New beta-lactam antibiotics, carpetimycins C and D

Two new carbapenem antibiotics, carpetimycins C and D have been isolated from the culture broth of Streptomyces sp. KC-6643, which produced carpetimycins A and B. The structures of carpetimycins C and D have been determined to be (5R,6R)-3-[2-acetamidoethyl-(R)-sulfinyl]-6-(1-hydroxy-1-methylethyl) -7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid and (5R,6R)-3-[2-acetamidoethyl-(R)-sulfinyl]-6-(1-hydroxysulfonyloxy-1 -methylethyl)-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid, respectively. Studies on the fermentation, isolation and physico-chemical properties of these antibiotics are also described.