INDOLES .11. SYNTHESES AND STEREOCHEMISTRY OF 8,13,13B-HEXAHYDROBENZ[A]INDOLO[2,3-H]QUINOLIZINES AND OF HEXAHYDRO-14H-BIS-INDOLO[3,2-A][2,3-H]-QUINOLIZINE

A new and efficient synthesis of substituted ,13,]3b-hexahydro-benz[a] indolo[2,3-h]quinolizines (5b,d) via lactamisation of dihydropyrano[3, 4-b]indol-1-one (3), cyclisation with phosphorus oxychloride and reduc tion with sodium borohydride is described. The unsubstituted 5,6,7,8,1 3,13b-hexahydro benz[a]indolo[2,3-h]quinolizine (5) is prepared by ana logy starting with the lactamisation of isochromanone with tryptamine. The unsubstituted b-hexahydro-14H-bisindolo[3,2-a][2,3-h]quinolizine (9) is synthesized by lactamisafion of 3 with tryptamine, cyclisation and again reduction of the intermediate immonium salt. The stereochemi stry of the unsubstituted quinolizine derivatives is investigated by H -1-, C-13-nmr-, NOE spectroscopy and by X-ray analysis.