Thioester synthesis

A mixture of {(R)-5-[(3-fluoro-5-thfluoromethyl-benzenesulfonyl)-methyl-amino]- 5,6,7,8-tetrahydro-naphthalen-1-yloxy}-acetic acid tert-butyl ester (150 mg, 0.29 mmol), potassium carbonate (300 mg, 2.17 mmol), and propane-2-thiol (165 mg, 2.17 mmol)) in N,N-dimethylformamide (2 ml) was heated at 150°C for 30 minutes in a microwave oven. To the reaction mixture was added an aqueous solution of saturated ammonium chloride (10 ml) and the resulting solution was extracted with ethyl acetate (3x20 ml). The combined organic layers were washed with water (20 ml) and brine (20 ml), and then concentrated to afford {(R)-5-[(3- isopropylsulfanyl-5-thfluoromethyl-benzenesulfonyl)-methyl-amino]-5, 6,7,8- tetrahydro-naphthalen-1-yloxy}-acetic acid terf-butyl ester (160 mg, 96%) as a viscous oil, which was used in the next step without purification. 


Patent reference: WO2010018112 (Roche)