反应详情

145 mg (2.6 mmol) of potassium hydroxide pellets are added to 0.5 g (2 mmol) of methyl 3-(chloromethylene)-2,3-dihydro-1-benzoxepin-7-carboxylate, prepared according to example 32, in solution in 8 ml of 80% aqueous ethanol, and the medium is brought to reflux for 3 hours. After cooling, the medium is brought to acidity by addition of 1N hydrochloric acid. The precipitate is filtered off and then washed with diisopropyl ether to provide 300 mg (63%) of 3-(chloromethylene)-2,3-dihydro-1-benzoxepin-7-carboxylic acid in the form of a white solid comprising two Z/E isomers as a mixture in an 85/15 ratio; M.p.>260° C.

1. customprepared
2. temperatureto reflux for 3 hours
3. temperatureAfter cooling
4. filtrationThe precipitate is filtered off
5. washwashed with diisopropyl ether