Synthesis of derivatives of 2,3-diamino-2,3-dideoxy-D-galactose

Abstract

The rearrangement which took place in the preparation of 2 is known."6The dibromide 2, on treatment with triethyl phosphite, gave the phosphonate 3 in 70% yield based on the Czcr diol. Selective reduction of 3 with Lindlar catalyst' resulted in retinyl phosphonate (4). The nmr spectra and the analytical data of 2 4 were compatible with the assigned structures.The phosphonate 4 and vitamin A aldehyde 5 were stirred with sodium methoxide in pyridine at 0 ' to yield 0-carotene. The reduction of an ethynyl function with Lindlar catalyst leads to the cis configuration.

Di-O-bromoethylidene-D-mannitol formation

“…On dissolving D-mannitol and bromoacetaldehyde diethyl acetal (BEA) in [3][4][5][6][7][8][9][10][11][12] N hydrochloric (or sulfuric) acid, exploratory investigations established that a mono-O-bromoethylidene-D-mannitol formed rapidly.…”

“…The esters differed strongly in their rotations and melting points, and the ester arising from the yellow isomer formed yellow crystals, too, whereas the other ester was colorless like its acid. It will be shown that the colorless acid was methyl 4,6-O-benzylidene-2-(2-carboxyanilino)-2,3-dideoxy-3-nitro-|3-D-glucopyranoside (2) and that the yellow acid was methyl 4,6-0-benzylidene-2-(2-carboxyanilino)-2,3-dideoxy-3-nitro-0-D-mannopyranoside (9).…”

“…However, either ester was obtained from its parent acid with diazomethane. The crystalline d-manno acid (9) and ester (10) are yellow, but are colorless in solution. Compound 2 was converted by several steps into methyl 2,3-diacetamido-2,3-dideoxy-/3-n-glucopyranoside (8), and compound 9 was similarly converted into new, 0-glycosidic derivatives of 2,3-diamino-2,3-dideoxy-D-mannose and finally into the reducing diamino sugar dihydrochloride (14).…”