Ethyl 2-chloro-5-isocyanatobenzoate → Ethyl 2-chloro-5-{3-[2-(ethoxycarbonyl)-1-methylpropenyl]ureido}-benzoate

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Reaction Steps

4.7 g of ethyl 3-amino-2-methylcrotonate, dissolved in 15 ml of absolute diethyl ether, are treated at 23° C., while stirring with a solution of 6.7 g of ethyl 2-chloro-5-isocyanatobenzoate and stirred for 2 hours. The reaction mixture is evaporated to dryness under reduced pressure and the residue is purified by chromatography on 400 g of silica gel using diethyl ether/n-hexane (1:1) as the eluent. There is obtained ethyl 2-chloro-5-{3-[2-(ethoxycarbonyl)-1-methylpropenyl]ureido}-benzoate, m.p. 88°-91° C.

Provenance & Evidence