Synthesis of N-acetylneuraminic acid 8-methyl ether

Abstract N -Acetylneuraminic acid 8-methyl ether ( 1 ) has been synthesized. Benzylation of 2-methyl-4,5-(4,6- O -benzylidene-2-deoxy-β- d -mannopyrano)-2-oxazoline ( 2 ), followed by mild, acid hydrolysis, yielded 2-acetamido-3- O -benzyl-4,6- O -benzylidene-2-deoxy- d -mannopyranose ( 3 ). Treatment of 3 with the potassium salt of di- tert -butyl oxaloacetate gave 6- O -benzyl-7,9- O -benzylidene- N -acetylneuraminic acid γ-lactone ( 4 ). Methylation of 4 , followed by removal of the benzyl and benzylidene groups and opening of the γ-lactone ring, then gave 1 . The inhibition by acid 1 of the hydrolysis of p -nitrophenyl N -acetyl-α- d -neuraminoside by Vibrio cholerae neuraminidase has been investigated.