Ethyl Acetate → 1-(4-Cyanophenyl)-1-(5-thiazolyl)-ethylene

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Reaction Steps

714 mg of methyltriphenylphosphonium bromide are introduced into 6.7 ml of ether, and 0.973 ml of 1.6M n-butyllithium in hexane is added at 7°. The orange suspension is stirred at the same temperature for 1.5 hours and then reacted with a suspension, cooled to 7°, of 5-(4-cyanobenzoyl)-thiazole (Example 8a) in 3 ml of ether. After stirring for 3 hours at RT, the ether is replaced by ethyl acetate and the mixture is stirred for a further 2 hours under reflux. The solid material is filtered off with suction and the mother liquor is concentrated. The residue is taken up in methylene chloride and the organic phase is washed in succession with 7 ml of 2N hydrochloric acid and with water, dried over sodium sulfate and concentrated. The crude product is purified by column chromatography (SiO2 0.04-0.06 mesh, 0.1 bar, hexane/ethyl acetate 2:1 to 1:1) and crystallised from hexane; m.p. 71°-73°; 1H-NMR (CDCl3): δ(ppm)=5.5 (s,1H), 5.73 (s,1H) 7.54 and 7.71 (m,4H), 7.69 (s,1H), 8.78 (s,1H).

Provenance & Evidence