| 摘要 |
Compounds of the formula I <IMAGE> in which R1 stands for hydrogen, alkyl, alkoxy, halogen, or trifluoromethyl, and R2 stands for a carboxy group or for a protected carboxy group, in particular an esterified carboxy group; or, if appropriate, a salt thereof, are obtained by oxidising the corresponding penicillanic acid derivatives or their sulfoxides with hydrogen peroxide in the presence of a tungsten or molybdenum catalyst. This process eliminates secondary degradative oxidative side reactions and simplifies the isolation and purification of the product, thus providing high yields and thereby being particularly suited for large scale production. The compounds of formula I, depending upon the meanings of R1 and R2, are of value as beta -lactamase inhibitors and/or antibiotics, and/or as intermediates in the production of antibiotics and/or beta -lactamase inhibitors. |
