| Abstrakt: |
Acid and base catalyzed intramolecular cyclizations of N-benzoylthioureidoacetal, containing four functional groups adjacent to thiourea such as benzocarbamoyl, acetal, thioure and amide, were investigated. The condensation reaction of N-benzoyl thiocarbamoylglycine amide in the presence of 10% aqueous NaOH provided 1-(2,2-dimethoxy)ethyl-imidazolidine-2-thione exclusively. In the presence of pyridine, it was transformed to 2-thiohydantoin. N-Benzoyl thiocarbamoyl glycine amide was completely transformed to an iminothiazolidine exclusively in the presence of Lewis acid such as borontrifluoride etherate or trimethylsilyl iodide. 1-(2,2-Dimethoxy)ethyl-imidazolidine-2-thione was transformed to imidazole[2,1- b]thiazole and pyrazino[5,1-a]imidazole in the presence of BF3.Et2O and formic acid, respectively. [ABSTRACT FROM AUTHOR] |
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