SYNTHESIS OF (6R,7R,8S,8AR)-6,7,8-TRIHYDROXYPERHYDRO[1,3]THIAZOLO[3,2-A]PYRIDINE AND ITS 8AS-EPIMER - NOVEL, BIOLOGICALLY-ACTIVE ANALOGS OF CASTANOSPERMINE

Concise syntheses of the title compounds 4a and 4b have been achieved from D-(-)-arabinose. In the first route the dithioacetal 9 was converted via the tosylate 10 to the hemiacetal 11 which was reacted with amino-ethanethiol.HCl to give a mixture of compounds 4. Alternatively, the thiazolidines 6 were cyclized (using Ph3P, CCl4, Et3N) to give 4a,b in a two-step approach without recourse to protecting groups. Castanospermine analogs 4 show in vitro activity against HIV at muM concentrations.