Abstract
Some nucleophilic reactions of 2-imino-2H-cycloheptoxazoles including their hydrolysis and reactions with hydrogen sulfide, thiols, and active methylene compounds were examined. Both acid and alkaline hydrolyses of 2-imino-2H-cycloheptoxazole (I) gave 2-ureidotropone (III). On the other hand, a simple standing of the aqueous solution of 2-imino-2H-cycloheptoxazole (I) gave 2-(2-troponylamino) cycloheptimidazole (XIV). Reaction of I with hydrogen sulfide gave 2-ureidotropothione (XVI), while the reaction with thiols gave 2-alkylthiocycloheptimidazoles (XXVI-XXVIII), besides N-carbamoyl-2-alkylthiotroponeimines (XXIX-XXXI). Reactions of I with malononitrile, cyanoacetamide, and benzoylacetonitrile gave 3-substituted 2-imino-1, 2-dihydrocyclohepta [b] pyrroles (XXXII-XXXIV), and a similar reaction with ethyl cyanoacetate gave ethyl 2-imino-1, 2-dihydrocyclohepta [b] pyrrole-3-carboxylate (XXXV) and 2-oxo-1, 2-dihydrocyclohepta [b] pyrrole-3-carbonitrile (XXXVI). Reactions with ethyl acetoacetate, ethyl benzoylacetate, acetylacetone, and diethyl malonate gave 3-acetyl-(XXXVIII) and 3-benzoylcyclohepta [b] pyrrol-2 (1H)-one (XXXIX), 3-acetyl-2-methylcyclohepta [b] pyrrole (XL), and ethyl 1, 2-dihydro-2-oxocyclohepta [b] pyrrole-3-carboxylate (XLI), respectively.
