Diethyl squarate → HCID 89526128, compound

Participants

Reaction Steps

0.86 ml of 3,4-diethoxycyclobut-3-ene-1,2-dione (5.9 mmol, 1.5 eq) was added to a solution of 0.59 g of 4-amino-1,3-dihydrobenzoimidazol-2-one (4.0 mmol, 1 eq) in 21 ml of ethanol. The reaction medium was stirred at ambient temperature for 2 days (formation of a precipitate). Ethanol was added in order to promote the fall of the precipitate, which was filtered off, washed with diethyl ether and dried under vacuum at 45° C. The residue was chromatographed on silica gel, eluted with 90/10 dichloromethane/methanol. 0.42 g of product was obtained in the form of a white solid. Yield=38.6%.

Provenance & Evidence