Synthesis of 3′-Deoxynucleosides I.: Synthesis of 9-(3-Deoxyaldofuranosyl) Adenines Derived from 3-Deoxy-d-galactose

Abstract

Diacetone glucose was tosylated at the 3-position and the tosyl group eliminated with potassium hydroxide to yield the furanoseen which on reduction gave rise to 1, 2: 5, 6-di- O -isopropylidene-3-deoxy-D-galactofuranose. This was hydrolyzed selectively to the 1,2-monoacetone derivative, which was converted via benzoylation and acetolysis to the 1,2-diacetate, 5,6-dibenzoate. Condensation of this compound with chloromercuri-6-benzamidopurine in the presence of titanium tetrachloride, followed by deblocking with methanolic sodium methoxide, yielded the nucleoside 9-(3-deoxy- β -D-galactofuranosyl) adenine. In a separate procedure, the 1,2- O -isopropylidene-3-deoxy-D-galactofuranose was oxidized with periodate and reduced with borohydride to give 1,2- O -isopropylidene-L-arabinofuranose, convertible to the corresponding adenine-L-arabinofuranoside by procedures similar to those employed for the galacto-derivative.