Discovery of novel spirocyclic inhibitors of fatty acid amide hydrolase (FAAH). Part 1: Identification of 7-azaspiro[3.5]nonane and 1-oxa-8-azaspiro[4. 5]decane as lead scaffolds

Article abstract of DOI:10.1016/j.bmcl.2011.08.055

Herein we report the identification of two new fatty acid amide hydrolase (FAAH) inhibitor lead series with FAAH k_inact/K_i potency values greater than 1500 M^-1s^-1. The two novel spirocyclic cores, 7-azaspiro[3.5]nonane and 1-oxa-8-azaspiro[4.5]decane, clearly distinguished themselves from the other spirocyclic cores on the basis of their superior potency for FAAH. Lead compounds from these two series have suitable FAAH potency and selectivity for additional medicinal chemistry optimization.

Full text of DOI:10.1016/j.bmcl.2011.08.055

Bioorganic & Medicinal Chemistry Letters 21 (2011) 6538–6544
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Discovery of novel spirocyclic inhibitors of fatty acid amide hydrolase
(FAAH). Part 1: Identification of 7-azaspiro[3.5]nonane
and 1-oxa-8-azaspiro[4.5]decane as lead scaffolds
⇑
Marvin J. Meyers , Scott A. Long, Matthew J. Pelc, Jane L. Wang, Scott J. Bowen, Mark C. Walker,
Barbara A. Schweitzer, Heather M. Madsen, Ruth E. Tenbrink, Joseph McDonald, Sarah E. Smith,
⇑
Susan Foltin, David Beidler, Atli Thorarensen
Pfizer Global Research & Development, St. Louis Laboratories, 700 Chesterfield Parkway West, Chesterfield, MO 63017, United States
a r t i c l e i n f o
a b s t r a c t
Article history:
Available online 22 August 2011
Herein we report the identification of two new fatty acid amide hydrolase (FAAH) inhibitor lead series
with FAAH kinact/Ki potency values greater than 1500 MÀ1 sÀ1
. The two novel spirocyclic cores,
7-azaspiro[3.5]nonane and 1-oxa-8-azaspiro[4.5]decane, clearly distinguished themselves from the other
spirocyclic cores on the basis of their superior potency for FAAH. Lead compounds from these two series
have suitable FAAH potency and selectivity for additional medicinal chemistry optimization.
Ó 2011 Elsevier Ltd. All rights reserved.
Keywords:
Fatty acid amide hydrolase, FAAH
Pain
Endocannabinoid
Fatty acid amide hydrolase (FAAH) is a serine hydrolase respon-
sible for the degradation of fatty acid amide signaling molecules
including the endocannabinoid anandamide (AEA).1 It has been
shown that inhibition of FAAH leads to elevated levels of AEA
and analgesic effects in rodent models of pain without evidence
of side effects commonly seen with cannabinoid receptor agonists.
These findings suggest that inhibition of FAAH may provide an
important class of analgesic agents.2
Due to the success of clinical candidate 8, we sought to identify
a novel core to replace the piperidine core common to many FAAH
inhibitors. Once a novel core was identified, it could be optimized
with the goal of discovering a new series of potent FAAH inhibitors
with a divergent biological profile. For example, we have replaced
the piperidine ring with azetidine (e.g., 9).9 However, successful
replacement was achievable only by optimizing the length of the
aliphatic linker between the core azetidine ring and the biaryl
ether. The work culminated in azetidine 9 which required a three
carbon linker for optimal potency. This was postulated to be due
to the requirement to optimally position the biaryl ether tail in
the lipophilic acyl chain binding channel. Failure to align this biaryl
ether group properly likely results in a suboptimal alignment of the
urea moiety for covalent binding to FAAH.
In the current manuscript, we report the identification of two
new FAAH inhibitor lead series with FAAH kinact/Ki potency values
greater than 1500 MÀ1 sÀ1 (vide infra). Once suitable cores were
identified, the goal of our medicinal chemistry optimization pro-
gram targeted FAAH kinact/Ki potency values greater than
2500 MÀ1 sÀ1, low in vivo clearance (CL <15), and oral efficacy of
1 mpk or less in rodent models of pain. This latter optimization ef-
fort is the subject of the subsequent manuscript in this journal.11
FAAH inhibitors can be broken down into the following modular
units: a tail group, an optional hydrocarbon linker, a piperidine-like
urea core, and a urea head group which acts as a leaving group upon
covalent binding to FAAH (Chart 2).12 With this knowledge in hand
and using molecular modeling and docking studies, we designed a
collection of spirocyclic cores (i–xiv) as replacements for the
There have been several reports of both reversible and covalent
inhibitors of FAAH and the subject has been recently reviewed.3
Reversible inhibitors include
a
-ketooxazole 24 and sulfonamide 4
(Chart 1).5 Examples of covalent inhibitors include carbamate 36
and urea 5.7 The FAAH program at Pfizer has reported on several
covalent inhibitors, including ureas 6–9.8–10 The efforts of Johnson
et al. at Pfizer led to the successful identification of urea
PF-04457845 (8), a covalent inhibitor with exquisite potency and
selectivity for FAAH.10 Urea 8 was found to be orally efficacious at
0.1 mpk in a rat model of pain and is being evaluated in human
clinical trials.
Abbreviations: FAAH, fatty acid amide hydrolase; AEA, anandamide; ABPP,
activity-based protein profiling; CFA, complete Freund’s adjuvant.
⇑
Corresponding authors at present address: Center for World Health and
Medicine at Saint Louis University, 1100 S. Grand Blvd., Saint Louis, MO 63104,
United States. Tel.: +1 314 977 5197; fax: +1 314 977 5220 (M.J.M.); tel.: +1 617 665
5604 (A.T.).
E-mail addresses: mmeyers8@slu.edu (M.J. Meyers), atli.thorarensen@pfizer.com
(A. Thorarensen).
0960-894X/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2011.08.055

M. J. Meyers et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6538–6544
6539
O
O
OH
N
O
H
N
N
2
anandamide (1, AEA)
OL-135 ( )
O
O
S
N
S
NH
N
O
NH2
N
S
O
H
O
O
4
URB597 (3)
O
O
R
6a R =
6b R =
N
N
H
N
N
N
H
∗
N
N
N
S
S
N
N
N
O
∗
JNJ-1661010/Takeda-25 (5)
O
O
N
F3C
N
F3C
N
N
N
H
N
H
N
O
N
O
PF-3845 (7)
PF-04457845 (8)
O
F3C
N
N
N
N
H
N
O
9
Chart 1. Substrate and inhibitors of FAAH.
methylenepiperidine core of compound 8. An evaluation of the SAR
of piperazine containing FAAH inhibitors such as 5 and 6 suggested
to us that a benzothiophene or phenylthiadiazole tail group would
be appropriate for evaluating diazospirocyclic cores (X = N) for
FAAH activity. Similarly, the biaryl ether tail of compounds 7 and
8 was identified as being suitable for azaspirocyclic cores (X = C).
Given our experience with azetidines such as 9, we evaluated each
core using variable linker lengths. Finally, three representative urea
head groups were selected: 3-pyridyl, 3-pyridazinyl, and 3,4-dim-
ethylisoxazol-5-yl. Thus, for each spirocyclic core we evaluated a
compound matrix comprising of 1–2 tail groups, a linker of 0–2
carbons and three head groups.
The FAAH binding site requires a flattened U-shaped compound
profile in order to align with the acyl chain binding channel (Fig. 1).
Using a docking protocol we have previously described,9 prototype
inhibitors were covalently attached to the FAAH crystal structure
and minimized in the binding channel. This ligand conformation
was then compared to low energy conformers generated from a
Monte Carlo style conformational search in the absence of protein.
Furthermore, hydrocarbon linker chains of 0–2 carbons were eval-
uated to allow the tail group opportunity to align appropriately. If
the minimized unbound conformer was of similar shape to the
bound conformer, we postulated that the energy penalty for bind-
ing to FAAH was minimal and gave the spirocyclic core higher pri-
ority for synthesis. For example, Figure 1 shows an overlay of both
free and bound low energy conformers of the 7-azaspiro[3.5]non-
ane core vii onto the X-ray crystal structure of FAAH inhibitor
7.12 Since this core could attain a similar overall shape to bound
7, this scaffold was given high priority.
Evaluation of these spirocyclic cores required the preparation of
Boc protected spirocycles with functionality enabling orthogonal
incorporation of a linker of varying lengths to tether the terminal
lipophilic tail. The Boc protected spirocyclic synthetic intermedi-
ates that were selected synthesis or purchase are shown in Chart
3.13–19 With spirocyclic synthetic intermediates 11–22 in hand, a
series of prototype compounds with varying length hydrocarbon
linkers were prepared. These analogs were prepared in a highly
divergent manner with representative examples shown in
Schemes 1 and 2. The synthesis of N-linked diazaspirocycles is
illustrated in Scheme 1 involving either an N-arylation or reductive
amination as the key bond disconnections. The synthesis of C-
linked azaspirocycles is illustrated in Scheme 2. The shortest linked
compounds (e.g., 29) were prepared by addition of a Grignard re-
agent followed by deoxygenation/debenzylation and nucleophilic
displacement to give the biaryl ether. The 1 or 2 atom linked ana-
logs (e.g., 32 and 35) differed by the requirement of homologation
followed by a Wittig olefination. In all instances, the final assembly
of the analogs included a Boc deprotection followed by urea forma-
tion. The synthesis of 6-azaspiro[2.5]octane containing compounds
required preparation from intermediate 3610 utilizing a Pd-cata-
lyzed diazomethane cyclopropanation as depicted in Scheme 3.
The array of compounds with varying spirocyclic cores were as-
sayed in an enzyme-coupled human FAAH assay as previously de-
scribed.8b Since these compounds covalently bind to the FAAH
enzyme, potency was measured using the second order rate con-
stant kinact/Ki. As these values are independent of preincubation
times and substrate concentrations, kinact/Ki values are, in this case,
preferred over IC50 values for assessing compound potency. A plot

6540
M. J. Meyers et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6538–6544
Tail Core
O
F3C
N
N
N
N
H
N
O
Head
Linker
O
Spirocyclic Core
Head
N
N
H
X
X = N or C
n = 0-2
Tail
(CH2)n
10
Tail Groups
Spirocyclic Cores
Head Groups
∗
∗
X = C
∗
∗
∗
N
N
N
N
N
F3C
N
N
N
∗
∗
∗
∗
∗
i
ii
iii
vi
N
O
∗
N
∗
∗
N
O
∗
N
X = N
N
∗
∗
N
∗
N
N
iv
v
∗
S
N
∗
∗
N
N
N
∗
∗
∗
N
∗
∗
vii
viii
xi
ix
S
∗
∗
∗
∗
N
N
N
N
O
∗
∗
O
O
x
xii
∗
N
N
∗
∗
xiii
xiv
Chart 2. Strategy to replace piperidine core with a spirocycle core.
(core vii) and 1-oxa-8-azaspiro[4.5]decane (core x), clearly distin-
guished themselves from the other cores on the basis of potency
for FAAH, being the only series with member compounds having
FAAH kinact/Ki values greater than 1000 MÀ1 sÀ1
.
A closer look at the SAR for specific examples from the most po-
tent cores 7-azaspiro[3.5]nonane (vii) and 1-oxa-8-azaspi-
ro[4.5]decane (x) is presented in Table 1. For both cores vii and
x, linkers of one to two carbons (entries 2–3, and 8) diminished
FAAH activity by four to fivefold relative to the no linker analogs
(29 and 41) which had FAAH potencies of 1570 and 3130 MÀ1 sÀ1
(entries 1 and 7).
Subtle changes in the makeup of the spirocycle resulted in dra-
matic losses in potency. For example, the diazaspiro analog of core
vii (25) was more than 100-fold less potent than the lead com-
pound 29 (entries 4 and 1). This may be due to required geometry
of the sp3 protonated nitrogen, presenting an undesirable cationic
core in a rather lipophilic binding site.8b,12 For core x, replacement
of the oxygen atom with carbon (44) or replacement with an iso-
meric furan (43) resulted in 10-fold reductions in FAAH activity
(entries 9 and 10). The enantiomers of racemic 41 were separated
by supercritical fluid chromatography using a chiral stationary
phase. Both enantiomers retained activity against FAAH with the
Figure 1. Overlay of (i) a minimized prototype from 7-azaspiro[3.5]nonane core vii
(green) covalently bound to FAAH, (ii) a minimized prototype from 7-azaspi-
ro[3.5]nonane core vii using a MacroModel conformer search (no protein; orange),
and (iii) a X-ray co-crystal structure (2WAP) of FAAH (yellow) and inhibitor 7
(purple).12
of the FAAH kinact/Ki potency values as a function of spirocyclic core
is shown in Figure 2. Two spirocyclic cores, 7-azaspiro[3.5]nonane

M. J. Meyers et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6538–6544
6541
NBoc
NBoc
NBoc
NBoc
NBoc
NBoc
HN
HN
O
HN
11
15
19
12
16
20
13
17
21
14a
NBoc
NBoc
O
O
HN
O
O
18
NBoc
NBoc
NBoc
NBoc
O
O
O
HN
O
O
22
Chart 3. Spirocyclic synthetic intermediates.
OH
F3C
N
O
B
OH
R
N
O
CHO
F3C
N
23
24
N
14a
a,b,c
N
R'
14b
c,d,e
14a
R = Boc, R' = H
14b R= H, R' = Cbz
O
N
O
N
N
N
H
N
N
H
N
F3C
N
O
N
N
N
O
F3C
25
26
Scheme 1. Representative synthesis of diazaspirocycle prototypes. Reagents and conditions: (a) Compound 23, Cu(OAc)2, NEt3, DCM (23%); (b) TFA, DCM (quant.); (c) phenyl
pyridazin-3-ylcarbamate, DIEA, CH3CN, room temp (39–81%); (d) H2, Pd/C (quant.); (e) compound 24, NaBH(OAc)3 (50%).
O
O
i,j,k
NBoc
b or c
a
N
N
O
O
HO
O
N
O
15
33
H
27
d,e
F3C
PO(OEt)2
N
O
g
30
g
NH
HCl
30
NBoc
N
O
NBoc
F3C
O
F3C
N
O
F3C
31
28
34
h,e,f
f
h,e,f
O
O
N
O
N
N
N
H
N
N
N
H
N
N
N
N
N
F3C
H
N
O
N
O
N
O
F3C
35
F3C
29
32
Scheme 2. Representative synthesis of azaspirocycle prototypes. Reagents and conditions: (a) 3-Benzyloxyphenylmagnesium bromide, 2-MeTHF, 0 °C; (b) Raney Ni, EtOH,
reflux; (c) (i) Et3SiH, TFA, BF3OEt2, DCM, 0 °C, (ii) H2, 10% Pd/C, MeOH, 45 psi (36–38% from 15); (d) 2-chloro-5-(trifluoromethyl)pyridine, cesium carbonate, DMF, 90 °C (85%);
(e) 4 N HCl/dioxane, DCM; (f) phenyl pyridazin-3-ylcarbamate, DIEA, CH3CN, room temp (36–96% over two steps); (g) KOtBu, THF (50–60%); (h) H2, 10% Pd/C, MeOH, 20 psi,
1 h (86–90%); (i) Ph3PCH3Br, KOtBu, THF (39%); (j) 9-BBN, H2O2 (16%); (k) DMP, DCM (92%).

6542
M. J. Meyers et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6538–6544
O
F3C
F3C
NBoc
a
b,c
F3C
N
NBoc
N
N
H
N
N
O
N
O
N
O
36
37
38
Scheme 3. Synthesis of 6-azaspiro[2.5]octane analogs. Reagents and conditions: (a) PdCl2(dba)2, CH2N2, DCM (14%); (b) TFA, DCM (99%); (c) phenyl pyridazin-3-ylcarbamate,
DIEA, CH3CN, room temp (5%).
Figure 2. Plot of hFAAH kinact/Ki values as a function of spirocycle core.
Table 1
FAAH potency data for representative compounds
F
O
F
F
R
N
H
Core
N
O
( )n
Entry
1
Compd
n
Core
R
hFAAH kinact/Kia (MÀ1 sÀ1
)
MW
483
C log P
∗
∗
∗
∗
∗
N
N
N
N
N
N
29
0
1570
4.5
∗
N
N
N
N
∗
∗
∗
N
N
N
2
3
4
5
32
35
25
39
1
2
0
0
272
344
497
511
484
500
5.0
5.6
2.7
4.6
∗
∗
∗
18.3
1760
N
∗
N
O
∗
∗

M. J. Meyers et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6538–6544
6543
Table 1 (continued)
Entry
Compd
n
Core
R
hFAAH kinact/Kia (MÀ1 sÀ1
)
MW
482
C log P
∗
N
N
6
40
0
914
5.2
∗
∗
∗
∗
∗
N
N
N
7
8
41
42
0
1
3130
846
499
512
2.9
4.1
∗
∗
N
O
O
N
∗
∗
∗
∗
N
N
N
O
N
N
9
43
44
0
0
229
307
499
497
2.9
5.1
∗
∗
N
N
∗
∗
∗
10
11
12
13
45
46
47
48
0
0
0
0
515
2080
1340
3040
516
498
499
499
3.1
3.7
2.9
2.9
N
O
∗
∗
O
O
O
O
∗
∗
∗
N
N
N
N
N
N
∗
∗
∗
∗
∗
N
N
14
a
Each kinact/Ki value corresponds to an average of at least two independent determinations.
R enantiomer (48) being somewhat more potent (entries 13 and
14). The reason for strong sensitivity to positioning of the oxygen
atom in the 1-oxa-8-azaspiro[4.5]decane (x) core but weak sensi-
tivity to changing the chiral center is unclear and cannot be readily
explained by molecular modeling studies.
With respect to the head urea leaving groups, the 7-azaspi-
ro[3.5]nonane (vii) core series tolerated both the 3-pyridazinyl
and 3,4-dimethylisoxazol-5-yl groups equally well (entries 1 and
5). In contrast, the 1-oxa-8-azaspiro[4.5]decane (x) core series pre-
ferred the more basic 3-pyridyl and 3-pyridazinyl groups over the
3,4-dimethylisoxazol-5-yl group by roughly fivefold (entries 7,11,
and 12).
compound 39 was found to be active, albeit at a higher dose. Given
the relatively modest potency for FAAH and marginal CNS drug-
like properties (MW at or near 500), these results suggested the
need for further optimization to improve in vivo efficacy.
In summary, two cores, 7-azaspiro[3.5]nonane (vii) and 1-oxa-
8-azaspiro[4.5]decane (x), clearly distinguished themselves from
the other spirocyclic cores on the basis of their potency for FAAH.
Lead compounds from these two series (29, 39, and 48) have suit-
able potency and selectivity for FAAH but marginal CNS drug-like
properties. The medicinal chemistry optimization of these two ser-
ies is the subject of the subsequent article in this journal.11
On the basis of their superior FAAH potencies, lead compounds
from these two series (29, 39, and 48) were selected for further
profiling and assayed for selectivity versus the serine hydrolase
superfamily of enzymes (>200 human enzymes, including FAA-
Acknowledgments
We would like to thank Prof. Benjamin F. Cravatt for his advice
and extensive discussions on this project, J.T. Collins for chiral res-
olutions, S. Yang for 2D NMR determinations, and T.K. Nomanbhoy
at ActivX Biosciences for ABPP proteome profiling.
H).8a,20 The three compounds were assayed at 100
lM in a func-
tional proteomic screen based on competitive activity-based
protein profiling (ABPP) in human brain membrane and soluble li-
ver proteonomes using a rhodamine-tagged fluorophosphonate
ABPP probe. As has been observed previously for compound 8,10
all three lead spirocycles 29, 39, and 48 were found to be exqui-
sitely selective for FAAH. In addition, in vitro assays suggested that
these series have low risk for high clearance, drug–drug interac-
tions or inhibition of the hERG channel (data not shown). Finally,
the lead compounds 29, 39, and 48 were evaluated in the rat CFA
pain model12,21 at 10, 25, and 10 mpk, ip, respectively. Only
References and notes
1. Ahn, K.; McKinney, M. K.; Cravatt, B. F. Chem. Rev. 2008, 108, 1687.
2. (a) Lambert, D. M.; Fowler, C. J. J. Med. Chem. 2005, 48, 5059; (b) Pacher, P.;
Batkai, S.; Kunos, G. Pharmacol. Rev. 2006, 58, 389; (c) Di Marzo, V. Nat. Rev.
Drug Disc. 2008, 7, 438.
3. (a) Otrubova, K.; Ezzili, C.; Boger, D. L. Bioorg. Med. Chem. Lett. 2011, 21, 4674;
(b) Seierstad, M.; Breitenbucher, J. G. J. Med. Chem. 2008, 51, 7327.

6544
M. J. Meyers et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6538–6544
4. Boger, D. L.; Miyauchi, H.; Du, W.; Hardouin, C.; Fecik, R. A.; Cheng, H.; Hwang,
I.; Hedrick, M. P.; Leung, D.; Acevedo, O.; Guimaraes, C. R. W.; Jorgensen, W. L.;
Cravatt, B. F. J. Med. Chem. 2005, 48, 1849.
5. Wang, X.; Sarris, K.; Kage, K.; Zhang, D.; Brown, S. P.; Kolasa, T.; Surowy, C.; El
Kouhen, O. F.; Muchmore, S. W.; Brioni, J. D.; Stewart, A. O. J. Med. Chem. 2009,
52, 170.
12. Ahn, K.; Johnson, D. S.; Mileni, M.; Beidler, D.; Long, J. Z.; McKinney, M. K.;
Weerpana, E.; Sadagopan, N.; Liimatta, M.; Smith, S. E.; Lazerwith, S.; Stiff, C.;
Kamtekar, S.; Bhattacharya, K.; Zhang, Y.; Swaney, S.; Becelaere, K. V.; Stevens,
R. C.; Cravatt, B. F. Chem. Biol. 2009, 16, 411.
13. Intermediates 11–14a, 16, 20–22 are available from a number of commercial
vendors.
6. Kathuria, S.; Gaetani, S.; Fegley, D.; Valino, F.; Duranti, A.; Tontini, A.; Mor, M.;
Tarzia, G.; La Rana, G.; Calignano, A.; Giustino, A.; Tattoli, M.; Palmery, M.;
Cuomo, V.; Piomelli, D. Nat. Med. 2003, 9, 76.
14. Intermediate 12 was prepared as described in Meyers, M. J.; Muizebelt, I.; van
Wiltenburg, J.; Brown, D. L.; Thorarensen, A. Org. Lett. 2009, 11, 3523.
15. Intermediate 15 was prepared as described in Meyers, M. J.; Schweitzer, B. A.;
Pelc, M.; Wang, J. L.; Long, S. A.; Thorarensen, A. WO2010/049841, 2010.
16. Intermediate 17 was prepared using diazomethane generated in situ from the
portionwise addition of 1-methyl-1-nitrosourea (Aldrich) to the biphasic
mixture of 40% KOH and intermediate 15 in 10:1 2-MeTHF/MeOH (93%).
17. Intermediate 18 was prepared as described in Long, S. A.; Wang, J. L.; Meyers,
M. J.; Pelc, M., Schweitzer, B. A.; Thorarensen, A. WO2010/058318, 2010.
18. Intermediate 19 was prepared from intermediate 15 by a Baeyer–Villiger
reaction using 30% hydrogen peroxide and 0.5 N sodium hydroxide in THF/
MeOH (47%).
7. Matsumoto, T.; Kori, M.; Miyazaki, J.; Kiyota, Y. WO 2006054652A1, 2006.
8. (a) Ahn, K.; Johnson, D. S.; Fitzgerald, L. R.; Liimatta, M.; Arendse, A.; Stevenson,
T.; Lund, E. T.; Nugent, R. A.; Nomanbhoy, T. K.; Alexander, J. P.; Cravatt, B. F.
Biochemistry 2007, 46, 13019; (b) Mileni, M.; Johnson, D. S.; Wang, Z.; Everdeen,
D. S.; Liimatta, M.; Pabst, B.; Bhattacharya, K.; Nugent, R. A.; Kamtekar, S.;
Cravatt, B. F.; Ahn, K.; Stevens, R. C. Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 12820;
(c) Johnson, D. S.; Ahn, K.; Kesten, S.; Lazerwith, S. E.; Song, Y.; Morris, M.; Fay,
L.; Gregory, T.; Stiff, C.; Dunbar, J. B.; Liimatta, M.; Beidler, D.; Smith, S.;
Nomanbhoy, T. K.; Cravatt, B. F. Bioorg. Med. Chem. Lett. 2009, 19, 2865.
9. Wang, J. L.; Bowen, S. J.; Schweitzer, B. A.; Madsen, H. M.; McDonald, J.; Pelc, M.
J.; Tenbrink, R. E.; Beidler, D.; Thorarensen, A. Bioorg. Med. Chem. Lett. 2009, 19,
5970.
19. Intermediate 20 was prepared from tert-butyl 1-oxo-7-azaspiro[3.5]nonane-7-
carboxylate by a Baeyer–Villiger reaction using 30% hydrogen peroxide and
0.5 N sodium hydroxide in THF/MeOH (46%).
10. Johnson, D. S.; Stiff, C.; Lazerwith, S. E.; Kesten, S. R.; Fay, L. K.; Morris, M.;
Beidler, D.; Liimatta, M. B.; Smith, S. E.; Dudley, D. T.; Sadagopan, N.;
Bhattachar, S. N.; Kesten, S. J.; Nomanbhoy, T. K.; Cravatt, B. F.; Ahn, K. ACS
Med. Chem. Lett. 2011, 2, 91.
11. Meyers, M. J.; Long, S. A.; Pelc, M. J.; Wang, J. L.; Bowen, S. J.; Schweitzer, B. A.;
Wilcox, M. V.; McDonald, J.; Smith, S. E.; Foltin, S.; Rumsey, J.; Yang, Y.-S.;
Walker, M. C.; Kamtekar, S.; Beidler, D.; Thorarensen, A. Bioorg. Med. Chem. Lett.
The subsequent manuscript in this issue.
20. (a) Cravatt, B. F.; Wright, A. T.; Kozarich, J. W. Annu. Rev. Biochem. 2008, 77, 383;
(b) Liu, Y.; Patricelli, M. P.; Cravatt, B. F. Proc. Natl. Acad. Sci. U.S.A. 1999, 96,
14694.
21. The Pfizer Institutional Animal Care and Use Committee reviewed and
approved the animal use in these studies. The animal care and use program
is fully accredited by the Association for Assessment and Accreditation of
Laboratory Animal Care, International.