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DOI: 10.1055/s-1995-4054
Michael Adducts in the Regioselective Synthesis of N-Substituted Azoles
Publikationsverlauf
Publikationsdatum:
31. Dezember 2000 (online)

Michael adducts of azoles (4-phenyl-, 4-methyl- and 4-nitroimidazole, 4-methylbenzimidazole, 1,2,4-triazole and theophylline) are shown to be valuable substrates for obtaining the N-substituted derivatives of the parent heterocycles by a quaternization-Hofmann elimination sequence. The effectiveness of the procedure is dependent on the regiochemical outcome of the first, N-protective step, i.e. the Michael addition. By choosing the appropriate Michael acceptor, alkylating agent and deprotection conditions, the thermodynamically less stable regioisomers of N-substituted azoles have been obtained in high yields.
azoles - Michael adducts - N-protection - regioselective alkylation