GENERAL METHODS OF SYNTHESIS OF INDOLE ALKALOIDS .7. SYNTHESES OF DL-DIHYDROGAMBIRTANNINE AND ASPIDOSPERMA-STRYCHNOS ALKALOID MODELS

The synthesis of dimethyl isoquinoline-4,5-dicarboxylate and its four-step conversion into the indole alkaloid dihydrogambirtannine are reported. The preparation of methyl 3-(β-chloroethyl)-2-indoleacetate, its N-alkylation of several β-acylpyridines, and hydrogenation of the salts are described. The use of the resultant 2-piperideines and related 2-methylindole compounds in a study of the rarely observed β-indole cyclization process and the synthesis of Aspidosperma and Strychnos alkaloid models are portrayed. © 1968, American Chemical Society. All rights reserved.