[C:1]([C:3]1([CH:9](C(O)=O)[C:10]([OH:12])=[O:11])[CH2:8][CH2:7][CH2:6][CH2:5][CH2:4]1)#[N:2]>C1(C)C=CC=CC=1>[C:1]([C:3]1([CH2:9][C:10]([OH:12])=[O:11])[CH2:8][CH2:7][CH2:6][CH2:5][CH2:4]1)#[N:2]35.5 g (1-Cyanocyclohexyl)-malonic acid are suspended in 400 mL toluene and heated, while stirring, for about one hour to 80-85° C. In the course of the decarboxylation, an almost clear solution is obtained. After filtration, the toluene is distilled off in a vacuum at 35° C. The crude product is dissolved in a saturated aqueous solution of sodium bicarbonate and stirred with ethyl acetate. After separating off the organic phase, the aqueous phase is acidified with concentrated hydrochloric acid, while cooling with ice to 5° C. The solid product which precipitates out is filtered off with suction and then washed with water. The filter cake is dissolved in ethyl acetate and the solution dried over anhydrous sodium sulphate. After filtration, the ethyl acetate is evaporated on a rotary evaporator at 35° C. The residue is dried to constant weight in a vacuum drying cabinet at 35° C. 19.6 g of the title compound are obtained (70% of theory); m.p. 102° C.
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