H), 3.58 (t,
1H, J ) 6.6), 3.22 (d, 2H, J ) 6.6), 0.96 (m, 6H); low-resolution
MS (FAB) m/ e 587 (MH+), 586 (M+), 422, 293; high-resolution
MS calcd 586.2587, found 586.2580. Anal. (C36H34N4O4) H,
N, C: calcd, 73.70; found, 72.70.
(EtOAc/hexanes, 1/1).
2-(2,4-Dioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]-
d ia ze p in -1-yl)-N -(4-flu or op h e n yl)-N -isop r op yla ce t a -
m id e (4j). Concentration of solvent afforded a white foam:
1H NMR (CDCl3, 300 MHz) δ 7.98 (s, 1H), 7.40-7.06 (m, 11H),
6.90 (m, 1H), 5.45 (m, 1H), 4.30 (d, 1H, J ) 16.2), 4.00 (d, 1H,
J ) 16.2), 3.55 (m, 2H), 1.08 (d, 6H, J ) 6.7); low-resolution
MS (FAB) m/ e 446 (MH+).
Gen er a l P r oced u r e for Alk yla tion of 1,5 Ben zod ia z-
ep in es a t C-3 follow ed by Dep r otection (if Need ed ) To
Affor d 1, 15-19, 26, 28, 29, 31-34, 36-45 (Ta bles 1-4).
To a stirring solution of 1.0 equiv of the desired 1,5-benzodi-
azepine substrate in 15 mL of DMF at 0 °C was added 1.1
equiv of the desired base (60% NaH in mineral oil, a 1.0 M
solution of NaN(TMS)2 in THF or a 0.5 M solution of KN-
(TMS)2 in toluene). The resulting solution was stirred 10-30
min, and then a solution of 1.1 equiv of the desired alkyl halide
(normally a 3-(bromomethyl)indazole derivative) in 3 mL of
DMF was added. The resulting solution was stirred 2 h at
room temperature and then quenched with 5 mL of H2O. The
reaction mixture was then poured into 50 mL of EtOAc and
extracted with H2O (2 × 50 mL). The organic layer was
separated and dried (MgSO4), and the solvents were removed
in vacuo. Deprotection, if needed, was carried out using one
of the following two methods unless otherwise indicated.
2-[3-(Ben zofu r an -3-ylm eth yl)-2,4-dioxo-5-ph en yl-2,3,4,5-
tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-isop r op yl-N-(4-
m eth oxyp h en yl)a ceta m id e (16). Purification by silica gel
MPLC on an Si60 column using hexane/EtOAc (5/2) as eluent
followed by lyophilization in acetonitrile/H2O afforded 292 mg
of a white amorphous solid: 1H NMR (CDCl3, 300 MHz) δ 7.56
(m, 2H), 7.43-6.86 (m, 16H), 5.05 (m, 1H), 4.40 (d, 1H, J )
16.6), 4.08 (d, 1H, J ) 16.6), 3.85 (s,3H), 3.68 (t, 1H, J ) 6.4),
3.47 (m, 2H), 1.11 (m, 6H); low-resolution MS (FAB) m/ e 588
(MH+); high-resolution MS calcd 588.2503, found 588.2498.
2-[3-(Ben zo[b]th iop h en e-3-ylm eth yl)-2,4-d ioxo-5-p h en -
yl-2,3,4,5-t et r a h yd r ob en zo[b][1,4]d ia zep in -1-yl]-N-iso-
p r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (17). Purification
by silica gel MPLC on an Si60 column using hexane/EtOAc
(5/2) as eluent followed by lyophilization in acetonitrile/H2O
afforded 222 mg of a white amorphous solid: 1H NMR (CDCl3,
300 MHz) δ 7.79 (m, 2H), 7.44-6.93 (m, 15H), 6.88 (dd, 1H, J
) 1.5, 8.1), 5.03 (m, 1H), 4.42 (d, 1H, J ) 16.6), 4.09 (d, 1H, J
) 16.6), 3.85 (s, 3H), 3.80 (t, 1H, J ) 6.6), 3.61 (m, 2H), 1.10
(t, 6H, J ) 6.8); low-resolution MS (FAB) m/ e 604 (MH+), 439;
high-resolution MS calcd 604.2271, found 604.2270.
2-[3-(Ben zo[d ]isoxa zol-3-ylm eth yl)-2,4-d ioxo-5-p h en yl-
2,3,4,5-tetr ah ydr oben zo[b][1,4]diazepin -1-yl]-N-isopr opyl-
N-(4-m eth oxyp h en yl)a ceta m id e (18). Purification by silica
gel chromatography using hexane/EtOAc (2/1) as eluent fol-
lowed by lyophilization in acetonitrile/H2O afforded 303 mg
of a white amorphous solid: 1H NMR (CDCl3, 300 MHz) δ 7.81
(d, 1H, J ) 7.8), 7.55-7.10 (m, 14H), 6.97 (m, 2H), 5.01 (m,
1H), 4.28 (m, 3H), 3.85 (m, 4H), 3.58 (dd, 1H, J ) 5.1, 16.6),
1.07 (d, 6H, J ) 6.6); low-resolution MS (FAB) m/ e 589 (MH+),
588 (M+), 424, 396. Anal. (C35H32N4O5) C, H, N.
2-[3-(Ben zo[d ]isoth ia zol-3-ylm eth yl)-2,4-d ioxo-5-p h en -
yl-2,3,4,5-t et r a h yd r ob en zo[b][1,4]d ia zep in -1-yl]-N-iso-
p r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (19). Purification
by silica gel MPLC on an Si60 column using hexane/EtOAc
(2/1) as eluent afforded a white amorphous solid (76%): 1H
NMR (CDCl3, 300 MHz) δ 8.12 (d, 1H, J ) 8.1), 7.84 (d, 1H, J
) 8.1), 7.49-7.21 (m, 11H), 7.13 (m, 2H), 6.98 (m, 2H), 5.00
(m, 1H), 4.52 (dd, 1H, J ) 5.0, 8.7), 4.26 (m, 2H), 3.96 (dd,
1H, J ) 8.7, 17.1), 3.83 (s, 3H), 3.64 (dd, 1H, J ) 5.0, 19.0),
1.06 (m, 6H); low-resolution MS (FAB) m/ e 605 (MH+), 604
(M+), 440. Anal. (C35H32N4O4S) C, H, N.
Meth od A: To a stirring solution of the material obtained
in the alkylation step described above in 10 mL of DCM was
added 3 mL of TFA. The resulting solution was stirred for 2
h, and the solvents were removed in vacuo. The resultant
material was purified by either silica gel flash column chro-
matography or reverse phase MPLC using the appropriate
eluent, and the combined filtrates were evaporated in vacuo
to give the desired analog.
Meth od B: The crude material obtained in the alkylation
step described above was dissolved in 10 mL of 4 N HCl in
dioxane, and the reaction mixture was stirred 6 h at room
temperature. The reaction mixture was diluted with 40 mL
of EtOAc and extracted with NaHCO3 (1 × 30 mL) and H2O
(1 × 30 mL). The organic layer was dried (MgSO4), and the
solvents were removed in vacuo. The resultant material was
purified by either silica gel flash column chromatography or
reverse phase MPLC using the appropriate eluent, and the
combined filtrates were evaporated in vacuo to give the desired
analog. Spectral data and purification protocol for the repre-
sentative compounds are as follows:
2-[3-(1H-In da zol-3-ylm eth yl)-2,4-dioxo-5-p h en yl-2,3,4,5-
ter a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-isop r op yl-N-(4-
m eth oxyp h en yl)a ceta m id e (1). Deprotection via method A,
purification of the residue by chromatography using hexane/
EtOAc (3/2 up to 2/3) as eluent followed by further purification
via reverse phase MPLC using a C-18 column and 60%
acetonitrile/40% H2O as eluent and lyophilization afforded 62
mg of a white amorphous solid: 1H NMR (CDCl3, 300 MHz) δ
7.81 (d, 1H, J ) 8.0), 7.41-6.90 (m, 17H), 5.00 (m, 1H), 4.23
(m, 3H), 3.84 (s, 3H), 3.79 (d, 1H, J ) 7.9), 3.61 (dd, 1H, J )
5.8, 16.1), 1.06 (m, 6H); low resolution MS (FAB) m/ e 588
(MH+), 423, 223. Anal. (C35H33N5O4) C, H, N.
Racemic 1 (40 mg) was dissolved in 250 mL of a mixture of
i-PrOH/CHCl3/hexane (32%/8%/60%) and separated on Chiral-
pack AD column 20 mm × 25 cm using hexane/i-PrOH/CHCl3
) 80%/16%/4% as eluent and a flow rate of 6 mL/min. Two
fractions were collected at tR(1) ) 39.4 min and tR(2) ) 76.6
min. The solvent was removed in vacuo to afford 18 mg of
one enantiomer (ee >99% by analytical HPLC) and 16 mg of
the other (ee >98% by analytical HPLC).
2-[3-(1H -In d ol-3-ylm et h yl)-2,4-d ioxo-5-p h en yl-2,3,4,5-
tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-isop r op yl-N-(4-
m eth oxyp h en yl)a ceta m id e (15). Deprotection via method
B and purification via silica gel chromatography using hexane/
EtOAc (2/1) as eluent followed by further purification by
reverse phase MPLC using a C-18 column and 65% acetoni-
trile/35% H2O as eluent and lyophilization afforded 52 mg
(54%) of a white amorphous solid: 1H NMR (DMSO-d6, 300
MHz) δ 10.73 (s, 1H), 7.46-6.88 (m, 18H), 4.78 (m, 1H), 4.38
N-Isop r op yl-N-(4-m eth oxyp h en yl)-2-[3-[(1-m eth yl-1H-
in d a zol-3-yl)m e t h yl]-2,4-d ioxo-5-p h e n yl-2,3,4,5-t e t r a -
h yd r oben zo[b][1,4]d ia zep in -1-yl]a ceta m id e (25). Purifi-
cation by silica gel chromatography using hexane/EtOAc (2/
1) as eluent followed by further purification via silica gel
MPLC using a Si60 column and hexane/EtOAc (1/1) as eluent
and lyophilization in acetonitrile/H2O afforded 100 mg of a
white amorphous solid: 1H NMR (CDCl3, 300 MHz) δ 7.74 (d,
1H, J ) 8.3), 7.25-6.76 (m, 16H), 4.85 (m, 1H), 4.11 (s, br,
2H), 3.97 (dd, 1H, J ) 5.6, 7.8), 3.77 (s, 3H), 3.70 (s, 3H), 3.63
(dd, 1H, J ) 7.8, 15.9), 3.48 (dd, 1H, J ) 5.6, 15.9), 0.92 (d,
6H, J ) 6.8); low-resolution MS (FAB) m/ e 602 (MH+), 437.
Anal. (C36H35N5O4) C, H, N.
2-[3-[(1-Ben zyl-1H -in d a zol-3-yl)m et h yl]-2,4-d ioxo-5-
p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-
isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (26). Purifi-
cation by silica gel flash column chromatography using hexane/
EtOAc (3/2) as eluent followed by lyophilization in acetonitrile/
H2O afforded 620 mg a white amorphous solid: 1H NMR
(CDCl3, 300 MHz) δ 7.86 (d, 1H, J ) 8.1), 7.40 (d, 1H, J )
7.9), 7.33-6.88 (m, 20H), 5.43 (s, 2H), 5.00 (m, 1H), 4.25 (m,
3H), 3.85 (m, 4H), 3.58 (dd, 1H, J ) 5.1, 16.0), 1.06 (d, 6H, J
) 6.6); low-resolution MS (FAB) m/ e 678 (MH+), 677 (M+),
513; high-resolution MS calcd 678.3082, found 678.3080.
2-[2,4-Dioxo-5-p h en yl-3-[(1H-p yr a zolo[3,4-b]p yr id in -4-
yl)m eth yl]-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-
N-isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (28). Depro-
tection via method B followed by purification by silica gel
MPLC using hexane/EtOAc (1/3) as eluent afforded 89 mg of

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2719
1
a white solid: mp 156-158 °C; H NMR (CDCl3, 400 MHz) δ
2-[3-(1H-In da zol-3-ylm eth yl)-2,4-d ioxo-5-p h en yl-2,3,4,5-
t et r a h yd r ob en zo[b][1,4]d ia zep in -1-yl]-N-isop r op yl-N-
p h en yla ceta m id e (37). Deprotection via method A followed
by purification via silica gel flash column chromatography
using MeOH 1%/CHCl3 99% as eluent afforded 240 mg of the
title compound: 1H NMR (400 MHz, CDCl3) δ 7.93 (d, 1H, J
) 8.4), 7.51-7.19 (m, 16H), 6.99 (m, 1H), 5.03 (m, 1H, J )
6.8), 4.29 (d, 1H, J ) 16.4), 4.26 (d, 1H, J ) 16.4), 4.14 (m,
1H), 3.89 (dd, 1H, J ) 16.5, 6.4), 3.82 (dd, 1H, J ) 16.5, 6.4),
1.08 (t, 6H, J ) 6.8); low-resolution MS (FAB) m/ e 558 (MH+);
tR ) 9.90 min (HPLC column: Dynamax C-8 2 mL/min, 50-
90% acetonitrile in aqueous TFA (0.1% v/v) over 15 min). Anal.
(C34H31N5O3) H, N, C: calcd, 73.23; found, 72.78.
10.51 (s, br, 1H), 8.48 (dd, 1H, J ) 1.2, 4.6), 8.25 (d, 1H, J )
7.0), 7.40-6.91 (m, 14H), 4.98 (m, 1H), 4.26 (m, 2H), 4.18 (dd,
1H, J ) 5.8, 7.8), 3.83 (s, 3H), 3.79 (dd 1H, J ) 7.8, 15.9), 3.60
(dd, 1H, J ) 5.7, 15.9), 1.05 (d, 6H, J ) 6.7); low-resolution
MS (FAB) m/ e 589 (MH+), 424. Anal. (C34H32N6O4) H, N, C:
calcd, 69.37; found, 68.69.
2-[2,4-Dioxo-5-p h en yl-3-[(1H-p yr a zolo[4,3-b]p yr id in -7-
yl)m eth yl]-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-
N-isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (29). Depro-
tection via method B followed by purification by silica gel
MPLC using hexane/EtOAc (1/4) as eluent afforded 146 mg of
1
a white solid: mp 173-176 °C; H NMR (CDCl3, 400 MHz) δ
10.50 (s, br, 1H), 8.33 (d, 1H, J ) 3.5), 7.59 (d, 1H, J ) 8.5),
7.39-6.88 (m, 14H), 4.97 (m, 1H), 4.41 (dd, 1H, J ) 6.8, 6.8),
4.28 (m, 2H), 3.92 (dd, 1H, J ) 7.9, 16.6), 3.82 (s, 3H), 3.76
(dd 1H, J ) 6.8, 16.6), 1.04 (d, 3H, J ) 6.6), 0.99 (d, 3H, J )
6.9); low-resolution MS (FAB) m/ e 589 (MH+), 588 (M+), 424.
Anal. (C34H32N6O4) C, H, N: calcd, 14.28; found, 13.73.
2-[3-[(4-F lu or o-1H -in d a zol-3-yl)m et h yl]-2,4-d ioxo-5-
p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-
isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (31). Depro-
tection via method A followed by purification via silica gel
column chromatography using hexane/EtOAc (2/1) as eluent
afforded 140 mg of a white solid (64%): mp 232-234 °C; 1H
NMR (CDCl3, 400 MHz) δ 7.43-6.90 (m, 16H), 5.02 (m, 1H),
4.32 (d, 1H, J ) 15.6), 4.20 (m, 2H), 3.84 (s, 3H), 3.73 (dd, 1H,
J ) 7.9, 15.7), 3.51 (dd, 1H, J ) 5.6, 16), 1.06 (t, 6H, J ) 6.8);
high-resolution MS (FAB) calcd 606.2517, found 606.2506.
N-(4-F lu or op h en yl)-2-[3-(1H -in d a zol-3-ylm et h yl)-2,4-
d ioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -
1-yl]-N-isop r op yla ceta m id e (38). Deprotection via method
B followed by purification via RP-HPLC (50-60% acetonitrile/
H2O over 30 min) afforded 87 mg of the title compound: 1H
NMR (CDCl3, 300 MHz) δ 7.85 (d, 1H, J ) 8.2), 7.43-7.09 (m,
15H), 6.96 (d, 1H, J ) 8.3), 5.01 (m, 1H), 4.98 (m, 2H), 3.82
(m, 2H), 1.05 (m, 6H); low-resolution MS (FAB) m/ e 576
(MH+); RP-HPLC tR ) 5.5 min (40-60% acetonitrile/H2O).
2-[3-(1H-In da zol-3-ylm eth yl)-2,4-d ioxo-5-ph en yl-2,3,4,5-
tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-isop r op yl-N-[4-
(tr iflu or om eth yl)p h en yl]a ceta m id e (39). Deprotection via
method B followed by purification via silica gel MPLC using
hexane/EtOAc (3/2) as eluent afforded 189 mg of a white
1
solid: mp 145-148 °C; H NMR (CDCl3, 400 MHz) δ 9.75 (s,
br, 1H), 7.82 (d, 1H, J ) 8.0), 7.73 (d, 2H, J ) 8.0), 7.42-7.07
(m, 13H), 6.93 (d, 1H, J ) 7.2), 5.03 (m, 1H), 4.19 (m, 3H),
3.79 (dd, 1H, J ) 7.5, 16.0), 3.61 (dd, 1H, J ) 5.8, 16.0), 1.07
(d, 6H, J ) 6.4); low-resolution MS (FAB) m/ e 626 (MH+), 625
(M+), 423. Anal. (C35H30F3N5O3) C, H, N.
2-[3-[(5-F lu or o-1H -in d a zol-3-yl)m et h yl]-2,4-d ioxo-5-
p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-
isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (32). Depro-
tection via method B followed by purification via silica gel
column chromatography using hexane/EtOAc (2/1) as eluent
2-[3-(1H-In da zol-3-ylm eth yl)-2,4-d ioxo-5-p h en yl-2,3,4,5-
tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-isop r op yl-N-(3-
m eth oxyp h en yl)a ceta m id e (40). Deprotection via method
B provided a viscous oil. Diethyl ether (40 mL) was added
and the resultant mixture stirred vigorously for 20 min. The
solids were allowed to settle, and the solvent was decanted.
This procedure was repeated three times and the final solid
dried by concentration in vacuo to afford 197 mg of a white
solid: 1H NMR (300 MHz, CDCl3) δ 8.05 (d, 1H, J ) 8.6), 7.76
(d, 1H, J ) 8.5), 7.67 (t, 1H, J ) 8.8), 7.5-7.2 (m, 12H), 7.16
(t, 1H, J ) 6.3), 6.98 (t, 2H, J ) 7.3), 5.05 (m, 1H, J ) 6.9),
4.36 (s, br, 2H), 3.94 (t, 1H, J ) 7.0), 3.82 (s, br, 2H), 3.74 (s,
3H), 1.16 (m, 6H); low-resolution MS (FAB) m/ e 588 (M+).
1
afforded 170 mg of a white solid (44%): mp 216-219 °C; H
NMR (CDCl3, 400 MHz) δ 7.43-6.90 (m, 16H), 5.02 (m, 1H),
4.32 (d, 1H, J ) 15.6), 4.20 (m, 2H), 3.84 (s, 3H) 3.73 (dd, 1H,
J ) 7.9, 15.7), 3.51 (dd, 1H, J ) 5.6, 16), 1.06 (t, 6H, J ) 6.8);
13C NMR (CDCl3, 100 MHz) δ 166.7, 166.6, 159.6, 144.3, 136.1,
131.4, 131.2, 129.6, 129.1, 128.2, 127.3, 126.6, 126.3, 126.0,
123.1, 114.7, 55.5, 46.5, 21.0, 20.7; high-resolution MS (FAB)
m/ e calcd 606.2517, found 606.2517.
2-[3-[(6-F lu or o-1H -in d a zol-3-yl)m et h yl]-2,4-d ioxo-5-
p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-
isopr opyl-N-ph en ylacetam ide (33). Deprotection via method
A afforded 240 mg of the title compound: 1H NMR (400 MHz,
DMSO-d6) δ 7.82-6.88 (m, 18H), 4.77 (m, 1H, J ) 6.8), 4.45
(d, 1H, J ) 16.8), 4.12 (m, 2H), 3.41 (m, 2H), 0.95 (t, 6H, J )
6.8); low-resolution MS (FAB) m/ e 576 (MH+); tR ) 10.31 min
(HPLC column: Dynamax C-8 2 mL/min, 50-90% acetonitrile
in aqueous TFA (0.1% v/v) over 15 min).
2-[3-[(7-F lu or o-1H -in d a zol-3-yl)m et h yl]-2,4-d ioxo-5-
p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-
isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (34). Depro-
tection via method A afforded a solid which was dissolved in
EtOAc and triturated with hexane to afford a white, amor-
phous solid (59%): mp 270-272 °C; 1H NMR (CDCl3, 400 MHz)
δ 7.34-7.23 (m, 3H), 7.20 (d, 1H, J ) 8.2), 7.12 (t, 1H, J )
4.7), 7.01-6.89 (m, 9H), 5.02 (m, 1H), 4.28 (m, 3H), 4.20 (m,
2H), 3.84 (s, 3H), 3.797 (dd,1H J ) 7.9, 16.3) 3.59 (dd, 1H, J
) 5.6, 16.4), 1.06 (t, 6H, J ) 7.2); 13C NMR (CDCl3, 100 MHz)
δ 166.6, 166.5, 165.7, 159.6, 149.2, 144.9, 141.3, 136.2, 131.4,
130.7, 129.7, 128.2, 127.3, 126.6, 123.1, 120.9, 120.8, 116.6,
114.7, 111.1, 110.9, 55.5, 51.7, 47.7, 46.5, 23.0, 20.9, 20.8; high-
resolution MS (FAB) calcd 606.2517, found 606.2510.
2-[3-(1H-In da zol-3-ylm eth yl)-2,4-d ioxo-5-p h en yl-2,3,4,5-
tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-isop r op yl-N-(2-
m eth oxyp h en yl)a ceta m id e (41). Deprotection via method
B provided a viscous oil. Diethyl ether (40 mL) was added
and the resultant mixture stirred vigorously for 20 min. The
solids were allowed to settle, and the solvent was decanted.
This procedure was repeated three times and the final gum
dried by concentration in vacuo. Recrystallization from 5%
MeOH in EtOAc afforded 126 mg of a white solid, which exists
as 3:2 mixture of rotamers (major rotamer recorded): 1H NMR
(300 MHz, CDCl3) δ 7.98 (t, 1H, J ) 8.0), 7.70 (m, 1H), 7.61
(s, 1H), 7.40-6.90 (m, 15H), 5.05 (m, 1H, J ) 6.9), 4.45 (d,
2H, J ) 16.4), 4.25 (d, 1H, J ) 17.5), 4.07 (d, 1H, J ) 16.4),
3.74 (m, 5H), 1.16 (m, 6H); low-resolution MS (FAB) m/ e 588
(M+); tR ) 27.29 min (RP-HPLC, 100% A to 100% C, 30 min).
2-[3-(1H-In da zol-3-ylm eth yl)-2,4-d ioxo-5-ph en yl-2,3,4,5-
tetr ah ydr oben zo[b][1,4]diazepin -1-yl]-N-isopr opyl-N-[3,4-
(m eth ylen ed ioxy)p h en yl]a ceta m id e (42). Deprotection via
method B provided a viscous oil. Diethyl ether (20 mL) was
added and the resultant mixture stirred vigorously for 20 min.
The solids were allowed to settle, and the solvent was
decanted. This procedure was repeated three times and the
final solid dried by concentration in vacuo to afford 106 mg of
a white solid: 1H NMR (300 MHz, CDCl3) δ 7.95 (d, 1H, J )
8.3), 7.68 (d, 1H, J ) 8.5), 7.59 (t, 1H, J ) 6.8), 7.2-7.5 (m,
11H), 7.12 (t, 1H, J ) 8.5), 6.94 (d, 1H, J ) 8.2), 6.84 (dd, 1H,
J ) 15.8, 8.3), 6.03 (s, 2H), 5.00 (m, 1H, J ) 6.9), 4.40 (m,
1H), 4.24 (t, 2H, J ) 6.1), 3.92 (dd, 1H, J ) 16.5, 7.7), 3.83
N-Isop r op yl-N-(4-m eth oxyp h en yl)-2-[3-[(4-p h en yl-2H-
p yr a zol-3yl)m e t h yl]-2,4-d ioxo-5-p h e n yl-2,3,4,5-t e t r a -
h yd r oben zo[b][1,4]d ia zep in -1-yl]a ceta m id e (36). Depro-
tection via method B followed by purification via silica gel
MPLC using hexane/EtOAc (3/2) as eluent afforded a white
1
solid: mp 160-164 °C; H NMR (CDCl3, 400 MHz) δ 7.57 (s,
1H), 7.39-7.15 (m, 14H), 7.06 (m, 1H), 6.97 (m, 2H), 6.87 (d,
1H, J ) 8.1), 5.04 (m, 1H), 4.28 (AB quartet, 2H, J ) 15.9),
3.85 (s, 3H), 3.54 (m, 3H), 1.09 (m, 6H); low-resolution MS
(FAB) m/ e 614 (MH+). Anal. (C35H30F3N5O3) C, H, N.

2720 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Henke et al.
(dd, 1H, J ) 16.5, 5.8), 1.08 (m, 6H); low-resolution MS (FAB)
m/ e 602 (M+); tR ) 23.06 min (RP-HPLC, 70% A to 70% C, 30
min).
tion via reverse phase MPLC using a C-18 column and 65%
acetonitrile/35% H2O as eluent followed by lyophilization
afforded 51 mg of a white amorphous solid: 1H NMR (DMSO-
d6, 300 MHz) δ 7.61-6.88 (m, 18H), 4.86 (m, 1H), 4.28 (m,
2H), 3.80 (s, 3H), 3.74 (s, 3H), 2.71 (dd, 2H, J ) 14.9, 35.4),
1.25 (s, 3H), 1.00 (m, 6H); low-resolution MS (FAB) m/ e 615
(MH+), 614 (M+); high-resolution MS calcd 615.2968, found
615.2971.
2-(1H-In d ol-3-ylm eth yl)-2-m eth oxyp r op a n ed ioic Acid
Dim eth yl Ester (6a ). A suspension of 1.0 g (6.17 mmol) of
dimethyl methoxymalonate, 1.07 g (6.17 mmol) of gramine,
and 0.46 mL of tributylphosphine in 20 mL of acetonitrile was
refluxed for 18 h. The solvent was removed in vacuo and the
residue diluted with EtOAc (50 mL) and extracted with HCl
(2 × 50 mL). The organic layer was separated and dried
(MgSO4) and the solvent removed in vacuo. Purification of
the crude material by silica gel flash column chromatography
using hexane/EtOAc (1/1) as eluent afforded 1.24 g of a clear,
yellow oil which solidified on standing: 1H NMR (CDCl3, 300
MHz) δ 8.06 (bs, 1H), 7.58 (m, 1H), 7.34-7.07 (m, 4H), 3.70
(s, 6H), 3.69 (s, 2H), 3.57 (s, 3H); low-resolution MS (FAB) m/ e
292 (MH+), 291 (M+).
N-Cyclop en tyl-2-[3-(1H-in d a zol-3-ylm eth yl)-2,4-d ioxo-
5-p h en yl-2,3,4,5,5a ,9a -h exa h yd r oben zo[b][1,4]d ia zep in -
1-yl]-N-(4-m eth oxyp h en yl)a ceta m id e (43). Deprotection
via method A followed by purification via silica gel flash
chromatography using EtOAc/hexanes (2/1) as eluent afforded
84 mg of a white foam: 1H NMR (CDCl3, 300 MHz) δ 7.82 (d,
1H, J ) 8.0), 7.41-7.06 (m, 13H), 6.93 (m, 3H), 4.94 (m, 1H),
4.24 (m, 3H), 3.84 (s, 3H), 3.80 (m, 1H), 3.62 (m, 1H), 1.88 (m,
2H), 1.51 (m, 4H), 1.29 (m, 2H); low-resolution MS (FAB) m/ e
614.3 (MH+).
N-Cyclop r op yl-2-[3-(1H-in d a zol-3-ylm eth yl)-2,4-d ioxo-
5-p h en yl-2,3,4,5,5a ,9a -h exa h yd r oben zo[b][1,4]d ia zep in -
1-yl]-N-p h en yla ceta m id e (44). Deprotection via method B
followed by silica gel flash chromatography eluted successively
with EtOAc/hexanes (1/1, 200 mL) (3/2, 200 mL) afforded 328
mg of a white solid: 1H NMR (CDCl3, 300 MHz) δ 7.86 (d, 1H,
J ) 8.1), 7.48-7.21 (m, 14H), 7.11 (m, 2H), 6.95 (m, 1H), 4.39
(m, 2H), 4.25 (m, 1H), 3.83 (m, 1H), 3.65 (m, 1H), 3.28 (m,
1H), 0.82 (m, 2H), 0.57 (m, 2H); low-resolution MS (FAB) m/ e
556.0 (MH+); TLC Rf ) 0.18 (EtOAc/hexanes, 1/1).
2-[3-(1H-In dol-3-ylm eth yl)-3-m eth oxy-2,4-dioxo-5-ph en -
yl-2,3,4,5-t et r a h yd r ob en zo[b][1,4]d ia zep in -1-yl]-N-iso-
p r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (21). A solution
of 1.23 g (4.22 mmol) of 2-(1H-indol-3-ylmethyl)-2-methox-
ypropanedioic acid dimethyl ester, 1.01 g (4.64 mmol, 1.1
equiv) of (BOC)2O, and 570 mg (4.64 mmol, 1.1 equiv) of DMAP
in 30 mL of acetonitrile was stirred at room temperature for
12 h. The solvent was removed in vacuo and the residue
diluted with EtOAc (50 mL) and extracted with HCl (2 × 50
mL). The organic layer was separated and dried (MgSO4) and
the solvent removed in vacuo. This material was dissolved in
30 mL of a 9/1 solution of EtOH/H2O and 10 mL of a solution
of 713 mg (12.7 mmol) of KOH in 9/1 EtOH/H2O was added
dropwise. The resulting solution was stirred 18 h at room
temperature, concentrated to remove the EtOH, diluted with
H2O (100 mL), and washed with EtOAc (2 × 20 mL). The
aqueous extract was acidified to pH 2 with concentrated HCl
and extracted with EtOAc (2 × 30 mL). The organic layer was
separated and dried (MgSO4) and the solvent removed in vacuo
to afford a white foam. This material was dissolved in 30 mL
of DCM and cooled to 0 °C, and 0.02 mL of DMF was added.
To this solution was added dropwise 815 µL (9.80 mmol) of
oxalyl chloride. The resulting solution was stirred 2 h at room
temperature, and then the solvent and excess oxalyl chloride
were removed in vacuo to yield the crude diacid chloride as
an orange-red oil. This material was immediately dissolved
in 30 mL of THF, and a solution of 763 mg (1.96 mmol) of
N-isopropyl-N-(4-methoxyphenyl)-2-[[2-(phenylamino)phenyl]-
amino]acetamide in 10 mL of THF was added dropwise over
2 min. The resulting solution was stirred 10 min at room
temperature and then refluxed for 24 h. The solution was
cooled to room temperature and the solvent removed in vacuo.
Purification by silica gel flash column chromatography using
hexane/EtOAc (2/1) as eluent followed by further purification
by reverse phase MPLC using a C18 column and 75% MeOH/
25% H2O as eluent followed by lyophilization in acetonitrile/
H2O afforded 150 mg of a white amorphous solid: 1H NMR
(DMSO-d6, 400 MHz) δ 10.77 (s, 1H), 7.57 (d, 1H, J ) 8.0),
7.45-6.91 (m, 15H), 6.69 (d, 1H, J ) 8.2), 4.82 (m, 1H), 4.26
(m, 2H), 3.79 (s, 3H), 3.54 (AB quartet, 2H, J ) 6.3, 15.2),
2.83 (s, 3H), 1.00 (m, 6H); low-resolution MS (FAB) m/ e 617
(MH+), 616 (M+); tR ) 13.50 min (RP-HPLC, 50-100% aceto-
nitrile, 30 min); high-resolution MS calcd 616.2686, found
616.2675.
N-ter t-Bu tyl-2-[3-(1H-in d a zol-3-ylm eth yl)-2,4-d ioxo-5-
p h en yl-2,3,4,5,5a ,9a -h exa h yd r oben zo[b][1,4]d ia zep in -1-
yl]-N-p h en yla ceta m id e (45). Deprotection via method B
followed by silica gel flash chromatography eluted successively
with EtOAc/hexanes (1/2 to 1/1) afforded a white foam: 1H
NMR (CDCl3, 300 MHz) δ 7.82 (d, 1H, J ) 7.5), 7.43-7.06 (m,
16H), 4.19 (m, 2H), 4.08 (m, 1H), 3.79 (m, 1H), 3.63 (m, 1H),
1.37 (s, 9H); low-resolution MS (FAB) m/ e 572.2 (MH+); TLC
Rf ) 0.41 (EtOAc/hexanes, 3/2); Anal. (C35H33N5O3) C, H, N.
Gen er a l P r oced u r e for Met h yla t ion of 1,5-Ben zod i-
a zep in es a t C3 follow ed by Dep r otection (if Need ed ) To
Affor d C3 Qu a r ter n a r y Com p ou n d s 20, 22, a n d 27 (Ta ble
2). To a stirring solution of 1.0 equiv of the desired 1,5-
benzodiazepine substrate in 15 mL of DMF at 0 °C was added
1.1 equiv of the desired base (60% NaH in mineral oil, a 1.0
M solution of NaN(TMS)2 in THF, or a 0.5 M solution of KN-
(TMS)2 in toluene). The resulting solution was stirred 10-30
min, and then a solution of 1.5 equiv of methyl iodide was
added. The resulting solution was stirred 2 h at room
temperature and then quenched with 5 mL of H2O. The
reaction mixture was then poured into 50 mL of EtOAc and
extracted with H2O (2 × 50 mL). The organic layer was
separated and dried (MgSO4), and the solvents were removed
in vacuo. Deprotection, if needed, was carried out using either
method A or method B outlined above in the General Proce-
dure for Alkylation of 1,5-Benzodiazepines at C3. Spectral
data and purification protocol for the representative com-
pounds are as follows:
2-[3-(1H-In d ol-3-ylm eth yl)-3-m eth yl-2,4-d ioxo-5-p h en -
yl-2,3,4,5-t et r a h yd r ob en zo[b][1,4]d ia zep in -1-yl]-N-iso-
p r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (20). Deprotection
via method B followed by purification via reverse phase MPLC
using a C-18 column and 65% acetonitrile/35% H2O as eluent
followed by lyophilization afforded 82 mg of a white amorphous
solid: 1H NMR (DMSO-d6, 300 MHz) δ 7.56-6.84 (m, 18H),
4.83 (m, 1H), 4.27 (m, 2H), 3.80 (s, 3H), 2.78 (d, 1H, J ) 15.1),
2.64 (d, 1H, J ) 15.0), 1.26 (s, 3H), 0.98 (m, 6H); low-resolution
MS (FAB) m/ e 601 (MH+), 600 (M+). Anal. (C37H36N4O4) H,
N, C: calcd, 73.98; found 73.27.
N-Isop r op yl-N-(4-m eth oxyp h en yl)-2-[3-[(1-m eth yl-1H-
in d a zol-3-yl)m eth yl]-3-m eth yl-2,4-d ioxo-5-p h en yl-2,3,4,5-
tetr ah ydr o-ben zo[b][1,4]diazepin -1-yl]acetam ide (27). Pu-
rification of the material by silica gel MPLC on an Si60 column
using hexane/EtOAc (4/3) as eluent followed by lyophilization
in acetonitrile/H2O afforded 124 mg of a white amorphous
solid: 1H NMR (DMSO-d6, 300 MHz) δ 7.48-6.95 (m, 16H),
6.71 (d, 1H, J ) 7.3), 4.78 (m, 1H), 4.21 (s, br, 2H), 3.95 (s,
3H), 3.74 (s, 3H), 2.79 (d, 2H, J ) 5.9), 1.20 (s, 3H), 0.93 (m,
6H); low-resolution MS (FAB) m/ e 616 (MH+); high-resolution
MS calcd 616.2920, found 616.2924.
2-[(1-Ben zyl-1H -in d a zol-3-yl)m et h yl]-2-m et h oxyp r o-
p a n ed ioic Acid Dim eth yl Ester (6b). To a stirring solution
of 183 mg (1.13 mmol) of dimethyl methoxymalonate in 5 mL
of DMF at 0 °C was added 1.35 mL (1.35 mmol, 1.2 equiv) of
a 1.0 M solution of NaN(TMS)2 in THF. The resulting solution
was stirred 5 min, and then a solution of 340 mg (1.13 mmol,
1.0 equiv) of 1-benzyl-3-(bromomethyl)-1H-indazole in 2 mL
of DMF was added. The reaction mixture was stirred 1 h at
room temperature, then poured into 50 mL of Et2O, and
extracted with H2O (2 × 50 mL). The organic layer was
2-[3-[(N-Meth ylin d ol-3-yl)m eth yl]-3-m eth yl-2,4-d ioxo-
5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-
isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (22). Purifica-

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2721
separated and dried (MgSO4) and the solvent removed in
vacuo. Purification by silica gel flash column chromatography
using hexane/EtOAc (4/1) as eluent afforded 350 mg of as a
clear, colorless oil which solidifies on standing: mp 94-96 °C;
1H NMR (CDCl3, 300 MHz) δ 7.68 (d, 1H, J ) 8.0), 7.31-7.07
(m, 8H), 5.54 (s, 2H), 3.80 (s, 2H), 3.72 (s, 6H), 3.51 (s, 3H);
low-resolution MS (FAB) m/ e 383 (MH+), 382 (M+), 350, 221.
Anal. (C21H22N2O5) Calcd: C, 65.96; H, 5.80; N, 7.33. Found:
C, 66.06; H, 5.75; N, 7.29.
3-yl)methyl]-3-methyl-2,4-dioxo-5-phenyl-2,3,4,5-terahydrobenzo-
[b][1,4]diazepin-1-yl]-N-isopropyl-N-(4-methoxyphenyl)aceta-
mide in 15 mL of a 10% solution of formic acid in absolute
ethanol was added 200 mg of 10% palladium on carbon. The
resulting black suspension was refluxed for 6 h and then cooled
to room temperature. The reaction mixture was filtered
through Celite to remove the catalyst and the solvent removed
in vacuo. Purification of the residue by silica gel flash column
chromatography using hexane/EtOAc (3/2) as eluent followed
by further purification via silica gel MPLC using an Si60
column and hexane/EtOAc (2/1) as eluent, and lyophilization
afforded 30 mg of a white amorphous solid: 1H NMR (DMSO-
d6, 300 MHz) δ 7.48-6.98 (m, 17H), 6.70 (d, 1H, J ) 7.8), 4.86
(m, 1H), 4.27 (m, 2H), 3.81 (s, 3H), 2.87 (dd, 2H), 1.29 (s, 3H),
1.00 (m, 6H); low-resolution MS (FAB) m/ e 602 (MH+), 437,
279, 223.
2-[2,4-Dioxo-5-p h en yl-3-[(4,5,6,7-t et r a h yd r o-1-b en zyl-
1H-in d a zol-3-yl)m eth yl]-2,3,4,5-tetr a h yd r oben zo[b][1,4]-
d ia zep in -1-yl]-N-isop r op yl-N-(4-m et h oxyp h en yl)a cet a -
m id e (49). To a stirring solution of 164 mg (0.36 mmol) of
2-(2,4-dioxo-5-phenyl-2,3,4,5-tetrahydrobenzo[b][1,4]diazepin-
1-yl)-N-isopropyl-N-(4-methoxyphenyl)acetamide in 5 mL of
DMF at 0 °C was added 0.430 mL (0.78 mmol, 1.2 equiv) of a
2-[(1-Ben zyl-1H -in d a zol-3-yl)m et h yl]-2-m et h oxyp r o-
p a n ed ioic Acid (47). A solution of 350 mg (0.92 mmol) of
2-[(1-benzyl-1H-indazol-3-yl)methyl]-2-methoxypropanedioic acid
dimethyl ester and 0.6 mL of 6 N NaOH in 10 mL of a 9/1/1
mixture of absolute EtOH/H2O/THF was stirred 22 h at room
temperature. The solvent was removed in vacuo and the
residue dissolved in 15 mL of H2O, cooled to 0 °C, and acidified
to pH 1 with 1 N HCl. The reaction mixture was then
extracted with EtOAc (2 × 30 mL), and the organic layers were
washed with brine (1 × 30 mL) and dried (MgSO4), and the
solvent was removed in vacuo to afford 324 mg of a light pink
1
solid: mp 144-145 °C; H NMR (DMSO-d6, 400 MHz) δ 7.67
(d, 1H, J ) 8.0), 7.52 (d, 1H, J ) 8.6), 7.29-7.15 (m, 6H), 7.04
(dd, 1H, J ) 7.5, 7.5), 5.55 (s, 2H), 3.58 (s, 2H), 3.33 (s, 3H);
low-resolution MS (FAB) m/ e 354 (MH+), 353 (M+), 310, 309,
295, 294. Anal. (C19H18N2O5) Calcd: C, 64.40; H, 5.12; N, 7.90.
Found: C, 64.60; H, 5.15; N, 7.94.
1.0 M solution of NaN(TMS)2
in THF. The resulting solution
was stirred 5 min, and a solution of 120 mg (0.39 mmol, 1.1
equiv) of 3-(bromomethyl)-4,5,6,7-tetrahydro-1-benzyl-1H-in-
dazole in 2 mL of DMF was added. The resulting solution was
stirred for 3 h at room temperature and then quenched with
5 mL of H2O. The reaction mixture was poured into 50 mL of
EtOAc and extracted with H2O (2 × 50 mL). The organic layer
was separated and dried (MgSO4), and the solvents were
removed in vacuo. Purification by silica gel flash column
chromatography using hexane/EtOAc (1/1) as eluent afforded
175 mg of a white solid: mp 173-176 °C; 1H NMR (CDCl3,
400 MHz) δ 7.37-6.84 (m, 18H), 5.02 (s, 2H), 4.99 (m, 1H),
4.22 (s, br, 2H), 4.10 (dd, 1H, J ) 5.3, 8.7), 3.823 (s, 3H), 3.36
(dd 1H, J ) 8.6, 15.6), 3.09 (dd, 1H, J ) 5.3, 15.6), 2.54-2.38
(m, 4H), 1.67 (m, 4H), 1.04 (d, 6H, J ) 6.6); low-resolution
MS (FAB) m/ e 682 (MH+).
2-[3-[(1-Ben zyl-1H-in d a zol-3-yl)m eth yl]-3-m eth oxy-2,4-
d ioxo-5-p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -
1-yl]-N-isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (48).
To a stirring solution of 320 mg (0.90 mmol) of 2-[(1-benzyl-
1H-indazol-3-yl)methyl]-2-methoxypropanedioic acid and 7 µL
of DMF in 8 mL of DCM at 0 °C was added dropwise 315 µL
(3.61 mmol, 4.0 equiv) of oxalyl chloride. The resulting
solution was stirred 2 h at room temperature, and then the
solvent and excess oxalyl chloride were removed in vacuo to
yield the crude diacid chloride as an orange-red oil. This
material was immediately dissolved in 8 mL of THF and cooled
to 0 °C, and a solution of 296 mg (0.76 mmol) of N-isopropyl-
N-(4-methoxyphenyl)-2-[[2-(phenylamino)phenyl]amino)aceta-
mide in 2 mL of THF was added dropwise over 2 min. The
resulting solution was stirred 10 min at room temperature and
then refluxed for 4 h. The solution was cooled to room
temperature and the solvent removed in vacuo. Purification
of the residue by silica gel flash column chromatography using
hexane/EtOAc (2/1) as eluent followed by further purification
by silica gel MPLC using an Si60 column and hexane/EtOAc
(3/1) as eluent followed by lyophilization in acetonitrile/H2O
afforded 220 mg of a white amorphous solid: 1H NMR (DMSO-
d6, 300 MHz) δ 7.91 (d, 1H, J ) 8.1), 7.58 (d, 1H, J ) 8.3),
7.44-7.00 (m, 19H), 6.65 (dd, 1H, J ) 1.0, 8.3), 5.54 (s, 2H),
4.82 (m, 1H), 4.26 (s, br, 2H), 3.95 (d, 1H, J ) 15.4), 3.82 (d,
1H, J ) 15.4), 3.80 (s, 3H), 2.90 (s, 3H), 0.99 (m, 6H); low-
resolution MS (FAB) m/ e 708 (MH+).
2-[3-(1H -In d a zol-3-ylm et h yl)-3-m et h oxy-2,4-d ioxo-5-
p h en yl-2,3,4,5-tetr a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-
isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (24). To a stir-
ring solution of 80 mg (0.11 mmol) of 2-[3-[(1-benzyl-1H-
indazol-3-yl)methyl]-3-methoxy-2,4-dioxo-5-phenyl-2,3,4,5-
t et r a h ydr oben zo[b][1,4]dia zepin -1-yl]-N-isopr opyl-N-(4-
methoxyphenyl)acetamide in 10 mL of a 10% solution of formic
acid in absolute ethanol was added 70 mg of 10% palladium
on carbon. The resulting black suspension was refluxed for 6
h and then cooled to room temperature. The reaction mixture
was filtered through Celite to remove the catalyst and the
solvent removed in vacuo. Purification of the residue via silica
gel MPLC using an Si60 column and hexane/EtOAc (1/1) as
eluent followed by lyophilization afforded 41 mg of a white
amorphous solid: 1H NMR (DMSO-d6, 300 MHz) δ 7.83 (d,
1H, J ) 8.3), 7.38-6.94 (m, 16H), 6.59 (d, 1H, J ) 7.1), 4.76
(m, 1H), 4.19 (s, br, 2H), 3.85 (d, 1H, J ) 15.7), 3.73 (m, 4H),
2.88 (s, 3H), 0.93 (m, 6H); low-resolution MS (FAB) m/ e 618
(MH+).
2-[2,4-Dioxo-5-ph en yl-3-[(4,5,6,7-tetr ah ydr o-1H-in dazol-
3-yl)m et h yl]-2,3,4,5-t et r a h yd r ob en zo[b][1,4]d ia zep in -1-
yl]-N-isop r op yl-N-(4-m eth oxyp h en yl)a ceta m id e (30). To
a stirring solution of 150 mg (0.22 mmol) of 2-[2,4-dioxo-5-
phenyl-3-[(4,5,6,7-tetrahydro-1-benzyl-1H-indazol-3-yl)methyl]-
2,3,4,5-tetrahydrobenzo[b][1,4]diazepin-1-yl]-N-isopropyl-N-(4-
methoxyphenyl)acetamide in 10 mL of a 10% solution of formic
acid in absolute ethanol was added 150 mg of 10% palladium
on carbon. The resulting black suspension was refluxed for 3
h and then cooled to room temperature. The reaction mixture
was filtered through Celite to remove the catalyst and the
solvent removed in vacuo. Purification of the residue via silica
gel MPLC using an Si60 column and hexane/EtOAc (1/5) as
eluent afforded 105 mg of as a white solid: mp 170-173 °C;
1H NMR (CDCl3, 400 MHz) δ 7.38-6.88 (m, 13H), 5.03 (m,
1H), 4.34 (d, 1H, J ) 16.8), 4.14 (d, 1H, J ) 16.8), 3.84 (s,
3H), 3.58 (dd, 1H, J ) 6.8, 6.8), 3.46 (dd, 1H, J ) 7.0, 14. 0),
3.30 (dd, 1H, J ) 7.5, 15.2), 2.60 (m, 2H), 2.36 (m, 2H), 1.70
(m, 4H), 1.08 (2 d, 6H, J ) 6.6); low-resolution MS (FAB) m/ e
592 (MH
+), 591 (M+), 427. Anal. (C35H37N5O4) Calcd: C,
71.05; H, 6.30; N, 11.84. Found: C, 70.20; H, 6.47; N, 11.66.
N-Isop r op yl-N-(4-m eth oxyp h en yl)-2-[3-[(5-m eth yl-2H-
p yr a zol-3-yl)m e t h yl]-2,4-d ioxo-5-p h e n yl-2,3,4,5-t e t r a -
h yd r oben zo[b][1,4]d ia zep in -1-yl]a ceta m id e (35). To a
stirring solution of 194 mg (0.30 mmol) of 2-[3-[(2-benzyl-5-
methyl-2H-pyrazol-3-yl)methyl]-2,4-dioxo-5-phenyl-2,3,4,5-
tetrahydrobenzo[b][1,4]diazepin-1-yl]-N-isopropyl-N-(4-meth-
oxyphenyl)acetamide in 10 mL of 5% formic acid (v/v) in
absolute ethanol is added 190 mg of 10% palladium on carbon.
The resulting mixture is heated to reflux for 2 h, cooled to room
temperature, and filtered through a pad of Celite to remove
the catalyst. The filtrate is concentrated, poured into 50 mL
of EtOAc, and washed successively with 1 N NaOH (1 × 50
mL) and H2O (1 × 50 mL). The organic layer is separated
and dried (MgSO4), and the solvents are removed in vacuo.
Purification by silica gel MPLC using EtOAc/chloroform (8/1)
as eluent afforded 112 mg of a white solid: mp 156-159 °C;
2-[3-(1H-In dazol-3-ylm eth yl)-3-m eth yl-2,4-dioxo-5-ph en -
yl-2,3,4,5-ter a h yd r oben zo[b][1,4]d ia zep in -1-yl]-N-isop r o-
p yl-N-(4-m eth oxyp h en yl)a ceta m id e (23). To a stirring
solution of 190 mg (0.28 mmol) of 2-[3-[(1-benzyl-1H-indazol-

2722 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Henke et al.
1H NMR (CDCl3, 400 MHz) δ 7.38-7.18 (m, 9H), 7.14 (d, 1H,
J ) 8.7), 7.06 (t, 1H, J ) 7.3), 6.96 (m, 2H), 6.86 (d, 1H, J )
7.6), 5.81 (s, 1H), 5.02 (m, 1H), 4.18 (dd, 2H, J ) 16.5, 86.1),
3.83 (s, 3H), 3.59 (t, 1H, J ) 6.8), 3.32 (ddd, 2H, J ) 7.5, 15.2,
34.3), 2.19 (s, 3H), 1.08 (m, 6H); low-resolution MS (FAB) m/ e
552 (MH+), 551 (M+), 387. Anal. (C32H33N5O4) Calcd; C, 69.67;
H, 6.03; N, 12.70. Found: C, 69.61; H, 6.11; N, 12.44.
3-Meth ylin d a zole (10). To a stirring solution of 36.2 g
(0.26 mol) of 2-fluoroacetophenone in 120 mL of ethylene glycol
was added 8.6 mL (0.27 mol, 1.05 equiv) of hydrazine. The
resulting solution was stirred 2 h at room temperature and
then heated at 165 °C for 40 h. The solution was cooled to
room temperature, poured into CH2Cl2 (200 mL), and extracted
with H2O (2 × 200 mL). The organic layers were combined
and dried (MgSO4), and the solvent was removed in vacuo.
Purification of the crude material by recrystallization form
hexane/CHCl3 afforded 26 g of a light tan solid: 1H NMR
(CDCl3, 300 MHz) δ 7.73 (d, 1H, J ) 8.1), 7.44 (m, 2H), 7.19
(dd, 1H, J ) 7.0, 7.0), 2.67 (s, 3H).
1-(ter t-Bu toxyca r bon yl)-3-m eth ylin d a zole (50). To a
stirring solution of 30.3 g (0.23 mol) of 3-methylindazole in
300 mL of CH3CN was added 35.0 mL (0.25 mol, 1.1 equiv) of
Et3N and 5.77 g (47.2 mmol, 0.2 equiv) of DMAP, and the
mixture was cooled to 0 °C. Next, 60.5 g (0.28 mol, 1.2 equiv)
of (BOC)2O in 200 mL of CH3CN was added dropwise with
stirring at 0 °C, and the resultant reaction mixture stirred 3
h at room temperature. The solvent was removed in vacuo
and the crude material partitioned between Et2O (300 mL)
and H2O (100 mL). The pH was adjusted to 2.0 with 1 N HCl,
and the organic phase was separated, dried (MgSO4), filtered,
and concentrated in vacuo to an orange oil which was purified
by filtration through a pad of silica gel using hexane/EtOAc
(4/1) as eluent. The filtrate was concentrated in vacuo to give
53.4 g of a white solid: 1H NMR (CDCl3, 300 MHz) δ 8.15 (d,
1H, J ) 7.8), 7.67 (d, 1H, J ) 7.8), 7.56 (dd, 1H, J ) 7.3, 7.3),
7.35 (dd, 1H, J ) 7.3, 7.3), 2.62 (s, 3H), 1.77 (s, 9H); TLC Rf )
0.66 (EtOAc/hexane, 1/2).
3-(2-Br om op h en oxy)a cr ylic Acid Eth yl Ester (11). To
a stirring solution of 972 mg (11.56 mmol) of ethyl propiolate
in 20 mL of THF at 0 °C was added a solution of 1.61 mL (11.56
mmol) of triethylamine in 5 mL of THF, followed by a solution
of 2.0 g (11.56 mmol) of 2-bromophenol in 5 mL of THF. The
resulting clear orange-brown solution was stirred 5 h at 0 °C,
poured into 100 mL of Et2O, and extracted with H2O (1 × 100
mL). The organic layer was separated, washed with saturated
Na2CO3 (1 × 100 mL), and dried (MgSO4), and the solvent was
removed in vacuo to provide 2.97 g of the title compound as
an orange oil: 1H NMR (CDCl3, 300 MHz) δ 7.71 (d, 1H, J )
12.3), 7.61 (d, 1H, J ) 7.4), 7.37-7.08 (m, 3H), 5.47 (d, 1H, J
) 12.3), 3.72 (s, 3H).
oil: 1H NMR (CDCl3, 300 MHz) δ 7.66 (d, 1H), 7.60 (s, 1H),
7.49 (d, 1H), 7.29 (m, 2H), 4.82 (d, 2H), 1.70 (m, 1H).
(1-Meth yl-1H-in d a zol-3-yl)m eth a n ol (52). To a stirring
solution of 440 mg (2.31 mmol) of 1-methyl-1H-indazole-3-
carboxylic acid methyl ester41 in 10 mL of DCM at -78 °C was
added dropwise over 5 min a solution of 5.8 mL (5.8 mmol,
2.5 equiv) of a 1.0 M solution of DIBAL-H in hexane. The
resulting solution was allowed to slowly warm to room tem-
perature over a 3 h period and then quenched by careful
addition of 5 mL of H2O. The reaction mixture was poured
into 100 mL of EtOAc, extracted with 1 N HCl (1 × 100 mL),
and dried (MgSO4), and the solvent was removed in vacuo.
Purification of the crude material by silica gel flash column
chromatography using hexane/EtOAc (1/1) as eluent afforded
340 mg of a pale yellow oil: 1H NMR (CDCl3, 300 MHz) δ 7.80
(d, 1H), 7.42-7.12 (m, 3H), 5.02 (d, 2H), 4.00 (s, 3H), 2.27 (m,
1H).
3-Meth yl-1H-p yr a zolo[3,4-b]p yr id in e (53). To a stirring
suspension of 5.0 g (51.5 mmol) of 3-amino-5-methylpyrazole
in 10.1 g (61.8 mmol, 1.2 equiv) of malonaldehyde dimethyl
acetal was added approximately 8 g of polyphosphoric acid,
and the resulting mixture was heated to 100 °C for 2 h. The
resulting black oil was poured onto crushed ice, made basic
by the addition of 3 N NaOH, and then extracted with EtOAc
(2 × 100 mL). The organic layers were combined and dried
(MgSO4), and the solvent was removed in vacuo. Purification
of the crude material by silica gel flash column chromatogra-
phy using hexane/EtOAc (1/1) as eluent afforded 160 mg of a
white solid: 1H NMR (CDCl3, 400 MHz) δ 8.57 (dd, 1H, J )
1.1, 4.7), 8.04 (dd, 1H, J ) 1.1, 8.0), 7.12 (dd, 1H, J ) 4.7,
8.0), 2.60 (s, 3H); low-resolution MS (FAB) m/ e 134 (MH+).
3-Meth yl-1-(ter t-bu toxyca r bon yl)p yr a zolo[3,4-b]p yr i-
d in e (54). To a stirring solution of 160 mg (1.20 mmol) of
3-methyl-1H-pyrazolo[3,4-b]pyridine in 5 mL of acetonitrile at
0
o C was added 167 µL (1.20 mmol) of Et3N and 145 mg (1.20
mmol) of DMAP. The resulting solution was stirred 2 min,
and then a solution of 315 mg (1.44 mmol, 1.2 equiv) of di-
tert-butyl dicarbonate in 1 mL of acetonitrile was added. The
resulting solution was warmed to room temperature and
stirred for 30 min. The reaction mixture was poured into 10
mL of EtOAc, extracted with brine (1 × 10 mL), and dried
(MgSO4), and the solvent was removed in vacuo. Purification
of the crude material by silica gel flash column chromatogra-
phy using hexane/EtOAc (1/1) as eluent afforded 253 mg of a
pale yellow oil: 1H NMR (CDCl3, 400 MHz) δ 8.72 (dd, 1H, J
) 1.5, 4.7), 7.99 (dd, 1H, J ) 1.5, 8.0), 7.26 (dd, 1H, J ) 4.7,
8.0), 2.59 (s, 3H), 1.71 (s, 9H).
1-(3-Nitr op yr id in -2-yl)eth a n on e (55). To a stirring solu-
tion of 4.40 g (16.05 mmol) of trifluoromethanesulfonic acid
3-nitropyridin-2-yl ester17 in 30 mL of DMF was added 3.96 g
(16.85 mmol, 1.05 equiv) of 1-ethoxy-1-(trimethylstannyl)
ethene,18 followed by 305 mg (1.61 mmol, 0.10 equiv) of copper-
(I) iodide and 560 mg (0.80 mmol, 0.05 equiv) of bis(triph-
enylphosphine)palladium(II) chloride. The resulting mixture
was heated to 80 °C for 4 h, cooled to room temperature, and
filtered through a pad of Celite. The filtrate was poured into
100 mL of EtOAc, extracted with H2O (1 × 100 mL), and dried
(MgSO4), and the solvent was removed in vacuo. Purification
of the crude material by silica gel flash column chromatogra-
phy using hexane/EtOAc (5/1) as eluent afforded 2.41 g of a
pale yellow oil. This material was dissolved in 80 mL of THF,
and 20 mL of 2 N HCl was added. The resulting solution was
stirred at 35 °C for 6 h and then cooled to room temperature.
The reaction was made basic by the addition of 2 N NaOH,
extracted with diethyl ether (2 × 100 mL), and dried (MgSO4),
and the solvent removed in vacuo to afford 2.0 g of a light
brown oil: 1H NMR (CDCl3, 400 MHz) δ 8.78 (dd, 1H, J )
1.2, 4.7), 8.20 (dd, 1H, J ) 1.2, 8.3), 7.58 (dd, 1H, J ) 4.7,
8.3), 2.69 (s, 3H).
Ben zofu r a n -3-ca r boxylic Acid Eth yl Ester (12).
A
stirring solution of 2.43 g (9.45 mmol) of 3-(2-bromophenoxy)-
acrylic acid ethyl ester, 1.98 g (7.56 mmol, 0.8 equiv) of
triphenylphosphine, 794 mg (9.45 mmol, 1.0 equiv) of NaHCO3,
and 848 mg (3.78 mmol, 0.4 equiv) of palladium(II) acetate in
25 mL of DMF was heated to 110 oC for 16 h. After being
cooled to room temperature, the reaction mixture was diluted
with 100 mL of Et2O, extracted with H2O (1 × 100 mL), and
dried (MgSO4), and the solvents were removed in vacuo.
Purification of the crude material by silica gel flash column
chromatography afforded 650 mg of a yellow oil: 1H NMR
(CDCl3, 300 MHz) δ 8.22 (s, 1H), 8.06 (m, 1H), 7.55 (m, 1H),
7.37 (m, 2H), 3.95 (s, 3H).
3-(Hyd r oxym eth yl)ben zofu r a n (51). To a stirring solu-
tion of 650 mg (3.69 mmol) of benzofuran-3-carboxylic acid
ethyl ester in 25 mL of DCM at -78 °C was added dropwise
over 5 min a solution of 9.22 mL (9.22 mmol, 2.5 equiv) of a
1.0 M solution of DIBAL-H in hexane. The resulting solution
was allowed to slowly warm to room temperature over a 4 h
period and then quenched by careful addition of 5 mL of H2O.
The reaction mixture was poured into 100 mL of EtOAc,
extracted with 1 N HCl (1 × 100 mL), and dried (MgSO4), and
the solvent was removed in vacuo. Purification of the crude
material by silica gel flash column chromatography using
hexane/EtOAc (4/1) as eluent afforded 444 mg of a pale yellow
1-(3-Am in op yr id in -2-yl)eth a n on e (14). To a solution of
1.90 g (11.43 mmol) of 1-(3-nitropyridin-2-yl)ethanone in 60
mL of absolute ethanol was added 600 mg of 10% palladium
on carbon. The resulting mixture was stirred at room tem-
perature for 24 h over an atmosphere of H2 gas (balloon). The
reaction mixture was filtered through a pad of Celite to remove

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2723
the palladium catalyst and the solvent was removed in vacuo.
Purification of the crude material by silica gel flash column
chromatography using hexane/EtOAc (1/1) as eluent afforded
1.22 g of a pale yellow solid: mp 64-65 °C (lit. mp 66-67
crude material by Kugelrohr distillation gave 740 mg of a pale
yellow thick oil: bp 225 °C at 0.8 mm; H NMR (CDCl3, 300
MHz) δ 7.32-7.24 (m, 3H), 7.10 (m, 2H), 5.17 (s, 2H), 4.62 (s,
2H), 2.46 (m, 4H), 1.72 (m, 4H); low-resolution MS (FAB) m/ e
243 (MH+).
1
1
°C); H NMR (CDCl3, 400 MHz) δ 8.00 (dd, 1H, J ) 1.5, 4.1),
7.18 (dd, 1H, J ) 4.1, 8.4), 6.97 (dd, 1H, J ) 1.5, 8.4), 6.14 (s,
br, 2H), 2.70 (s, 3H).
1-Ben zyl-1H-in d a zole-3-ca r boxylic Acid Ben zyl Ester
(8b). To a stirring solution of 750 mg (4.62 mmol) of 1H-
indazole-3-carboxylic acid14 in 20 mL of DMF was added 1.92
g (13.86 mmol, 3.0 equiv) of K2CO3, followed by 1.43 mL of
benzyl bromide. The reaction mixture was stirred for 15 min
at room temperature and then heated at 60 °C for 16 h. The
reaction was cooled to room temperature, poured into 100 mL
of 1 N HCl, and extracted with EtOAc (2 × 100 mL). The
organic layers were washed with H2O (2 × 100 mL) and dried
(MgSO4), and the solvent was removed in vacuo. Purification
of the crude material by silica gel flash column chromatogra-
phy using a gradient elution of hexane/EtOAc (20/1 to 2/1)
afforded 735 mg of a yellow oil which later solidified: 1H NMR
(CDCl3, 300 MHz) δ 8.20 (d, 1H), 7.55 (d, 2H), 7.40-7.18 (m,
11H), 5.70 (s, 2H), 5.57 (s, 2H).
(1-Ben zyl-1H-in d a zol-3-yl)m eth a n ol (59). To a stirring
solution of 735 mg (2.15 mmol) of 1-benzyl-1H-indazole-3-
carboxylic acid benzyl ester in 15 mL of DCM at -78 °C was
added dropwise over 5 min a solution of 5.4 mL (5.4 mmol,
2.5 equiv) of a 1.0 M solution of DIBAL-H in hexane. The
resulting solution was allowed to slowly warm to room tem-
perature over a 4 h period and then quenched by careful
addition of 5 mL of H2O. The reaction mixture was poured
into 100 mL of EtOAc and extracted with 1 N HCl (1 × 100
mL), and dried (MgSO4), and the solvent was removed in
vacuo. Purification of the crude material by silica gel flash
column chromatography using hexane/EtOAc (1/1) as eluent
afforded 448 mg of a pale yellow solid: 1H NMR (CDCl3, 300
MHz) δ 7.80 (d, 1H), 7.40-7.08 (m, 8H), 5.50 (s, 2H), 5.04 (d,
2H), 2.24 (m, 1H).
5-Meth yl-2H-p yr a zole-3-ca r boxylic Acid Meth yl Ester
(60). To a stirring solution of 2.0 g (13.87 mmol) of methyl
acetopyruvate in 40 mL of absolute ethanol at 0 °C was added
0.48 mL (15.27 mmol, 1.1 equiv) of hydrazine. The resulting
solution was stirred for 1 h at room temperature and then
heated to reflux for 3 h. The solution was then cooled to room
temperature and the solvent removed in vacuo to give a clear
yellow oil: 1H NMR (CDCl3, 300 MHz) δ 6.61 (s, 1H), 3.97 (s,
3H), 2.40 (s, 3H).
2-Ben zyl-5-m eth yl-2H-pyr azole-3-car boxylic Acid Meth -
yl Ester (8c). To a stirring solution of 21.91 g (13.63 mmol)
of 5-methyl-2H-pyrazole-3-carboxylic acid methyl ester in 50
mL of DMF was added 2.88 g (20.44 mmol, 1.5 equiv) of K2-
CO3, followed by 1.95 mL (16.35 mmol, 1.2 equiv) of benzyl
bromide. The reaction mixture was stirred 15 min at room
temperature and then heated at 50 °C for 20 h. The reaction
was cooled to room temperature, poured into 100 mL of 1 N
HCl, and extracted with Et2O (2 × 100 mL). The organic
layers were washed with H2O (2 × 100 mL) and dried (MgSO4),
and the solvent was removed in vacuo. Purification of the
crude material by silica gel flash column chromatography
using a gradient elution of hexane/EtOAc (10/1 to 1/1) afforded
833 mg of a yellow oil: 1H NMR (CDCl3, 300 MHz) δ 7.42-
7.25 (m, 5H), 6.68 (s, 2H), 5.74 (s, 2H), 3.86 (s, 3H), 2.34 (s,
3H).
3-Meth yl-1H-p yr a zolo[4,3-b]p yr id in e (56). To a cold (0
°C) solution of 570 mg (8.25 mmol, 1.05 equiv) of NaNO2 in 15
mL of 2 N H2SO4 was added a cold (0 °C) solution of 1.07 g
(7.86 mmol) of 1-(3-aminopyridin-2-yl)ethanone in 15 mL of 2
N H2SO4. The reaction mixture was stirred 30 min at 0 °C
and then was warmed to room temperature and stirred for 15
min. The reaction mixture was then recooled to 0 °C, and a
cold (0 °C) solution of 3.58 g (18.86 mmol, 2.4 equiv) of SnCl2
in 10 mL of concentrated HCl was added dropwise over 5 min.
The resulting orange suspension was stirred 20 min at 0 °C
and then was warmed to room temperature and stirred 20 min.
The reaction mixture was then poured into 75 mL of cold 3 N
NaOH and extracted with a 1/1 mixture of EtOAc and diethyl
ether (2 × 150 mL). The organic layers were combined and
dried (MgSO4), and the solvent was removed in vacuo. Puri-
fication of the crude material by silica gel flash column
chromatography using hexane/EtOAc (1/2) as eluent afforded
553 mg of a tan solid: 1H NMR (CDCl3, 400 MHz) δ 10.21 (s,
br, 1H), 8.58 (dd, 1H, J ) 1.0, 4.3), 7.77 (dd, 1H, J ) 1.0, 8.4),
7.28 (dd, 1H, J ) 4.3, 8.4), 2.69 (s, 3H); low-resolution MS
(FAB) m/ e 134 (MH+).
3-Meth yl-1-(ter t-bu toxyca r bon yl)p yr a zolo[4,3-b]p yr i-
d in e (57). To a stirring solution of 530 mg (3.98 mmol) of
3-methyl-1H-pyrazolo[4,3-b]pyridine in 15 mL of acetonitrile
at 0 °C was added 582 µL (4.18 mmol, 1.05 equiv) of Et3N and
486 mg (3.98 mmol) of DMAP. The resulting solution was
stirred 2 min, and then a solution of 1.04 g (4.78 mmol, 1.2
equiv) of di-tert-butyl dicarbonate in 3 mL of acetonitrile was
added. The resulting solution was warmed to room temper-
ature and stirred for 90 min. The reaction mixture was poured
into 40 mL of EtOAc, extracted with brine (1 × 40 mL), and
dried (MgSO4), and the solvent was removed in vacuo. Puri-
fication of the crude material by silica gel flash column
chromatography using hexane/EtOAc (12/1) as eluent afforded
854 mg of a white solid: 1H NMR (CDCl3, 400 MHz) δ 8.65
(dd, 1H, J ) 1.3, 4.4), 8.37 (d, 1H, J ) 8.3), 7.41 (dd, 1H, J )
4.4, 8.3), 2.70 (s, 3H), 1.72 (s, 9H); low-resolution MS (FAB)
m/ e 234 (MH+).
4,5,6,7-Te t r a h yd r o-1-b e n zyl-1H -in d a zole -3-ca r b ox-
ylic Acid Eth yl Ester (8a ). To a stirring solution of 2.0 g
(10.30 mmol) of 4,5,6,7-tetrahydro-1H-indazole-3-carboxylic
acid ethyl ester11c in 50 mL of DMF was added 1.85 g (13.838
mmol, 1.3 equiv) of K2CO3, followed by 1.35 mL (11.33 mmol,
1.1 equiv) of benzyl bromide. The reaction mixture was stirred
15 min at room temperature and then heated at 60 °C for 16
h. The reaction was cooled to room temperature, poured into
100 mL of 1 N HCl, and extracted with Et2O (2 × 100 mL).
The organic layers were washed with H2O (2 × 100 mL) and
dried (MgSO4), and the solvent was removed in vacuo. Puri-
fication of the crude material by silica gel flash column
chromatography using a gradient elution of hexane/EtOAc (6/1
to 3/1) afforded 1.05 g of a yellow oil which later solidified:
1H NMR (CDCl3, 300 MHz) δ 7.37-7.23 (m, 3H), 7.13 (m, 2H),
5.31 (s, 2H), 4.39 (q, 2H, J ) 7.2), 2.74 (m, 2H), 2.40 (m, 2H),
1.72 (m, 4H), 1.39 (t, 3H, J ) 7.2).
(4,5,6,7-Tet r a h yd r o-1-b en zyl-1H -in d a zol-3-yl)m et h a -
n ol (58). To a stirring solution of 1.0 g (3.52 mmol) of 4,5,6,7-
tetrahydro-1-benzyl-1H-indazole-3-carboxylic acid ethyl ester
in 15 mL of THF at 0 °C was added dropwise over 5 min a
solution of 5.3 mL (5.3 mmol, 1.5 equiv) of a 1.0 M solution of
LiAlH4 in THF. The resulting solution was stirred at room
temperature for 30 min then heated to 50 °C for 1 h. The
reaction mixture was cooled to 0 °C and worked up by carefully
quenching first with 0.22 mL of H2O, then 0.22 mL of 15%
NaOH, and then 0.66 mL of H2O. The resulting slurry was
filtered and the filter cake triturated with 20 mL of EtOAc
and refiltered. The filtrates were combined and dried (MgSO4),
and the solvent was removed in vacuo. Purification of the
(2-Ben zyl-5-m eth yl-2H-p yr a zol-3-yl)m eth a n ol (61). To
a stirring solution of 833 mg (3.61 mmol) of 2-benzyl-5-methyl-
2H-pyrazole-3-carboxylic acid methyl ester in 5 mL of THF at
0 °C was added dropwise over 5 min a solution of 5.5 mL (5.5
mmol, 1.5 equiv) of a 1.0 M solution of LiAlH4 in THF. The
resulting solution was stirred at room temperature for 48 h.
The reaction mixture was cooled to 0 °C and worked up by
carefully quenching first with 0.20 mL of H2O, then 0.20 mL
of 15% NaOH, and then 0.60 mL of H2O. The resulting slurry
was filtered and the filter cake triturated with 20 mL of EtOAc
and refiltered. The filtrates were combined and dried (MgSO4),
and the solvent was removed in vacuo. Purification of the
crude material by Kugelrohr distillation gave 710 mg of a clear
oil: 1H NMR (CDCl3, 300 MHz) δ 7.41-7.29 (m, 3H), 7.16 (m,
2H), 6.07 (s, 1H), 5.37 (s, 2H), 4.55 (s, 2H), 2.30 (s, 3H); low-
resolution MS (FAB) m/ e 203 (MH+).

2724 J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17
Henke et al.
Gen er a l P r oced u r e for Br om in a tion of 3-Hyd r oxy-
in d a zole Der iva tives To P r ovid e Com p ou n d s of Gen er a l
F or m u la 9. To a stirring solution of 1.2 equiv of triph-
enylphosphine in CCl4 at 0 °C was added 1.1 equiv of Br2. The
resulting orange-yellow suspension was stirred 10 min at 0
°C, and then a solution of the requisite alcohol in 5 mL of CCl4
was added over 2 min. The resulting solution was stirred 1.5
h at room temperature, and the solvent was removed in vacuo.
Purification of the crude material was achieved by silica gel
flash column chromatography. Purification conditions and
spectral data for representative compounds are as follows:
1-Ben zyl-3-(br om om eth yl)-4,5,6,7-tetr a h yd r o-1H-in d a -
zole (9a ). Chromatography using hexane/EtOAc (5/1) as
eluent afforded a clear oil (39%): 1H NMR (CDCl3, 300 MHz)
δ 7.32-7.24 (m, 3H), 7.10 (m, 2H), 5.17 (s, 2H), 4.49 (s, 2H),
2.48 (m, 4H), 1.74 (m, 4H); low-resolution MS (FAB) m/ e 305
(MH+).
3-(Br om om eth yl)-4-ph en yl-1-(ter t-bu toxycar bon yl)-2H-
p yr a zole (9m ). Chromatography using hexane/EtOAc (20/
1) as eluent afforded a white solid (61%): 1H NMR (CDCl3,
400 MHz) δ 8.09 (s, 1H), 7.53 (d, 2H, J ) 7.2), 7.43 (m, 2H),
7.36 (m, 1H), 4.57 (s, 2H), 1.65 (s, 9H).
3-(Br om om eth yl)-1-(ter t-bu toxyca r bon yl)p yr a zolo[4,3-
b]p yr id in e (9n ). Chromatography using hexane/EtOAc (4/
1) as eluent afforded a white solid (43%): 1H NMR (CDCl3,
400 MHz) δ 8.75 (dd, 1H, J ) 1.4, 4.5), 8.40 (d, 1H, J ) 8.3),
7.47 (dd, 1H, J ) 4.5, 8.3), 4.90 (s, 2H), 1.73 (s, 9H);
low-resolution MS (FAB) m/ e 312 (MH+).
Ack n ow led gm en t. We gratefully acknowledge Dr.
Laurence J . Miller (Mayo Clinic, Rochester, MN) for
providing the CHO-K1 cells stably transfected with
human CCK-A and CCK-B receptors. We are indebted
to Mr. Larry Shampine, Mr. Doug Minick, and Mr.
Roderick Davis for analytical support.
1-Ben zyl-3-(br om om eth yl)-1H-in d a zole (9b). Chroma-
tography using hexane/EtOAc (5/1) as eluent afforded 305 mg
of a white solid: 1H NMR (CDCl3, 300 MHz) δ 7.82 (d, 1H),
7.40-7.16 (m, 8H), 5.59 (s, 2H), 4.90 (s, 2H).
Refer en ces
1-Meth yl-3-(br om om eth yl)-1H-in d a zole (9c). Chroma-
tography using hexane/EtOAc (5/1) as eluent afforded a yellow
solid (72%): 1H NMR (CDCl3, 300 MHz) δ 7.82 (d, 1H), 7.40
(m, 2H), 7.22 (m, 1H), 4.82 (s, 2H), 4.03 (s, 3H).
3-(Br om om eth yl)-1-(ter t-bu toxyca r bon yl)in d ole (9d ).
Purification by trituration with hexane, filtration of the solids,
and removal of solvent in vacuo afforded a yellow solid (69%):
1H NMR (CDCl3, 300 MHz) δ 8.15 (d, 1H, J ) 7.8), 7.64 (m,
2H), 7.33 (m, 2H), 4.63 (s, 2H), 1.71 (s, 9H).
3-(Br om om eth yl)ben zoisoth ia zole (9e). Chromatogra-
phy using hexane/EtOAc (10/1) as eluent afforded a clear
colorless oil (51%): 1H NMR (CDCl3, 300 MHz) δ 8.12 (d, 1H,
J ) 7.9), 7.94 (d, 1H, J ) 7.9), 7.55 (m, 2H), 4.89 (s, 2H).
1-Ben zyl-5-(br om om eth yl)-3-m eth yl-1H-p yr a zole (9f).
Chromatography using hexane/EtOAc (5/1) as eluent afforded
a clear oil: 1H NMR (CDCl3, 300 MHz) δ 7.32 (m, 3H), 7.19
(m, 2H), 6.16 (s, 1H), 5.42 (s, 2H), 4.32 (s, 2H), 2.31 (s, 3H);
low-resolution MS (FAB) m/ e 265 (M+).
3-(Br om om eth yl)ben zofu r a n (9g). Chromatography us-
ing hexane/EtOAc (20/1) as eluent afforded a clear, colorless
oil (48%): 1H NMR (CDCl3, 300 MHz) δ 7.71 (m, 2H), 7.50 (m,
1H), 7.37 (m, 2H), 4.62 (s, 2H).
Gen er a l P r oced u r e for Ra d ica l Br om in a tion of In d a -
zole Der iva tives To P r ovid e Com p ou n d s of Gen er a l
F or m u la 9. A stirring solution of a suitably protected
indazole or analog thereof in CCl4 was heated to reflux, and
then a mixture of 1.1 equiv of N-bromosuccinimide and 0.1
equiv of benzoyl peroxide was added portionwise over 5 min
as a solid. The resulting solution was heated at reflux for 4.5
h and then cooled to room temperature. The reaction mixture
was filtered through a pad of Celite to remove the precipitated
succinimide, and the solvent was removed in vacuo. Purifica-
tion of the crude material was achieved by silica gel flash
column chromatography. Purification conditions and spectral
data for representative compounds are as follows:
3-(Br om om eth yl)-1-(ter t-bu toxycar bon yl)in dazole (9h ).
Chromatography using hexane/EtOAc (15/1) to hexane/EtOAc
(3/1) as eluent afforded a white solid (60%): 1H NMR (CDCl3,
300 MHz) δ 8.20 (d, 1H, J ) 7.8), 7.88 (d, 1H, J ) 7.8), 7.60
(dd, 1H, J ) 7.3, 7.3), 7.41 (dd, 1H, J ) 7.3, 7.3), 4.91 (s, 2H),
1.77 (s, 9H); TLC Rf ) 0.56 (EtOAc/hexane, 1/5).
3-(Br om om eth yl)-1-(ter t-bu toxyca r bon yl)p yr a zolo[3,4-
b]p yr id in e (9i). Chromatography using hexane/EtOAc (3/1)
as eluent afforded a white solid (54%): 1H NMR (CDCl3, 400
MHz) δ 8.75 (dd, 1H, J ) 1.4, 4.6), 8.21 (dd, 1H, J ) 1.4, 8.0),
7.32 (dd, 1H, J ) 4.6, 8.0), 4.74 (s, 2H), 1.70 (s, 9H).
3-(Br om om eth yl)-6-flu or o-1-(ter t-bu toxyca r bon yl)-1H-
in d a zole (9j). Chromatography eluted successively with
DCM/hexanes (1/2 to 1/1) afforded an amber oil (57%): 1H
NMR (CDCl3, 300 MHz) δ 7.82 (m, 2H), 7.13 (m, 1H), 4.76 (s,
2H), 1.72 (s, 9H); TLC Rf ) 0.17 (EtOAc/hexanes, 1/19).
3-(Br om om eth yl)ben zisoxa zole (9k ). Chromatography
using hexane/EtOAc (10/1) as eluent afforded a white solid
(48%): 1H NMR (CDCl3, 400 MHz) δ 7.85 (d, 1H, J ) 8.3),
7.58 (m, 3H), 4.86 (s, 2H).
(1) (a) Crawley, J . N.; Corwin, R. L. Biological Actions of Cholecys-
tokinin. Peptides 1994, 4, 731-755. (b) Larson, L.-I.; Rehfeld,
J . F. Localisation and Molecular Heterogeneity of Cholocysto-
kinin in the Central and Peripheral Nervous System. Brain Res.
1979, 165, 201-218. (c) Reeve, J . R., J r.; Eysselein, V.; Walsh,
J . H.; Ben Avram, C. M.; Shively, J . E. New Molecular Forms of
Cholecystokinin. Microsequence Analysis of Forms Previously
Characterized by Chromatographic Methods. J . Biol. Chem.
1986, 261, 16392-16397.
(2) Schwartz, G. J .; McHugh, P. R.; Moran, T. H. Gastric Loads and
Cholecystokinin Synergistically Stimulate Rat Vagal Afferents.
Am. J . Physiol. 1993, 265, R872-R876.
(3) Dourish, C. T.; Ruckert, A. C.; Tattersall, F. D.; Iversen, S. D.
Evidence that Decreased Feeding Induced by Systemic Injection
of Cholecystokinin is Mediated by CCK-A Receptors. Eur. J .
Pharmacol. 1989, 173, 233-234.
(4) Dourish, C. T.; Hill, D. R. Classification and Function of CCK
Receptors. Trends Pharmacol. Sci. 1987, 8, 207-208.
(5) Kissileff, H. R.; Pi-Sunyer, F. X.; Thornton, J .; Smith, G. P.
C-Terminal Octapeptide of Cholecystokinin Decreases Food
Intake in Man. Am. J . Clin. Nutr. 1981, 34, 154-160.
(6) Pi-Sunyer, F. X.; Kissileff, H. R.; Thornton, J .; Smith, G. P.
C-Terminal Octapeptide of Cholecystokinin Decreases Food
Intake in Obese Men. Physiol. Behav. 1982, 29, 627-630.
(7) (a) Sitzmann, J . V.; Pitt, H. A.; Steinborn, P. A.; Pasha, Z. R.;
Sanders, R. C. Cholecystokinin Prevents Parenteral Nutrition
Induced Biliary Sludge in Humans Surg. Gynacol. Obstetrics
1990, 170, 25-31. (b) Froehlich, F.; Gonvers, J . J .; Fried, M.
Role of Nutrient Fat and Cholecystokinin in Regulation of
Gallbladder Emptying in Man. Dig. Dis. Sci. 1995, 40, 529-
533. (c) Roslyn, J . J .; DenBesten, L.; Pitt, H. A.; Kuchenbecker,
S.; Polarek, J . W. Effects of Cholecystokinin on Gallbladder
Stasis and Cholesterol Gallstone Formation. J . Surg. Res. 1981,
30, 200-204.
(8) Silverstone, T. In Obesity: Theory and Therapy; Stunkard, A.
J ., Wadden, T. A., Eds.; Raven Press, Ltd.: New York, 1993; pp
275-283.
(9) Henke, B. R.; Willson, T. M.; Sugg, E. E.; Croom, D. K.;
Dougherty, R. W., J r.; Queen, K. L.; Birkemo, L. S.; Ervin, G.
N.; Grizzle, M. K.; J ohnson, M. F.; J ames, M. K. 3-(1H-
Indazol-3-ylmethyl)-1,5-benzodiazepines: CCK-A Agonists That
Demonstrate Oral Activity as Satiety Agents. J . Med. Chem.
1996, 39, 2655-2658.
(10) Abdel-Magid, A. F.; Maryanoff, C. A.; Carson, K. G. Reductive
Amination of Aldehydes and Ketones by Using Sodium Triac-
etoxyborohydride. Tetrahedron Lett. 1990, 31, 5595-5598.
(11) Indole-3-carboxylic acid is commercially available from the
Aldrich Chemical Co. Leading references to the preparation of
other derivatives include the following: (a) Indazole-3-carboxylic
acid: Ferrari, M; Ripa, A; Ripa, G; Sisti, M. An improved
synthesis of indazole-3-carboxylic acid. J . Heterocycl. Chem.
1989, 26, 531-532. (b) Benzothiophene-3-carboxylic acid: Bon-
jouklian, R. A direct synthesis of benzothiophene-3-carboxylic
acid from benzothiophene. Synth. Commun. 1985, 15, 711-713.
(c) 4,5,6,7-Tetrahydro-1H-indazole-3-carboxylic acid: Ainsworth,
C. Indazole Analog of Tryptamine: A New Synthesis of Inda-
zoles. J . Am. Chem. Soc. 1957, 79, 5242-5245. (d) Benzisoxazole-
and benzisothiazole-3-carboxylic acid: Hrib, N. J .; J urcak, J . G.;
Burgher, K. L.; Conway, P. G.; Hartman, H. B.; Kerman, L. L.;
Roehr, J . E.; Woods, A. T. Benzisoxazole- and Benzisothiazole-
3-carboxamides as Potential Atypical Antipsychotic Agents. J .
Med. Chem. 1994, 37, 2308-2314.
(12) Horner, L.; Oediger, H.; Hoffman, H. Ann. 1959, 626, 26-34.
(13) Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic
Synthesis, 2nd ed.; J ohn Wiley and Sons, Inc.: New York, 1991.

Potent, Orally Active CCK-A Agonists
J ournal of Medicinal Chemistry, 1997, Vol. 40, No. 17 2725
(14) Snyder, H. R.; Thompson, C. B.; Hinman, R. L. The Synthesis
of an Indazole Analog of DL-Tryptophan. J . Am. Chem. Soc.
1952, 74, 2009-2012.
(31) (a) Evans, B. E.; Bock, M. G. Promiscuity in Receptor Ligand
Research: Benzodiazepine-based Cholecystokinin Antagonists.
Adv. Med. Chem. 1993, 2, 111-52. (b) Evans, B. E.; Rittle, K.
E.; Bock, M. G.; DiPardo, R. M.; Freidinger, R. M.; Whitter, W.
L.; Gould, N. P.; Lundell, G. F.; Homnick, C. F.; Veber, D.F.;
Anderson, P.S.; Chang, R.S. L.; Lotti, V. J .; Cerino, D. J .; Chen,
T. B.; King, P. J .; Kunkel, K. A.; Springer, J . P.; Hirshfield, J .
Design of Nonpeptidal Ligands for a Peptide Receptor: Chole-
cystokinin Antagonists. J . Med. Chem. 1987, 30, 1229-1239. (c)
Evans, B. E.; Rittle, K. E.; Bock, M. G.; DiPardo, R. M.;
Freidinger, R. M.; Whitter, W. L.; Lundell, G. F.; Veber, D. F.;
Anderson, P. S.; Chang, R. S. L.; Lotti, V. J .; Cerino, D. J .; Chen,
T. B.; King, P. J .; Kunkel, K.A.; Springer, J . P.; Hirshfield, J .
Methods for Drug Discovery: Development of Potent, Selective,
Orally Effective Cholecystokinin Antagonists. J . Med. Chem.
1988, 31, 2235-2246. (d) Bock, M. G.; Dipardo, R. M.; Evans,
B. E.; Rittle, K. E.; Whitter, W. L.; Veber, D. F.; Anderson, P.
S.; Freidinger, R. M. Benzodiazepine Gastrin and Brain CCK
Receptor Ligands: L365, 260. J . Med. Chem. 1989, 32, 13-16.
(32) (d) Yu, M. J .; Thrasher, K. J .; McCowan, J . R.; Mason, N. R.;
Mendelsohn, L. G. Quinazoline Cholecystokinin-B Receptor
Ligands. J . Med. Chem. 1991, 34, 1505-1508. (e) Yu, M. J .;
McCowan, J . R.; Mason, N. R.; Deeter, J . B.; Mendelsohn, L. G.
Synthesis and X-ray Crystallographic Analysis of Quinazoline
Cholecystokinin/Gastrin Receptor Ligands. J . Med. Chem. 1992,
35, 2534-2542.
(33) (a) Hermkens, P. H. H.; Ottenheijm, H. C. J .; van der Werf-
Pieters, J . M. L.; Broekkamp, C. L. E.; de Boer, T.; van Nispen,
J . W. CCK-A Agonists: Endeavours Involving Structure-Activity
Relationship Studies. Recl. Trav. Chim. Pays-Bas 1993, 112, 95-
106. (b) Shiosaki, K.; Lin, C. W.; Kopecka, H.; Craig, R.;
Wagenaar, F. L.; Bianchi, B.; Miller, T.; Witte, D.; Nadzan, A.
M. Development of CCK-Tetrapeptide Analogues as Potent and
Selective CCK-A Receptor Agonists. J . Med. Chem. 1990, 33,
2950-2952. (c) Shiosaki, K.; Lin, C. W.; Kopecka, H.; Tufano,
M. D.; Bianchi, B. R.; Miller, T. R.; Witte, D. G.; Nadzan, A. M.
Boc-CCK-4 Derivatives Containing Side-Chain Ureas as Potent
and Selective CCK-A Receptor Agonists. J . Med. Chem. 1991,
34, 2837-2842. (d) Dezube, M.; Sugg, E. E.; Birkemo, L. S.;
Croom, D. K.; Dougherty, R. W., J r.; Ervin, G. N.; Grizzle, M.
K.; J ames, M. K.; J ohnson, M. F.; Mosher, J .T.; Queen, K. L.;
Rimele, T. J .; Sauls, H. R.; Triantafillou, J . A. Modification of
Receptor Selectivity and Functional Activity in Cholecystokinin
Peptoid Ligands. J . Med. Chem. 1995, 38, 3384-3390.
(34) SPARTAN, Version 3.5, Wavefunction, Inc. 18401 Von Karman
Ave., #370, Irvine, CA 92715. The ab initio molecular orbital
calculations were carried out using the SPARTAN program on
a Silicon Graphics Indigo workstation on the C3 heterocyclic
fragment only. The 3-21G* basis set was used, and full geometry
optimizations were performed. Electrostatic potential surface
color-coded onto the electron density was calculated in each case.
(35) (a) Grider, J . Role of cholecystokinin in the regulation of
gastrointestinal motility J . Nutr. 1994, 124, 1334S-1339S. (b)
Reidelberger, R. D.; Varga, G.; Liehr, R.-M.; Castellanos, D. A.;
Rosenquist, G. L.; Wong, H. C.; Walsh, J . H. Cholecystokinin
suppresses food intake by a nonendocrine mechanism in rats.
Am. J . Physiol. 1994, 267, R901-R908.
(15) March, J . Advanced Organic Chemistry, 3rd ed.; J ohn Wiley &
Sons: New York, 1985; pp 608-626.
(16) (a) 3-Methylbenzisoxazole: Stokker, G. Preparation of 1,2-
benzisoxazoles from Salicylaldoximes via trichloroacetyl isocy-
anate. J . Org. Chem. 1983, 48, 2613-15. (b) 3-Methyl-1H-
pyrazolo[3,4-b]pyridine: Abignente, E.; De Caprariis, P.; Stein,
M. L. New Isoxazolo[5,4-b]pyridine-3-acetic Acids. Farmaco, Ed.
Sci. 1975, 30, 992-1000.
(17) Heck, R. F. Palladium Reagents in Organic Synthesis. In Best
Synthetic Methods, 2nd ed.; Katritzky, A. R., Meth-Cohn, O.,
Rees, C. W., Eds.; Academic Press: London, 1985; pp 276-287.
(18) Etchevarren, A. M.; Stille, J . K. Palladium-Catalyzed Coupling
of Aryl Triflates with Organostannanes J . Am. Chem. Soc. 1987,
109, 5478-5486.
(19) Gadwood, R. C.; Rubino, M. R.; Nagarajan, S. C.; Michel, S. T.
Generation of (1-Alkoxycyclopropyl)lithium Reagents. J . Org.
Chem. 1985, 50, 3255-3260.
(20) Kwan, H. B.; McKee, B. H.; Stille, J . K. Palladium-Catalyzed
Coupling Reactions of (R-Ethoxyvinyl)trimethylstannane with
Vinyl and Aryl Triflates. J . Org. Chem. 1990, 55, 3114-3118.
(21) Aquino, C. J .; Armour, D. R.; Berman, J . M.; Birkemo, L. S.;
Carr, R. A. E.; Croom, D. K.; Dezube, M.; Dougherty, R. W.;
Ervin, G. N.; Grizzle, M. K.; Head, J . E.; Hirst, G. C.; J ames, M.
K.; J ohnson, M. F.; Long, J . E.; Miller, L. J .; Queen, K. L.;
Rimele, T. J .; Smith, D. N.; Sugg, E. E. Discovery of 1,5-
Benzodiazepines with Peripheral Cholecystokinin (CCK-A) Re-
ceptor Agonist Activity I. Optimization of the Agonist “Trigger”.
J . Med. Chem. 1996, 39, 562-569.
(22) Evans, B. E.; Bock, M. G.; Rittle, K. E; Dipardo, R. M.; Whitter,
W. L; Veber, D. L.; Anderson, P. S.; Freidinger, R. M. Design of
Potent, Orally Effective, Nonpeptidyl Antagonists of the Peptide
Hormone Cholecystokinin. Proc. Natl. Acad. Sci. U.S.A. 1986,
83, 4918-4922.
(23) Sugg, E. E.; Kimery, M. J .; Ding, J . M.; Kenakin, D. C.; Miller,
L. J .; Queen K. L.; Rimele, T. J . CCK-A Receptor Selective
Antagonists Derived from the CCK-A Receptor Selective Tet-
rapeptide Agonist Boc-Trp-Lys(Tac)-Asp-MePhe-NH2 (A-71623).
J . Med. Chem. 1995, 38, 207-211.
(24) (a) Ulrich, C. D.; Ferber, I.; Holicky, E.; Hadac, E.; Buell, G.;
Miller, L. J . Molecular Cloning and Functional Expression of
the Human Gallbladder Cholecystokinin A Receptor. Biochem.
Biophys. Res. Commun. 1993, 193, 204-211. (b) de Weerth, A.;
Pisegna, J . R.; Huppi, K.; Wank, S. A. Molecular Cloning,
Functional Expression and Chromosomal Localization of the
Human Cholecystokinin Type A Receptor. Biochem. Biophys.
Res. Commun. 1993, 194, 811-818.
(25) (a) Pisegna, J . R.; de Weerth, A.; Huppi, K.; Wank, S. A.
Molecular Cloning of the Human Brain and Gastric Cholecys-
tokinin Receptor: Structure, Functional Expression and Chro-
mosomal Localization. Biochem. Biophys. Res. Commun. 1992,
189, 296-303. (b) Lee, Y. M.; Beinborn, M.; McBride, E. W.; Lu,
M.; Kolakowski, L. F., J r.; Kopin, A. S. The Human Brain
Cholecystokinin-B/Gastrin Receptor. Cloning and Characteriza-
tion. J . Biol. Chem. 1993, 268, 8164-8169.
(26) Makovec, F.; Bani, M.; Cereda, R.; Chiste, R.; Pacini, M. A.;
Revel, L.; Rovati, L. C. Antispasmodic Activity on the Gallblad-
der of the Mouse of CR1409 (Lorglumide), a Potent Antagonist
of Peripheral Chlolecystokinin. Pharmacol. Res. Commun. 1987,
19, 41-51.
(27) For the effects of CCK on rat feeding behavior by peripheral and
centrally mediated pathways and gastric emptying, see: (a)
Della-Fera, M. A.; Coleman, B. D.; Baile, C. A. CNS injection of
CCK in rats: Effects on Real and Sham Feeding and Gastric
Emptying. Am. J . Physiol. 1990, 258, R1165-R1169. (b) Craw-
ley, J . Clarification of the Behavioral Functions of Peripheral
and Central Cholecystokinin: Two Separate Peptide Pools.
Peptides 1985, 6, 129-36. (c) Moran, T. H.; McHugh, P. R.
Cholecystokinin Suppresses Food Intake by Inhibiting Gastric
Emptying. Am. J . Physiol. 1982, 242, R491-R497.
(28) Willson, T. M.; Henke, B. R.; Momtahen, T. M.; Myers, P. L.;
Sugg, E. E., Unwalla, R. J .; Croom, D. K.; Grizzle, M. K.;
J ohnson, M. F.; Queen, K. L.; Rimele, T. R.; Yingling, J . D.;
J ames, M. K. 3-[2-(N-Phenylacetamide)]-1,5-benzodiazepines:
Orally Active, Binding Selective CCK-A Agonists. J . Med. Chem.
1996, 39, 3030-3034.
(29) Hirst, G. C.; Aquino, C.; Birkemo, L.; Croom, D. K.; Dezube, M.;
Dougherty, R.W.; Ervin, G. N.; Grizzle, M. K.; Henke, B.; J ames,
M. K.; J ohnson, M. F.; Momtahen, T.; Queen, K. L.; Sherrill, R.
G.; Szewczyk, J .; Willson, T. M.; Sugg, E. E. Discovery of 1,5-
Benzodiazepines with Peripheral Cholecystokinin (CCK-A) Re-
ceptor Agonist Activity (II): Optimization of the C3 Amino
Substituent. J . Med. Chem. 1996, 39, 5236-5245.
(30) Chang, R. S.; Lotti, V. J .; Monaghan, R. L.; Birnbaum, J .;
Stapley, E. O.; Goetz, M. A.; Albers-Schonberg, G.; Patchett, A.
A.; Liesch, J . M.; Hensens, O. D. A Potent Nonpeptide Chole-
cystokinin Antagonist Selective for Peripheral Tissues Isolated
from Aspergillus Alliaceus. Science 1985, 230, 177-179.
(36) Scarpignato, C.; Capovilla, T.; Bertaccini, G. Action of caerulein
on gastric emptying of the conscious rat. Arch. Int. Pharmaco-
dyn. Ther. 1980, 246, 286-294.
(37) Liddle, R. A.; Gertz, B. J .; Kanayama, S.; Beccaria, L.; Coker,
L. D.; Turnbull, T. A.; Morita, E. T. 1989, Effects of a novel
cholecystokinin (CCK) receptor antagonist, MK-329, on gall-
bladder contraction and gastric emptying in humans. Implica-
tions for the physiology of CCK. J . Clin. Invest. 1989, 84, 1220-
1225.
(38) Sugg, E. E.; Birkemo, L.; Gan, L.-S.; Tippin, T. K. Orally active
nonpeptide CCK-A agonists. In Integration of Pharmaceutical
Discovery and Development: Case Histories; Borchardt, R. T.,
Freidinger, R. M., Sawyer, T., Smith, P., Eds.; Plenum Publish-
ing Corp.: New York, in press.
(39) Bock, M. G.; DiPardo, R. M.; Evans, B. E.; Rittle, K. E.; Whitter,
W. L.; Garsky, V. M.; Gilbert, K. F.; Leighton, J . L.; Carson, K.
L.; Melin, E. C.; Veber, D. F.; Chang, R. S. L.; Lotti, V. J .;
Freedman, S. B.; Smith, A. J .; Patel, S.; Anderson, P. S.;
Freidinger, R. M. Development of 1,4-Benzodiazepine Cholecys-
tokinin Type B Antagonists. J . Med. Chem. 1993, 36, 4276-
4292.
(40) Still, W. C.; Kahn, M.; Mitra, A. J . Rapid Chromatographic
Technique for Preparative Separations with Moderate Resolu-
tion. J . Org. Chem. 1978, 43, 2923-2925.
(41) Fludzinski, P.; Evrard, D. A.; Bloomquist, W. E.; Lacefield, W.
B.; Pfeifer, W.; J ones, N. D.; Deeter, J . B.; Cohen, M. L. Indazoles
as Indole Bioisosteres: Synthesis and Evaluation of the Tropanyl
Ester and Amide of Indazole-3-carboxylate as Antagonists at the
Serotonin 5HT3
Receptor. J . Med. Chem. 1987, 30, 1535-1537.
J M970265X