Synthesis
To a methanolic (200 mL) solution of cyanoacetic acid (8.7 g, 102 mmol) was added isobutyraldehyde (18.6 mL, 204 mmol) and the solution was stirred and a slight exothermic phenomenon was observed.After 30 min, piperidine (11.1 mL, 112 mmol) was added and stirring was continued for 1 hr. Subsequently, the solvent was removed by vacuum distillation under mild heating conditions. The crude product was diluted with ether and washed sequentially with 125 mL of 1.0 M HCl and brine. The organic phase was dried over anhydrous sodium sulfate and concentrated to give 11.2 g of a colorless oil, 2-cyano-4-methylpent-2-enoic acid, which precipitates on standing.
References
[1] Organic Process Research and Development, 2014, vol. 18, # 1, p. 109 - 121
[2] Patent: WO2012/25861, 2012, A1. Location in patent: Page/Page column 22
[3] Journal of the Chemical Society, 1932, p. 445,453
[4] Journal of the Chemical Society, 1933, p. 613
[5] Patent: WO2014/39899, 2014, A1. Location in patent: Page/Page column 52
