Patent ID: 7582748

Claim:
A process for the preparation of β-L-2′-deoxythymidine comprising the steps of: (a) reacting a L-2-deoxyribose with an alcohol to form a L-1-O-alkyl-2-deoxyribose; (b) protecting the remaining free hydroxyls of the L-1-O-alkyl-2-deoxyribose to form protected L-1-O-alkyl-2-deoxyribose; (c) reacting the protected L-1-O-alkyl-2-deoxyribose with an anhydrous acid halide to form a protected L-1-halo-2-deoxyribose, wherein the anhydrous acid halide is produced in situ by the reaction of an acyl halide with a sub-equivalent amount of a second alcohol; (d) coupling the protected L-1-halo-2-deoxyribose with silylated thymine in chloroform to form a protected β-L-2′-deoxythymidine and a protected α-L-2′-deoxythymidine, wherein the ratio of the silylated thymine to the protected L-1-halo-2-deoxyribose is at least 1:1 and wherein the ratio of the protected β-L-2′-deoxythymidine to the protected α-L-2′-deoxythymidine is greater than about 10:1; and then (e) deprotecting the protected β-L-2′-deoxythymidine to obtain a β-L-2′-deoxythymidine.