Synthesis of gbs-carbolines and their tetrahydro derivatives

• Main Author: Zarrinmayeh, Hamideh
• Other Authors: Behforouz, Mohammad
• Format: Others
• Published: 2011
• Subjects: Carbolines.
• Online Access: http://cardinalscholar.bsu.edu/handle/handle/183303; http://liblink.bsu.edu/uhtbin/catkey/479637

The synthesis of 3-carbomethoxy-1,4-dimethyl-acarboline (50a), 3-carbomethoxy-l-ethyl-4-methyl-~carboline(50b), 3-carbomethoxy-4-methyl-l-phenyl-acarboline(50c), 3-carbomethoxy-4-methyl-1-(2-pyridyl)$-carboline(50d), 3-carbomethoxy-1-(2-furyl)-4-methyl$-carboline(50f), 3-carbomethoxy-4-methyl-l-styryl-Scarboline(50g), 3-carbo-methoxy-4-methyl-1-(2-quinolyl)R-carboline(50h), 1-acethyl-3-carbomethoxy-4-methyl-SS-carboline(50i) and 3-carbomethoxy-1-(2-hydroxyphenyl)4-methyl-1-2-3-4-tetrahydro-S-carboline are described. Treatment of a-methyltryptophan methyl ester with acetaldehyde, propionaldehyde, benzaldehyde, pyridine carboxaldehyde, salicylaldehyde, furfural, cinnamaldehyde, quinolin carboxaldehyde or pyruvic aldehyde in aprotic solvents afforded the corresponding tetrahydro-S-carboline. These compounds were dehydrogenated in the presence of palladium-charcoal(10%) in refluxing xylene to give the S-carbolines. The percent yield, mp, nmr and it data are given for these compounds.In some cases it was noticed that all, or a portion of, the dehydrogenation reaction leading to the a-carboline occurs during the cyclization (50i). In addition, the stereoselective preparation of the starting material, S-methyltryptophan methyl esters, in a good yield is described.