C-2 and C-4 reactions of cephalosporanates and their (S)- and (R)-oxides with toluene-p-sulphonyl azide, acrylonitrile, and ethyl chloroformate

David H Bremner, Malcolm M Campbell

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Abstract

Comparative reactions of cephalosporanates and their (S)- and (R)-oxides were performed. Diazo-exchange leading to 2-diazoceph-3-ems was accomplished only with the (S)-oxide. The 2-diazoceph-3-ems reacted with halogens and pseudohalogens to give 2,2-disubstituted ceph-3-ems. Michael additions with acrylonitrile, were performed, the cephalosporanates giving mainly a 4ß-(2-cyanoethyl)ceph-2-em. The (S)-oxides gave 2a-(2-cyanoethyl)ceph-3-em adducts, whereas the (R)-oxides gave the 4ß-adducts. Ethyl chloroformate reacted in the presence of triethylamine only with the (S)-oxides, giving by a Pummerer rearrangement both 2ß- and 2ß-(ethyl carbonate)s.

Original languageEnglish
Pages (from-to)2298-2308
Number of pages11
JournalJournal of the Chemical Society, Perkin Transactions 1
Issue number20
Publication statusPublished - 1977

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Acrylonitrile
Azides
Toluene
Oxides
Halogens
ethyl chloroformate

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title = "C-2 and C-4 reactions of cephalosporanates and their (S)- and (R)-oxides with toluene-p-sulphonyl azide, acrylonitrile, and ethyl chloroformate",
abstract = "Comparative reactions of cephalosporanates and their (S)- and (R)-oxides were performed. Diazo-exchange leading to 2-diazoceph-3-ems was accomplished only with the (S)-oxide. The 2-diazoceph-3-ems reacted with halogens and pseudohalogens to give 2,2-disubstituted ceph-3-ems. Michael additions with acrylonitrile, were performed, the cephalosporanates giving mainly a 4{\ss}-(2-cyanoethyl)ceph-2-em. The (S)-oxides gave 2a-(2-cyanoethyl)ceph-3-em adducts, whereas the (R)-oxides gave the 4{\ss}-adducts. Ethyl chloroformate reacted in the presence of triethylamine only with the (S)-oxides, giving by a Pummerer rearrangement both 2{\ss}- and 2{\ss}-(ethyl carbonate)s.",
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journal = "Journal of the Chemical Society, Perkin Transactions 1",
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T1 - C-2 and C-4 reactions of cephalosporanates and their (S)- and (R)-oxides with toluene-p-sulphonyl azide, acrylonitrile, and ethyl chloroformate

AU - Bremner, David H

AU - Campbell, Malcolm M

PY - 1977

Y1 - 1977

N2 - Comparative reactions of cephalosporanates and their (S)- and (R)-oxides were performed. Diazo-exchange leading to 2-diazoceph-3-ems was accomplished only with the (S)-oxide. The 2-diazoceph-3-ems reacted with halogens and pseudohalogens to give 2,2-disubstituted ceph-3-ems. Michael additions with acrylonitrile, were performed, the cephalosporanates giving mainly a 4ß-(2-cyanoethyl)ceph-2-em. The (S)-oxides gave 2a-(2-cyanoethyl)ceph-3-em adducts, whereas the (R)-oxides gave the 4ß-adducts. Ethyl chloroformate reacted in the presence of triethylamine only with the (S)-oxides, giving by a Pummerer rearrangement both 2ß- and 2ß-(ethyl carbonate)s.

AB - Comparative reactions of cephalosporanates and their (S)- and (R)-oxides were performed. Diazo-exchange leading to 2-diazoceph-3-ems was accomplished only with the (S)-oxide. The 2-diazoceph-3-ems reacted with halogens and pseudohalogens to give 2,2-disubstituted ceph-3-ems. Michael additions with acrylonitrile, were performed, the cephalosporanates giving mainly a 4ß-(2-cyanoethyl)ceph-2-em. The (S)-oxides gave 2a-(2-cyanoethyl)ceph-3-em adducts, whereas the (R)-oxides gave the 4ß-adducts. Ethyl chloroformate reacted in the presence of triethylamine only with the (S)-oxides, giving by a Pummerer rearrangement both 2ß- and 2ß-(ethyl carbonate)s.

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