Abstract
The Sowden's synthetic procedure of D-mannosamine hydrochloride was simplified, and modified in order to prepare N-acetyl-D-mannosamine. By the action of ammonia on 1-nitro-1-deoxy-D-mannitol pentaacetate (I), I was directly transformed in a yield of 70.5% to 1-nitro-2-acetamido-1, 2-dideoxy-D-mannitol (III) without isolating the intermediate, D-arabino-1-nitro-tetraacetoxy-1-hexene (II). 1-Nitro-2-acetamido-1, 2-dideoxy-D-glucitol (IV) was produced as a by-product in a yield of 8.3%. The barium salt of aciform of III was decomposed with sulfuric acid in the cold in order to prevent hydrolysis of the N-acetyl group and facilitate separation of the product from the inorganic salt. The yield of N-acetyl-D-mannosamine was 66.3%. An unfractionated mixture of the two epimeric D-arabino-1-nitro-1-deoxy-hexitols which had been obtained from D-arabinose was acetylated and transformed to III in a yield of 26.5% from D-arabinose. III and IV exhibited a negative and a positive Cotton effect respectively in their optical rotatory dispersion curves.
