Studies related to penicillins. Part VII. The structure of the epimers derived from 6β-substituted penicillanic acids
- 1 January 1972
- journal article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- Vol. 6, 895-899
- https://doi.org/10.1039/p19720000895
Abstract
Methoxymethyl 6β-(2-hydroxy-1-naphthylmethyleneamino)penicillanate (6) is equilibrated with an epimer when treated with 1,5-diazabicyclo[4,3,0]non-5-ene in dichloromethane. Acidic hydrolysis of the epimer yields methoxymethyl 6-aminopenicillanate, which reacts with N-ethoxycarbonylphthalimide to give methoxymethyl 6-phthalimidopenicillanate. This last substance is identical with the epimer derived from the base-catalysed isomerisation of methoxymethyl 6β-phthalimidopenicillanate (2). Methoxymethyl 6β-aminopenicilanate (7) and its epimer react with sodium nitrite and dilute hydrochloric acid to give methoxymethyl 6α-chloropenicillanate (17). The epimers, therefore, possess the R-stereochemistry at position 5 and they are 6α-substituted penicillanic acid derivatives. Methoxymethyl 6-diazopenicillanate is implicated in the deamination of both amines.Keywords
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