Preparative synthesis of 1-deoxy-D-erythro-2-pentulose and some of its derivatives

Abstract

Methyl 4,6-O-benzylidene-2-deoxy-α-D-erythro-hexopyranosid-3-ulose (1) was converted, by means of lithium hydroxide in a two-phase system, into 3,5-O-benzylidene-1-deoxy-keto-D-erythro-2-pentulose (2) in 55% yield. Compound 2 was further characterized as its (2,4-dinitrophenyl)hydrazone 3, its 4-acetate 4, and the 4-benzoate 5. The configurational assignment for the corresponding pentitol derivatives (6 and 8) of 2 was achieved by 1Hmr analysis of the cyclic carbonates 11 (from 6) and 13 (from 8) and confirmed by comparing the physical constants of the 1-deoxypentitols having the D-ribo (12) and D-arabino (14) configurations with literature data. Hydrolysis of 2 with mild acid afforded the title ketose (9) as a syrup that gave a crystalline (2,4-dinitrophenyl)hydrazone (10), and an acyclic triacetate (15) as an oil. A mechanism for the chain degradation of compound 1 to give 2 is proposed.