SYNTHESIS OF NEW GUANIDINE DERIVATIVES FROM YDROSPIRO[PIPERIDINE-4,1'-[1H]PYRIDO[3,4-B]INDOLE]

The reaction of the isothiourea derivative 2 with mcthylaminc or pyrro lidine resulted in guanidines 3a-3b. Using hydrazine under the same co nditions the tetrazole derivative 4 was obtained. On reacting 2 with p iperidine, morpholine, methylhydrazine, phenylhydrazine, hydroxylamine or sodium hydroxide, cyclization took place leading to the novel 4-cy animino-1,2,3,4,6,7,12, 3,12b-ethanopyrimido[1',6':1,2]pyrido[3,4-b]in dole (5). Some structural aspects of 5 and other model compounds were analysed mainly by C-13 nmr spectroscopy.