The pictet-spengler reaction of Nb-hydroxytryptamines and cysteinals. I. Isolation of tetracyclic intermediates and formation of optically active Nb-hydroxy-tetrahydro-β-carbolines.

Abstract The Pictet-Spengle P-S reaction of N b -hydroxytryptamines 5 and cysteinals 6 in the presence of trifluoroacetic acid(TFA) at room, temperature gave the tetracyclic compounds 7 α as well as the corresponding N b -hydroxy-β-carbolines 8 . The optically active nitrones 9 , isolated from the similar reaction of 5 and optically active 6 , gave optically active 7 α and 8 .