| 摘要 |
<p>An improved process is provided herein for producing a compound of the formula I I 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 a salt thereof in case R2 is a carboxy group or R2 contains a basic or acidic group, the compounds of formula I, depending upon the meanings of R1 and R2, being of value at .beta.-lactamase inhibitors and/or antibiotics, and/or as intermediates in the production of antibiotics and/or .beta.-lactamase inhibitors. According to the improved process, certain penicillanic acid derivatives or their sulfoxides are oxidized to the corresponding sulphones with hydrogen peroxide in the presence of a tungsten or molybdenum catalyst. This new 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.</p> |
