Synthesis and X-ray structural investigation of (5R*,6S*)-1-benzoyl-5-methylthio-6-methoxy-1-azapenam

Abstract The compound (5R*,6S*)-1-benzoyl-5-methylthio-6-methoxy-1-azapenam ( 3 ) has been synthesized and its structure investigated by X-ray diffraction. The compound crystallizes in a monoclinic system, space group Cc, Z = 4, a = 12.01(1), b = 16.51(1), c = 8.048(6) A, β = 115.87(6)°. The structure was solved by direct methods and refined by a full-matrix, least-squares procedure to give R = 0.070, R w = 0.046, w = 1.34/(σ 2 F ). The expected cis configuration around the β-lactam ring was fully confirmed.