Michael Adducts in the Regioselective Synthesis of N-Substituted Azoles

All articles of this category 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