Trifluoroacetic acid → HCID 19605035, compound

Participants

Reaction Steps

A 30 ml potion of trifluoroacetic acid was added to 10.24 g 4,5-bis(ethoxycarbonyl)-2-t-butoxycarbonylaminomethylthiazole, and the mixture was then stirred at room temperature for 1 hour. The reaction solution was concentrated under reduced pressure, and an aqueous saturated sodium hydrogencarbonate solution was then added so as to adjust the pH of the solution to about 8. Further, 150 ml of dichloromethane was added thereto, and a mixture of 27 ml of formic acid and 13.5 ml of acetic anhydride which had been beforehand reacted with each other at 50° C. for 30 minutes was then added at room temperature with vigorous stirring, followed by stirring for additional 1 hour. The organic layer was separated, and the aqueous layer was further extracted with dichloromethane three times. The combined organic layer was dried over anhydrous sodium sulfate and then filtered, and the solvent was evaporated under reduced pressure. To the resulting unpurified 4,5-bis(ethoxycarbonyl)-2-(formylamino)methylthiazole, 30 ml of toluene and 13.3 ml of phosphorus oxychloride were added, followed by stirring at 100° C. for 80 minutes. After cooled to room temperature, the reaction solution was concentrated under reduced pressure, and the resulting residue was then diluted with dichloromethane. Afterward, an aqueous potassium carbonate solution was added so as to adjust the pH of the solution to about 8. The organic layer was separated, and it was further extracted four times from the aqueous layer with dichloromethane. The combined organic layer was dried over anhydrous sodium sulfate and then filtered, and the solvent was evaporated under reduced pressure. The resulting residue was purified by a silica gel column chromatograph to obtain 6.6 g of the title compound.

Provenance & Evidence