Yield:1042986-10-6 94%

Reaction Conditions:

Stage #1: 2-chloro-3-(5-ethoxycarbonyl-2-thenoyl)pyridinewith sodium hydroxide;ethanol;water in tetrahydrofuran at 20; for 18 h;
Stage #2: with hydrogenchloride;ethanol;water in tetrahydrofuran; pH=2 - 3;

Steps:

15

To 2-chloro-3-(5-ethoxycarbonyl-2-thenoyl)pyridine (5 g, 17 mmol) in tetrahydrofuran (50 ml) and ethanol (5 ml) was added a solution of sodium hydroxide (1.4 g, 40 mmol) in water (15 ml). The reaction mixture was stirred at room temperature for 18 hours. The solution was acidified to pH 2-3 by addition of concentrated HCl and extracted into ethyl acetate. The organic layer was washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuo to give the acid (4.3 g, 94% yield).

References:

WO2008/94992,2008,A2 Location in patent:Page/Page column 187