5478
J. R. Merritt et al. / Bioorg. Med. Chem. Lett. 20 (2010) 5477–5479
substitution of this triazole with a methyl group at position 3, com-
pound 5, dramatically reduced CCR1 binding potency.
Me
N
Cl
O
F3C
O
The most significant overall improvement was observed with
1,3,4-triazole. Compound 6 was significantly more potent for inhi-
bition of binding and chemotaxis than the original amide lead. It
also exhibited moderate microsomal stability and pharmacokinet-
ics. Interestingly, further substitution of this triazole, did not re-
duce potency as it had for the 1,2,4-triazole 5. Indeed compound
7 had an IC50 of 2.9 nM for inhibition of chemotaxis. Furthermore,
introduction of the methyl group at position 2 improved micro-
somal stability and pharmacokinetics.
Compound 7 was selected for further evaluation. Additional
pharmacokinetic studies in rat showed that this compound has a
plasma half-life of 3.8 h, 26% bioavailability and low clearance of
2.8 mL/min/kg. Tmax was at 1.1 h with a Cmax of 1124 ng/mL. CYP
N
N
H
1
Cl
Cl
Cl
N
N
N
N
F3C
N
F3C
N
O
O
O
N
H
N
N
H
N
3
2
Cl
Cl
N
N
N
N
N
N
F3C
F3C
O
N
N
N
N
H
profiling showed no inhibition at less than 10
lM for 3A4, 2D6,
H
2C9, 1A2, and 2C19 isoforms.23
5
4
In summary, further optimization of our original amide lead for
CCR1 was achieved. A 1,3,4-triazole replacement for the amide
moiety resulted in improved potency while retaining good bio-
availability and metabolic profile.
Cl
N
N
N
F3C
N
F3C
N
N
O
O
N
N
N
H
N
H
Supplementary data
6
7
Supplementary data associated with this article can be found, in
Figure 2. Amide lead and bioisosteric heterocycles for CCR1.
References
Cl
H
N
COOH
S
N
1. Furuichi, K.; Ji-Liang Gao, J.; Horuk, R.; Wada, T.; Kaneko, S.; Murphy, P. M. J.
Immunol. 2008, 81, 8670.
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S.; Roodman, G. Exp. Hematol. 2005, 33, 272.
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a, b
c
Boc
N
Boc
Cl
N
N
N
d, e
7
Boc
5. Snowden, N.; Hajeer, A.; Thomson, W.; Ollier, B. Lancet 1994, 343, 547.
6. Rottman, J. B.; Slavin, A. J.; Silva, R.; Weiner, H. L.; Gerard, C. G.; Hancock, W. W.
Eur. J. Immunol. 2000, 30, 2372.
N
Scheme 1. Reagents and conditions: (a) 4-chlorobenzylamine, HBTU, DIEA, DMF;
(b) Lawesson’s reagent, toluene, refluxed 2 h; (c) acetohydrazide, Hg(OAc)2, MeCN;
(d) 4 M HCl in dioxane; (e) 1-isocyanato-4-(trifluoromethyl)benzene, DCM.
7. Baranzini, S. E.; Elfstrom, C.; Chang, S. Y.; Butunoi, C.; Murray, R.; Higuchi, R.;
Oksenberg, J. R. J. Immunol. 2000, 165, 6576.
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9. Gladue, R. P.; Tylaska, L. A.; Brissette, W. H.; Lira, P. D.; Kath, J. C.; Poss, C. S.;
Brown, M. F.; Paradis, T. J.; Conklyn, M. J.; Ogborne, K. T.; McGlynn, M. A.; Lillie,
B. M.; DiRico, A. P.; Mairs, E. N.; McElroy, E. B.; Martin, W. H.; Stock, I. A.;
Shepard, R. M.; Showell, H. J.; Neote, K. J. Biol. Chem. 2003, 278, 40473.
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2006, 67, 1880.
2, afforded similar potency as for the original lead 1, Table 1. How-
ever, as is typical for imidazoles,18 this compound had poor micro-
somal stability which translated to poor pharmacokinetics. The
tetrazole 3 likewise had poor microsomal stability but significantly
improved potency. The 1,2,4-triazole, 4, showed marked improve-
ment in microsomal stability which translated to improved phar-
macokinetics. However, this compound was no more potent for
inhibition of chemotaxis than the original amide lead 1. Further
12. Norman, P. Expert Opin. Ther. Pat. 2009, 19, 1629.
13. Vergunst, C. E.; Gerlag, D. M.; von Moltke, L.; Karol, M.; Wyant, T.; Chi, X.;
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2010).
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Table 1
In vitro CCR1 binding, chemotaxis, liver microsome stability and in vivo rat AUC for
selected compounds (data shown are standard deviation of two or more
measurements)
HLM21
%
RLM %
AUC(0–1)
22
Compd CCR1
CCR1
binding19 chemotaxis20 remaining remaining po (ng/ml h)
IC50 (nM) IC50 (nM)
17. Synthetic details for compounds 2–7 are available in the Supplementary data.
18. Tang, C.; Chiba, M.; Nishime, J.; Hochman, J. H.; Chen, I. W.; Williams, T. M.; Lin,
J. H. Drug Metab. Dispos. 2000, 28, 680.
1
2
3
4
5
6
7
140 10
65 22
22
16
6.5 2.0
9
4
78
39
59
61
ND
52
74
55
25
81
ND
41
87
9390 1590
100 36
ND
4459 2453
ND
19. Biological Assays: Materials and methods. Recombinant membranes were
prepared by cloning human CCR1 into an episomal expression vector (Horlick-
20
32
6
8
2000) and stably expressing in HEK293 cells. [125I]-MIP1
a was obtained from
22
9
Perkin–Elmer (Waltham, MA) and SPA beads were obtained from GE
healthcare (Piscataway, NJ). The human monocytic cell line, THP-1, was
810 127 ND
17
69 0.2
5
4
2
657 289
7649 4033
purchased from ATCC (Manassas, VA). Recombinant human MIP1
a was
2.9 0.8
100
obtained from R&D Systems (Minneapolis, MN). Plates used for chemotaxis