| 摘要 |
<p>Cephalosporins(I; R1 = H, lower alkyl; R2 = H, OH; R3 = OH, lower alkanoyloxy; R4 = H, methoxy; R5 = acetoxy, -S-R6; R6 = 5 membered heterocycles; Y = H, protecting group) were prepd. by the reaction of II and III(X2 = halogen). Thus, 1 mole 7-[D(-)-α-phenylacetamido -3-(5-methyl-1,3,4-tri azol-2-ylthiomethyl)-3-cephem-4-carboxylic acid and 1.2 mole N-methylisocyanate were reacted gave 7-[D(-)-α-(3-methyl-1-ureido)-α-phenylacetamido)-3-(5-methyl-1,3,4-thiadiazol-2-yl-thiomethyl)-3-cephem-4-carboxylic acid(IV). 4 g IV and 1.9 g 3,4-diacetoxybenzoyl chloride were reacted in 80 ml dichloromethane for 5 hr to give I.</p> |
