Heterocyclic mesomeric betaines and analogs

Heterocyclic Mesomeric Betaines and Analogs in Natural Product Chemistry. Betainic Alkaloids and Nucleobases... 

Heterocyclic iminium salts, oxidative transformation, 41, 275 Heterocyclic mesomeric betaines and analogs in natural product chemistry, 85, 67 Heterocyclic oligomers, 15, 1 Heterocyclic products, natural, synthesis of by hetero Diels-Alder cycloaddition reactions, 42, 245... 

The second chapter (A. Schmidt, Clausthal, Germany) provides a concise review of heterocyclic mesomeric betaines and their analogs as found in natural products. Finally, L Hermecz (Budapest, Hungary) provides part two of his survey of pyrido-oxazines, pyrido-thiazines, pyrido-diazines and their benzologs. This encompasses a large variety of heterocycles, many of which are of increasing importance because of their physiological activity. Much of this material has not been reviewed for decades and the subject has advanced enormously in this period. 

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