1820
D. C. Beshore et al. / Bioorg. Med. Chem. Lett. 11 (2001) 1817–1821
Table 3. Pharmacokinetic profiles for selected compounds in dogsa
The studies described herein have examined the SAR of
amino acid-based linkers of 16-, 17-, and 18-membered
macrocyclic FPTase inhibitors. We have identified a
series of highly potent compounds that exhibit
improved pharmacokinetic profiles relative to 1. Con-
formational analysis has provided an enhanced under-
standing of structural preferences for the binding of
macrocyclic inhibitors that contain an amino acid-based
linker.
Compd
T1/2 (h)
Cl (mL/min/kg)
VD (l/kg)
1
2
4
6
8
9
10
29
1.0
3.5
3.0
4.8
2.2
2.4
0.8
3.4
5.1
1.1
0.44
0.30
0.55
0.37
0.45
0.26
0.98
0.35
2.36
0.95
2.23
1.65
17.3
1.49
aCompounds were administered intravenously to two dogs (1 mg/kg)
along with 11 other compounds and an internal standard. Plasma
extracts were analyzed by LC/MS/MS and reported data is the aver-
age of two dogs (see ref 9).
Acknowledgements
The authors thank Dr. A. S. Kim and Dr. B. W. Trotter
for manuscript suggestions and Dr. C. S. Hamann for
compound analysis of FPTase inhibition.
(Fig. 2, top).10 The most prominent structural difference
is the conformation about the amide N-C(O) bond. The
N-H amide in 6 adopts a cis amide conformation with
respect to the naphthyl and the carbonyl of the amide,
while the N-Me analogue 19 adopts the opposite amide
conformation. These results are consistent with pre-
viously reported data regarding the lowest energy con-
formations of N-H and N-Me anilides.8 As a result of
these differences, the trajectory of the naphthyl group
has changed by nearly 90ꢁ. It has been shown in pre-
vious studies that the overall orientation of the carbonyl
group within the active site of FPTase is an important
feature of structurally related, highly potent FTIs.5d The
lowest calculated energy conformation of 15b places the
carbonyl group in the presumed enzyme-bound con-
formation.5d Best-fit overlays of 6 and 19 onto 1 (Fig. 2,
bottom) require that they deviate from their lowest
energy conformations by 5.7 and 11.5 kcal/mol, respec-
tively. The higher energy required for the N-Me amide
to adopt this presumed FPTase-bound conformation
relative to 6 may account for its reduced potency. These
results reinforce the notion that the orientation of the
carbonyl group is important, and imply that the trajec-
tory of the naphthyl group may also play a role in
obtaining highly potent FTIs.
References and Notes
1. (a) Kato, K.; Cox, A. D.; Hisaka, M. M.; Graham, S. M.;
Buss, J. E. Proc. Natl. Acad. Sci. U.S.A. 1992, 89, 6403. (b)
Rowinsky, E. K.; Windle, J. L.; Von Hoff, D. D. J. Clin.
Oncol. 1999, 17, 3631.
2. Rodenhuis, S. Semin. Cancer Biol. 1992, 3, 241.
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Annu. Rep. Biopharmacol. Toxicol. 1997, 37, 143.
4. (a) Recent reviews: Williams, T. M. Expert Opin. Ther. Pat.
1999, 9, 1263. (b) Dinsmore, C. J. Curr. Opin. Oncol. Endocr.
Metab. Invest. Drugs 2000, 2, 26. (c) Bell, I. M. Expert Opin.
Ther. Pat. 2000, 10, 1813.
5. (a) Williams, T. M.; Bergman, J. M.; Brashear, K.; Breslin,
M. J.; Dinsmore, C. J.; Hutchinson, J. H.; MacTough, S. C.;
Stump, C. A.; Wei, D. D.; Zartman, C. B.; Bogusky, M. J.;
Culberson, J. C.; Buser-Doepner, C.; Davide, J.; Greenberg,
I. B.; Hamilton, K. A.; Koblan, K. S.; Kohl, N. E.; Liu, D.;
Lobell, R. B.; Mosser, S. D.; O’Neill, T. J.; Rands, E.; Scha-
ber, M. D.; Wilson, F.; Senderak, E.; Motzel, S. L.; Gibbs,
J. B.; Graham, S. L.; Heimbrook, D. C.; Hartman, G. D.;
Oliff, A. I.; Huff, J. R. J. Med. Chem. 1999, 42, 3779. (b)
Dinsmore, C. J.; Bogusky, M. J.; Culberson, J. C.; Bergman,
J. M.; Homnick, C. F.; Zartman, C. B.; Mosser, S. D.; Scha-
ber, M. D.; Robinson, R. G.; Koblan, K. S.; Huber, H. E.;
Graham, S. L.; Hartman, G. D.; Huff, J. R.; Williams, T. M.
J. Am. Chem. Soc. 2001, 123, 2107. (c) Bell, I. M.; Beese, L. S.;
Beshore, D. C.; Bogusky, M. J.; Buser-Doepner, C.; Culber-
son, J. C.; Gallicchio, S. N.; Gibbs, J. B.; Graham, S. L.;
Hartman, G. D.; Heimbrook, D. C.; Huber, H. E.; Kassahun,
K.; Koblan, K. S.; Kohl, N. E.; Lobell, R. B.; Rodrigues, D.
A.; Taylor, J. S.; Williams, T. M. Enzyme Mechanisms 17th
Conference, Marco Island, FL, Jan 3–7, 2001. (d) Dinsmore,
C. J.; Bergman, J. M.; Bogusky, M. J.; Culberson, J. C.;
Hamilton, K. A.; Graham, S. L. Org. Lett. 2001, 3, 865.
6. The (S) enantiomers of compounds 7, 8, 12, 13, 15, 16, 19,
and 20 fell within this range (data not shown).
7. (a) Graham, S. L.; deSolms, S. J.; Giuliani, E. A.; Kohl,
N. E.; Mosser, S. D.; Oliff, A. I.; Pompliano, D. L.; Rands, E.;
Breslin, M. J.; Deanna, A. A.; Garsky, V. M.; Scholz, T. H.;
Gibbs, J. B.; Smith, R. L. J. Med. Chem. 1994, 37, 725. (b)
Lobell, R.; Gibson, R.; Davide, J.; Kohl, N.; Burns, D.
Manuscript in preparation. To assess the potency of the FTIs
in cells, we utilized a competitive binding assay to determine
the concentration of the FTI required to displace 50% of a
radiolabeled FTI from FPTase in cultured v-Ha-ras trans-
formed RAT1 cells. This radiotracer, [125I] 4-{[5-({(2S)-4-(3-
iodophenyl)-2-[2-(methylsulfonyl)ethyl]-5-oxopiperazin-1-yl}-
methyl)-1H-imidazol-1yl]methyl} benzonitrile, has ꢂ50,000
Figure 2. Top: Overlay of calculated lowest energy conformations of 6
(pink) and 19 (green). Bottom: Overlay of 6 (pink, 5.7 kcal/mol relative
to lowest energy conformation) and 19 (green, 11.5 kcal/mol relative to
lowest energy conformation) with the lowest calculated energy con-
formation of 1 (see ref 10).