Ammonium Chloride → Methyl 3-chloro-5-(hydroxymethyl)benzoate

In a 3 liter 3-necked round-bottom flask equipped with mechanical stirrer and nitrogen inlet was placed 5-chloroisophthalic acid monomethyl ester (29.4 g). Borane tetrahydrofuran complex in tetrahydrofuran solution (1M, 280 ml) was then added to the flask dropwise at room temperature. The resulting solution was stirred at room temperature overnight. The reaction mixture was poured into saturated aqueous ammonium chloride solution (750 ml) and extracted with ethyl acetate (3×500 ml). The combined organic layers were agitated with 2% aqueous hydrochloric acid, washed with water, dried and the solvent eliminated in the rotavap yielding 29.4 g of 3-chloro-5-hydroxymethyl benzoic acid methyl ester as a clear oil.