6-MERCAPTO AND OTHER SUBSTITUTED DERIVATIVES OF 9-D-ARABINO- AND 9-D-XYLOPYRANOSYLPURINE . SYNTHESIS AND SPECTRAL PROPERTIES

The 6-mercaptopurine nucleosides of α- and β-D-arabinopyranose and β-D-xylopyranose (3a, 3b, and 10b, respectively) and 9-(β-D-xylopyranosyl)thioguanine (18), together with some intermediates and derivatives, have been synthesized and their properties have been studied. The nmr evidence support the 1C conformation for all nucleosides of α-arabinopyranose and the C1 conformation for those of β-xylopyranose. A pronounced shielding effect upon the nmr signals of the acetyl protons is noted in those purine pentopyranosides where both the C-2′ aeetoxy group and the C-1′ purine ring are equatorial. This effect is absent from the corresponding anomers where the purine ring is axial. Some of these pentopyranosyl purines disobeyed Hudson’s isorotation rules. © 1969, American Chemical Society. All rights reserved.