Cycloaddition reactions of cephalosporin compounds. IX—1H and 13C NMR stereochemical study of the 1,3‐dipolar cycloadditions of diazoalkanes to 2‐methylenecephem derivatives

J. Cs. Jászberény, J. Pitlik, Gy Batta, K. Kövér, K. Kollár

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

A series of known and novel 2‐methylenecephem derivatives were prepared and their reactions with diazomethane, phenyldiazomethane and diphenyldiazomethane were studied. The initially formed 1‐pyrazolino derivatives easily underwent spontaneous loss of nitrogen, leading to 2‐spirocyclopropylcephems. The two reaction products, formed in a 3:1 to 8:1 ratio on addition of diphenyldiazomethane, were separated by column chromatography and distinguished by their 1H and 13C NMR spectra. The 1H NMR spectra did not exclude the possibility of 1‐pyrazoline formation, but elemental analysis and 13C data corroborated the previous assumption that loss of nitrogen took place, even in those cases when it did not occur during the reaction.

Original languageEnglish
Pages (from-to)658-664
Number of pages7
JournalMagnetic Resonance in Chemistry
Volume26
Issue number8
DOIs
Publication statusPublished - 1988

Fingerprint

Cycloaddition
Cephalosporins
Nitrogen
Nuclear magnetic resonance
Diazomethane
Derivatives
Column chromatography
Reaction products
Chemical analysis
diphenyldiazomethane

Keywords

  • C NMR
  • H NMR
  • H‐{H}
  • ASIS
  • Cephalosporins
  • Configuration determination
  • Conformation study
  • DEPT
  • INEPT
  • NOE

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

Cite this

Cycloaddition reactions of cephalosporin compounds. IX—1H and 13C NMR stereochemical study of the 1,3‐dipolar cycloadditions of diazoalkanes to 2‐methylenecephem derivatives. / Cs. Jászberény, J.; Pitlik, J.; Batta, Gy; Kövér, K.; Kollár, K.

In: Magnetic Resonance in Chemistry, Vol. 26, No. 8, 1988, p. 658-664.

Research output: Contribution to journalArticle

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AB - A series of known and novel 2‐methylenecephem derivatives were prepared and their reactions with diazomethane, phenyldiazomethane and diphenyldiazomethane were studied. The initially formed 1‐pyrazolino derivatives easily underwent spontaneous loss of nitrogen, leading to 2‐spirocyclopropylcephems. The two reaction products, formed in a 3:1 to 8:1 ratio on addition of diphenyldiazomethane, were separated by column chromatography and distinguished by their 1H and 13C NMR spectra. The 1H NMR spectra did not exclude the possibility of 1‐pyrazoline formation, but elemental analysis and 13C data corroborated the previous assumption that loss of nitrogen took place, even in those cases when it did not occur during the reaction.

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