The total syntheses of the (+/-)-1-carba analogues of cefoxitin (11), 7 alpha-methoxydeacetylcephalothin (5) and cefamandole (31) and the (+/-)-1-oxa analogue of cefamandole (43) are described. Their bioactivity spectra against 14 typical organisms are similar to those of their natural 1-thia counterparts, with the 1-carba compounds somewhat less active and the 1-oxa compound more active than the natural ones.
Addition of tris(dipivalomethanate)europium(III) resulted in chemical shifts which revealed the characteristic coupling pattern for the -pyrone protons: -H, d,
The total synthesis of di-3-phenyl-, 3-p-carbomethoxyphenyl-, and 3-(4-thiazolyl)-7/3-(2-thienyl)acetamidodecephalosporanic acids 12a-c is described.Cephalosporins 1 are a class of semisynthetic antibiotics that are being increasingly used because of their breadth of spectrum, potency, acid stability, and high degree of tolerance by man. In recent years an intensive worldwide effort has been made to obtain modified cephalosporins with improved properties.2 Variations at the 3 position have been
Aus der bekannten Thioformyl‐Verbindung (‐I) entstehen mit den Chlorketonen (II) die S‐Arylacylverbindungen (III), die durch NaH zu (IV) cyclisiert werden.
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