Hydrochloric Acid → (S)-[1-[[[[4-[[1,4-Dihydro-4-oxo-5-(phenylmethoxy)-1-(phenylmethyl)-2-pyridinyl]methyl]-2,3-dioxo-1-piperazinyl]sulfonyl]amino]carbonyl]-2-oxo-3-azetidinyl]carbamic acid, phenylmethyl ester

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Reaction Steps

To a solution of (S)-3-[[(phenylmethoxy)carbonyl]amino]-2-azetidinone (0.44 g, 2.0 mmol) in 25 ml of dry ethyl acetate was added 0.28 g (2.0 mmol) of chlorosulfonyl isocyanate and the solution was stirred for 30 minutes at room temperature. To this were added 12 ml of dichloromethane, 0.61 g (6 mmol) of triethylamine and a prestirred (three hours) mixture of 1-[[1,4-dihydro-4-oxo-5-(phenylmethoxy)-1-(phenylmethyl)-2-pyridinyl]methyl]-2,3-piperazinedione (0.83 g, 2.0 mmol) and N-methyl-N-(trimethylsilyl)trifluoroacetamide (1.59 g, 8.0 mmol) in 25 ml of dry ethyl acetate. After stirring for three days at room temperature, ice water was added and the pH was adjusted to one with hydrochloric acid. The insoluble residue was filtered off and dried in vacuo yielding 1.15 g of the title compound of 72% purity.

Provenance & Evidence