Example 1 Preparation of ethyl 2-hydroxy-6-methylbenzoate: a stirred mixture of trans-2-butenal (21.0 g, 0.30 mol) and anhydrous sodium acetate (25.0 g, 0.30 mol) in glacial acetic acid was heated to reflux temperature under nitrogen protection. Ethyl 2-chloroacetoacetate (41.1 g, 95%, 0.25 mol) was added dropwise over 2.25 hours. The reaction mixture was continued to be heated at reflux temperature for 16 h. Subsequently, it was cooled to room temperature and concentrated in vacuum to give the crude product. The crude product was partitioned between ethyl acetate and water. The organic phase was diluted with hexane and washed sequentially with water and aqueous sodium bicarbonate, and finally concentrated in vacuum to afford the target product ethyl 2-hydroxy-6-methylbenzoate as an oil in a yield of 41.0 g with a purity of 71.4% (65% yield), and the product structure was confirmed by nuclear magnetic resonance (NMR) analysis.
