Asiyeh Mosallanezhad and Hamzeh Kiyani* Pages 28 - 35 ( 8 )
Background: 4-Arylmethylideneisoxazol-5(4H)-ones are a class of organic compounds with a variety of applications in the agriculture, filter dyes, photonic devices, and pharmaceutical industries. They are also used as synthetic precursors for the synthesis of other organic compounds. As a result, efforts are being made to search new and available catalyst and green methods toward their synthesis.
Objective: The aim of this work is to investigate the catalytic activity of salicylic acid as an inexpensive, easy to handle, and safe catalyst to synthesis of some derivatives of isoxazole-5(4H)-ones in water medium.
Methods: To aqueous solution of equal amounts of aryl/heteroaryl aldehydes, β-ketoesters, and hydroxylamine hydrochloride; salicylic acid (15 mol%) was added and the reaction mixture was stirred at room temperature for a specified periods. The precipitated product was filtered and washed with water to obtain 3-substituted-4-arylmethylideneisoxazol-5(4H)-ones. The reaction conditions were also optimized and extended to synthesis other isoxazol-5(4H)-ones.
Results: The salicylic acid is found to possess acceptable catalytic activity for the promotion of three-component cyclocondensation of aryl/heteroaryl aldehydes, β-ketoesters, and hydroxylamine hydrochloride. The three-component reaction led to construction of 3-substituted-4-arylmethylideneisoxazol- 5(4H)-ones in good to high isolated reaction yields.
Conclusion: The efficient and environmental friendliness procedure for the synthesis of isoxazol- 5(4H)-ones is introduced. The reaction also carried out smoothly in water as a cost-effective, simple, green, and non-toxic solvent at room temperature without using heating, microwave, and ultrasound sources.
Green synthesis, hydroxylamine hydrochloride, isoxazol-5(4H)-ones, β-keto ester, salicylic acid, water.
School of Chemistry, Damghan University, Damghan, School of Chemistry, Damghan University, Damghan