Acetic Acid → 9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-1,2,3,9-tetrahydro-4H-carbazol-4-one glyoxylic acid

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Reaction Steps

A mixture containing 2.83 g (0.01 mole) of 3-hydroxy-methyl-9-methyl-1,2,3,9-tetrahydro-4H-carbazol-4-one-3-glyoxylic acid lactone [compound of the formula (Ic)]and 1.64 g (0.02 mole) of 2-methylimidazole in 6.0 ml of sulfolane (tetramethylenesulfone) is heated in an oil bath of 150 to 160° C. for 15 minutes while stirring. After cooling down and diluting with 60 ml of acetone the precipitate is filtered off, washed with acetone and dried to give 0.95 g of the title compound, m.p.: 190°-200° C. (with decomposition). The active agent content of this product measured by titration with perchloric acid in glacial acetic acid was found to be 96%. In the combined filtrate of the reaction, ondansetron could be detected by thin layer chromatography. The most important characteristics of the title product are as follows:

Provenance & Evidence