Yield:138320-26-0 99%

Reaction Conditions:

Stage #1: salicylaldehydewith potassium carbonate in N,N-dimethyl-formamide;toluene at 60 - 70; for 0.5 h;
Stage #2: methyl 2-bromohexanoate in N,N-dimethyl-formamide;toluene at 80 - 100; for 2 h;

Steps:

3.A A. Synthesis of Compounds of Formula 3

387.3 g (2.8 mol) of anhydrous potassium carbonate and 97.6 g (0.8 mol) of 2-hydroxybenzaldehyde were added to a 2 L three-necked flask.140 g of N,N-dimethylformamide, 600 g of toluene, stirring at a temperature of 60-70° C. for 0.5 hours,176.0 g (0.84 mol) of alkyl 2-bromohexanoate are added dropwise at a temperature of 80-100° C. and the reaction is stirred for 2 hours.500g of water was added and the aqueous layer was separated. The organic layer was washed once with 500 g of water, and the solvent was distilled off at 0.09 MPa/80.Intermediate 198.2 g of Formula 3 was obtained, GC purity 98.9%, yield 99.0%(Based on 2-hydroxybenzaldehyde).

References:

CN107382925,2017,A Location in patent:Paragraph 0110-0112