Synthesis of anomeric sulfonamides and their behaviour under radical-mediated bromination conditions

O-Peracetylated methyl 3-( d -glycopyranosylthio)propanoates of β- d - gluco , and α- and β- d - galacto configurations were oxidized to the corresponding S,S -dioxides (sulfones) by Oxone ® or MCPBA. Oxidation of the β- d - gluco derivative with H 2 O 2 /Na 2 WO 4 gave the corresponding S -oxide (sulfoxide). DBU-induced elimination of methyl acrylate from the β- d - gluco and β- d - galacto configured S,S -dioxides (sulfones) gave O-peracetylated β- d -glycopyranosyl-1- C -sulfinates which, on treatment with H 2 NOSO 3 H, furnished the corresponding β- d -glycopyranosyl-1- C -sulfonamides. Radical-mediated bromination of the protected methyl 3-(β- d -glycopyranosylthio)propanoate S,S -dioxides gave mixtures of 1- C - and 5- C -bromoglycosyl compounds. Similar brominations of the O-peracetylated β- d -glycopyranosyl-1- C -sulfonamides resulted in the formation of α- d -glycopyranosyl bromides and 1- C - and 5- C -bromoglycosyl sulfonamides. A rationale for these observations was proposed. Methyl 3-(β- d -glucopyranosylthio)propanoate, its S,S -dioxide, and β- d -glucopyranosyl-1- C -sulfonamide proved inefficient when tested as inhibitors of rabbit muscle glycogen phosphorylase b .