Ease of Cyclization to the β-Lactam Ring 1
✍ Scribed by Bose, Ajay K.; Ghosh-Mazumdar, B. N.; Chatterjee, B. G.
- Book ID
- 126992184
- Publisher
- American Chemical Society
- Year
- 1960
- Tongue
- English
- Weight
- 672 KB
- Volume
- 82
- Category
- Article
- ISSN
- 0002-7863
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📜 SIMILAR VOLUMES
The cyclization of hydroxamate 1 unexpectedly afforded two isomeric @lactams 2 and 1. The mechanism for the formation of 2 has been shown by carbon-13 labeling to involve a novel 1,2-acyl migration-cyclization process.
Ring opening of N-carboxylated [~-lactams with trimethylsilyldiazomethane anion followed by photolytic W~lll rcarrangmnent provided y-lactalns in a stcreospecific manner.
There has been considerable recent interest in the synthesis of monocyclic 6-lactams as a result of the isolation, from fermentation cultures, of antibiotics such as nocardicin A (1j1,2.3 and the observation of the remarkably high antimicrobial activity associated with these products.'
The 71&-amino-cephalosporin sulphones, generated in situ from the appropriate 7[5-tBoe-amino derivative and diazotized in a une-pot reaction in aq. HCIO4 -MeOH -NaNO2, rearrange exclusively to the triazoles $ in a multistep reaction.