SYNTHESIS AND ANALYSIS OF 1,2,3,4-TETRAHYDRO-(9H)-PYRIDO[3,4-B]INDOLE

The synthesis of 1,2,3,4-tetrahydro-(9H)-pyrido[3,4-b]indole derivatives was carried out in one pot, by condensation of tryptamin with cycloalkanones in the presence of a polyphosphate ester as the catalyst in moderate to low yields, the aldol condensation being the main products. Reaction of tryptamine and cyclic ketones was also carried out in two stage through the imine intermediate with protic catalysis giving the tetrahydro-beta-carbolines 8-14, in good yields. 2-Methyl derivatives 15-21, of the tetrahydro-beta-carbolines, were obtained in good yields, using methyl iodide in dimethyl sulphoxide-potassium carbonate.