Penam 6-hydroxy

A number of differently-substituted penam derivatives (79f,g) have been obtained as intermediates in the total syntheses developed mainly by the Woodward-Heusler and Sheehan groups, but no exact biological data are known. For the corresponding hydroxy penams and cephems, see [55] and [142]. The 3-hydroxypenam is in equilibrium with the open form ((81) (82)), but its methyl ether (83) and acetyl derivative (84) can be prepared pure. It is most surprising that the derivative (85) possesses an appreciable biological effect MIC values, S. aureus 6.3 jug/ml, Strept. 

Mention has already been made of attempts to obtain 2-hydroxy- and 3-hydroxypenams (compounds 301 and 303), from which penems might have been generated by loss of the elements of water. The reductive elimination performed on the 2,3-diphenylthiopenam 316 by Kametani [182], and the oxidative elimination accomplished by Hanessian on the 2-methylthio compound 298 [29], are successful examples of penem synthesis achieved from isolated penam intermediates. Other examples of this strategy involve Pummerer-type rearrangements. The preparation of penem 306 by treatment of penam sulfoxide... 

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