Sodium hydride → 3-(4-Bromothiophen-2-yl)but-2-enoic acid

Temperature

0 °C

A solution of ethyl (diethoxyphosphino)acetate (34 mL, 171 mmol) in THF (35 mL) was added dropwise via addition funnel, over 20 minutes, to a 0° C. suspension of NaH (6.9 g, 60% oil dispersion, 172 mmol) in THF (200 mL). The resulting mixture was stirred at 0° C. for 30 minutes, then treated with a solution of 1-(4-bromo-2-thienyl)ethanone (23.6 g, 115 mmol) in THF (75 mL). The reaction was warmed to room temperature, stirred for 4 hours, quenched with water, neutralized with 2N HCl, and extracted three times with ethyl acetate. The combined extracts were washed with brine, dried (Na2SO4), filtered, and concentrated. The concentrate was dissolved in ethanol (350 mL) and THF (190 mL), treated with 2N LiOH (115 mL), stirred overnight at room temperature, and concentrated. The remaining aqueous solution was washed with diethyl ether, acidified with 2N HCl, and filtered. The filter cake was washed with water and dried to provide 22.38 g (79% yield) of the desired product as a mixture of E and Z isomers. MS (ESI(+)) m/e 244.7, 246.7 (M+H)+.

1. temperatureThe reaction was warmed to room temperature
2. stirringstirred for 4 hours
3. customquenched with water
4. extractionextracted three times with ethyl acetate
5. washThe combined extracts were washed with brine
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated
9. dissolutionThe concentrate was dissolved in ethanol (350 mL)
10. additionTHF (190 mL), treated with 2N LiOH (115 mL)
11. stirringstirred overnight at room temperature
12. concentrationconcentrated
13. washThe remaining aqueous solution was washed with diethyl ether
14. filtrationfiltered
15. washThe filter cake was washed with water
16. customdried

ORD record

ord-7409f33392074324be1bb3ca0f40997b

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07737160B2