Development of novel benzomorpholine class of diacylglycerol acyltransferase i inhibitors

Article abstract of DOI:10.1021/ml400527n

Diacylglycerol acyltransferase 1 (DGAT1) presents itself as a potential therapeutic target for obesity and diabetes for its important role in triglyceride biosynthesis. Herein we report the rational design of a novel class of DGAT1 inhibitors featuring a

Full text of DOI:10.1021/ml400527n

Letter
pubs.acs.org/acsmedchemlett
Development of Novel Benzomorpholine Class of Diacylglycerol
Acyltransferase I Inhibitors
Gang Zhou,* Nicolas Zorn, Pauline Ting, Robert Aslanian, Mingxiang Lin, John Cook, Jean Lachowicz,
Albert Lin, Michelle Smith, Joyce Hwa, Margaret van Heek, and Scott Walker
Discovery and Preclinical Sciences, Merck Research Laboratories, 126 East Lincoln Avenue, Rahway, New Jersey 07065, United States
S
* Supporting Information
ABSTRACT: Diacylglycerol acyltransferase 1 (DGAT1)
presents itself as a potential therapeutic target for obesity
and diabetes for its important role in triglyceride biosynthesis.
Herein we report the rational design of a novel class of
DGAT1 inhibitors featuring a benzomorpholine core (23n).
SAR exploration yielded compounds with good potency and
selectivity as well as reasonable physical and pharmacokinetic
properties. This class of DGAT1 inhibitors was tested in
rodent models to evaluate DGAT1 inhibition as a novel approach for the treatment of metabolic diseases. Compound 23n
conferred weight loss and a reduction in liver triglycerides when dosed chronically in mice with diet-induced obesity and depleted
serum triglycerides following a lipid challenge.
KEYWORDS: DGAT1, diacylglycerol acyltransferase inhibitor, benzomorpholine, postprandial triglyceridemia (PPTG)
isorders in triglyceride (TG) metabolism (dyslipidemia)
Drelated to either absorption or de novo synthesis have
been implicated in the pathogenesis of a variety of diseases and
risk factors, including obesity, type II diabetes, dyslipidemia,
metabolic syndrome, atherosclerosis, and coronary heart
disease.1,2 Therapeutic agents that can decrease the synthesis
of TG by inhibiting enzymes in corresponding metabolic
pathways may be valuable as therapeutic options for the
treatment of dyslipidemia.3
Acyl-CoA:diacylglycerol acyltransferase (DGAT), which is
widely expressed in mammalian adipose tissue, small intestine,
liver, and mammary gland, is a potential therapeutic target
because it catalyzes the final step of esterification of 1,2-
diacylglycerol with fatty acyl CoA to form triglycerides at the
endoplasmic reticulum.4,5 In theory, DGAT plays an essential
role in the metabolism of cellular diacylglycerol and is critically
important for triglyceride absorption and production as well as
energy storage homeostasis.6 Two DGAT enzymes DGAT1
and DGAT2, which are encoded by a distinct gene family, share
very limited sequence homology.7,8 Research has shown that
knockout DGAT1 mice (DGAT1−/−) are resistant to diet-
induced obesity,9 exhibit increased insulin sensitivity relative to
wild-type littermates,10 and have decreased adiposity (probably
due to increased energy expenditure).11 On the contrary,
DGAT2−/− mice are not viable due to lipopenia and skin
homeostasis abnormalities.12 The large body of genetic,
biochemical, and phenotypic evidence has spurred intense
research efforts to discover selective, small molecule inhibitors
of DGAT1.13−19 Typical representative structures are shown in
Figure 1.14−19 While structural diversity is noticeable among
the reported DGAT1 inhibitors, most possess a carboxylic acid
moiety. Several candidates display excellent dose-dependent
Figure 1. Structures of selected DGAT1 inhibitors.
weight gain inhibition in diet induced obesity (DIO) models
and have entered clinical trials.16
The structural analysis of these compounds inspired us to use
compound 518 (green) as the starting point for pharmacophore
modeling. Key elements of the pharmacophore-based modeling
approach of our efforts are presented in Figure 2. Indole
compound 7 (yellow) was initially proposed to probe the
effects of torsional constraints on the urea motif by formation
of an additional ring. This modification appeared structurally to
be well tolerated because overlap of the urea hydrogen bond
Received: December 22, 2013
Accepted: March 1, 2014
Published: March 1, 2014
© 2014 American Chemical Society
544
dx.doi.org/10.1021/ml400527n | ACS Med. Chem. Lett. 2014, 5, 544−549

ACS Medicinal Chemistry Letters
Letter
low clearance (Clrat/hu = 9/11 μL/min/Mcells), and better
plasma stability (∼10% loss of parent compound measured in
human plasma at 25 °C after 12 h). Compound 9 also
demonstrated acceptable selectivity over hDGAT2 (IC50 >10
μM), hACAT2 (IC50 = 9.7 μM), and a clean ancillary profile
except CYP 1A1 induction (10-fold at 30 μM). As a result, the
benzomorpholine class emerged as the new lead series for
optimization.
The results of subsequent SAR investigations of the
benzomorpholine core are summarized in Table 1. Changing
the topology by moving the trans-phenylcyclohexaneacetic acid
substituent around the benzomorpholine ring resulted in
dramatic potency loss (to C-8 and C-6 positions in compounds
10 and 11, respectively). Incorporation of nitrogen into the
core aromatic ring was not tolerated (analogs 12 and 13).
Introduction of a methyl group at the oxazine C-3 position
(compounds 14) proved to be detrimental to activity. In
contrast, introduction of a methyl group at the oxazine C-2
position (compound 16) increased in vivo efficacy (85%
decrease of TG levels in PPTG assay compared to 9) as well as
ACAT2 selectivity (hACAT2 IC50 = 5.0 μM) and plasma
exposure levels. Addition of a carbonyl group at the C3-position
of 16 resulted in an inactive compound (compound 15).
The SAR of the absolute stereochemistry in 16 was also
investigated. (S)-Enantiomer 18 displayed 6-fold less activity
relative to the R-enantiomer 17. (R)-Enantiomer 17 also
demonstrated excellent triglyceride lowering effect in vivo as
well as good selectivity over hDGAT2 and hACAT1 (IC50 = 10
μM) and moderate selectivity over hACAT2(IC50 = 2.0 μM).
Compound 17 had a clean off-target profile with the exception
of moderate CYP450 2C9 liver enzyme inhibition (IC50 = 14
μM). It is not surprising that 2,2-dimethyl substitution at the C-
2 position resulted in a 10-fold loss in potency (data not
shown). One-carbon extension of the methyl group at the
oxazine C-2 position was tolerated (as shown for compound
19), but further elongation of the alkyl chain (compound 20)
or branching (analog 21) resulted in loss of potency.
In concert with the SAR exploration around the bicyclic core,
extensive work was undertaken to optimize the urea moiety.
Representative examples of these modifications are summarized
in Table 2. Replacement of the urea motif in compounds 22a−
d resulted in partial to complete loss of DGAT1 inhibition,
showing the critical importance of the urea hydrogen bond
acceptor−donor pattern. On the urea aromatic ring, small and
lipophilic substituents were better tolerated at the ortho- and
para-positions than at the meta-position, as shown in
compounds 22e−j. Incorporation of polar substituents
generally resulted in significant loss of activity (compounds
22k and 22l). This SAR trend was also observed in the indoline
series (data not shown). Notably, fluorinated compound 22j
displayed excellent in vivo efficacy (triacylglyceride reduction of
91% at 10 mg/kg and 59% at 3 mg/kg for the 2 h time-point
compared to the vehicle-treated group), as well as good
selectivity toward hDGAT2 (inactive), hACAT1 (IC50 = 24
μM), and hACAT2 (IC50 = 9.6 μM). Analog 22j also showed
good PK properties (rat AUC = 23 μM.h @ 10 mg/kg, Caco2
= 239 nm/s, sol = 100 μM, hepatocyte clearance of 19 and 1.0
mL/min/kg in human and rat, respectively) and in vitro safety
profile (with no hERG, PXR, or liver enzymes inhibition or
induction issues).
Figure 2. Lead structure design based on Abbott and AstraZeneca
DGAT1 inhibitors. Pharmacophore models of 5 (green), 6 (yellow),
and 8 (cyan) were developed with full conformational analysis for the
lowest energy conformations (Sybyl 8.0).
donor and acceptor features was observed between compounds
5 and 7. To our surprise, in vitro DGAT1 data for indole 7
showed low enzyme inhibition. Further modeling work
suggested it is beneficial to replace the benzoylcyclopentyl
carboxylic acid fragment of compound 7 with the phenyl-
cyclohexaneacetic acid moiety, as presented in many reported
DGAT1 inhibitors, including compound 6.14 Model overlay of
the resulting indole inhibitor 8 with AstraZeneca amino-
oxadiazole 6 showed excellent alignment of all pharmacophore
features. This proposal was later confirmed by a dramatic
improvement in DGAT1 enzyme potency for indole 8 over 7.
Lead compound 8 displayed encouraging properties. It
showed selectivity for DGAT1 over DGAT2 and ACAT
enzymes (∼100-fold), acceptable physicochemical and pharma-
cokinetic properties (MW = 455, Caco2 = 170 nm/s, sol =20
μM, PPB = 99.8%, in vitro Clrat/hu = 3.9/7.6 μL/min/Mcells,
reasonable rat oral bioavailability and half-life) and presented
no off-target liability except CYP 1A1 induction (3-fold at 30
μM). When dosed orally in mice, compound 8 demonstrated
moderate efficacy measured by triacylglyceride reduction in our
in vivo postprandial triglyceridemia (PPTG) assay (−45% at 10
mg/kg @ 2 h). However, instability issues were revealed when
decomposition of indole 8 in both human and mouse plasma
was observed (∼40% loss of parent compound measured in in
vitro human plasma at 25 °C after 12 h). Furthermore, the
decomposition of 8 generated a potentially genotoxic aniline
byproduct under these conditions. Therefore, our lead
optimization strategy was focused on improving both in vitro
and in vivo DGAT1 potency while increasing plasma stability.
We reasoned that the plasma stability issue of 8 is probably
due to the indole urea moiety. Further research was focused on
scaffold replacements of the indole ring and rapidly identified
benzomorpholine compound 9 with improved plasma stability
in vitro activity and in vivo efficacy. Triglyceride levels in the
PPTG assay were decreased by 52% at 10 mg/kg in comparison
to the vehicle. Pharmacokinetic properties for compounds 9
were dramatically improved (AUC = 58 μM·h at 10 mg/kg, t1/2
= 4 h, rat oral bioavailability >90%) due to the combination of
improved solubility (100 μM), Caco2 permeability (448 nm/s),
In an effort to alleviate issues related to the formation of
potential genotoxic aniline metabolites, alkyl amines were also
incorporated. In comparison to the aryl urea compound 9, the
545
dx.doi.org/10.1021/ml400527n | ACS Med. Chem. Lett. 2014, 5, 544−549

ACS Medicinal Chemistry Letters
Letter
Table 1. Core Modification on the Benzooxazine Ring
Table 2. SAR Exploration of the Urea Moiety on the
a,b
Dihydrobenzooxazine
a
Assay values are the average of at least two independent
b
determinations. Enzyme species indicated between parentheses: h =
human, m = mouse.
ureas generally suffered reduced in vitro DGAT1 potency
(compound 22o) while long aliphatic chains such as the
heptanylurea analog 22p could restore in vitro potency levels of
aryl ureas, while maintaining acceptable selectivity over
DGAT2, ACAT1 (>100×), and ACAT2 (>20×) and a good
safety profile. Compound 22p is also particularly noteworthy
because of its reasonable in vivo efficacy in the PPTG model
(reduction of plasma TG levels by 48% at 3 mg/kg and 2 h
time-point) in spite of its low plasma exposure after oral dosing,
poor solubility, and low permeability (total rat AUC of 195 nM·
h, Cmax of 65 nM at tmax of 2 h with a plasma solubility at pH 7
of 5 μM and Caco2 of 35 nm/s). In a recent literature report,20
experiments have shown that DGAT1 deficient mice with
specific local expression of DGAT1 in the intestine completely
reversed the resistance to diet induced obesity and hepatic
steatosis normally associated with the DGAT1 knockout
mouse, indicating that decreasing effects of DGAT1 on body
weight are potentially attributed to the inhibition of the enzyme
in the intestine. Compounds showing low systemic exposure,
extended phenyl methyl urea analog 22m suffered a 10-fold loss
in DGAT1 activity. Further extension of the alkyl chain (e.g.
phenybutyl urea analog 22n) helped regain in vitro potency for
DGAT1 but was accompanied by loss of both in vivo biological
activity (−23% TG reduction at 10 mg/kg) and selectivity over
ACATs (∼10× selectivity only). Short and branched aliphatic
546
dx.doi.org/10.1021/ml400527n | ACS Med. Chem. Lett. 2014, 5, 544−549

ACS Medicinal Chemistry Letters
Letter
such as 22p, may be especially interesting because of the
potentially reduced systemic toxicity.
Table 3. Structure−Activity Relationship of Right-Hand Side
a,b
Carboxylic Acid-Bearing Tails
Extensive work on the right-hand side carboxylic acid-
containing fragment was also pursued to mitigate the potential
risk of idiosyncratic toxicity associated with glucuronidation of
the carboxylic acid moiety. Key examples selected from a large
set of modifications are presented in Table 3. Initial
implementation of common strategies involving increase of
steric hindrance at the α-position of the carboxylate or
bioisosteric replacements led to loss of DGAT1 enzyme
potency and in vivo efficacy (as exemplified by methyl-
substituted analog 23a or acid isosteres 23b−d). Scaffold
replacement efforts also showed limited success. Compound
23e, bearing the trans-cyclopentane carboxylic acid piece
reported by Abbott,18 displayed a 10-fold loss of enzyme
activity, a trend in agreement with the SAR observed in the
indole series originally investigated. In addition, replacement of
the trans-cyclohexaneacetic acid by its cis analog 23f resulted in
complete loss of in vivo efficacy in mice although good in vitro
DGAT1 potency was retained. Alternatively, replacement of the
cyclohexyl ring with some ether-linked acids (compounds 23g−
j) was explored in combination with a pyridyl moiety (to
replace phenyl). Most of these compounds were less potent
than the corresponding phenylcyclohexyl acid (compound 19),
except compound 23j, which maintains potency. Surprisingly,
23j compound was extremely efficacious in vivo with a 73%
plasma TG level reduction at 0.3 mg/kg po dose in mice, along
with excellent blood exposure (total rat AUC of 46 μM.h at 10
mg/kg) and clean off-target profile, except for inhibition of
P450 2C9 liver enzyme (IC50 = 0.5 μM) and induction of 2B
liver enzyme (5-fold at 30 μM). The corresponding pyrimidine
analogue (compound 23k), however, is 5-fold less potent in
enzyme activity.
Finally, the optimal groups in three regions (X, Y, and R as
shown in structure 23) were combined to provide compound
23l and its enantiomers. Similarly, the (R)-enantiomer 23n is
more potent in vivo than the (S)-enantiomer 23m even though
they have similar in vitro potency. The reason for these
discrepancies remains unclear.
Although several designed DGAT1 inhibitors were able to
achieve very significant in vivo efficacy after a lipid challenge in
our murine PPTG assay, we did not observe good correlation
between pharmacodynamic (PPTG) and pharmacokinetic
models within our acid series. To further explore other
beneficial effects of this series of compounds, a body weight
loss study was conducted to evaluate and benchmark chronic
efficacy in a rodent model. Methyl-substituted benzooxazine
23n was selected as a tool compound based on its good overall
properties: long duration of plasma TG level reduction in
mouse (−87% at the 12 h time-point), high pH 7 solubility (50
μM), high Caco2 permeability (201 nm/s), acceptable
hepatocyte clearance (14 and 10 mL/min/Mcells in human
and rat, respectively), and clean ancillary profile (no P450
CYPs or P-gp inhibition, no PXR and CYP activation or ion
channel activity, and no Ames toxicity).
Pharmacokinetic parameters for compound 23n in key
animal species are summarized in Table 4. Data collected in
rats, mice, monkeys, and dogs confirmed the excellent oral
bioavailability of 23n and high protein binding (PPB > 99.5% in
human and mouse), features also observed for other carboxylic
acids within this chemotype.
a
Assay values are the average of at least two independent
b
determinations. Enzyme species indicated between parentheses: h =
human, m = mouse.
chronic efficacy study, benzooxazine 23n demonstrated a
statistically significant decrease in body weight (>5% for 30
mg/kg, PO, qd). In comparison, compound 5 induced a 2%
The results of a chronic weight loss study in diet-induced
obese mice are presented in Figure 3. During the 11-day
547
dx.doi.org/10.1021/ml400527n | ACS Med. Chem. Lett. 2014, 5, 544−549

ACS Medicinal Chemistry Letters
Letter
a
Table 4. Pharmacokinetic Parameters for Lead Compound 23n in Rats, Mice, Dogs, and Monkeys
b
PPTG 3 mg/kg (time point)
AUC (μM·h)
Cl (μL/min/Mcells)
Cmax (μM)
t1/2 (h)
F (%)
rat
41
3.7
23
64
10
6.2
16
14
9.1
0.6
3.3
5.7
3.0
6.2
3.0
3.0
75
89
mouse
dog
−93% (2 h), −87% (12 h)
monkey
a
Assay values are the average of at least two independent determinations: 10 mg/kg for PO in rats, 1 mg/kg for PO in mice, 2 mg/kg for PO in dogs,
b
and 3 mg/kg for PO in monkeys. All values are mean values SEM for n = 8 (p < 0.01).
10 μM) for 105 out of 110 targets in the panel, including
potential targets that can affect food intake and body weight,
such as the cannabinoid (CB1), cholecystokinin (CCK),
dopamine (D2), histamine, serotonin, neuropeptide Y, and
purinergic receptor (PX). The five targets from the panel that
showed measurable inhibition with compound 23n are the
peptidase CASP8 (IC50 6.8 μM), CASP9 (IC50 5.0 μM), EGF
Receptor (IC50 7.5 μM), insulin receptor (IC50 5.7 μM), and
prostanoid IP (IC50 1.0 μM). These off target activities are
highly unlikely to be related to the food intake effect observed
with compound 23n.
In summary, a novel class of benzomorpholine compounds
has been identified as potent DGAT1 inhibitors, based on
pharmacophore modeling. SAR investigations have led to the
identification of several compounds with good pharmacokinetic
and pharmaceutical profiles. In vivo mouse PPTG studies have
shown that low doses of the DGAT1 inhibitors significantly
reduce TG absorption and plasma levels following a lipid
challenge. Treatment of DIO mice with the benzomorpholine
lead 23n for 11 days showed inhibition of body weight gain and
decrease in food intake. These results provide further insights
into the use of DGAT1 inhibition as a novel approach for the
treatment of metabolic diseases.
Figure 3. Body weight change and food effects on DIO mice (dosed in
0.5% methylcellulose (vehicle) at 10 mg/kg/day for compound 5; in
0.5% methylcellulose suspension at 30 mg/kg/day for compound 23n)
over a two-week period. Weight changes are registered as the percent
to day-zero value from the same group of mice for each measurement
time point. Food intake changes are expressed as the number of grams
difference of food consumed to day-zero value from the same group of
mice for each measurement time point.
ASSOCIATED CONTENT
* Supporting Information
■
S
Experimental data details of syntheses and characterization, in
vitro and in vivo biological assay for 8−23n. This material is
available free of charge via the Internet at http://pubs.acs.org.
body weight reduction after 10 mg/kg PO dosing. Interestingly,
a transient drop in food intake (days 1−4) was observed for
mice treated with lead compound 23n. No measurable
differences in locomotive activity were observed in the drug-
treated mice throughout the whole study, indicating that
treatment did not cause any adverse behavior effect. This body
weight reduction might be partly due to the reduced food
intake. The exact mechanism of how selective DGAT1
inhibitors can affect food intake is not clear. It is hypothesized
that inhibiting DGAT1 can affect fatty acid composition,
distribution, and sensing mechanisms, which might exhibit a
feedback mechanism on food intake.21
AUTHOR INFORMATION
Corresponding Author
*Phone: 732-594-2487. E-mail: gang.zhou@merck.com.
Notes
■
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank Dr. Malcolm MacCoss for suggestions; Dr. Grant
Wishart for structure modeling; Tze-Ming Chan for NMR
structure analysis; and Kung-I Feng for plasma stability assays.
ABBREVIATIONS
ACAT, acyl-CoA:cholesterol acyltransferase; CASP, caspase;
CYP, cytochrome P; EGF, epidermal growth factor; hERG,
Compound 23n was also sent to a screening panel of 110
enzymes, receptors, and ion channels to further assess
selectivity (data in Supporting Information). The results
■
showed compound 23n had a clean off target profile (IC50
>
human ether-a-
̀
gogo-related gene; pgp, p-glycoprotein; PPAR,
548
dx.doi.org/10.1021/ml400527n | ACS Med. Chem. Lett. 2014, 5, 544−549

ACS Medicinal Chemistry Letters
Letter
(19) Birch, A. M.; Birtles, S.; Buckett, L. K.; Kemmitt, P. D.; Smith,
G. J.; Smith, T. J. D.; Turnbull, A. V.; Wang, S. J. Y. Discovery of a
potent, selective, and orally efficacious pyrimidinooxazinyl bicyclooc-
taneacetic acid diacylglycerol acyltransferase-1 inhibitor. J. Med. Chem.
2009, 52, 1558−1568.
(20) Lee, B.; Fast, A. M.; Zhu, J.; Cheng, J.; Buhman, K. K. Intestine
specific expression of acyl CoA:diacylglycerol acyltransferase I reverses
resistance to diet-induced hepatic steatosis and obesity in DGAT1−/−
mice. J. Lipid Res. 2010, 51, 1770−1780.
(21) Okawa, M.; Fujii, K.; Ohbuchi, K.; Okumoto, M.; Aragane, K.;
Sato, H.; Tamai, Y.; Seo, T.; Itoh, Y.; Yoshimoto, R. Role of MGAT2
and DGAT1 in the release of gut peptides after triglyceride ingestion.
Biochem. Biophys. Res. Commun. 2009, 390, 377−381.
peroxisome proliferator activated receptor; PXR, Pregnane X
receptor
REFERENCES
■
(1) Semenkovich, C. F. Insulin resistance and atherosclerosis. J. Clin.
Invest. 2006, 116, 1813−1822.
(2) McGarry, J. D. Dysregulation of fatty acid metabolism in the
etiology of type 2 diabetes. Diabetes 2002, 51 (1), 7−18.
(3) Shi, Y.; Burn, P. Lipid metabolic enzymes: emerging drug targets
for treatment of obesity. Nat. Rev. 2004, 3, 695−710.
(4) Zammit, V. A.; Buckett, L. K.; Turnbull, A. V.; Wure, J.; Proven,
A. Diacylglycerol acyltransferases: Potential roles as pharmacological
targets. Pharmacol. Ther. 2008, 118, 295−302.
(5) Yen, C. E.; Stone, S. J.; Koliwad, D.; Harris, C.; Farese, R. V., Jr.
DGAT enzymes and triacylglycerol biosynthesis. J. Lipid Res. 2008, 49,
2283−2301.
(6) Chen, H. C.; Farese, R. V. DGAT and triglyceride synthesis: a
new target for obesity treatment. Trends Cardiovasc. Med. 2000, 10,
188−192.
(7) Cases, S.; Smith, S. J.; Zheng, Y-W; Myers, H. M.; Lear, S. R.;
Sande, E.; Novak, S.; Collins, C.; Welch, C. B.; Lusis, A. J.; Erickson, S.
K.; Farese, R. V., Jr. Identification of a gene encoding an acyl
CoA:diacylglycerol acyltransferase, a key enzyme in triacylglycerol
synthesis. Proc. Natl. Acad. Sci. U.S.A. 1998, 95, 13018−13023.
(8) Cases, S.; Stone, S. J.; Zhou, P.; Yen, E.; Tow, B.; Voelker, T.;
Farese, R. V., Jr. Cloning of DGAT2, a second mammalian
diacylglycerol acyltransferase, and related family members. J. Biol.
Chem. 2001, 276, 38870−38876.
(9) Smith, S. J.; Cases, S.; Jensen, D. R.; Chen, H. C.; Sande, E.; Tow,
B.; Sanan, D. A.; Raber, J.; Eckel, R. H.; Farese, R. V., Jr. Obesity
resistance and multiple mechanisms of triglyceride synthesis in mice
lacking DGAT. Nat. Genet. 2000, 25, 87−90.
(10) Chen, H. C.; Jensen, D. R.; Myers, H. M.; Eckel, R. H.; Farese,
R. V. Obesity resistance and enhanced glucose metabolism in mice
transplanted with white adipose tissue lacking acyl CoA:diacylglycerol
acyltransferase 1. J. Clin. Invest. 2003, 111 (11), 1715−1722.
(11) Chen, H. C.; Ladha, Z.; Smith, S. J.; Farese, R. V. Analysis of
energy expenditure at different ambient temperatures in mice lacking
DGAT1. Am. J. Physiol. Endocrinol. Metab. 2003, 284 (1), 213−218.
(12) Stone, S. J.; Myers, H. M.; Watkins, S. M.; Brown, B. E.;
Feingold, K. R.; Elias, P. M.; Farese, R. V., Jr. Lipopenia and skin
barrier abnormalities in DGAT2-deficient mice. J. Biol. Chem. 2004,
279, 11767−11776.
(13) King, A. J.; Judd, A. S.; Souers, A. J. Inhibitors of diacylglycerol
acyltransferase: a review of 2008 patents. Expert Opin. Ther. Pat. 2010,
20, 19−29.
(14) Birch, A. M.; Bowker, S. S.; Butlin, R. J.; Donald, C. S.; McCoull,
W.; Nowak, T.; Plowright, A. T. Oxadiazole derivatives as dgat
inhibitors. Patent WO 2006/064189, 2006.
(15) Fox, B. M.; Iio, K.; Li, K.; Choi, R.; Inaba, T.; Jackson, S.;
Sagawa, S.; Shan, B.; Tanaka, M.; Yoshida, A.; Kayser, F. Discovery of
pyrrolopyridazines as novel DGAT1 inhibitors. Bioorg. Med. Chem.
Lett. 2010, 20, 6030−6033.
(16) Devita, R. J.; Pinto, S. Current Status of the Research and
Development of Diacylglycerol O-Acyltransferase 1 (DGAT1)
Inhibitors. J. Med. Chem. 2013, 56, 9820−9825.
(17) Smith, R.; Campbell, A.-M.; Coish, P.; Dai, M.; Jenkins, S.;
Lowe, D.; O’Connor, S.; Su, N.; Wang, G.; Zhang, M.; Zhu. L.
Preparation of Benzazolylaminobiphenyloxoalkanoates for the Treat-
ment of Obesity. US 2004/0224997, 2004.
(18) Zhao, G.; Souers, A. J.; Voorbach, M.; Falls, H. D.; Droz, B.;
Brodjian, S.; Lau, Y. Y.; Iyengar, R. R.; Gao, J.; Judd, A. S.; Wagaw, S.
H.; Ravn, M. M.; Engstrom, K. M.; Lynch, J. K.; Mulhern, M. M.;
Freeman, J.; Dayton, B. D.; Wang, X.; Grihalde, N.; Fry, D.; Beno, D.
W. A.; Marsh, K. C.; Su, Z.; Diaz, G. J.; Collins, C. A.; Sham, H.; Reilly,
R. M.; Brune, M. E.; Kym, P. R. Validation of diacyl glycerolacyl-
transferase I as a novel target for the treatment of obesity and
dyslipidemia using a potent and selective small molecule inhibitor. J.
Med. Chem. 2008, 51, 380−383.
549
dx.doi.org/10.1021/ml400527n | ACS Med. Chem. Lett. 2014, 5, 544−549