Dicyclohexylcarbodiimide → HCID 20074083, compound

Participants

Reaction Steps

A solution of 540 mg of dicyclohexylcarbodiimide in 5 ml of tetrahydrofuran was added dropwise to a mixture of 810 mg of N-tert-butoxycarbonyl-2-(3-pyridyl)thiazolidine-4-carboxylic acid, 260 mg of 4-methylpiperidine, 530 mg of 1-hydroxybenzotriazole and 10 ml of tetrahydrofuran with ice cooling, and the mixture was stirred with ice cooling for 1 hour and then at room temperature for 12 hours. The reaction mixture was diluted with 30 ml of ethyl acetate, and the insoluble matter was filtered off. The filtrate was washed in sequence with saturated aqueous solution of sodium hydrogen carbonate and saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate and concentrated under reduced pressure to give 4-methyl-1-[3-tert-butoxycarbonyl-2-(3-pyridyl)thiazolidin-4-ylcarbonyl]piperidine. Trifluoroacetic acid (5 ml) was added to the thus-obtained compound, and the mixture was stirred at room temperature for 1 hour. The reaction mixture was concentrated under reduced pressure, the residue was dissolved in ethyl acetate, and the solution was washed in sequence with saturated aqueous solution of sodium hydrogen carbonate and saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate and concentrated under reduced pressure The residue thus obtained was purified by silica gel column chromatography (eluent: ethyl acetate) to give 4-methyl-1-[2-(3-pyridyl)thiazolidin-4-ylcarbonyl]piperidine. This compound was dissolved in ethyl acetate, and 3 ml of 2N hydrogen chloride solution in dioxane was added The resultant solid was collected by filtration, washed with ethyl acetate and dried to give 530 mg of 4-methyl-1-(3-pyridyl)thiazolidin-3-ylcarbonyl]piperidine dihydrochloride. Melting point 130° C.

Provenance & Evidence