反应详情

To a solution of 2-methoxycarbonyl-3-chloro4-(acetoxymethyl)thiophene (83 g, 0.33 mol) in 1,4-dioxane (350 mL) was added a solution of sodium hydroxide (26.5 g, 0.66 mol) in water (200 mL) and the mixture stirred at ambient temperature. After 1 hour the dioxane was removed in vacuo and the aqueous solution washed with ethyl acetate (2×100 mL). The aqueous layer was brought to pH 2 by addition of concentrated HCl, then extracted with n-butanol (4×200 mL). The combined extracts were concentrated and the resulting solid dried in vacuo to afford 63 g (90% yield) of 2-carboxy-3-chloro-4-(hydroxymethyl)thiophene as a tan powder; NMR (DMSO-d6) 7.7 (s, 1), 4.4 (s, 2) ppm.

1. customAfter 1 hour the dioxane was removed in vacuo
2. washthe aqueous solution washed with ethyl acetate (2×100 mL)
3. additionThe aqueous layer was brought to pH 2 by addition of concentrated HCl
4. extractionextracted with n-butanol (4×200 mL)
5. concentrationThe combined extracts were concentrated
6. customthe resulting solid dried in vacuo