Synthetic Study of Amino-sugars from Pyridines. IV. Synthesis of 5-Amino-5-deoxypiperidinoses from the Singlet Oxygen Adduct of 1-Acyl-1, 2-dihydropyridines. (1)

1-Methoxycarbonyl-1, 2-dihydropyridine (1a) was reacted with singlet oxygen to afford an unstable endo-peroxide (5), which was reactive enough and produced 6 and 7 by the reaction with thiols. The product (6 or 7) afforded 8 and 9 by the further addition of thiols. Either of 6 or 7 was rearranged to 11 in hot acetic acid or toluene. As shown by the transformation of 9 into 10, the sulfur group adjacent to the nitrogen atom could be converted to the oxygen function, and using this procedure, 5-amino-5-deoxyribose derivative (19) and 5-amino-5-deoxylyxose derivative (20) were synthesized from 17 and 18, which were obtained by the osmium tetroxide oxidation of 6 and 7.