Synthesis
GENERAL METHOD: α-substituted ethyl acetate (1.0 mmol) and phenyl iododo diacetate (1.0 mmol) were dissolved in ethanol (5 mL) under continuous stirring conditions. After 10 min of reaction, benzaldehyde or salicylaldehyde (1.0 mmol) was added to the system and the reaction was continued with stirring until the appropriate time. The progress of the reaction was monitored by thin layer chromatography (TLC). After the TLC showed that the reaction was complete, the ethanol was evaporated under reduced pressure. Subsequently, the product was extracted with ethyl acetate and the organic phase was dried with anhydrous sodium sulfate (Na2SO4) and concentrated again under reduced pressure to remove the solvent. The resulting crude product was purified by recrystallization from a solvent mixture of ethyl acetate and hexane to finally obtain the target compound 7-hydroxy-2-oxochromene-3-carbonitrile (3a-3h and 4a-4r series derivatives).
References
[1] Synthetic Communications, 2005, vol. 35, # 6, p. 785 - 790
[2] Phosphorus, Sulfur and Silicon and the Related Elements, 2002, vol. 177, # 11, p. 2555 - 2559
[3] Tetrahedron Letters, 2017, vol. 58, # 32, p. 3183 - 3187
[4] Journal of Heterocyclic Chemistry, 2007, vol. 44, # 4, p. 867 - 870
[5] Journal of the Iranian Chemical Society, 2016, vol. 13, # 1, p. 149 - 153
