The azetidinone disulphide (1b), a structural analogue of Kamiya's disulphide (1a), has been synthesized. Some cyclization reactions of the disulphides (1) (Br2 in CH2Cl2 and AcOAg in ClCH2CO2H-CH2Cl2) leading to penam and cepham derivatives through episulphonium ions (2), have been studied. The data obtained show that changing the substituent X in (1a) and (1b) brings about changes in the distribution of the positive charge in the intermediate episulphonium ions (2a) and (2b), and thus affects to some extent the regioselectivity of the episulphonium ring opening and the chemical behaviour of (1a) and (1b).
Importance of the C(3) substituent of the penam derivative in interconversion reactions of penam and cepham systems
ROSSELLO, ARMANDO
1984-01-01
Abstract
The azetidinone disulphide (1b), a structural analogue of Kamiya's disulphide (1a), has been synthesized. Some cyclization reactions of the disulphides (1) (Br2 in CH2Cl2 and AcOAg in ClCH2CO2H-CH2Cl2) leading to penam and cepham derivatives through episulphonium ions (2), have been studied. The data obtained show that changing the substituent X in (1a) and (1b) brings about changes in the distribution of the positive charge in the intermediate episulphonium ions (2a) and (2b), and thus affects to some extent the regioselectivity of the episulphonium ring opening and the chemical behaviour of (1a) and (1b).File in questo prodotto:
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