Synthesis of new derivatives of carbo(hetero)cyclospirobutanoic lactones
The diethyl esters of 2-oxo-1-oxaspiro[4,4]nonan-3,4-dicarboxylic, 2-oxo-1-oxaspiro[4,5]decan-3,4-dicarboxylic and 7,7-di-methyl-1,8-dioxaspiro-[4,5]decan-3,4-dicarboxylic acids (la-c) are transformed by hydrochloric acid into 2-oxo-1-oxa-spiro[4,4]nonan-, 2-oxo-1-oxaspiro-[4,5]decan-, and 7,7-dimethyl-1,8-dioxaspiro[4,5]decan-4-carboxylic acids (Ila-c), which are converted into the acyl chlorides IIIa-c, and the latter into the chloromethyl ketones IVa-c. Reaction of the acyl chlorides of IIa and IIb with thiosemicarbazide gives the acid thiosemicarbazides Va and Vb, which form the triazoles VIa and VIb in potassium hydroxide solution, and the thiadiazoles VIIa an VIIb in sulfuric acid. Reaction of the chloromethyl ketones IVa-c with formamide gives the imidazoles VIIIa-c. The diesters Ia-creatwithbenzylamine to form the N-benzylimides IXa-c.