Acetic Acid → ethyl 2-chloro-5-(1,2,4,5,6,7-hexahydro-2,4-dioxo-3H-cyclopenta[d]pyrimidin-3-yl)-benzoate

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Reaction Steps

A solution of 118.0 g of ethyl 2-chloro-5-{3-[2-(ethoxycarbonyl)-1-cyclopenten-1-yl]ureido}-benzoate in 800 ml of absolute 1,2-dimethoxyethane, is added dropwise while stirring at 20° C. during 10 minutes to a suspension of 7.7 g of sodium hydride in 800 ml of absolute 1,2-dimethoxyethane. The reaction mixture is subsequently stirred for 1 hour, treated with 20 ml of acetic acid and evaporated to dryness under reduced pressure. The residue is dissolved in 2 l of methylene chloride and washed twice with 1 l of water. The organic phase is dried over anhydrous sodium sulphate and evaporated up to crystallization. The residue is treated with 1 l of n-hexane and the crystals are filtered off under suction and rinsed with n-hexane. There is obtained ethyl 2-chloro-5-(1,2,4,5,6,7-hexahydro-2,4-dioxo-3H-cyclopenta[d]pyrimidin-3-yl)-benzoate, m.p. 178°-180° C.

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