67-56-1

2067-33-6

5454-83-1

5-Bromovaleric acid (2.01 g, 10.0 mmol) was dissolved in methanol (10 mL) and the solution was subsequently transferred into a syringe. The syringe was mounted on a syringe pump and the methanol solution was pumped at a flow rate of 0.177 mL/min into a stainless steel column (4.0 mm ID x 50 mm length, 0.53 mL internal volume) filled with HO-SAS (334 mg). The stainless steel column was immersed in an oil bath preheated to 110°C and connected to a back pressure regulator (set pressure 75 psi). As the reaction mixture flowed out of the column outlet, the fraction collected during the first 10 min was discarded. The reaction mixture was then collected over the next 3 minutes and n-decane was added as an internal standard for gas chromatography (GC) analysis. The reaction mixture was continued to be collected in a glass flask for 30 min, after which the solvent was removed by rotary evaporation. The crude product was purified by fast column chromatography on silica gel (SiO2) with an eluent ratio of hexane/ethyl acetate (5:1), resulting in methyl 5-bromovalerate (1.13 g, 99% yield).