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US 5,633,367 AGranted
Process for the preparation of a 2-substituted 3,3-difluorofuran
AssigneeEli Lilly and Company
InventorDouglas P. Kjell
Life of this patent
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Abstract
A process for the preparation of a 2-substituted-3,3-difluorofuran using diethyl ammonium sulfur trifluoride (DAST) and pyridine hydrogen fluoride. The process is particularly useful for producing a 2',2'-difluoronucleoside, particularly 1-(2',2'-difluoro-.beta.-D-arabinofuranosyl)cytosine (also known as 2'-deoxy-2',2'-difluorocytidine), a known antiviral and antitumor agent.
Claims6
A process for the preparation of a 2',2'-difluoronucleoside which comprises:
- reacting a 2-ketonucleoside of the formula ##STR16## with diethylammonium sulfur trifluoride (DAST) in the presence of a catalytic amount of pyridine hydrofluoride and a non-reactive halogenated hydrocarbon solvent at a temperature which produces the 2',2'-difluoronucleoside, wherein x is a non-interfering, non-reactive hydroxy protectinq group selected from the group consisting of acetyl, formyl, 2-chloroacetyl, benzyl, diphenylmethyl, triphenylmethyl, 4-nitrobenzyl, phenoxycarbonyl, t-butyl, methoxymethyl, tetra-hydropyranyl, allyl, tetrahydrothienyl, 2-methoxyethoxymethyl, methoxyacetyl, phenoxyacetyl, isobutyryl, ethoxycarbonyl, end benzyloxycarbonyl, and B is a N-linked nucleobase.
Dependencies are inferred from the claim text.