The direct azidation of various heterocyclic beta-ketoesters, lactones, and lactams is reported. By using tosylazide and an organic base such as L-proline or TBD, the direct alpha-insertion of azide into these substrates was achieved in moderate to good yields, without competitive deacylating diazo transfer. This procedure represents an interesting alternative to the usual two-step approach of alpha-halogenation and subsequent displacement with azide ion. (C) 2009 Elsevier Ltd. All rights reserved.
The direct azidation of various heterocyclic beta-ketoesters, lactones, and lactams is reported. By using tosylazide and an organic base such as L-proline or TBD, the direct alpha-insertion of azide into these substrates was achieved in moderate to good yields, without competitive deacylating diazo transfer. This procedure represents an interesting alternative to the usual two-step approach of alpha-halogenation and subsequent displacement with azide ion. (C) 2009 Elsevier Ltd. All rights reserved.
Antibacterial 7.beta.-(oxo-saturated heterocyclic carbonamido)-3-cephem-4-carboxylic acid derivatives of the formula: ##STR1## (wherein R is hydrogen or methoxy; R.sup.1 is hydrogen or a nucleophilic group; R.sup.2 is hydrogen, light metal, or a carboxy protecting group; X is oxygen, sulfur, sulfinyl, or sulfonyl; Y is alkylene containing one or more hetero atoms; and Z is hydrogen or a substituent).