| 摘要 |
The invention relates to compounds of the formula: <IMAGE> wherein R stands for benzyl, phenoxymethyl, 4-amino-4-carboxy-1-butyl, R3O-, R3S-, R3R4N- wherein R3 is loweralkyl, aryl or arylloweralkyl, R4 is hydrogen or R3, and OH when the radicals R3O-, R3S- and R3R4N-are hydrolyzed; R 2 is hydrogen or methoxy, and R1 is hydrogen or a cleavable radical such as -CH2OCH3, loweralkyl, 2,2,2-trichloroethyl, benzyl, p-nitrobenzyl, benzhydryl, phenoxyethyl or trimethylsilyl. The novel compounds are useful intermediates in the preparation of known penicillin and cephalosporin derivatives. |
