Acetic acid, (cyclopentylthio)- (9CI) synthesis

Yield:-

Reaction Conditions:

Stage #1: ethyl 2-(cyclopentylthio)acetatewith water;potassium hydroxide in ethanol; for 3 h;Reflux;
Stage #2: with hydrogenchloride in dichloromethane;water; pH=~ 2;Cooling with ice;

Steps:

143.143B

Example 143B 2-(cyclopentylthio)acetic acid A solution of 20% aqueous KOH (14.8 g, 52.8 mmol) was added to a solution of the product from Example 143A (8.89 g, 46.7 mmol) in EtOH (30 mL), and the resulting mixture was heated at reflux for 3 hours. The reaction solution was cooled to room temperature and concentrated under vacuum. The residue was diluted with water (20 mL) and CH₂Cl₂ (50 mL) and cooled in ice as 37% HCl (15 mL) was added gradually with good stirring (final pH ~2). The aqueous layer was separated and extracted with CH₂Cl₂ (50 mL) and the combined organic phase was washed with brine (30 mL), dried (Na₂SO₄), filtered, and concentrated under vacuum to provide the title compound. ¹H NMR (300 MHz, CDCl₃) δ ppm 1.44-1.66 (m, 4H), 1.67-1.86 (m, 2H), 1.93-2.12 (m, 2H), 3.14-3.31 (m, 1H), 3.30 (s, 2H).

References:

US2012/122888,2012,A1 Location in patent:Page/Page column 44-45