Studies on enolization of aldehydo-aldose derivatives

Abstract

Acetylation of the 2,3- O-isopropylidene derivative ( 1) of d-glyceraldehyde with hot acetic anhydride in the presence of sodium acetate give a mixture of ( Z)- and ( E)-enol acetates ( 2 and 3), together with the acetylated racemic aldehydrol ( 4) of 1. Likewise, the acyclic aldehydo 2,3:4,5-diisopropylidene acetals of d- and l-arabinose, d-xylose, and d-ribose underwent conversion into enol acetates, with the ( Z) isomers preponderating, and convertible photochemically into the corresponding ( E) isomers. Under other conditions of acetylation, the aldehydo derivatives were converted into the corresponding aldehydrol diacetates.