Patent ID: 6870052

Claim:
A method for producing a compound of the formula 1 wherein each R individually is H, an aliphatic acyl group or an aromatic acyl group; A is selected from the group consisting of wherein X is selected from the group consisting of hydrogen, fluorine, alkoxy, alkyl, haloalkyl, alkenyl, haloalkenyl, alkynyl, amino, monalkylamino, dialkylamino, cyano and nitro; which comprises: A) reacting a 2,3, 5-tri-O-aryl or alkyl-4-xylose diaryl or dialkyl dithioacetal in the presence of a leaving group at the 4 hydroxyl position to produce the corresponding 1,4-dithio-D-arabinofuranoside; B) reacting said arabinofuranoside from step A) to acidolysis to form the corresponding O-acetyl-4-thio-D arabinofuranose; C) reacting said O-acetyl-4-thio-D-arabinofuranose from step B) with a compound selected from the group consisting of a cytosine, a 5-aza compound, a 6-aza compound and blocked derivatives thereof to form the corresponding 4-thio-α,β-Darabinofuranosyl compound; E) separating out the α form of the anomeric mixture of step D) to thereby obtain the compound of formula 1.