Triethylamine → 4-Methyl-N-[2-(1,2,3,4-tetrahydro-1-quinolinyl)phenyl]piperazinecarboxamide maleate

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Reaction Steps

A stirred solution, under nitrogen of 1-(2-aminophenyl)-1,2,3,4-tetrahydroquinoline (4.50 g, 0.020 mole), and triethylamine (3.04 g, 0.030 mole) in dichloromethane (50 ml) was cooled to 0° C. and phenylchloroformate (4.70 g, 0.030 mole) was added dropwise at such a rate such as to keep the reaction temperature below 5° C. The addition took 10 minutes. The mixture was stirred for 1 hour at ice-bath temperature, 1 hour at room temperature, and N-methylpiperazine (8.02 g, 0.080 mole) was added dropwise over a 5 minute period. The solution was stirred for 2 hours, N-methyl-piperazine (4.01 g, 0.040 mole) was added and the solution was stirred overnight. Water (100 ml) was added with vigorous stirring. The layers were separated, and the organic phase was washed twice with water, dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was dissolved in ethanol (100 ml) and treated with a warm solution of maleic acid (2.6 g 0.022 mole) in ethanol (15 ml). The precipitate was collected to provide 6.1 g (65%) of product. Recrystallization from methanol afforded the analytical sample, mp 171°-173° C. dec.

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