Piperidinium acetate → HCID 178480362, compound

Participants

Reaction Conditions

Reaction Steps

A solution of tert-butyl[(3R)-2-oxopyrrolidin-3-yl]carbamate (1.87 g) and iodomethane (0.70 mL) in THF (5 mL) and DMF (5 mL) was added to a solution of 60% sodium hydride (0.53 g, containing mineral oil) in THF (10 mL). The reaction mixture was stirred at room temperature overnight, saturated aqueous ammonium chloride solution was added, and the mixture was extracted with ethyl acetate. The extract was washed with water and saturated brine, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography is (ethyl acetate/methanol). To a solution of the obtained solid in ethyl acetate (20 mL) was added 4N hydrogen chloride/ethyl acetate solution (20 mL), the mixture was stirred at room temperature for 2 hr, and the reaction mixture was concentrated. To a solution of the obtained residue in methanol (20 mL) was added AMBERLYST (registered trademark) A21, and the mixture was stirred for 15 min. The reaction solution was filtered, AMBERLYST (registered trademark) A21 was removed, and the filtrate was concentrated under reduced pressure. To a solution of the obtained residue in ethanol (10 mL) was added 4-thioxo-1,3-thiazolidin-2-one (889 mg), and the mixture was stirred at room temperature for 5 hr. The reaction mixture was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (NH, ethyl acetate/methanol) to give a mixture (0.32 g) of 4-{[(3R)-1-methyl-2-oxopyrrolidin-3-yl]amino}-1,3-thiazol-2(5H)-one and 4-{[(3R)-2-oxopyrrolidin-3-yl]amino}-1,3-thiazol-2(5H)-one, and 4-{[(3R)-2-oxopyrrolidin-3-yl]amino}-1,3-thiazol-2(5H)-one (0.14 g). To a solution of the mixture (0.32 g) of 4-{[(3R)-1-methyl-2-oxopyrrolidin-3-yl]amino}-1,3-thiazol-2(5H)-one and 4-{[(3R)-2-oxopyrrolidin-3-yl]amino}-1,3-thiazol-2(5H)-one, and 1-[2,4-bis(trifluoromethyl)benzyl]piperidine-4-carbaldehyde (761 mg) in 2-propanol (5 mL) was added piperidinium acetate (217 mg). The reaction mixture was stirred at 80° C. for 6 hr and concentrated under reduced pressure. Water was added to the residue, and the mixture was extracted with ethyl acetate. The extract was washed with water and saturated brine, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate/methanol). The obtained solid was recrystallized from ethyl acetate/heptane to give the title compound (200 mg).

Provenance & Evidence