Preparation of methyl 4,6-O-benzylidene-2,3-dideoxy-2,3-dinitro-α-D-glucopyranoside and its selective conversion into the corresponding 2-nitro-2-enopyranoside
Abstract Treatment of methyl 4,6- O -benzylidene-2,3-dideoxy-3-nitro-α- D - erythro -hex-2-enopyranoside ( 3 ) with sodiumnitrite in benzene-water in the presence of small amounts of tributylhexadecylphosphonium bromide as a phase-transfer catalyst afforded the 2-nitro alkene 4 in 47% yield. A similar reaction in the presence of 1.3 equiv. of acetic acid gave the 2,3-dinitro derivative 5 in 58% yield;