Potassium Hydroxide → 5-Mercapto-2,2-dimethylpentanoic acid ethyl ester

Ethyl 5-bromo-2,2-dimethylpentanoate (9.1 g, 38.4 mmol) in 100 mL EtOH, was treated with thiourea (3.65 g, 48.0 mmol) and KOH (2.69 g, 48.0 mmol) and stirred at rt for 10 minutes. After gentle heating (40-45 C.) for one hour, the solution was cooled and quenched by adding it to a stirred solution of 100 g ice, 100 mL conc. HCl, and 100 mL water. This aqueous layer was then extracted with 3×200 mL methylene chloride. The combined organics were washed with 5% NaHCO3 (2×200 mL), then sat. NH4Cl (300 mL), and dried over Na2SO4 overnight. The organics were evaporated to yield the product as a clear, pale yellow oil (6.57 g, yield 90%). 1H NMR (300 MHz, CDCl3), d (ppm): 4.11 (q, 2H, J 7.1); 2.47 (t, 2H, J 6.9); 1.70-1.46 (m, 4H); 1.25 (t, 3H, J 7.1); 1.17 (s, 6H). 13C NMR (75 MHz, CDCl3), d (ppm): 177.5, 60.1, 41.9, 39.7, 32.3, 25.00, 24.95, 14.1.