2-Acetamido-2-deoxy-D-mannono-1,5-lactone: Synthesis and Inhibition of 2-Acetamido-2-deoxy-'B-D-glucosidase

Sa？etak 2-Acetamido-2-deoxy-n-mannono-1,5-lactone (I) was prepared by mild hydrolysis of 2-acetamido-2-deoxy-4,6-0-isopropylidene- n-mannono-1,5-lactone (IV). The inhibitory activity of I and of the isomeric 1,4-lactone II, as well as of 2-acetamido-2-deoxy-n-mannonic acid (III), was assayed against 2-acetamido-2-deoxy-B-n-glucosidase from bull· epididymis. The free acid III exhibits no inhibitory activity. The two lactones act as competitive inhibitors against p-nitrophenyl 2-acetamido- 2-deoxy-B-n-glucopyranoside (inhibition constants Ki 33 · ~Lmol/dm3 and 8.3 mmol/dm3 for I and II, respectively), whereas against p-nitrophenyl 2-acetamido-2-deoxy-B-D-galactopyranoside only lactone I exhibits weak inhibitory activity (Ki, 9.3 mmol/dm3)