Abstract: In the present paper a series of 1,2-disubstituted-, 1,2,3-trisubstituted-1,2,3,4 tetrahydro-tetrahydro-β-carbolines, and substituted indolo[2, 3-a] quinolizines were characterized by high resolution NMR. The stereochemistry of some compounds were discussed based on two dimensional NOE spectra. In methyl 1-(2,2-dimethoxyethyl)-2-(Boc-Gly)-1, 2, 3, 4-tetrahydro-3-carbolinecarboxylate (I) there is NOE correlation between 1-H and 3-H of isomer Ⅰ_b only, suggesting a configuration of 1R, 3S for Ⅰ_a and a configuration of 1S, 3S for Ⅰ_b In 1-(2,2-dimethoxyethyl)-2-propenalyl-1,2,3,4-tetrahydrocarboline (Ⅲ) no NOE correlation between 5'-H and 4'-H was observed, which means that the substituent propenalyl on 2 position takes E Configuration. In 2-hydroxy-1, 2, 6, 7, 12, 12b hexahydroindolo[2, 3-a]quinolizine-1-aldehyde (Ⅴ) NOE correlation occurs between 1-CHO and 2-H,indicating that 1-H and 2-OH take the same orientation. The compound IV, 6,7,12, 12b-tetrshydroindolo[2,3-a] quinolisine-1-aldehyde can be obtained from the isomer of V, in which the 1-H and 2-OH take trans orientation only. For 1-(2,2-dimethoxyethyl)-2-(Boc-L-Ala)-1,2,3,4-tetrahydrocarboline (Ⅱ), the two isomers Ⅱ_a and Ⅱ_b have the same NOE correlations between 1-H and 3-H, 2'-H, 3'-H,5'-CH₃. Their configurations were determined based on the chemical shifts of 1-H.

Key words: Substituted tetrahydro-β-carboline, Substituted-indolo[2,3-a] quinolizine, ¹H NMR, Stereochemistry