Optimization of 1,3,4-benzotriazepine-based CCK2 antagonists to obtain potent, orally active inhibitors of gastrin-mediated gastric acid secretion

Article abstract of DOI:10.1021/jm070139l

Starting from a novel, achiral 1,3,4-benzotriazepine-based CCK2 receptor antagonist, a process of optimization has afforded further compounds of this type that maintain the nanomolar affinity for recombinant, human CCK2 receptors and high selectivity over

Full text of DOI:10.1021/jm070139l

J. Med. Chem. 2007, 50, 3101-3112
3101
Optimization of 1,3,4-Benzotriazepine-Based CCK2 Antagonists to Obtain Potent, Orally Active
Inhibitors of Gastrin-Mediated Gastric Acid Secretion
Iain M. McDonald,* James W. Black, Ildiko M. Buck, David J. Dunstone, Eric P. Griffin, Elaine A. Harper, Robert A. D. Hull,
S. Barret Kalindjian, Elliot J. Lilley, Ian D. Linney, Michael J. Pether, Sonia P. Roberts, Mark E. Shaxted, John Spencer,
Katherine I. M. Steel, David A. Sykes, Martin K. Walker, Gillian F. Watt, Laurence Wright, Paul T. Wright, and Wei Xun
James Black Foundation, 68 Half Moon Lane, Dulwich, London, SE24 9JE, United Kingdom
ReceiVed February 6, 2007
Starting from a novel, achiral 1,3,4-benzotriazepine-based CCK2 receptor antagonist, a process of optimization
has afforded further compounds of this type that maintain the nanomolar affinity for recombinant, human
CCK2 receptors and high selectivity over CCK1 receptors observed in the initial lead but display more
potent inhibition of pentagastrin-stimulated gastric acid secretion in vivo. Moreover, this has largely been
achieved without altering their potency at wild-type canine and rat receptors, as judged by their displacement
of [125I]-BH-CCK-8S in a radioligand binding assay and by their activity in an isolated, perfused rat stomach
bioassay, respectively. 2-(5-Cyclohexyl-1-(2-cyclopentyl-2-oxo-ethyl)-2-oxo-1,2-dihydro-3H-1,3,4-benzot-
riazepin-3-yl)-N-(3-(5-oxo-2,5-dihydro- [1,2,4]oxadiazol-3-yl)-phenyl)-acetamide (47) was identified as the
most effective compound stemming from this approach, proving to be a potent inhibitor of pentagastrin-
stimulated gastric acid secretion in rats and dogs by intravenous bolus as well as by enteral administration.
Chart 1. Amino Acid-Based CCK2 Receptor Antagonist 1 and
Other CCK2 Receptor Antagonists Devised by a Rational
Approach
Introduction
The association of the hormone CCKa with the mediation of
pain, panic, and anxiety through its stimulation of CCK2
receptors in the CNS, has focused interest on the discovery of
CCK2 receptor antagonists, long considered to have the potential
to provide novel means of controlling these disorders.1,2 The
closely related hormone gastrin also potently stimulates CCK2
receptors, being a primary stimulant of gastric acid secretion
and a key growth factor for the histamine-storing ECL cells of
the stomach. Studies have also suggested that gastrin plays a
role in the progression of some gastrointestinal tumors, including
the premalignant condition of Barrett’s oesophagus. Thus, it has
been proposed that CCK2 receptor antagonists may also have a
potential role in the treatment of gastric acid-related conditions
(such as gastro esophageal reflux disease and proton pump
inhibitor-evoked rebound gastric acid hypersecretion)3 as well
as some cancers.4-6
Despite the availability of a number of CCK2 receptor
antagonists that have generally demonstrated high CCK2 recep-
tor affinity as well as selectivity over the CCK1 receptor
subtype,7,8 their further progress and clinical efficacy has been
hampered for different reasons. Amino acid (e.g., 1 (CR2194))
and peptoid-based CCK2 antagonists have been described. In
the latter case, these compounds have been devised by a rational
approach starting from the peptide hormone (Chart 1). Com-
pound 1 achieved inhibition of gastrin-stimulated gastric acid
output in man when administered by continuous intravenous
infusion.9 The peptoid-based compound 2 (CI-988) failed to
affect CCK-4 induced symptoms in patients with panic disor-
der10 and was shown subsequently to be an agonist in certain
animal in vivo assays.11 We obtained 3 (JB95008), also by a
rational approach,12 and although it suffered from low oral
bioavailability, when delivered by continuous intravenous
infusion, it lead to an increase in survival time in a small,
placebo-controlled clinical trial in pancreatic cancer patients.6
Advancement of this rational process led to imidazole-based
compounds such as 4 (JB99157). Although 4 was orally active,
it was insufficiently potent in its inhibitory effect on pentagas-
trin-stimulated gastric acid secretion in vivo.13
A quite different approach led workers at Merck to the 1,4-
BDZ-based CCK2 receptor antagonist 5 (L-365,260; Chart 2).14
Compound 5 progressed to human studies in which it proved
capable of reversing the anxiogenic effects produced by tetra-
gastrin,15 but it was ineffective in patients with panic disorder.16
In a separate study, 5 inhibited gastrin-stimulated gastric acid
secretion when given orally.17 Its low potency in this trial was
ascribed partly to its poor oral bioavailability. Other CCK2
receptor antagonists based on a BDZ ring system have all
followed the disclosure of 5, including compounds that lacked
charged functionality (e.g., 6 (GR 199114X))18 and those that
contain acidic (e.g., 7 (L-736,380),19 8 (Z-360))20 or basic (e.g.,
9 (L-740,093),21 10 (YF476))22 substituents. The efficacy of
these molecules and their superiority or otherwise to 5 has been
* To whom correspondence should be addressed. Phone: +44-(0)20-
7737-8282. Fax: +44-(0)20-7274-9687. E-mail: iain.mcdonald@kcl.ac.uk.
a Abbreviations: CCK, cholecystokinin; ECL, enterochromaffin-like;
BDZ, benzodiazepine.
10.1021/jm070139l CCC: $37.00 © 2007 American Chemical Society
Published on Web 05/31/2007

3102 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13
Chart 2. BDZ-Based CCK2 Receptor Antagonists
McDonald et al.
Figure 1. 1,3,4-Benzotriazepine-based CCK2 receptor antagonist
obtained following optimization of initial lead.
further examples of this class of compounds with respect to
their affinity for CCK2 receptors and in relation to their
inhibition of pentagastrin-stimulated gastric acid secretion in
in vivo assays.
Results and Discussion
The compounds prepared for biological testing (12-55) were
synthesized by the general route outlined in Scheme 1. The
2-aminophenyl ketones (56a-56e) were prepared either by
reaction of 2-aminobenzonitrile with an appropriate alkyl
Grignard reagent or by directed ortho-metalation of N-tert-
butoxycarbonyl aniline followed by acylation with an appropri-
ate alkyl ester. Their treatment with ethyl hydrazinoacetate
afforded the ethoxycarbonylmethyl hydrazones (57a-57e), from
which the corresponding 1,3,4-benzotriazepines (58a-58e) were
obtained by reaction with triphosgene. The N-1 substituent was
introduced by base-mediated alkylation using the appropriate
alkyl halide to give 59a-59o and subsequent hydrolysis of the
ethyl ester group of the N-3 ethoxycarbonylmethyl substituent
made available the corresponding carboxylic acid derivatives,
60a-60o. Compounds 60a-60o were reacted, using carbodi-
imide activation, with the appropriately substituted aniline, 61a-
61q (Table 1), affording the N-3 acetamide derivatives 62-92,
in which the functionality on the anilide moiety was in protected
form (X). Compound 60a was reacted similarly with amino-
substituted bicyclic heteroaromatic systems, 61v-61ab (Table
2) to afford 93-99. Deprotection of compounds 62-99, using
the appropriate conditions, yielded 12-32, 34, 39-46, and 48-
55. The unprotected substituted anilines 61r-61u (Table 1) were
also reacted with N-3 carboxymethyl-substituted 1,3,4-benzo-
triazepines 60a and 60i (either using carbodiimide activation
or via the corresponding acid chloride) to obtain 35-38 and
47 directly. Compound 33 was obtained by treatment of 11 with
methanesulfonamide and EDCI.
established mostly in animal models of gastrin-stimulated gastric
acid secretion, such as Ghosh and Schild rat or gastric fistula
dog. Compound 10 is the most significant compound that
stemmed from this approach, and it was subsequently shown,
on oral dosing in an acute study in healthy volunteers, to have
a profound inhibitory effect upon intragastric pH,23 but this effect
was not maintained on repeat dosing for 7 days.24 However, in
a subsequent study, 10 was shown to inhibit pentagastrin-
stimulated gastric acid secretion effectively, following an acute
as well as a chronic dosing regimen,25 indicating that its capacity
for CCK2 receptor antagonism remained undiminished during
this period. Thus, the potential utility of CCK2 receptor
antagonists remains unresolved, but encouraged by the effect
of 3 in pancreatic cancer patients, we have aimed to help clarify
their possible role by devising potent, orally active CCK2
receptor antagonists.
We have shown previously that 1,3,4-benzotriazepine-based
analogues of 1,4-BDZ CCK2 receptor antagonists display high
affinity for CCK2 receptors.26 However, in contrast to the latter
compounds, where ligand stereochemistry has a strong bearing
on CCK receptor subtype selectivity, the 1,3,4-benzotriazepine-
based derivatives are achiral (and as such, they can be
synthesized in a relatively straightforward manner), yet they
are highly selective for CCK2 over CCK1 receptors. The
structural aspects and in vitro biological activity of initial
examples of this novel class of CCK2 receptor antagonists gave
a clue to their relationship to the 1,4-BDZ-based compounds
and identified some of the chemical features that influence their
pharmacological and physicochemical properties. In particular,
compound 11 (Figure 1), which contained a carboxylic acid
substituent, not only displayed high CCK2 affinity in a radio-
ligand binding assay and potent antagonism in a functional
bioassay, but was also sufficiently soluble to enable its satisfac-
tory evaluation in in vivo assays. In this paper, we describe
the results of these experiments and the characterization of
The biological activity of the compounds was examined in
vitro (Tables 3 and 4) and in vivo using assays that have been
described elsewhere. N-Methyl-D-glucamine salts of compounds
11-31, 33-42, 44-49, and 51-54 were prepared for biological
testing. Compounds 32, 43, and 50 were isolated as hydrochlo-
ride salts directly from their synthesis. Compound 55 was
obtained as the trifluoroacetate salt in a similar manner. The
affinity of the 1,3,4-benzotriazepines for CCK2 receptors was
determined primarily in a radioligand binding assay using
recombinant, human CCK2 receptors expressed in NIH3T3
cells.27 Similarly, their selectivity with respect to CCK1 receptors
was established using recombinant, human CCK1 receptors
expressed in PC3 or CHO-K1 cells.26 Most examples were
subsequently tested for in vitro functional activity by their
inhibition of pentagastrin-stimulated gastric acid secretion in
an isolated, lumen-perfused, immature rat stomach bioassay.28
For progression to in vivo assays, greatest emphasis was
placed on those compounds that displayed <10 nM affinity at
human CCK2 receptors (pKI g 8) and where their potency in

Inhibitors of Gastrin-Mediated Gastric Acid Secretion
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13 3103
Scheme 1. Synthesis of 1,3,4-Benzotriazepinesa
a Reagents and conditions: (a) NH2NHCH2CO2Et‚HCl, pyridine/EtOH; (b) (Cl3CO)2CO, NEt3/CH2Cl2; (c) R1Br, NaH/DMF (59a-59f, 59h-59o); (d)
MeCOCH2Br, K2CO3, KI/MeCN (59g); (e) NaOH/EtOH-H2O; (f) EDCI, HOBt, DMAP/DMF (35-38, 54-60, 62-99); (g) NaOH/EtOH (12, 13, 26, 28,
30, 39, 40, 48, 49, 52, 54); (h) LiOH/THF-H2O (14-25, 29, 31, 41, 42, 44, 45, 51, 53); (i) CF3CO2H/DCM (27, 46, 55); (j) NH3-MeOH (34); (k)
HCl-dioxan (32, 43, 50); (l) 60m, (COCl)2, DMF/DCM, then 61r, NEt3/DCM (47); (m) MeSO2NH2, EDCI, HOBt, DMAP/DMF (33). b See Table 1. c See
Table 3. d See Table 2. e See Table 4.
the functional assay (pA2) was within 30-fold of this parameter.
In vivo potency was assessed initially by intravenous bolus
administration in a Ghosh and Schild rat model of pentagastrin-
stimulated gastric acid secretion.12 The inhibitory effect was
normalized with respect to a standard dose of 4 (see Experi-
mental Section). The data obtained are displayed graphically
in Figure 2. When the same reference was used, it was also
possible to gain an indication of the enteral potency of each
compound by a method of intragastric delivery (Figure 3).29
For comparative purposes, the ratio of their potencies by the
respective routes was used to gauge their bioavailability in this
species (Figure 4). Following determination of their affinity for

3104 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13
Table 1. 3-Substituted Anilines 61a-61u Used in Scheme 1
McDonald et al.
Table 2. Amino-Substituted Bicyclic Heteroaromatic Systems 61v-61ab Used in Scheme 1
position of
attachment
position of
attachment
cmpd
X
Y
Z
cmpd
X
Y
Z
61v
61w
61x
61y
CO2Et
CH
CH
N
CH
N
CH
CH
6
6
6
5
61z
61aa
61ab
CO2Me
CO2Et
CO2t-Bu
N
CH
N
CH
CH
CH
5
4
4
CO2t-Bu
CO2Me
CO2Et
CH
canine CCK2 receptors, by displacement of [125I]-BH-CCK-8S
from CCK2 receptors in canine gastric mucosa,26 the effects of
the same subset of compounds on pentagastrin-stimulated gastric
acid output in conscious, chronic gastric fistula dogs, by
intravenous bolus and intragastric routes of delivery were
examined.12 The results of these experiments are shown graphi-
cally in Figures 5 and 6.
In our earlier studies, we had found that the presence of a
C-5 cyclohexyl group conferred higher affinity than either a
2-pyridyl or a phenyl substituent in this position. On making
further changes of this type (12-15), only the cycloheptyl
derivative 14 showed comparable affinity to 11, with less potent
compounds generally being obtained (Table 3). The significantly
lower affinity observed for the N-1 methyl (16), acetylmethyl
(17), and isoamyl (18) derivatives suggested that both the ketone
carbonyl group and the bulky hydrophobic tert-butyl group of
the pinacolyl group present in 11 were important elements in
achieving high receptor affinity. This view was borne out with
the lower affinity that resulted when amide- (19) and ether-
based (20) substituents were used in its place. On the other hand,
affinity was maintained at human CCK2 receptors with respect
to 11, with N-1 1-adamantyl- or o-tolyl-carbonylmethyl-bearing
derivatives, 21 and 22, respectively. As might be expected given
the lower potency of 22 (pA2 ) 8.12 ( 0.12) compared to 11
(pA2 ) 9.01 ( 0.16) in the rat in vitro assay, it was considerably
less effective in vivo as judged by its behavior in the rat in
vivo assays (Figures 2 and 3).
Introduction of alicyclic keto-methylene N-1 substituents in
place of pinacolylmethyl, in certain 1,4-BDZ-based CCK2
receptor antagonists, had afforded more potent derivatives.30 In
line with the earlier parallels that we had drawn between this
class and 1,3,4-benzotriazepine-based CCK2 receptor antago-
nists, compounds containing substituents of this type (23-25)
displayed higher affinity at human CCK2 receptors than the
corresponding pinacolyl derivative 11. Compound 23 stood out
among the examples of this type due to its effectiveness in the
We have previously reported on the in vitro biological activity
of 11 at CCK2 receptors (Table 3).26 In contrast to closely related
1,3,4-benzotriazepine-based derivatives containing a basic sub-
stituent, the presence of the carboxylic acid group on the anilide
moiety endowed 11 with sufficient aqueous solubility to enable
its assessment in the rat in vivo assay. Compound 11 (pA2 )
9.01 ( 0.16) was as potent as 4 (pA2 ) 9.06 ( 0.32) in the in
vitro rat bioassay and it was as effective in the in vivo assay by
intravenous bolus administration (Figure 2). When these same
compounds were assessed by the intragastric route in this assay,
11 was less active than 4 (Figure 3). The affinity of 4 (pKI )
7.71 ( 0.12) and 11 (pKI ) 7.91 ( 0.20) for canine CCK2
receptors was also similar, and by intravenous bolus delivery
in the in vivo setting, judging from the effect of only a single
dose of each compound, their potency was within approximately
3-fold of one another (Figure 5). Although 11 was far short of
the potency observed for 10 by a considerable margin in the
rat in vivo assay by both routes of administration, the behavior
of 11 indicated that a compound based on a 1,3,4-benzotriaz-
epine ring system was orally active and provided the impetus
to attempt to obtain superior compounds through the preparation
of analogues of 11.

Inhibitors of Gastrin-Mediated Gastric Acid Secretion
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13 3105
a
Table 3. In Vitro Biological Data for 1,3,4-Benzotriazepine-Based CCK2 Receptor Antagonists
b
c
d
e
cmpd
R
R1
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
CH3
R2
CCK2
CCK1
CCK2
CCK2
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
4
c-C6H11
Me2CHCH2
c-C5H9
c-C7H13
1-Ad
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
CO2H
8.29 ( 0.05
7.05 ( 0.18
7.62 ( 0.09
8.32 ( 0.22
7.62 ( 0.16
5.92 ( 0.16
6.48 ( 0.10
7.69 ( 0.12
7.79 ( 0.12
6.31 ( 0.17
8.25 ( 0.10
8.12 ( 0.12
9.00 ( 0.18
9.10 ( 0.12
8.92 ( 0.03
8.67 ( 0.14
8.73 ( 0.14
9.19 ( 0.07
8.97 ( 0.07
8.37 ( 0.21
8.26 ( 0.28
8.21 ( 0.17
8.41 ( 0.12
9.00 ( 0.14
9.70 ( 0.13
8.71 ( 0.13
8.33 ( 0.13
9.15 ( 0.06
8.80
<5f
9.01 ( 0.16
7.91 ( 0.20
5.15 ( 0.09f
<5f
5.24 ( 0.10f
6.43 ( 0.07f
<5f
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
c-C6H11
MeCOCH2
<5f
Me2CH(CH2)2
pyrrolidin-1-yl-COCH2
EtO(CH2)2
<5f
<5f
NTg
1-AdCOCH2
2-MeC6H4COCH2
c-C5H9COCH2
c-C6H11COCH2
1-Me-c-C5H9COCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
t-BuCOCH2
c-C5H9COCH2
c-C5H9COCH2
c-C5H9COCH2
c-C5H9COCH2
5.72 ( 0.07f
<5f
8.12 ( 0.12
8.71 ( 0.20
7.58 ( 0.05
8.15 ( 0.32
<5f
5.10 ( 0.07h
5.40 ( 0.04h
<5f
CH2CO2H
(CH2)2CO2H
SCH2CO2H
8.01 ( 0.20
8.35 ( 0.22
8.56 ( 0.15
8.28 ( 0.10
8.24 ( 0.36
<5h
6.19 ( 0.03f
5.19 ( 0.04h
<5f
N(Me)CH2CO2H
SO2CH2CO2H
OCH2CO2H
NHCH2CO2H
CONHSO2Me
5.39 ( 0.11f
5.07 ( 0.08f
5.53 ( 0.14f
5.76 ( 0.09h
6.23 ( 0.01h
5.19 ( 0.02f
<5h
1(2)H-tetrazol-5-yl
1,2,4-oxadiazol-3-yl-5(2H)-one
N(Me)-1(2)H-tetrazol-5-yl
CH2-1(2)H-tetrazol-5-yl
SCH2-1(2)H-tetrazol-5-yl
3-C6H4CO2H
2-thiazol-4-yl-CO2H
4-oxazol-2-yl-CO2H
5-furan-2-yl-CO2H
1-imidazol-4-yl-(1H)-CH2CO2H
1-pyrrol-2-yl-CH2CO2H
CH2CO2H
8.11 ( 0.18
8.02 ( 0.37
7.62 ( 0.21
8.50 ( 0.12
8.35 ( 0.16
8.33 ( 0.08
6.41 ( 0.08h
6.26 ( 0.07h
<5h
9.18 ( 0.03
9.44
9.61
6.18 ( 0.04h
6.34 ( 0.01h
5.77 ( 0.05h
NTg
8.39 ( 0.10
9.04 ( 0.02
9.55 ( 0.18
9.47 ( 0.05
9.97 ( 0.02
9.48 ( 0.08
7.71 ( 0.05
9.86 ( 0.13
<5h
9.13 ( 0.22
8.91 ( 0.20
8.74 ( 0.34
8.83 ( 0.18
9.06 ( 0.32
10.10 ( 0.09
8.20
(CH2)2CO2H
5.60 ( 0.07h
6.33 ( 0.04h
5.68 ( 0.06h
<5f
8.37 ( 0.39
8.35 ( 0.06
8.32 ( 0.21
7.94 ( 0.18
8.98 ( 0.09i
1,2,4-oxadiazol-3-yl-5(2H)-one
SCH2CO2H
10
7.54 ( 0.02h
a Data were generally obtained from at least three separate experiments. Where no SEM is recorded, the data were obtained from two experiments. b pKI
( SEM values obtained from competition with 20 pM [125I]-BH-CCK-8S for recombinant, human CCK2 receptors expressed in NIH3T3 cells. c pKI ( SEM
values obtained from competition with 20 pM [3H] L-364,718 for recombinant, human CCK1 receptors expressed in either PC3 or CHO-K1 cells. d pA2 (
SEM values, estimated from single shifts of pentagastrin concentration-effect curves in isolated, lumen-perfused immature rat stomachs. e Except for compound
10, pKI ( SEM values obtained from competition with 20 pM [125I]BH-CCK-8S for CCK2 binding sites in canine gastric mucosa. f PC3 cells. g Not tested.
h CHO-K1 cells. i Reported pKI ( SEM value obtained from competition with [125I]-BH-CCK-8S for recombinant, canine CCK2 receptors expressed in
CHO-K cells.33
in vivo assays. Although the similar potency of 23 and 11 in
the rat in vitro bioassay was maintained in the in vivo assay
when the compounds were administered by intravenous bolus
delivery (Figure 2), the inhibitory effect achieved by 23 when
given by the intragastric route was far greater than that produced
by the same dose of 11 (Figure 3). This difference in potency
was also evident in the dog in vivo assay, where 23 was
significantly more effective than 11 by the intravenous route
(Figure 5), yet the compounds had shown similar affinity in
the canine CCK2 receptor radioligand binding assay. Just as had
been observed for 23 in the rat in vivo assay, potent inhibition
of the pentagastrin-stimulated gastric acid output following
enteral administration of this compound was also achieved in
dogs (Figure 5). Moreover, the dose-dependent behavior of 23
in this species confirmed that it was considerably more potent
than 4 and 11. Thus, from the profile of 23, the cyclopentyl-
carbonylmethyl group appeared to be the preferred N-1 sub-
stituent, particularly with respect to its impact on in vivo
potency.
Previously we had considered that the carboxylic acid group
on the anilide ring of 11 had little direct role in receptor
interaction, because its presence was not essential in achieving
high receptor affinity, at least in the human CCK2 receptor
radioligand binding assay.26 However, as its presence appeared
to be an important factor in the effectiveness of 11 in both the
in vitro functional assay and the in vivo assays, we prepared
compounds in which an acid group was retained, but in which
it was attached to the anilide moiety by a range of linkers (26-
32). In some instances this led to significantly higher affinity
than 11 for human CCK2 receptors (Table 3). This was most
marked for lipophilic linkers such as methylene (26), ethylene
(27), thiomethylene (28), and N-methyl amino methylene (29),

3106 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13
McDonald et al.
Table 4. In Vitro Biological Data for 1,3,4-Benzotriazepine-Based CCK2 Receptor Antagonistsa
b
c
d
c
cmpd
position of attachment
Y
Z
CCK2
CCK1
CCK2
9.07 ( 0.23
CCK2
49
50
51
52
53
54
55
6
6
6
5
5
4
4
CH
CH
N
CH
N
CH
N
9.53 ( 0.11
7.77 ( 0.13
9.08 ( 0.10
9.11 ( 0.01
8.03 ( 0.03
8.22 ( 0.02
8.56 ( 0.05
6.26 ( 0.03
<5
8.62 ( 0.18
CH
CH
CH
CH
CH
5.67 ( 0.10
5.60 ( 0.10
5.09 ( 0.06
<5
CH
N
5.16 ( 0.01
a Data were generally obtained from at least three separate experiments. b pKI ( SEM values obtained from competition with 20 pM [125I]-BH-CCK-8S
for recombinant, human CCK2 receptors expressed in NIH3T3 cells. c pKI ( SEM values obtained from competition with 20 pM [3H]-L-364,718 for recombinant,
human CCK1 receptors expressed in CHO-K1 cells. d pA2 ( SEM values, estimated from single shifts of pentagastrin concentration-effect curves in isolated,
lumen-perfused immature rat stomachs. e pKI ( SEM values obtained from competition with 20 pM [125I]BH-CCK-8S for CCK2 binding sites in canine
gastric mucosa.
Figure 2. Inhibition achieved by compounds of pentagastrin-stimulated
gastric acid secretion following intravenous bolus administration in the
Ghosh and Schild rat assay. Data was obtained from at least three
separate rats. aRelative to a 0.5 mg/kg (iv bolus) dose of 4. Calculated
using ∆pH at peak inhibition of stimulated gastric acid output produced
by a submaximal continuous iv infusion of pentagastrin.
Figure 4. Relative activity of compounds following intragastric and
intravenous bolus administration in the Ghosh and Schild rat assay.
aCalculated from ratio of intragastric and intravenous potency.
of administration (Figures 2 and 3). In the dog in vivo assay,
26 showed dose-dependent inhibition when given intravenously
and appeared to be more potent than 11 (Figure 5). Several
compounds containing acid mimics (33-35) appeared to offer
advantages over 11, including those where this group was
attached to the anilide ring by linkers (36-38). Not only was
higher affinity at human CCK2 receptors achieved in some cases,
but more specific benefits were apparent from their in vivo
potency. In particular, while the 1(2)H-tetrazol-5-yl-containing
compound (34) showed broadly similar behavior to 11 in the
rat in vivo assay by intravenous bolus administration (Figure
2), both the 1,2,4-oxadiazol-3-yl-5(2H)-one- (35) and N(Me)-
1(2)H-tetrazol-5-yl-containing (36) derivatives were deemed to
be significantly more potent by this route, as judged by the
degree of inhibition produced at the doses used. Moreover, this
was achieved even though 35 and 36 were around 10-fold less
potent than 11 in the rat in vitro assay. At a 10-fold higher
dose than that used in the intravenous experiment, 36 was only
weakly effective when given intragastrically (Figure 3). The
index of relative activity for 35 was not significantly different
to that of 11 (Figure 4), but since a 10-fold lower dose of 35
by either route was capable of achieving a similar degree of
inhibition to that produced by 11, the 1,2,4-oxadiazol-3-yl-
5(2H)-one substituent, present in 35, was deemed to be superior
to a carboxylic acid in terms of its influence on in vivo potency.
Figure 3. Inhibition achieved by compounds of pentagastrin-stimulated
gastric acid secretion following intragastric bolus administration in the
Ghosh and Schild rat assay. Data was obtained from at least three
a
separate rats. See legend to Figure 2.
although more polar linkers containing sulfonyl (30), ether (31),
and amino (32) groups were also tolerated without altering
affinity relative to that of 11. Changes of this type generally
resulted in lower potency than 11 in the rat in vitro assay, but
among those compounds that were examined in the rat in vivo
assays, 26-28 were at least as effective as 11 by both routes

Inhibitors of Gastrin-Mediated Gastric Acid Secretion
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13 3107
Figure 5. Inhibition achieved by selected compounds (11 (×), 23 ([),
26 (0), 34 (9), 35 (b), 45 (]), 46 (2), 47 (4), and 48 (O)) of the
gastric acid secretion produced by a continuous intravenous infusion
of pentagastrin, following intravenous bolus administration in conscious
gastric fistula dogs. Each data point is the mean ( SEM determined
from 3 to 6 dogs. The pentagastrin infusion rate was sufficient to
produce submaximal acid output in each animal. The inhibition of
gastric acid secretion is expressed as the percentage change in acid
output between the mean acid output, measured during the two 15 min
acid collection periods immediately preceding bolus dosing of the
compound, and the peak inhibition produced by the compound during
the four 15 min acid collection periods post-dosing. For comparison, 4
and 10 produced inhibitions of 66% (at 1 mg/kg) and 97% (at 0.05
mg/kg), respectively.
Figure 7. Time-course of the inhibition achieved by 47 (solvent (b),
0.01 mg/kg (O), 0.03 mg/kg (9), 0.1 mg/kg (0), 0.3 mg/kg (2)) of the
gastric acid secretion produced by a continuous intravenous infusion
of pentagastrin, following intraduodenal bolus administration in
conscious, dual gastric fistula dogs. Each data point is the mean (
SEM determined from 3 to 6 dogs. The pentagastrin dose used was
sufficient to produce submaximal acid output in each animal. The
inhibition of gastric acid secretion is expressed as the percentage change
in acid output between the mean acid output measured during the two
15 min acid collection periods immediately preceding intraduodenal
bolus dosing of the compound and the acid output during the collection
periods post-dosing.
above, made further progression of compounds of this type
unattractive. In addition, compounds containing acid-substituted
bicyclic heteroaromatic groups in place of the 3-carboxyanilide
moiety of 11, also showed potent in vitro activity (Table 4).
Indole- (49, 52, 54) and indazole-based (51, 53, 55) substituents
were well tolerated, with the human CCK2 receptor affinity
showing only minimal sensitivity to changes in the position of
attachment. The low relative activity index for 49 in the rat in
vivo assay (Figure 4) stems from the potent antagonism
produced by 49 by intravenous delivery (Figure 2), but only
weak inhibition of pentagastrin-stimulated gastric acid secretion
being achieved by the intragastric route (Figure 3).
From the foregoing discussion of the structure-activity in
relation to the in vivo potency of this series of 1,3,4-
benzotriazepine-based CCK2 receptor antagonists, the presence
of the cyclopentylcarbonylmethyl N-1 substituent, as in 23, led
to the most marked improvement over 11, particularly in the
dog in vivo assay. Consequently, compounds were prepared
bearing this side chain in combination with what were judged
to be the optimum acidic substituents (45-48) in anticipation
that these derivatives would likely show the most potent
inhibition of pentagastrin-stimulated gastric acid secretion in
vivo. As with 23, all these examples displayed e1 nM affinity
at human CCK2 receptors and potency in the rat in vitro
functional bioassay within 10-fold of this value (Table 3).
Furthermore, comparison of their respective affinities for human
CCK1 receptors indicated that their selectivity remained at least
100-fold in favor of human CCK2 receptors. Of this group, the
acetic acid-containing derivative 45 was the least effective in
the rat in vivo assay and, along with the 1,2,4-oxadiazol-3-yl-
5(2H)-one-containing analogue 47, did not significantly differ
in potency relative to their respective 1-pinacolylmethyl-
containing analogues, 26 and 35 (Figures 2 and 3). On the other
hand, the degree of inhibition achieved following intravenous
bolus or intragastric administration by a 5-fold lower dose of
the carboxymethylthio (48) and carboxyethyl (46) compounds
than that used to achieve a comparable inhibition by 28 and
27, respectively, was consistent with the cyclopentylcarbonyl
methyl N-1 substituent contributing to an improved in vivo
profile. However, this pattern was altered when the same group
of compounds was assessed in the dog in vivo model. In this
Figure 6. Inhibition achieved by selected compounds (4 (0), 10 (9),
23 ([), 35 (b), 45 (]), 46 (2), 47 (4), 48 (O)) of the gastric acid
secretion produced by a subcutaneous bolus dose of pentagastrin,
following intragastric bolus administration in conscious gastric fistula
dogs. Each data point is the mean ( SEM determined from 3 to 6
dogs. The test compounds were given intragastrically, in a volume of
50 mL via the gastric fistula, followed 1 h later by a subcutaneous
dose of pentagastrin, sufficient to produce submaximal acid output in
each animal. Gastric contents were collected subsequently at 15 min
intervals for a period of 90 min. The inhibition of gastric acid secre-
tion is expressed as a percentage of the total acid secreted during this
period following compound treatment of that produced when the same
animal was treated with water (50 mL) prior to the pentagastrin
challenge.
In the dog in vivo assay, the difference in behavior between 34
and 35 was more marked, with the latter compound being around
10-fold more potent by the intravenous route (Figure 5). The
potency of 35 following enteral administration, evident in the
rat in vivo assay, was maintained in the dog assay, where 35
showed dose-dependent inhibition (Figure 6).
Compounds containing acid-substituted aromatic and hetero-
cyclic-substituted anilide groups (39-44) also maintained the
high affinity at human CCK2 receptors and selectivity over
human CCK1 receptors shown by the earlier derivatives (Table
3). However, their higher molecular weight and lengthier
syntheses, which were not offset by significantly greater in vivo
potency than that displayed by some of the examples discussed

3108 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13
McDonald et al.
Experimental Section
All the compounds in Tables 3 and 4, except for 32, 43, 50, and
55, were tested as N-methyl-D-glucamine salts. These salts were
prepared by stirring an aqueous mixture of the compound with one
equivalent of N-methyl-D-glucamine until a solution was obtained
(a minimum amount of 1,4-dioxan was added if necessary to
complete dissolution) and the solutions were freeze-dried. Com-
pounds 32, 43, and 50 were obtained as hydrochloride salts directly
from the reaction medium. Compound 55 was obtained similarly
as the trifluoroacetate salt. The hydrochloride and trifluoroacetate
salts were freeze-dried as above for biological testing.
Flash column chromatography was performed on Merck silica
1
gel 60 (40-63 µm) using the reported solvent systems. H NMR
Figure 8. Plasma concentrations of 47 following intravenous bolus
(2.5 mg/kg (b)) and enteral (10 mg/kg (O)) administration. Each data
point is the mean concentration from two dogs. The following
pharmacokinetic parameters were calculated: Vdss (iv) ) 0.13 L/kg;
spectra were recorded on a Bruker DRX-300 instrument at 300
MHz and the chemical shifts (δH) were recorded relative to an
internal standard.
(N′-((2-Amino-phenyl)-cyclohexyl-methylene)-hydrazino)-
acetic Acid Ethyl Ester (57a). A mixture of (2-aminophenyl)-
cyclohexylmethanone (56a;31 20.3 g, 0.1 mol), ethyl hydrazinoac-
etate HCl (23.25 g, 0.15 mol), and pyridine (12.1 mL, 0.15 mol)
was heated at reflux in EtOH (400 mL) for 72 h. On cooling, the
solid precipitate was removed by filtration. The filtrate was
evaporated and the residue was suspended in saturated NaHCO3-
EtOAc (1:1/500 mL). The organic layer was separated, washed with
brine (250 mL), and dried (MgSO4). Filtration and evaporation of
the solvent gave the crude product, which was purified by
chromatography (EtOAc-hexane (1:4)) to afford 57a as a pale
Cl (iv) ) 0.2 L/h/kg; Cmax (po) ) 15.0 µM; t1/2â (po) ) 4.1 h; Fabs
)
41%.
case, 47 and 46 were the most effective compounds. Compound
47 showed dose-dependent and potent inhibition of pentagastrin-
stimulated gastric acid output by intravenous bolus (ID50 < 0.03
mg/kg) and intragastric (ID50 ) 0.016 mg/kg) administration.
The benzotriazepine-based compounds described above and
in the preceding paper26 initially stemmed from consideration
of 1,4-BDZ-based CCK2 receptor antagonists. Initial examples
of this series were considerably less potent than the most highly
optimized 1,4-BDZ derivatives, such as 10, but through efficient
use of a combination of in vitro and in vivo assays, and placing
particular emphasis on data generated from these latter assays,
it has been possible to largely bridge this deficit. An obvious
chemical advantage offered by examples of the current series
over compounds such as 10 and the majority of the other 1,4-
BDZ-based CCK2 receptor antagonists, is the absence of a chiral
center, thereby allowing their synthesis in a relatively straight-
forward manner. In addition, the biological profile of compounds
such as 47, where the high CCK2 receptor affinity, evident in
in vitro radioligand binding and functional bioassays, was also
manifest in potent inhibition of pentagastrin-stimulated gastric
acid secretion, following enteral dosing in both rats and dogs.
In particular, the potency of 47 was within 3-fold of that of 10
by intragastric dosing in dogs and the dose-dependent and
sustained gastric acid suppression achieved by this compound
following intraduodenal bolus dosing in dual fistula dogs
suggested that the inhibitory effects were long lasting (Figure
7). The effect of 47 on pentagastrin-stimulated gastric acid
secretion in dogs was also consistent with the observed
pharmacokinetic profile (Figure 8). Compound 47 benefits from
a higher margin of receptor selectivity over the CCK1 receptor
than 10 and was also found to be highly selective over a broad
range of other targets. (Compound 47 was at least 500-fold
selective for CCK2 receptors over 137 other membrane receptor
and enzyme targets, based on its activity in these assays at 10
µM.) In a calcium fluorimetry assay in NIH3T3 cells expressing
recombinant, human CCK2 receptors, 47 did not stimulate Ca2+
mobilization on its own, but produced a rightward shift of the
concentration-effect curves of CCK-8S, with potency consistent
with its receptor affinity determined in the radioligand binding
assay (data not shown). The collective properties of 47 justified
its subsequent progression to clinical studies with a view to
exploring its potential role ultimately in gastric acid related
disorders, such as gastro esophageal reflux disease, and proton
pump inhibitor-evoked rebound gastric acid hypersecretion as
well as in the inhibition of the growth of some gastrointestinal
tumors.
1
yellow foam (21.2 g, 71%). H NMR (CDCl3) 7.17 (1H, dd, J )
7.8, 7.2 Hz, H-4), 6.98 (1H, d, J ) 7.8 Hz, H-6), 6.80 (1H, dd, J
) 7.8, 7.2 Hz, H-5), 6.73 (1H, d, J ) 7.8 Hz, H-3), 5.32 (1H, t, J
) 6.0 Hz, dNNH), 4.16 (2H, q, J ) 7.2 Hz, COCH2), 3.95 (2H,
br s, NH2), 3.89 (2H, 2 × d, J ) 3.9, 3.6 Hz, NCH2CO), 2.37 (1H,
m, CHCdN), 1.80 (1H, m, CH), 1.75-1.61 (4H, m, CH2), 1.33-
1.19 (8H, m, CH, CH2, and COCH2CH3).
Compounds 57b-57e were obtained by the same method used
to prepare 57a.
(5-Cyclohexyl-2-oxo-1,2-dihydro-3H-1,3,4-benzotriazepin-3-
yl)-acetic Acid Ethyl Ester (58a). A solution of bis(trichlorom-
ethyl) carbonate (11.4 g, 39 mmol) in DCM (100 mL) was added
dropwise over 1 h to a solution of 57a (23.39 g, 77.0 mmol), and
NEt3 (26.8 mL, 0.19 mol) in DCM (300 mL) at 0 °C. The reaction
mixture was stirred at 0 °C for 1 h, washed successively with H2O
(300 mL), saturated NaHCO3 (300 mL), brine (300 mL), and dried
(MgSO4). Filtration and evaporation of the solvent gave the crude
product, which was purified by recrystallization (Et2O-hexane (1:
3)) to afford 58a as a yellow solid (15.8 g, 62%). 1H NMR (CDCl3)
7.35 (2H, m, H-8 and H-9), 7.14 (1H, br s, NH), 7.10 (1H, d, J )
8.4 Hz, H-7), 6.85 (1H, d, J ) 7.8 Hz, H-6), 4.32 (2H, s, NCH2-
CO), 4.18 (2H, q, J ) 6.9 Hz, COCH2), 2.68 (1H, m, CHCdN),
1.81-1.68 (5H, m, CH and CH2), 1.49-1.22 (8H, m, CH, CH2,
and COCH2CH3); 13C NMR (CDCl3) 169.5, 169.2, 164.1 (CO2Et/
C-2/ C-5), 142.2 (Ar-C), 131.7 (Ar-CH), 127.4 (Ar-CH), 126.9 (Ar-
C), 124.0 (Ar-CH),120.6 (Ar-CH), 61.1 (CO2CH2), 52.9 (NCH2-
CO2), 44.6 (CHCdN), 31.8, 26.6, 26.5 (CH2), 14.6 (CH3).
Compounds 58b-58e were obtained by the same method used
to prepare 58a.
(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihydro-
3H-1,3,4-benzotriazepin-3-yl)-acetic Acid Ethyl Ester (59a). NaH
(60% dispersion in mineral oil, 0.48 g, 12.0 mmol) was added in
small portions to an ice-cooled solution of 58a (3.29 g, 10.0 mmol)
in DMF (30 mL). The mixture was stirred at ambient temperature
for 30 min then 1-bromo-3,3-dimethyl-butan-2-one (1.60 mL, 12.0
mmol) was added. The reaction mixture was stirred at ambient
temperature for 2 h, diluted with H2O (200 mL), and extracted with
EtOAc (40 mL × 3). The combined extracts were washed with
brine (50 mL) and dried (MgSO4). Filtration and evaporation of
the solvent gave the crude product, which was purified by
chromatography (EtOAc-DCM (1:9)) to afford 59a as a yellow
foam (3.59 g, 84%). 1H NMR (CDCl3) 7.37 (2H, m, H-8 and H-9),
7.17 (1H, dd, J ) 7.5, 8.4 Hz, H-7), 6.93 (1H, d, J ) 8.4 Hz, H-6),

Inhibitors of Gastrin-Mediated Gastric Acid Secretion
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13 3109
4.66 (2H, s, NCH2COt-Bu), 4.35 (1H, m, NCH2CO2C), 4.13 (3H,
q, J ) 6.9 Hz, COCH2 and NCH2CO2C), 2.74 (1H, m, CHCdN),
1.90-1.70 (6H, m, CH2), 1.31-1.16 (16H, m, CH2, COCH2CH3,
and C(CH3)3).
Compounds 59b-59f and 59h-59o were obtained by the same
method used to prepare 59a.
H2O (20 mL), and acidified to pH 2 with 2 N HCl. The mixture
was extracted with CHCl3 (20 mL × 3) and the combined extracts
were dried over MgSO4. Filtration and evaporation of the solvent
gave the crude product, which was purified by chromatography
(EtOAc-hexanes (1:1)-neat EtOAc) to afford 12 as an off-white
foam (0.18 g, 44%). 1H NMR (DMSO-d6) 13.0 (1H, br s (ex. D2O),
CO2H), 10.01 (1H, s, CONH), 8.17 (1H, s, Ar-H), 7.70 (1H, d, J
) 7.8 Hz, Ar-H), 7.60-7.49 (3H, m, Ar-H), 7.38 (1H, t, J ) 7.8
Hz, Ar-H), 7.24 (1H, t, J ) 8.4 Hz, Ar-H), 7.13 (1H, d, J ) 7.8
Hz, Ar-H), 4.74 (2H, br s, NCH2COt-Bu), 4.35 (1H, br, NCH2-
CONH), 4.02 (1H, br, NCH2CONH), 2.85 (1H, br, Me2CHCH2),
2.35 (1H, br, Me2CHCH2), 1.74 (1H, m, Me2CHCH2), 1.15 (9H, s,
C(CH3)3), 0.85 (6H, br, (CH3)2CH). The compound was further
characterized as the N-methyl-D-glucamine salt. Anal. (C27H32N4-
O5‚C7H17NO5‚2.0H2O) C, H, N.
(5-Cyclohexyl-1-(2-oxo-propyl)-2-oxo-1,2-dihydro-3H-1,3,4-
benzotriazepin-3-yl)-acetic Acid Ethyl Ester (59g). A mixture
of 58a (300 mg, 1.00 mmol), K2CO3 (166 mg, 1.20 mmol), KI (20
mg), and 1-chloro-propan-2-one (90 µL, 1.10 mmol) in MeCN (5
mL) was heated at reflux for 48 h. A further portion of 1-chloro-
propan-2-one (180 µL, 2.20 mmol) was added and heating was
continued for 16 h. On cooling, the reaction mixture was filtered
and the filtrate was evaporated. The residue was suspended in
saturated NaHCO3-EtOAc (1:1/60 mL). The organic layer was
separated and dried (MgSO4). Filtration and evaporation of the
solvent gave the crude product, which was purified by chromatog-
raphy (EtOAc-DCM (1:19)) to afford 59g as a colorless foam (297
Compounds 13, 26, 28, 30, 39, 40, 48, 49, 52, and 54 were
obtained by the same method used to prepare 12.
3-(2-(5-Cyclopentyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid
(13). 1H NMR (DMSO-d6) was obtained. The compound was further
characterized as the N-methyl-D-glucamine salt. Anal. (C28H32-
N4O5‚C7H17NO5‚2.0H2O) C, H, N.
1
mg, 77%). H NMR (CDCl3) was obtained.
(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihydro-
3H-1,3,4-benzotriazepin-3-yl)-acetic Acid (60a). A solution of 59a
(3.57 g, 8.20 mmol) and 1.0 M NaOH (8.70 mL, 8.70 mmol) in
EtOH (30 mL) was stirred at ambient temperature for 16 h. The
mixture was concentrated under reduced pressure, diluted with H2O
(30 mL), and acidified to pH 3 with 1 N HCl. The mixture was
extracted with DCM (30 mL × 2) and the combined extracts were
dried over MgSO4. Filtration and evaporation of the solvent afforded
60a as a pale yellow foam (3.10 g, 95%). 1H NMR (CDCl3) 11.00
(1H, br s, CO2H), 7.45 (2H, m, H-8 and H-9), 7.25 (1H, m, H-7),
6.97 (1H, d, J ) 8.4 Hz, H-6), 4.68 (2H, 2 × d, J ) 17.4 Hz,
NCH2COt-Bu), 4.25 (1H, d, J ) 16.7 Hz, NCH2CO2H), 3.90 (1H,
d, J ) 16.7 Hz, NCH2CO2H), 2.80 (1H, m, CHCdN), 2.08-1.61
(6H, m, CH2), 1.44-1.18 (13H, m, CH2 and C(CH3)3).
(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-ace-
tic Acid (26). 1H NMR (CDCl3) was obtained. The compound was
further characterized as the N-methyl-D-glucamine salt. Anal.
(C30H36N4O5‚C7H17NO5‚2.0H2O) C, H, N.
(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenylsulfa-
1
nyl)-acetic Acid (28). H NMR (DMSO-d6) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C30H36N4O5S‚C7H17NO5‚3.0H2O) C, H, N.
(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzenesulfo-
Compounds 60b-60o were obtained by the same method used
to prepare 60a.
1
nyl)-acetic Acid (30). H NMR (DMSO-d6) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C30H36N4O7S‚C7H17NO5‚2.0H2O) C, H, N.
3′-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-biphenyl-3-
carboxylic Acid (39). 1H NMR (CDCl3) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C35H38N4O5‚C7H17NO5‚1.9H2O) C, H, N.
4-(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-
thiazole-2-carboxylic Acid (40). 1H NMR (CDCl3) was obtained.
The compound was further characterized as the N-methyl-D-
glucamine salt. Anal. (C32H35N5O5S‚C7H17NO5‚2.0H2O) C, H, N.
(3-(2-(5-Cyclohexyl-1-(2-cyclopentyl-2-oxo-ethyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenylsulfa-
nyl)-acetic Acid (48). 1H NMR (CDCl3) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C31H36N4O5S‚C7H17NO5‚5.0H2O) C, H, N.
(6-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-indol-1-yl)-
acetic Acid (49). 1H NMR (CDCl3) was obtained. The compound
was further characterized as the N-methyl-D-glucamine salt. Anal.
(C32H37N5O5‚C7H17NO5‚2.0H2O) C, H, N.
(5-Cyclohexyl-1-(2-cyclopentyl-2-oxo-ethyl)-2-oxo-1,2-dihydro-
3H-1,3,4-benzotriazepin-3-yl)-acetic Acid (60m). Yield ) 95%.
1H NMR (CDCl3) 11.00 (1H, br s), 7.45 (2H, m), 7.25 (1H, m),
7.03 (1H, d, J ) 8.4 Hz), 4.55 (2H, s), 4.24 (1H, d, J ) 13.8 Hz),
3.90 (1H, d, J ) 13 Hz), 2.91 (1H, m), 2.82 (1H, m), 1.82-1.57
(14H, m), 1.28 (4H, m); 13C NMR (CDCl3) 206.5 (CO2H), 172.3,
171.6, 163.6 (c-C5H9CO/ C-2/ C-5), 144.4 (Ar-C), 132.1 (Ar-CH),
129.6 (Ar-C), 127.0 (Ar-CH), 125.4 (Ar-CH), 121.0 (Ar-CH), 57.0
(c-C5H9COCH2), 52.8 (NCH2CO2), 49.2, 44.2 (CHCdN/CHCOCH2),
33.1, 30.2, 29.3, 26.9, 26.4, 26.3 (CH2).
3-(2-(1-(3,3-Dimethyl-2-oxo-butyl)-5-isobutyl-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid
Methyl Ester (62). Compound 60b (0.39 g, 1.0 mmol) was added
to a solution of 61a (0.18 g, 1.2 mmol), HOBt (0.21 g, 1.6 mmol),
DMAP (1 mg), and EDCI (0.30 g, 1.6 mmol) in DMF (5 mL). The
solution was maintained at ambient temperature for 16 h, diluted
with H2O (30 mL), and extracted with EtOAc (20 mL × 2). The
combined extracts were washed with 5% KHSO4 (20 mL), saturated
NaHCO3 (20 mL), and brine (20 mL) and dried (MgSO4). Filtration
and evaporation of the solvent gave the crude product which was
purified by chromatography (EtOAc-hexanes (1:1-4:1)) to afford
1
62 as a yellow oil (0.48 g, 80%). H NMR (CDCl3) 8.39 (1H, s,
CONH), 7.94-7.88 (2H, m, Ar-H), 7.74 (1H, d, J ) 7.8 Hz, Ar-
H), 7.51-7.43 (2H, m, Ar-H), 7.39-7.31 (2H, m, Ar-H), 7.04 (1H,
d, J ) 8.3 Hz, Ar-H), 4.71 (1H, d, J ) 17.3 Hz, NCH2COt-Bu),
4.59 (1H, d, J ) 17.3 Hz, NCH2COt-Bu), 4.27 (2H, s, NCH2-
CONH), 3.90 (3H, s, CO2CH3), 2.84 (1H, m, Me2CHCH2), 2.55
(1H, m, Me2CHCH2), 1.91 (1H, m, Me2CHCH2), 1.26 (9H, s,
C(CH3)3), 0.98-0.90 (6H, m, (CH3)2CH).
(5-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-indol-1-yl)-
acetic Acid (52). 1H NMR (CDCl3) was obtained. The compound
was further characterized as the N-methyl-D-glucamine salt. Anal.
(C32H37N5O5‚C7H17NO5‚1.9H2O‚0.6dioxan) C, H, N.
(4-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-indol-1-yl)-
acetic Acid (54). 1H NMR (CDCl3) was obtained. The compound
was further characterized as the N-methyl-D-glucamine salt. Anal.
(C32H37N5O5‚C7H17NO5‚1.6H2O‚0.5dioxan) C, H, N.
3-(2-(5-Cycloheptyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid
(14). 1.0 M LiOH (0.9 mL, 0.9 mmol) was added to a solution of
64 (0.16 g, 0.29 mmol) in THF-H2O (2:1/9 mL), and the mixture
Compounds 63-99 were obtained by the same method used to
prepare 62.
3-(2-(1-(3,3-Dimethyl-2-oxo-butyl)-5-isobutyl-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid (12).
A solution of 62 (0.42 g, 0.8 mmol) and 2.0 M NaOH (0.46 mL,
0.9 mmol) in EtOH (5 mL) was stirred at room temperature for 21
h. The reaction mixture was concentrated in vacuo, diluted with

3110 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13
McDonald et al.
was stirred at ambient temperature for 16 h. The reaction mixture
was concentrated in vacuo, diluted with H2O (50 mL), and acidified
to pH 3 with 1 N HCl. The mixture was extracted with DCM (30
mL × 2) and the combined extracts were washed with brine (50
mL) and dried (MgSO4). Filtration and evaporation of the solvent
afforded 14 as an off-white solid (0.16 g, 100%). 1H NMR (CDCl3)
was obtained. The compound was further characterized as the
N-methyl-D-glucamine salt. Anal. (C30H36N4O5‚C7H17NO5‚3.5H2O)
C, H, N.
(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenoxy)-
acetic Acid (31) 1H NMR (DMSO-d6) was obtained. The compound
was further characterized as the N-methyl-D-glucamine salt. Anal.
(C30H36N4O6‚C7H17NO5‚1.5H2O) C, H, N.
2-(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-ox-
azole-4-carboxylic Acid (41). 1H NMR (CDCl3) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Found: Anal. (C32H35N6O5‚C7H17NO5‚1.6H2O) C, H, N.
5-(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-fu-
ran-2-carboxylic Acid (42). 1H NMR (CDCl3) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C33H36N4O6‚C7H17NO5‚1.7H2O) C, H, N.
Compounds 15-25, 29, 31, 41, 42, 44, 45, 51, and 53 were
obtained by the same method used to prepare 14.
3-(2-(5-Adamantan-1-yl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-
1,2-dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzo-
1
ic Acid (15). H NMR (DMSO-d6) was obtained. The compound
was further characterized as the N-methyl-D-glucamine salt. Anal.
(C33H38N4O5‚C7H17NO5‚2.0H2O) C, H, N.
3-(2-(5-Cyclohexyl-1-methyl-2-oxo-1,2-dihydro-3H-1,3,4-ben-
zotriazepin-3-yl)-acetylamino)-benzoic Acid (16). 1H NMR (DM-
SO-d6) was obtained. The compound was further characterized as
the N-methyl-D-glucamine salt. Anal. (C24H26N4O4‚C7H17NO5‚
1.4H2O) C, H, N.
(2-(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-
pyrrol-1-yl)-acetic Acid (44). 1H NMR (CDCl3) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C34H39N5O5‚C7H17NO5‚2.2H2O) C, H. N: calcd, 10.09;
found, 9.65.
3-(2-(5-Cyclohexyl-1-(2-oxo-propyl)-2-oxo-1,2-dihydro-3H-
1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid (17). H
(3-(2-(5-Cyclohexyl-1-(2-cyclopentyl-2-oxo-ethyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-ace-
tic Acid (45). 1H NMR (CDCl3) was obtained. The compound was
further characterized as the N-methyl-D-glucamine salt. Anal.
(C31H36N4O5‚C7H17NO5‚2.1H2O) C, H, N.
(6-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-indazol-1-yl)-
acetic Acid (51). 1H NMR (DMSO-d6) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C31H36N6O5‚C7H17NO5‚CH2Cl2) C, H, N.
(5-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-indazol-1-yl)-
acetic Acid (53). 1H NMR (CDCl3) was obtained. The compound
was further characterized as the N-methyl-D-glucamine salt. Anal.
(C31H36N6O5‚C7H17NO5‚2.3H2O) C, H, N.
3-(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-
propionic Acid (27). A mixture of 77 (0.22 g, 0.36 mmol) in
trifluoroacetic acid (2 mL) was stirred at ambient temperature for
2 h. After concentration, the resulting gum was re-evaporated from
DCM (20 mL × 2). Trituration of the residue with Et2O afforded
27 as a yellow solid (0.19 g, 97%). 1H NMR (CDCl3) was obtained.
The compound was further characterized as the N-methyl-D-
glucamine salt. Anal. (C31H38N4O5‚C7H17NO5‚3.0H2O) C, H, N.
Compounds 46 and 55 were obtained by the same method used
to prepare 27.
1
NMR (CDCl3) was obtained. The compound was further character-
ized as the N-methyl-D-glucamine salt. Anal. (C26H28N4O5‚C7H17-
NO5‚2.9H2O) C, H, N.
3-(2-(5-Cyclohexyl-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-3H-
1
1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid (18). H
NMR (DMSO-d6) was obtained. The compound was further
characterized as the N-methyl-D-glucamine salt. Anal. (C28H34N4-
O4‚C7H17NO5‚1.3H2O) C, H, N.
3-(2-(5-Cyclohexyl-1-(2-oxo-2-pyrrolidin-1-yl-ethyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid
1
(19). H NMR (CDCl3) was obtained. The compound was further
characterized as the N-methyl-D-glucamine salt. Anal. (C29H33N5-
O5‚C7H17NO5‚2.3H2O) C, H, N.
3-(2-(5-Cyclohexyl-1-(2-ethoxy-ethyl)-2-oxo-1,2-dihydro-3H-
1
1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid (20). H
NMR (CDCl3) was obtained. The compound was further character-
ized as the N-methyl-D-glucamine salt. Anal. (C27H32N4O5‚C7H17-
NO5‚1.8H2O) C, H, N.
3-(2-(1-(2-Adamantan-1-yl-2-oxo-ethyl)-5-cyclohexyl-2-oxo-
1,2-dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzo-
ic Acid (21). 1H NMR (CDCl3) was obtained. The compound was
further characterized as the N-methyl-D-glucamine salt. Anal.
(C35H40N4O5‚C7H17NO5‚2.7H2O) C, H, N.
3-(2-(5-Cyclohexyl-1-(2-oxo-2-o-tolyl-ethyl)-2-oxo-1,2-dihydro-
3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid (22).
1H NMR (DMSO-d6) was obtained. The compound was further
characterized as the N-methyl-D-glucamine salt. Anal. (C32H32N4-
O5‚C7H17NO5‚1.4H2O) C, H, N.
3-(3-(2-(5-Cyclohexyl-1-(2-cyclopentyl-2-oxo-ethyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-
propionic Acid (46). 1H NMR (CDCl3) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C32H38N4O5‚C7H17NO5‚1.8H2O) C, H, N.
3-(2-(5-Cyclohexyl-1-(2-cyclopentyl-2-oxo-ethyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid
(4-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-indazol-1-yl)-
1
(23). H NMR (CDCl3) was obtained. The compound was further
1
characterized as the N-methyl-D-glucamine salt. Anal. (C30H34N4-
O5‚C7H17NO5‚1.9H2O) C, H, N.
acetic Acid Trifluoroacetate Salt (55). H NMR (CDCl3) was
obtained. Anal. (C31H36N6O5‚CF3CO2H) C, H, N.
3-(2-(1-(2-Cyclohexyl-2-oxo-ethyl)-5-cyclohexyl-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzoic Acid
2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-N-(3-(2H-tetrazol-5-yl)-phen-
yl)-acetamide (34). A solution of 83 (141 mg, 0.22 mmol) in
saturated methanolic ammonia (10 mL) was stirred overnight at
ambient temperature. After concentration in vacuo, the residue was
dissolved in H2O-MeOH (10:1/22 mL) and acidified to pH 3 by
the addition of 5% KHSO4 solution. Compound 34 was isolated as
a light pink solid by filtration of the reaction mixture and dried in
vacuo (70 mg, 60%). 1H NMR (CDCl3) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C29H34N8O3‚C7H17NO5‚2.5H2O) C, H, N.
1
(24). H NMR (CDCl3) was obtained. The compound was further
characterized as the N-methyl-D-glucamine salt. Anal. (C31H36N4-
O5‚C7H17NO5‚2.9H2O) C, H, N.
3-(2-(5-Cyclohexyl-1-(2-(1-methyl-cyclopentyl)-2-oxo-ethyl)-
2-oxo-1,2-dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-
benzoic Acid (25). 1H NMR (CDCl3) was obtained. The compound
was further characterized as the N-methyl-D-glucamine salt. Anal.
(C31H36N4O5‚C7H17NO5‚2.8H2O) C, H, N.
((3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-
methyl-amino)-acetic Acid (29). 1H NMR (DMSO-d6) was
obtained. The compound was further characterized as the N-methyl-
D-glucamine salt. Anal. (C31H39N6O5‚C7H17NO5‚H2O) C, H, N.
(4-(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-
dihydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-
imidazol-1-yl)-acetic Acid Hydrochloride Salt (43). Compound
88 (275 mg, 0.5 mmol) was dissolved in 4 M HCl-dioxan (5 mL),

Inhibitors of Gastrin-Mediated Gastric Acid Secretion
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13 3111
and the solution was stirred at room temperature for 2 h. The solvent
was evaporated, and the residue was dissolved in DCM (20 mL)
and washed with H2O (20 mL × 2). The organic phase was
separated and dried over MgSO4. Filtration and evaporation of the
solvent afforded 43 (215 mg, 81%). 1H NMR (DMSO-d6/D2O) was
obtained. Anal. (C33H38N6O5‚1.6HCl‚0.5dioxan) C, H, N.
(6-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-benzimidazol-
1-yl)-acetic Acid Hydrochloride Salt (50). Compound 50 was
obtained by the same method used to prepare 43. 1H NMR (DMSO-
d6) was obtained. Anal. (C31H36N6O5‚HCl) C, H, N.
triethylamine (6.1 mL, 44 mmol) in DCM (50 mL) was added
dropwise. The reaction mixture was allowed to warm to ambient
temperature, stirred for 16 h, washed with 1 N HCl (50 mL × 2)
and brine (50 mL × 2), and dried (MgSO4). Filtration and
evaporation of the solvent gave the crude product, which was
purified by chromatography (MeOH-DCM (1:19)) to afford 47
1
as a pale solid (2.5 g, 92%). H NMR (CDCl3) was obtained. 13C
NMR (CDCl3) 207.0 (dNCO2), 171.9, 169.4, 163.5, 160.8, 157.4
(c-C5H9CO/ C-2/ C-5/ CH2CONH/ ArC(dNs)NH), 144.6 (Ar-C),
138.8 (Ar-C), 132.2 (Ar-CH), 130.3 (Ar-CH), 129.8 (Ar-C), 126.9
(Ar-CH), 125.7 (Ar-CH), 124.3 (Ar-C), 123.8 (Ar-CH), 122.2 (Ar-
CH), 121.3 (Ar-CH), 118.2 (Ar-CH), 57.2 (c-C5H9COCH2), 55.4
(NCH2CONH), 49.3, 44.3 (CHCdN/ CHCOCH2), 33.1, 30.5, 29.3,
26.8, 26.4, 26.2 (CH2). The compound was further characterized
as the N-methyl-D-glucamine salt. Anal. (C31H34N6O5‚C7H17NO5‚
1.7H2O) C, H, N.
(3-(2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-di-
hydro-3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenylamino)-
acetic Acid Hydrochloride Salt (32). Step A. (tert-Butoxycarbonyl-
(3-(2-(5-cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihydro-
3H-1,3,4-benzotriazepin-3-yl)-acetylamino)-phenyl)-amino)-
acetic acid was obtained by the same method used to prepare 12
2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-N-(3-methanesulfonylami-
nocarbonyl-phenyl)-acetamide (33). Methanesulfonamide (96 mg,
1.00 mmol) was added to a solution of 11 (409 mg, 0.80 mmol),
EDC (207 mg, 1.08 mmol), and DMAP (122 mg, 1.00 mmol) in
DCM (20 mL) at ambient temperature. After stirring for 17 h, the
mixture was washed with 5% KHSO4 (50 mL) and brine (50 mL)
and dried (MgSO4). Filtration and evaporation of the solvent gave
the crude product, which was purified by chromatography (MeOH-
DCM (1:10)) to afford 33 as a white crystalline solid (392 mg,
1
except that 79 was used in place of 62 (76%). H NMR (DMSO-
d6) 12.80 (1H, br s), 9.81 (1H, s), 7.52-7.47 (3H, m), 7.23-7.17
(4H, m), 6.88 (1H, d), 4.78 (2H, m), 4.25 (1H, d), 4.14 (2H, s),
3.94 (1H, d), 2.86 (1H, m), 1.90-1.45 (6H, m), 1.36-1.19 (13H,
m), 1.12 (9H, s).
Step B. Compound 32 was obtained by the same method used
to prepare 43, except that (tert-butoxycarbonyl-(3-(2-(5-cyclohexyl-
1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihydro-3H-1,3,4-benzot-
riazepin-3-yl)-acetylamino)-phenyl)-amino)-acetic acid was used in
place of 88 (74%). 1H NMR (DMSO-d6) was obtained. Anal.
(C30H37N5O5‚HCl‚0.5dioxan) C, H, N.
1
83%). H NMR (DMSO-d6) was obtained. The compound was
further characterized as the N-methyl-D-glucamine salt. Anal.
(C30H37N5O6S‚C7H17NO5‚2.0H2O) C, H, N.
2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-N-(3-(5-oxo-2,5-dihydro-1,2,4ox-
adiazol-3-yl)-phenyl)-acetamide (35). Compound 60a (0.20 g, 0.5
mmol) was added to a solution of 61r32 (0.17 g, 0.6 mmol), HOBt
(0.10 g, 0.7 mmol), DMAP (1 mg), and EDCI (0.14 g, 0.7 mmol)
in DMF (10 mL). The solution was maintained at ambient
temperature for 16 h, diluted with H2O (30 mL), and extracted with
EtOAc (20 mL × 2). The combined extracts were washed with
5% KHSO4 (20 mL) and brine (20 mL) and dried (MgSO4).
Filtration and evaporation of the solvent gave the crude product,
which was purified by chromatography (EtOAc-DCM (1:6)) to
afford 35 as an orange solid (0.06 g, 22%). 1H NMR (CDCl3) was
obtained. The compound was further characterized as the N-methyl-
D-glucamine salt. Anal. (C30H34N6O5‚C7H17NO5‚2.0H2O) C, H, N.
Compounds 36-38 were obtained by the same method used to
prepare 35.
2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-N-(4-(methyl-(2H-tetrazol-5-
yl)-amino)-phenyl)-acetamide (36). 1H NMR (DMSO-d6) was
obtained. The compound was further characterized as the N-methyl-
D-glucamine salt. Anal. (C30H37N9O3‚C7H17NO5) C, H, N.
2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-N-(3-(1H-tetrazol-5-ylmethyl)-
phenyl)-acetamide (37). 1H NMR (CDCl3) was obtained. The
compound was further characterized as the N-methyl-D-glucamine
salt. Anal. (C30H36N8O3‚C7H17NO5‚1.9H2O) C, H. N: calcd, 16.77;
found, 16.08.
In Vivo Method: Intravenous bolus administration of compounds
in the anesthetized rat preparation was conducted as described
previously.12 A modification of this method that has been described
in detail elsewhere,29 also allowed intragastric delivery of com-
pounds in this species. The inhibitory effect for each compound
was determined from the maximum increase in pH achieved by
the compound (∆pH) of the stimulated gastric acid output (fall in
basal pH) produced by a submaximal continuous intravenous
infusion dose of pentagastrin. Because only a relatively low
throughput was possible in this assay, the inhibition achieved by
each compound was normalized with respect to that achieved by
an intravenous bolus dose of 4 (0.5 mg/kg) sufficient to produce
submaximal inhibition of the pentagastrin-stimulated acid output
in the same animal. Consequently, compounds that are recorded
as producing greater than 100% inhibition arise where the inhibition
achieved by 4 was relatively low in any given rat. Following dose-
ranging studies, a dose of test compound was selected, such that
the extent of the inhibitory effect, as judged by the rise in pH, was
not greater than the respective increase in gastric acid secretion
(i.e., the fall in pH) evoked by the infusion of pentagastrin. This
was considered to provide the most reliable method of comparing
the potency of compounds that were not assayed in the same
experiment.
Administration of the compounds by intravenous bolus and
intragastric routes to conscious chronic gastric fistula dogs followed
the previously published protocol.12
2-(5-Cyclohexyl-1-(3,3-dimethyl-2-oxo-butyl)-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-N-(3-(1H-tetrazol-5-ylmeth-
1
ylsulfanyl)-phenyl)-acetamide (38). H NMR (CDCl3) was ob-
Acknowledgment. The authors thank Etienne Ghoos, Claire
Mackie, Inge Pareyns, Jan Schurkes, Philip Timmerman, and
Luc Ver Donck (Johnson and Johnson PRD, Beerse, Belgium)
for conducting the in vivo pharmacodynamic and pharmacoki-
netic experiments in dogs.
tained. The compound was further characterized as the N-methyl-
D-glucamine salt. Anal. (C30H36N8O3‚C7H17NO5‚1.5H2O‚0.5dioxan)
C, H, N.
2-(5-Cyclohexyl-1-(2-cyclopentyl-2-oxo-ethyl)-2-oxo-1,2-dihy-
dro-3H-1,3,4-benzotriazepin-3-yl)-N-(3-(5-oxo-2,5-dihydro-[1,2,4]-
oxadiazol-3-yl)-phenyl)-acetamide (47). Oxalyl chloride (1.9 mL,
22 mmol) was added dropwise to a solution of 60m (6.0 g, 14.6
mmol) in DCM (100 mL) containing DMF (0.1 mL) at 0 °C under
argon. The reaction mixture was allowed to warm to ambient
temperature and stirred for 2.5 h. The solvent was evaporated in
vacuo, and the residue was resuspended in DCM (30 mL × 2) and
evaporated to dryness. The residue was dissolved in DCM (50 mL),
cooled to 0 °C, to which a solution of 61r32 (3.36 g, 19 mmol) and
Supporting Information Available: Experimental procedures
for the preparation of compounds 61e, 61g, 61h, 61j-61q, 61v,
61w, and 61y-61ab, 1H NMR data for compounds 13-55, 57a-
57e, 58b-58e, 59b-59o, 60b-60o, and 63-99, and elemental
analysis of the novel compounds listed in Tables 3 and 4. This
material is available free of charge via the Internet at http://
pubs.acs.org.

3112 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 13
McDonald et al.
(19) Castro, J. L.; Ball, R. G.; Broughton, H. B.; Russell, M. G.; Rathbone,
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