Abstract: L-Tryptophanc methyl ester reacts with corresponding monoacetal of malonaldchydc under Pictct-Spenglcr conditions followed by Michael additions of methyl vinyl ketone to give diastereoisomcrs of tetrahydro-β-carbolines l_a,b, 2_a,b and 3_a,b. Their COSY and NOESY 2D-NMR spectroscopy were studied here. It was shown that in 1_a, 2_a, and 3_a, there were NOE relationships between 3-H and 3'-H, in l_b, 2_b, and 3_b however there were NOE relationships between OCH₃ and CO₂CH₃ (for l_b and 2_b) or between 5'-CH₃ and CO₂CH₃ (for 3_b). Based on the results of NOE and the help of Dreiding Stereomodels their conformations were discussed.

Key words: Stereo chemistry, Tetrahydro-β-carboline, 2D-KMR