Acetylenic TACE inhibitors. Part 2: SAR of six-membered cyclic sulfonamide hydroxamates

Article abstract of DOI:10.1016/j.bmcl.2005.06.072

The SAR of a series of potent sulfonamide hydroxamate TACE inhibitors bearing a butynyloxy P1′ group was explored. In particular, compound 5k has excellent in vitro potency against TACE enzyme and in cells, and oral activity in an in vivo model of TNF-α production and a collagen-induced arthritis model.

Full text of DOI:10.1016/j.bmcl.2005.06.072

Bioorganic & Medicinal Chemistry Letters 15 (2005) 4345–4349
Acetylenic TACE inhibitors. Part 2: SAR of six-membered
cyclic sulfonamide hydroxamates
J. I. Levin,a,* J. M. Chen,a L .M. Laakso,a M. Du,a X. Du,a A. M. Venkatesan,a
V. Sandanayaka,a A. Zask,a J. Xu,a W. Xu,b Y. Zhangb and J. S. Skotnickia
aWyeth Research, 401N. Middletown Road, Pearl River, NY 10965, USA
bWyeth Research, 200 Cambridge Park Drive, Cambridge, MA 02140, USA
Received 12 May 2005; revised 9 June 2005; accepted 13 June 2005
Available online 9 August 2005
Abstract—The SAR of a series of potent sulfonamide hydroxamate TACE inhibitors bearing a butynyloxy P10 group was explored.
In particular, compound 5k has excellent in vitro potency against TACE enzyme and in cells, and oral activity in an in vivo model of
TNF-a production and a collagen-induced arthritis model.
Ó 2005 Elsevier Ltd. All rights reserved.
The ability of biologics that modulate levels of the pro-
inflammatory cytokine TNF, including TNF-soluble
receptors and TNF antibodies, to effectively treat rheu-
matoid arthritis (RA), has fueled the search for orally
active mediators of TNF.1 Small molecule inhibitors of
TNF-a converting enzyme (TACE/ADAM-17), the
metalloprotease responsible for the cleavage of the
26 kDa membrane-bound form of TNF, may offer an
effective treatment for RA by limiting the release of
17 kDa soluble TNF.2,3
are excellent inhibitors of TACE in a cell-free enzyme
assay and many also potently inhibit the LPS-induced
release of soluble TNF in THP-1 cells. Selectivity for
TACE over MMP-1, oral activity in an in vivo mouse
model of TNF-a production, and oral activity in a
mouse collagen-induced arthritis (CIA) efficacy model
has also been demonstrated. We were interested in
extending the use of the butynyloxy P10 group to a series
of sulfonamide hydroxamates, 5, derived from morpho-
line, thiomorpholine, and piperazine scaffolds (Fig. 2).
The ability of sulfonamide hydroxamate derivatives of
six-membered ring cyclic amino acids, bearing a variety
of P10 groups, to provide potent inhibitors of MMPs
and cell-free TACE, including one that advanced to clin-
ical trials, is well documented and made these scaffolds
A variety of small molecule TACE inhibitors possessing
excellent enzyme and cellular potency have been dis-
closed.4,5 Some of these compounds inhibit TACE while
sparing the structurally similar MMPs,4 in an effort to
avoid dose-related toxicities displayed by many MMP
inhibitors in clinical trials.6 Broad spectrum MMP/
TACE inhibitors5 are of interest, since a variety of
MMPs have been found to be over-expressed in RA
synovial tissue and have been implicated in the destruc-
tion of cartilage in RA joints.7
O
HO
HN
O
N
SO2
O
O O2S
NH
HO
HO
N
H
Br
OH
1
We,8 and others,9 have previously disclosed several ser-
ies of sulfonamide and sulfone hydroxamic acid TACE
inhibitors bearing novel propargylic P10 groups, exem-
plified by compounds 1–4 (Fig. 1). These compounds
2
O
O
O2
S
O
O O2S
N
N
H
HO
N
H
N
NH
Keywords: TACE; MMP; Hydroxamate; Rheumatoid arthritis.
*
3
4
Corresponding author. Tel.: +8456023053; fax: +8456025561; e-mail:
levinji@wyeth.com
Figure 1. Wyeth butynyloxy P10 TACE inhibitors.
0960-894X/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2005.06.072

4346
J. I. Levin et al. / Bioorg. Med. Chem. Lett. 15 (2005) 4345–4349
O
O
O
i, ii
O O2S
N
O O2S
NH
O O2S
NH
HO
N
MeO
MeO
H
Br
R
X
R
OH
O
6
7
5
iii
Figure 2. Six-membered cyclic a-sulfonamide hydroxamates.
O
O
iv, v
particularly interesting in our search for more potent,
orally active inhibitors of TACE.10
O O2S
N
O O2S
N
HO
N
MeO
H
O
Sulfonamide hydroxamic acids 5 (Table 1) were pre-
pared as shown in Schemes 1–3. Thus, in Scheme 1, sul-
fonamide 68f reacted with triphenylphospine and DEAD
to afford an intermediate aziridine that was then con-
verted into bromide 7 with bromoethanol and BF3-eth-
erate.11 Ring closure of 7 proceeded in the presence of
potassium carbonate in DMF to give the desired mor-
pholine scaffold 8. Hydrolysis of ester 8 with lithium
hydroxide followed by conversion into the acid chloride
and subsequent reaction with hydroxylamine gave the
racemic hydroxamic acid 5a.
O
5a
8
Scheme 1. Reagents: (i) PPh3, DEAD; (ii) Br(CH2)2OH, BF3-Et2O;
(iii) K2CO3; (iv) LiOH; (v) (a) (COCl)2, DMF; (b) NH2OH.
The piperazine sulfonamides were prepared from the
mono-protected racemic piperazine ethyl ester 12
(Scheme 3). Sulfonylation with 4-butynyloxybenzene-
sulfonyl chloride afforded sulfonamide 13. The
NH-piperazine was prepared by ester hydrolysis of 13,
conversion of the resulting carboxylic acid into the cor-
responding hydroxamate, accomplished with hydroxyl-
amine after activation with EDC/HOBT, and removal
of the Boc protecting group with TFA to give 5c. N-
Substituted piperazines were available via removal of
the Boc group of 13 followed by functionalization of
the piperazine nitrogen to provide a tertiary amine,
amides, ureas, and sulfonamides 14. Hydrolysis of the
ester with sodium or lithium hydroxide gave the
carboxylates that were subsequently converted into the
desired racemic hydroxamates, 5d–5j with EDC/HOBT
or oxalyl chloride, followed by hydroxylamine.
The thiomorpholine derivatives 5b, 5k, and 5l resulted
from initial S-alkylation of the thiol amino acid with
bromoethanol followed by sulfonylation with 4-butyn-
yloxybenzenesulfonyl chloride and formation of the t-
butyl ester with t-butyl bromide to give alcohol 10
(Scheme 2). The alcohol was converted into the corre-
sponding bromide and then cyclized with potassium car-
bonate to give 11. Deprotection of the ester with TFA
followed by hydroxamate formation then gave the
thiomorpholines 5b, 5k, and 5l. Of these, 5b and 5l
were racemic while 5k, derived from D-penicillamine
was obtained in optically pure form.
Table 1. In vitro potency of cyclic sulfonamide hydroxamic acids
O
O O2S
HO
N
N
H
R
X
R
5
Comp
R
X
TACEa
THPb
MMP-1a
MMP-9a
MMP-13a
5a
5b
H
O
5
3
80
84
71
25
81
86
81
81
59
73
94
94
162
148
676
3197
357
498
201
96
170
21
26
12
8
H
S
NH
5c
5d
H
23
28
13
12
9
14
H
NCH2-3-Py
NCOCH3
NCO-2-C4H3S
NCO2CH3
NSO2CH3
NCON(CH2CH3)2
NCOC4H8
S
108
88
49
22
119
9
5e
H
5f
5g
H
251
71
H
5h
5i
H
7
51
6
H
28
28
8
1752
1248
7
221
209
12
NTc
97
83
3
5j
5k (TMI-1)
H
CH3
5l
–(CH2)4–
S
43
24
11
a IC50 (nM).
b % Inhibition at 3 lM.
c NT, not tested.

J. I. Levin et al. / Bioorg. Med. Chem. Lett. 15 (2005) 4345–4349
4347
O
line 5b are potent inhibitors of TACE enzyme in a
cell-free assay. An X-ray crystal structure of 5b was ob-
tained (Fig. 3) and shows that the butynyloxy P10 moi-
ety is positioned in the center of the uniquely shaped
channel connecting the S10 and S30 subsites of TACE.14
Both 5a and 5b are also moderately selective, 30- and 50-
fold, respectively, for TACE over MMP-1, and less than
5-fold selective over MMP-13. In addition, morpholine
5a is more than 30-fold selective over MMP-9. In con-
trast, piperazine 5c, a 23 nM inhibitor of TACE with
30-fold selectivity over MMP-1, is most potent against
MMP-13 (IC50 = 8 nM) and MMP-9 (IC50 = 14 nM).
The ability of compounds 5a–5c to inhibit TNF produc-
tion in LPS-stimulated THP-1 cells15 parallels their
potency in the cell-free TACE assay. Thus, morpholine
5a and thiomorpholine 5b provide 80% and 84% inhibi-
tion at 3 lM, respectively, while piperazine 5c is slightly
less potent, providing 71% inhibition (IC50s were not
determined). Although piperazine sulfonamide 5c is less
potent in cells than the morpholine and thiomorpholine,
this scaffold was the most amenable to analog synthesis
in pursuit of increased cellular potency.
O
i, ii, iii
NH2
SH
O O2S
NH
HO
R
tBuO
R
OH
R
S
9a (R = H)
9b (R = Me)
9c (R = -(CH2)4-
R
10
iv, v
O
O
vi, vii
O O2S
N
O O2S
N
HO
N
tBuO
H
R
R
S
S
R
R
5b (R = H)
5k (R = Me)
5l (R = -(CH2)4-
11
Scheme 2. Reagents: (i) Br(CH2)2OH, NaOH; (ii) 4-buty-
nyloxybenzenesulfonyl chloride, Na2CO3; (iii) tBuBr, K2CO3; (iv)
PPh3, CBr4; (v) K2CO3; (vi) TFA; (vii) (a) (COCl)2, DMF or EDC,
HOBT; (b) NH2OH.
The selected N-substituted piperazines 5d–5j are all
highly active inhibitors of cell-free TACE enzyme with
only a 4-fold range in potency despite a wide variation
in shape and size. However, differences are apparent in
the selectivity profiles and cellular potencies of these
analogs. Thus, picolyl derivative 5d, a 28 nM inhibitor
of TACE, is over 100-fold selective for TACE over
MMP-1, but is unfortunately only weakly active in
THP-1 cells. Acetamide 5e, lacking a basic nitrogen in
the piperazine ring, is somewhat more potent against
TACE than 5d, but is several times less selective than
5d over MMP-1. Thienyl amide 5f is equipotent to 5e
against TACE, with slightly improved selectivity over
MMP-1, -9, and -13. Carbamate 5g and sulfonamide
5h are the most potent piperazine analogs against cell-
free TACE, retaining excellent potency against MMP-
13 as well, but lacking substantial selectivity over
MMP-1. Compounds 5e–5h are also equivalent in
potency to the morpholine and thiomorpholine analogs,
5a and 5b, in THP-1 cells, and more active at 3 lM than
analogs 5c and 5d, bearing a basic nitrogen. Urea deriv-
atives 5i and 5j are less potent against TACE and in cells
O
O
H
N
O O2S
N
i
EtO
EtO
N
N
Boc
12
Boc
13
ii, iii
iv, v, ii
iv, v
O
O
O O2S
N
O O2S
N
HO
N
EtO
H
N
R
N
R
5c-5j
14
Scheme 3. Reagents: (i) 4-Butynyloxybenzenesulfonyl chloride,
Na2CO3; (ii) TFA; (iii) R1Cl, or R1COCl, or CH3SO2Cl, or
R1R2NCOCl; (iv) NaOH or LiOH; (v) (a) (COCl)2, DMF; (b)
NH2OH.
All of the sulfonamide hydroxamic acids were tested
in vitro12 for their ability to inhibit MMP-1, MMP-9,
MMP-13, and TACE.13 The inhibition of these enzymes
may help to prevent cartilage degradation in RA, and
therefore may be therapeutically desirable.8 However,
inhibitors of TACE with various MMP inhibition pro-
files were also sought in order to gain insight into the
possible source of musculoskeletal side effects seen in
clinical trials of many broad-spectrum MMP inhibitors.6
The in vitro potencies for the cyclic sulfonamide
hydroxamic acid analogs bearing a butynyloxy P10
group are shown in Table 1.
A comparison of the potency and selectivity of the three
heterocyclic sulfonamide hydroxamate scaffolds, 5a–5c
(Table 1), shows that morpholine 5a and thiomorpho-
Figure 3. X-ray structure of compound 5b bound to TACE.

4348
J. I. Levin et al. / Bioorg. Med. Chem. Lett. 15 (2005) 4345–4349
than the less sterically bulky amide, carbamate, and sul-
fonamide analogs. But, this steric bulk may account for
their relatively good selectivity, greater than 40-fold, for
TACE over MMP-1. The dramatic differences in cellular
activity seen in the piperazine series among compounds
with similar levels of enzyme activity does not appear to
correlate with any particular physical property. For
example, the cLogP values for 5d, 5i, and 5j are 2.1,
2.9, and 2.6, respectively, and their topological polar
surface areas are virtually identical. Properties that have
been postulated by others to impact activity in human
whole blood are cell permeability and protein binding.
However, there is less than 1% protein in the THP assay
and we have not seen any correlation between perme-
ability or protein binding, and cell activity.16
its poor PK properties and present problems for its
development as a therapeutic agent for RA.
In summary, we have synthesized a series of sulfonamide
hydroxamate derivatives of six-membered cyclic amino
acids bearing a butynyloxy P10 group as inhibitors of
MMPs and TACE. All of these compounds are potent
inhibitors of TACE in an isolated enzyme assay, most
are potent in THP-1 cells, and 5d possesses greater than
100-fold selectivity for TACE over MMP-1. Oral activ-
ity has been demonstrated for several of these com-
pounds in a mouse model of LPS-stimulated TNF-a
production. Thiomorpholine (5k, TMI-1) is among the
most potent sulfonamide hydroxamates described to
date at inhibiting LPS-stimulated TNF production in
cells, whole blood, and in vivo, and shows excellent oral
potency in a standard model of human RA. Additional
SAR information on the structural series exemplified by
5k, and improvements of that lead, will be presented in
due course.
Although some of the analogs 5a–5j demonstrate good
cellular activity, increased potency in THP-1 cells was
still desirable. Interestingly, appending two methyl
groups on the thiomorpholine ring of 5b, as in penicil-
lamine derivative 5k (TACE IC50 = 8 nM), abolishes
selectivity for TACE over MMP-1 and improves activ-
ity in THP-1 cells, providing 94% inhibition of LPS-
stimulated TNF production at 3 lM and an IC50 of
0.2 lM. Compound 5k also potently inhibits LPS-stim-
ulated TNF-a production in human whole blood with
an IC50 of 0.3 lM. The loss of TACE selectivity over
MMP-1 for 5k is due to a 20-fold increase in potency
against MMP-1, rather than a loss of TACE activity,
indicative of beneficial interactions with the S20 pocket
of this enzyme. This is consistent with the SAR we
have described for N-methyl sulfonamide hydroxa-
mates derived from acyclic amino acids, wherein amino
acids with lipophilic side chains afforded increased
potency against MMP-1.8c To explore whether bulkier
substituents were tolerated at this position on the thi-
omorpholine, particularly in terms of cellular potency,
the spiro-fused cyclopentyl analog 5l was also pre-
pared. This compound was in fact more potent against
both MMP-1 and MMP-13 than against TACE,
although the excellent cellular potency of 5k was
retained.
Acknowledgments
We thank D. Barone, T. Cummons, G. Jin, R. Mulvey,
A. Sung, and S. Skala for technical support in the en-
zyme and in vivo assays, and R. A. Black, R. Cowling,
L. Killar, K. M. Mohler for their insight and guidance
during the course of this work. We also thank Uday Jain
and the Wyeth PCC group for physical data, and C.
Huselton and Wyeth DSM for PK data.
References and notes
1. (a) Newton, R. C.; Decicco, C. P. J. Med. Chem. 1999, 42,
2295; (b) Palladino, M. A.; Bahjat, F. R.; Theodorakis, E.
A.; Moldawer, L. L. Nat. Rev. Drug Discovery 2003, 2,
736.
2. Skotnicki, J. S.; Levin, J. I. Ann. Rep. Med. Chem. 2003,
38, 153.
3. (a) Newton, R. C.; Solomon, K. A.; Covington, M. B.;
Decicco, C. P.; Haley, P. J.; Friedman, S. M.; Vaddi, K.
Ann. Rheum. Dis. 2001, 60, iii25; (b) Moss, M. L.; Bartsch,
J. Biochemistry 2004, 43, 7227.
4. Duan, J. J.-W.; Chen, L.; Wasserman, Z. R.; Lu, Z.; Liu,
R.-Q.; Covington, M. B.; Qian, M.; Hardman, K. D.;
Magolda, R. L.; Newton, R. C.; Christ, D. D.; Wexler, R.
R.; Decicco, C. P. J. Med. Chem. 2002, 45, 4954.
5. (a) Kottirsch, G.; Koch, G.; Feifel, R.; Neumann, U. J.
Med. Chem. 2002, 45, 2289; (b) Koch, G.; Kottirsch, G.;
Wietfeld, B.; Kusters, E. Org. Process Res. Dev. 2002, 6,
652; (c) Trifilieff, A.; Walker, C.; Keller, T.; Kottirsch, G.;
Neumann, U. Br. J. Pharmacol. 2002, 135, 1655; (d)
Letavic, M. A.; Axt, M. Z.; Barberia, J. T.; Carty, T. J.;
Danley, D. E.; Geoghegan, K. F.; Halim, N. S.; Hoth, L.
R.; Kamath, A. V.; Laird, E. R.; Lopresti-Morrow, L. L.;
McClure, K. F.; Mitchell, P. G.; Natarajan, V.; Noe, M.
C.; Pandit, J.; Reeves, L.; Schulte, G. K.; Snow, S. L.;
Sweeney, F. J.; Tan, D. H.; Yu, C. H. Bioorg. Med. Chem.
Lett. 2002, 12, 1387.
The in vivo activity of most of the compounds in Table 1
was initially measured by their ability to inhibit the LPS-
stimulated production of TNF-a after oral dosing in a
mouse.15 Analogs 5a, 5b, and 5h, dosed at 50 mg/kg
po, provided 88%, 75%, and 62% inhibition, respective-
ly, of TNF-a levels 1 h after administration of LPS. The
most potent analog in this model was penicillamine
derivative 5k (also designated TMI-1) with an ED50 of
5 mg/kg po. Compound 5k is reproducibly active at
reducing clinical severity scores in a mouse prophylactic
collagen-induced arthritis (CIA) efficacy model at
10 mg/kg po bid.15 Unfortunately, while 5k has excellent
bioavailability at 10 mg/kg in the DBA mouse (71%), it
is poorly bioavailable at 10 mg/kg po in the rat (5%),
and the dog (0%). Although this analog is permeable
in Caco-2 cells and is not highly protein bound
(ꢀ40%), its moderate solubility in simulated gastric
and intestinal fluids (<75 lg/mL) and multiple metabo-
lites (in vitro liver microsomes), including loss of the
butynyl P10 group, are issues that may contribute to
6. (a) Peterson, J. T. Heart Failur. Rev. 2004, 9, 63; (b)
Renkiewicz, R.; Qiu, L.; Lesch, C.; Sun, X.; Devalaraja,
R.; Cody, T.; Kaldjian, E.; Welgus, H.; Baragi, V. Arth.
Rheum. 2003, 48, 1742.

J. I. Levin et al. / Bioorg. Med. Chem. Lett. 15 (2005) 4345–4349
4349
7. (a) Yoshihara, Y.; Nakamura, H.; Obata, K.; Yamada,
H.; Hayakawa, T.; Fujikawa, K.; Okada, Y. Ann. Rheum.
Dis. 2000, 59, 455; (b) Konttinen, Y. T.; Ainola, M.;
Valleala, H.; Ma, J.; Ida, H.; Mandelin, J.; Kinne, R. W.;
Santavirta, S.; Sorsa, T.; Lopez-Otin, C.; Takagi, M. Ann.
Rheum. Dis. 1999, 58, 691.
Li, J.; Pease, L.; Glaser, K.; Morgan, D.; Michaelides, M.;
Davidsen, S. Bioorg. Med. Chem. Lett. 2001, 11, 2907; (d)
Cheng, M.; De, B.; Pikul, S.; Almstead, N. G.; Natchus,
M. G.; Anastasio, M. V.; McPhail, S. J.; Snider, C. E.;
Taiwo, Y. O.; Chen, L.; Dunaway, C. M.; Gu, F.; Dowty,
M. E.; Mieling, G. E.; Janusz, M. J.; Wang-Weigand, S. J.
Med. Chem. 2000, 43, 369; (e) Sorbera, L. A.; Castaner, J.
Drugs Future 2000, 25, 150; (f) Almstead, N. G.; Bradley,
R. S.; Pikul, S.; De, B.; Natchus, M. G.; Taiwo, Y. O.; Gu,
F.; Williams, L. E.; Hynd, B. A.; Janusz, M. J.; Dunaway,
C. M.; Mieling, G. E. J. Med. Chem. 1999, 42, 4547; (g)
Pikul, S.; McDow Dunham, K. L.; Almstead, N. G.; De,
B.; Natchus, M. G.; Anastasio, M. V.; McPhail, S. J.;
Snider, C. E.; Taiwo, Y. O.; Rydel, T.; Dunaway, C. M.;
Gu, F.; Mieling, G. E. J. Med. Chem. 1998, 41, 3568.
11. For a similar route see: Bender, S. L.; Melnick M. J. US
Patent 5,753,653 1998; Chem. Abstr. 1998, 129, 16140.
12. (a) Weingarten, H.; Feder, J. Anal. Biochem. 1985, 147,
437; (b) Inhibitor concentrations were run in triplicate.
MMP IC50 determinations were calculated from a 4-
8. (a) Chen, J. M.; Jin, G.; Sung, A.; Levin, J. I. Bioorg. Med.
Chem. Lett. 2002, 12, 1195; (b) Levin, J. I.; Chen, J. M.;
Du, M. T.; Nelson, F. C.; Killar, L. M.; Skala, S.; Sung,
A.; Jin, G.; Cowling, R.; Barone, D.; March, C. J.;
Mohler, K. M.; Black, R. A.; Skotnicki, J. S. Bioorg. Med.
Chem. Lett. 2002, 12, 1199; (c) Levin, J. I.; Chen, J. M.;
Cheung, K.; Cole, D.; Crago, C.; Delos Santos, E.; Du,
X.; Khafizova, G.; MacEwan, G.; Niu, C.; Salaski, E. J.;
Zask, A.; Cummons, T.; Sung, A.; Xu, J.; Zhang, Y.; Xu,
W.; Ayral-Kaloustian, S.; Jin, G.; Cowling, R.; Barone,
D.; Mohler, K. M.; Black, R. A.; Skotnicki, J. S. Bioorg.
Med. Chem. Lett. 2003, 13, 2799; (d) Zask, A.; Kaplan, J.;
Du, X.; MacEwan, G.; Sandanayaka, V.; Eudy, N.; Levin,
J.; Jin, G.; Xu, J.; Cummons, T.; Barone, D.; Ayral-
Kaloustian, S.; Skotnicki, J. Bioorg. Med. Chem. Lett.
2005, 15, 1641; (e) Venkatesan, A. M.; Davis, J. M.;
Grosu, G. T.; Baker, J.; Zask, A.; Levin, J. I.; Ellingboe,
J.; Skotnicki, J. S.; DiJoseph, J. F.; Sung, A.; Jin, G.; Xu,
W.; Joseph McCarthy, D.; Barone, D. J. Med. Chem.
2004, 47, 6255; (f) Levin, J. I.; Nelson, F. C.; Delos Santos,
E.; Du, M. T.; MacEwan, G.; Chen, J. M.; Ayral-
Kaloustian, S.; Xu, J.; Jin, G.; Cummons, T.; Barone, D.
Bioorg. Med. Chem. Lett. 2004, 14, 4147.
parameter logistic fit of the data within
experiment.
a single
13. Jin, G.; Huang, X.; Black, R.; Wolfson, M.; Rauch, C.;
McGregor, H.; Ellestad, G. A.; Cowling, R. Anal.
Biochem. 2002, 302, 269.
14. PDB deposition number: 1ZXC For the X-ray crystal
structure of TACE see: Maskos, K.; Fernandez-Catalan,
C.; Huber, R.; Bourenkov, G. P.; Bartunik, H.; Ellestad,
G. A.; Reddy, P.; Wolfson, M. F.; Rauch, C. T.; Castner,
B. J.; Davis, R.; Clarke, H. R. G.; Petersen, M.; Fitzner, J.
N.; Cerretti, D. P.; March, C. J.; Paxton, R. J.; Black, R.
A.; Bode, W. Proc. Natl. Acad. Sci. U.S.A. 1998, 95, 3408.
15. For descriptions of cellular and in vivo assays as well as a
summary of the pharmacology of TMI-1 (5k) see: Zhang,
Y.; Xu, J.; Levin, J.; Hegen, M.; Li, G.; Robertshaw, H.;
Brennan, F.; Cummons, T.; Clarke, D.; Vansell, N.;
Nickerson-Nutter, C.; Barone, D.; Mohler, K.; Black, R.;
Skotnicki, J.; Gibbons, J.; Feldman, M.; Frost, P.; Larsen,
G.; Lin, L.-L. J. Pharmacol. Exp. Ther. 2004, 309, 348.
16. Levin, J. I.; Du, M. T. Drug Design Discovery 2003, 18,
123.
9. Tsukida, T.; Moriyama, H.; Inoue, Y.; Kondo, H.;
Yoshino, K.; Nishimura, S. Bioorg. Med. Chem. Lett.
2004, 14, 1569.
10. (a) Chen, J. J.; Dewdney, N.; Lin, X.; Martin, R. L.;
Walker, K. A. M.; Huang, J.; Chu, F.; Eugui, E.;
Mirkovic, A.; Kim, Y.; Sarma, K.; Arzeno, H.; Van Wart,
H. E. Bioorg. Med. Chem. Lett. 2003, 13, 3951; (b) Letavic,
M. A.; Barberia, J. T.; Carty, T. J.; Hardink, J. R.; Liras,
J.; Lopresti-Morrow, L. L.; Mitchell, P. G.; Noe, M. C.;
Reeves, L. M.; Snow, S. L.; Stam, E. J.; Sweeney, F. J.;
Vaughn, M. L.; Yu, C. H. Bioorg. Med. Chem. Lett. 2003,
13, 3243; (c) Holms, J.; Mast, K.; Marcotte, P.; Elmore, I.;