Synthesis and antiviral evaluation of 2′,3′-dideoxy-2′ -fluoro-3′-C-hydroxymethyl-β-D-arabinofuranosyl pyrimidine nucleosides

Article abstract of DOI:10.1081/NCN-120022679

The synthesis and anti-HBV and anti-HIV activity of a number of 2′,3′-dideoxy-2′-fluoro-3′-C-hydroxymethyl-β -D-arabinofuranosyl pyrimidine nucleosides are reported.

Full text of DOI:10.1081/NCN-120022679

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Synthesis and Antiviral Evaluation of 2′,3′-Dideoxy-2′-
fluoro-3′-C-hydroxymethyl-β-D-arabinofuranosyl
Pyrimidine Nucleosides
Abdalla E. A. Hassan a c , Balakrina S. Pai b , Stefania Lostia a , Lieven Stuyver a , Michael J.
Otto a , Raymond F. Schinazi b & Kyoichi A. Watanabe a
a Pharmasset Inc. , Tucker, Georgia, USA
b Emory University School of Medicine/Veterans Affairs Medical Center , Decatur, Georgia,
USA
c Pharmasset Inc. , 1860 Montreal Road, Tucker, GA, 30084, USA
Published online: 31 Aug 2006.
To cite this article: Abdalla E. A. Hassan , Balakrina S. Pai , Stefania Lostia , Lieven Stuyver , Michael J. Otto , Raymond F.
Schinazi & Kyoichi A. Watanabe (2003) Synthesis and Antiviral Evaluation of 2′,3′-Dideoxy-2′-fluoro-3′-C-hydroxymethyl-β-
D-arabinofuranosyl Pyrimidine Nucleosides, Nucleosides, Nucleotides and Nucleic Acids, 22:5-8, 891-894, DOI: 10.1081/
NCN-120022679
To link to this article: http://dx.doi.org/10.1081/NCN-120022679
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NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS
Vol. 22, Nos. 5–8, pp. 891–894, 2003
Synthesis and Antiviral Evaluation of 20,30-Dideoxy-20-fluoro-
30-C-hydroxymethyl-b-D-arabinofuranosyl
Pyrimidine Nucleosides
2
1
Abdalla E. A. Hassan,1, Balakrina S. Pai, Stefania Lostia,
Lieven Stuyver,1 Michael J. Otto,1 Raymond F. Schinazi,2
and Kyoichi A. Watanabe1
*
1Pharmasset Inc., Tucker, Georgia, USA
2Emory University School of Medicine=Veterans Affairs Medical Center,
Decatur, Georgia, USA
ABSTRACT
The synthesis and anti-HBV and anti-HIV activity of a number of 20,30-dideoxy-
20-fluoro-30-C-hydroxymethyl-b-d-arabinofuranosyl pyrimidine nucleosides are
reported.
Key Words: Synthesis; Fluorination; Anti-HBV; Anti-HIV.
We have been interested in the synthesis and the biological activity of novel 1-(2-
deoxy-2-fluoro-b-arabino-furanosyl) nucleoside analogues related to D=L FMAU,
FIAU, ara-C and ara-A. L-FMAU is now in phase II clinical trials for the treatment
of chronic hepatitis B virus (HBV) infection.[1] It is now recognized that branched–
chain sugar nucleosides can show biological activity. For instance, 20,30-dideoxy-30-
C-hydroxymethylcytidine (1) a simple 30-homologue of 20-deoxycytidine, has potent
*Correspondence: Abdalla E. A. Hassan, Pharmasset Inc., 1860 Montreal Road, Tucker, GA
30084, USA; Fax: þ1 678 395 0039; E-mail: ahassan@services.pharmasset.com.
891
DOI: 10.1081/NCN-120022679
Copyright # 2003 by Marcel Dekker, Inc.
1525-7770 (Print); 1532-2335 (Online)
www.dekker.com

892
Hassan et al.
Chart 1.
anti-HIV activity (EC50 ¼ 0.01 mM).[2] Both a- and b-isomers of 20,30-dideoxy-30-C-
hydroxy-methylthioguanosine inhibit the growth of WI-L2 human lymphoblastoid
cells.[3] Also, 2,3-dideoxy-nucleosides with 20-fluoro in the b-configuration such as
9-(2,3-dideoxy-2-fluoro-b-d-threo-pentofuranosyl)-adenine (2) showed a potent
anti-HIV activity.[4] Herein, we report on the synthesis and the antiviral activity of
pyrimidine nucleosides 3 that combine both of the 30-deoxy-30-C-hydroxymethyl
and the 20-b-fluorine moieties (Chart 1).
The key glycon intermediate, 3-deoxy-3-C-hydroxymethyl-2-fluoro-arabino-
furanose derivative 9 was synthesized in 5 steps from the known 3-deoxy-3-C-hydro-
xymethyl-d-ribose derivative 4[5] (Sch. 1). Conventional transformations of 4
furnished the b-fluorination precursor 8. Attempts to fluorinate the imidazolyl-
sulfonate derivative 8 under several conditions, however were unsuccessful. Direct
fluorination of 7 using DAST in the presence of pyridine gave the desired compound
Scheme 1. Reagents and conditions: a) n-Bu4NF, THF, 30 min., r.t., 82%; b) BzCl, Pyr., 0ꢀC,
95%; c) i) 20% HCl, MeOH, 30 min, 55ꢀC; ii) BzCl, Et3N, DMAP, CH2Cl2, 86%; d) conc.
H2SO4, Ac2O, AcOH, 0ꢀC-r.t., 3 hr, 77%; e) HCl gas, AcCl, CH2Cl2 then H2O, CH3CN,
46%; f) DAST, Pyr., CH2Cl2, r.t., 20 hr, 78%; g) HBr, AcOH, r.t., 12 hr; h) silylated nucleo-
base, CHCl3, reflux, 20–30 hr; i) NH3, MeOH, then HPLC purification.

Pyrimidine Nucleosides 20,30-Modified
893
9 in good yield. Bromination of 9 with HBr in CH2Cl2, gave a bromo derivative 10,
which was coupled with silylated thymine, cytosine, and 5-fluorocytosine in reflux
CHCl3 to give the protected nucleosides, 11a–c, along with the corresponding a-
anomers (b : a=3-15 : 1). The protected anomers were treated with NH3=MeOH and
the desired b-anomers (3a–c) were purified by HPLC. The newly synthesized nucleo-
sides were evaluated for their anti-HIV in human PBM cells[6] and HBV activity in
primary human lymphocytes (PBMC) and in liver cells (HepG2.2.15[8] and=or
AD38 cells[9]).
Of the synthesized compounds, 5-fluorocytosine derivative 3b showed potent
and selective anti-HBV in HepG2.2.15 cells and HIV activity in PBM (EC50 ¼ 0.13
and 3.3 mM, respectively. Compounds 3a–c did not show cytotoxicity up to
100 mM in PBM, CEM, and Vero cells.
ACKNOWLEDGMENTS
This research is Supported in part by NIH and the Department of Veterans
Affairs.
REFERENCES
1. Chu, C.K.; Ma, T.W.; Shanmuganathan, K.; Wang, C.G.; Xiang, Y.J.; Pai, S.B.;
Yao, G.Q.; Sommadossi, J.-P.; Cheng, Y.-C. Use of 20-fluoro-5-methyl-b-L-
arabinofuranosyluracil as a novel antiviral agent for hepatitis B virus and
Epstein-Barr virus. Antimicrob. Agents Chemother. 1995, 6, 979–981.
2. Svansson, L.; Kvarnstrom, I.; Classon, B.; Samuelsson, B. Synthesis of 20,30-
dideoxy-30-C-hydroxymethyl nucleosides as potential inhibitors of HIV.
J. Org. Chem. 1991, 56, 2993–2995.
3. Acton, E.M.; Goerner, R.N.; Uh, H.S.; Ryan, K.J.; Herny, D.W. Improved
antitumor effects in 30-branched homologs of 20-deoxythioguanine. Synthesis
and evaluation of thioguanine nucleosides of 2,3-dideoxy-3-(hydroxymethyl)-
D-erythro-pentofuranose. J. Med. Chem. 1979, 22, 518–525.
4. Marquez, V.E.; Tseng, C.K.-H.; Kelley, J.A.; Mitsuya, H.; Brtoder, S; Roth,
J.S.; Drosicoll, J.S. 20,30-Dideoxy-20-fluoro-ara-A an acid-stable purine nucleo-
side active against human immunodeficiency virus (HIV). Biochem. Pharmacol.
1987, 36, 2719.
5. Lin, T-S.; Zhu, J-L; Dustschman, G.E.; Cheng, Y-C.; Prusoff, W.H. Syntheses
and biological evaluations of 30-deoxy-30-C-branched-chain-substituted nucleo-
sides. J. Med. Chem. 1993, 36, 353–362.
6. Schinazi, R.F.; Sommadossi, J.P.; Saalmann, V.; Cannon, D.L.; Xie, M.-Y.;
Hart, G.C.; Smith, G.A.; Hahn, E.F. Activities of 30-azido-30-deoxythymidine
nucleotide dimers in primary lymphocytes infected with human immunodefi-
ciency virus type 1. Antimicrob. Agents Chemother. 1990, 34, 1061–1067.
7. Ladner, S.K.; Otto, M.J.; Barker, C.S.; Zaifert, K.; Wang, G.H.; Guo, J.T.;
Seeger, C.; King, R.W. Inducible expression of human hepatitis B virus

894
Hassan et al.
(HBV) in stably transfected hepatoblastoma cells: a novel system for screening
potential inhibitors of HBV replication. Antimicrob. Agents Chemother. 1997,
41, 1715–1720.
8. Pai, B.S.; Lui, S.H.; Zhu, Y.L.; Chu, K.C.; Cheng, Y.C. Inhibition of hepatitis B
virus by a novel L-nucleoside, 20-fluoro-5-methyl-b-L-arabinofuranosyl uracil.
Antimicrob. Agents Chemother. 1996, 40, 380–386.
9. Stuyver, L.J; Lostia, S.; Adams, M.; Mathew, J.S.; Pai, B.S.; Grier, J.; Tharnish,
P.M.; Choi, Y.; Chong, Y.; Choo, H.; Chu, K.C.; Otto, M.J.; Schinazi, R.F.
Antiviral activity and cellular toxicity of modified 20,30-dideoxy-20,30-didehy-
drocytidine analogues. Antimicrob. Agents Chemother. 2002, 46, 3854–3860.