FACILE SYNTHESES OF PSEUDO-ALPHA-D-ARABINOFURANOSE, AND 2 PSEUDO-D-ARABINOFURANOSYLNUCLEOSIDES, (-CYCLARADINE AND (+)-1-PSEUDO-BETA-D-ARABINOFURANOSYLURACIL, FROM D-ARABINOSE())

An optically active pseudo-sugar, pseudo-alpha-D-arabinofuranose, was efficiently synthesized from D-arabinose by using a stereoselective ni tromethane addition reaction to form a branched nitropyranose (6) as a key step. Furthermore, two biologically active pseudo-beta-D-arabinof uranosylnucleosides, (+)-cyclaradine and (+)-1-pseudo-beta-D-arabinofu ranosyluracil, were also synthesized from the nitrocyclopentene deriva tive (12), which was prepared from a synthetic intermediate of pseudo- arabinofuranose, via Michael-type reaction introducing nucleic acid ba se moieties.