ACS Medicinal Chemistry Letters
Page 6 of 8
a The HCV replicon data is run in triplicate and the inter well variability must be less then +/ꢀ 0.5 delta Ct; NA: Not Available
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Despite the fact that base modifications are often not accepted by polyꢀ
merases and can lead to undesired toxicity, we identified several substituꢀ
tions to the purine base that allow their NTP to be recognized by HCV
polymerase. Thus, we discovered phosphoramidates 32, 33, 36, 37, 38, 45,
40, 44 and 43 which displayed EC50 values in the low micromolar range
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against HCV without apparent toxicity in Huh7, PBM, CEM and Vero
cells up to 100 ꢀM. Phosphoramidate 43 (2ꢀF, 6ꢀNH2), one of the most
potent compounds, was further characterized. Interestingly, we found that
43, unlike its corresponding nucleoside 28, produced high levels of 28ꢀTP
in Huh7 cells. The 28ꢀTP was shown to be a substrate of HCV NS5B
polymerase and was incorporated as an adenosine analog. Further preclinꢀ
ical profiling of compound 43 and exploration of its prodrug portion is in
progress. We thus envisage comparing this compound or a related prodrug
to Sofosbuvir, INXꢀ189 and IDXꢀ184 in different cellular and animal
assays and evaluate the potential therapeutic benefit of such 2ꢀposition
modification in purine nucleosides and nucleotides.
Sofia, M. J.; Bao, D.; Chang, W.; Du, J.; Nagarathnam, D.; Rachakonda,
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S.; Reddy, P. G.; Ross, B. S.; Wang, P.; Zhang, H.ꢀR; Bansal, S.; Espiritu,
C.; Keilman, M.; Lam, A. M.; Micolochick Steuer, H. M.; Niu, C.; Otto,
M. J.; Furman, P. A. Discovery of a βꢀDꢀ2'ꢀdeoxyꢀ2'ꢀαꢀfluoroꢀ2'ꢀβꢀCꢀ
methyluridine nucleotide prodrug (PSIꢀ7977) for the treatment of hepatitis
C virus. J. Med. Chem. 2010, 53, 7202ꢀ7218.
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For a review of NS5B antiꢀHCV agents, see: Sofia, M. J.; Chang, W.;
Furman, P. A.; Mosley, R. T.; Ross, B. S. Nucleoside, nucleotide, and
nonꢀnucleoside inhibitors of hepatitis C virus NS5B RNAꢀdependent
RNAꢀpolymerase. J. Med. Chem. 2012, 55, 2481ꢀ2531.
6 Eldrup, A. B.; Allerson, C. R.; Bennett, C. F.; Bera, S.; Bhat, B.; Bhat,
N.; Bosserman, M. R.; Brooks, J.; Burlein, C.; Carroll, S. S.; Cook, P. D.;
Getty, K. L.; MacCoss, M.; McMasters, D. R.; Olsen, D. B.; Prakash, T.
P.; Prhavc, M.; Song, Q.; Tomassini, J. E.; Xia, J. Structureꢀactivity relaꢀ
tionship of purine ribonucleosides for inhibition of hepatitis C virus RNAꢀ
dependent RNA polymerase J. Med. Chem. 2004, 47, 2283ꢀ2294.
ASSOCIATED CONTENT
Supporting Information
Biological assays and complete experimental section with full
characterization of all new compounds is available free of charge via the
.
7 Xu, Y.; Ikeda, R.; Sugiyama, H. 8ꢀMethylguanosine: a powerful ZꢀDNA
stabilizer. J. Am. Chem. Soc. 2003, 125, 13519ꢀ13524.
AUTHOR INFORMATION
Corresponding Author
.
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Schaeffer, H. J. US Pat. 1980, 19804199574, 18 pp
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Lioux, T.; Gosselin, G.; Mathé, C. Azido/tetrazole tautomerism in 2ꢀ
azidoadenine βꢀDꢀpentofuranonucleoside derivatives. Eur. J. Org. Chem.
2003, 20, 3997ꢀ4002.
Funding Sources
This work was supported in part by NIH grant 5P30ꢀAIꢀ50409 (CFAR)
and by the Department of Veterans Affairs.
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Sodum, R. S.; Fiala, E. S. N2ꢀamination of guanine to 2ꢀ
hydrazinohypoxanthine, a novel in vivo nucleic acid modification proꢀ
duced by the hepatocarcinogen 2ꢀnitropropane. Chem. Res. Toxicol. 1998,
11, 1453ꢀ1459.
ACKNOWLEDGMENT
(Dr. Schinazi is the Chairman and a major shareholder of CoCrystal
Pharma, Inc. Emory received no funding from CoCrystal Pharma, Inc. to
perform this work and vice versa.
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Elzein, E.; Kalla, R.; Li, X.ꢀF.; Perry, T.; Marquart, T.; Micklatcher,
M.; Li, Y.; Wu, Y.ꢀZ.; Zeng, D.; Zablocki, J. N6ꢀCycloalkylꢀ2ꢀsubstituted
adenosine derivatives as selective, high affinity adenosine A1 receptor
agonists. Bioorg. Med. Chem. Lett. 2007, 17, 161ꢀ166.
ABBREVIATIONS
RNA, ribo nucleic acid; HCV, hepatitis C; FDA, Food and Drug Adminꢀ
istration; DBU, 1,8ꢀdiazabicyclo[5.4.0]undecꢀ7ꢀene; TMSOTf, trimeꢀ
thylsilyl trifluoromethanesulfonate; Boc, tertꢀButyloxycarbonyl; CBz,
benzyloxy carbamate; TFA, trifluoroacetic acid; TMSI, trimethylsilyl
iodide; HOAc, acetic acid; NMI, 1ꢀmethylimidazole; LC, liquid chromaꢀ
tography; MS, mass spectrometry; NTP, nucleoside triphosphate; NMP,
nucleoside monophosphate; NDP, nucleoside diphosphate; TP, triphosꢀ
phate.
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Pradere, U.; GarnierꢀAmblard, E. C.; Coats, S. J.; Amblard, F.; Schinaꢀ
zi, R. F. Synthesis of nucleoside phosphate and phosphonate prodrugs,
Chem. Rev., 2014, 114, 9154ꢀ9218.
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McGuigan, C.; Ranjith, J.; Pathirana, N.; Balzarini, J.; De Clercq, E.
Intracellular delivery of bioactive AZT nucleotides by aryl phosphate
derivatives of AZT. J. Med. Chem. 1993, 36, 1048ꢀ1052.
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