Uses
Methyl 2-bromobenzoate under Heck reaction with acrylonitrile results in lactonization to give the benzofuran-2-one 3-(cyanomethyl)-2-coumaranone. It is an important raw material and intermediate used in Organic Synthesis, Pharmaceuticals, Agrochemicals
Synthesis
Preparation of methyl o-bromobenzoate: In a 250 ml three-necked flask, add 0.04 mol of methyl benzoate and 100 ml of acetic acid, stir to dissolve, and then cool to 0 C using an ice-salt bath. Dissolve 0.05 mol of Br2 in 50 ml of acetic acid, and slowly add the bromine-acetic acid solution dropwise to the above reaction system. After the addition is complete, control the temperature at 20-25 C and stir the reaction for 12 hours. Take a sample for TLC; no raw material I1-3 remains. After the reaction is complete, add NaOH aqueous solution to neutralize the reaction solution, add dichloromethane for extraction, separate the layers, filter the organic phase, distill the filtrate under reduced pressure until no fraction remains, and pass it through a neutral silica gel column to obtain the intermediate methyl o-bromobenzoate.
Purification Methods
A solution of the ester in ether is washed with 10% aqueous Na 2CO3, water, then dried and distilled. [Beilstein 9
