The Pictet-Spengler condensation of various tryptamine-2-carboxylic acids 9a-f with carbonyl compounds in benzene/dioxane/trifluoroacetic acid (Table I) with simultaneous loss of carbon dioxide afforded directly the corresponding 1, 2, 3, 4-tetrahydro-@-carbolines 14a-j in good to excellent yields. This reaction greatly enhances the use of the Abramovitch- Shapiro method for the synthesis of highly oxygenated ring A substituted 1, 2, 3, 4- ...