The Synthesis of the d-Manno Analogue of Muramic Acid, 2-Amino-3-O-(d-1-carboxyethyl)-2-deoxy-d-mannose

The synthesis of the d-manno analogue of muramic acid, 2-amino-3-O-(d-1-carboxyethyl)-2-deoxy-d-mannose, was started from methyl 2-acetamido-4,6-O-benzylidene-3-O-(methylsulfonyl)-α-d-altropyranoside, which was transformed into methyl 2-acetamido-4,6-O-benzylidene-2-deoxy-α-d-mannopyranoside. After condensation with l-2-chloropropionic acid and removal of the protective benzylidene group, hydrolysis gave the title compound in amorphous form. The N-acetyl derivative, also amorphous, could be easily identified from the d-gluco and d-galacto analogues by gas-liquid chromatography of the per(trimethylsilyl) derivatives of the N-acetyl derivatives. Separation of the d-gluco and d-manno analogues was also accomplished on the per-(trimethylsilyl) derivatives of the methyl N-acetyl-α-d-glycoside, methyl esters, and amides.