The reaction of 4-[((p-nitrobenzoyl)oxy)methyl]-3-cephem derivative 4 with bromine in methanol afforded a mixture of the 3-bromo-4-methoxy adducts 5 and 6 and of the unexpected 4-spiro orthoesters 7 and 8. The structure and configuration of 7 and 8 were demonstrated through the determination of the solid-state structure of 7 and by 1H and 13C NMR studies and chemical transformations. The mechanism and the stereochemical outcome of the reaction are discussed.
Uncommon formation of spiro orthoesters in the bromomethoxylation reaction of a 4-[(aroyloxy)methyl]-3-cephem derivative
LAPUCCI, ANNALINA;NENCETTI, SUSANNA;ROSSELLO, ARMANDO;
1991-01-01
Abstract
The reaction of 4-[((p-nitrobenzoyl)oxy)methyl]-3-cephem derivative 4 with bromine in methanol afforded a mixture of the 3-bromo-4-methoxy adducts 5 and 6 and of the unexpected 4-spiro orthoesters 7 and 8. The structure and configuration of 7 and 8 were demonstrated through the determination of the solid-state structure of 7 and by 1H and 13C NMR studies and chemical transformations. The mechanism and the stereochemical outcome of the reaction are discussed.File in questo prodotto:
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