反应详情

The 2'-deoxyerythropentofuranosyl, the xylofuranosyl and the arabinofuranosyl analogs of compound 7 can be prepared in a manner similar to that described for compound 7 (scheme VI). Thus reacting 4 with 1-chloro-2-deoxy-3,5-di-O-(p-toluoyl)-α-D-erythropentofuranose followed by deblocking yields 5-amino-3-(2-deoxy-β-D-erythropentofuranosyl)thiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione (36). Likewise after deblocking of the respective intermediates, 4 and 1,2,3,5-tetra-O-acetyl-D-xylofuranose will yield 5-amino-3-(β-D-xylofuranosyl)thiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione (38) and 4 and 1-chloro-2,3,5-tri-O-benzyl-α-D-arabinofuranose will yield 5-amino-3-(β-D-arabinofuranosyl)thiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione (40). The tri-O-acetyl (40) prodrug form of compound 7 is prepared from 4 and 1,2,3,5-tetra-O-acetyl-D-ribofuranose and the 2,3-di-O-isopropylidene derivative (42) is prepared directly from 7 (scheme VI).