Trifluoroacetic acid → 1,3-Dibenzyltetrahydro-1H-thieno[3,4-d]imidazole-2,4-dione

Participants

Reaction Conditions

Reaction Steps

To 240 ml of a chloroform solution containing 30 g of (4R,5R)-1,3-dibenzyl-2-oxo-5-(mercaptomethyl)imidazolidin-4-carboxylic acid, 22.7 g of pyridine and 2.6 ml of trifluoroacetic acid was added dropwise 60 ml of a chloroform solution containing 17.4 g of dicyclohexylcarbodiimide at 5° C. over 30 minutes. After the solution was refluxed for 5 hours, it was concentrated under reduced pressure. The concentrate was dissolved in ethyl acetate and concentrated, and after the procedure was repeated, 300 ml of ethyl acetate was added to the residue, and the mixture was stirred at 50° C. for 30 minutes. After cooling to 25° C., insoluble materials were filtered off. After the filtrate was concentrated, 85 ml of methanol was added to the concentrate and the mixture was dissolved under heating. After cooling the solution, precipitated crystal was collected by filtration, and washed with cold methanol. Precipitated crystal was dried by blowing air at 50° C. to give 21.3 g of (3aS,6aR)-1,3-dibenzyl-hexahydro-4H-thieno[3,4-d]imidazol-2,4-dione as colorless crystal.

Provenance & Evidence