Ethanol → Ethyl 5-bromothiophene-3-carboxylate

5-bromo-thiophene-3-carboxylic acid (18.2 g, 0.09 mol) was dissolved in absolute ethanol (150 ml) and H2SO4 (5 ml), and the mixture was refluxed for 5 hours. The mixture was concentrated under vacuum to give a yellow oil, then diluted with a mixture of ethyl acetate (100 ml) and saturated brine (200 ml), and mixed, let standing for layer separation. The aqueous layer was washed with ethyl acetate (25 ml twice). The extract and the organic layer was adjusted with Na2CO3 (10%) to pH=8, and the organic phase was separated and washed with saturated brine to pH=7, dried over anhydrous Na2SO4 over night. The organic layer was concentrated under reduced pressure to give 5-bromo-thiophene-3-carboxylic acid ethyl ester as yellow oil (15 g).

1. concentrationThe mixture was concentrated under vacuum
2. customto give a yellow oil
3. additionmixed
4. customlet standing for layer separation
5. washThe aqueous layer was washed with ethyl acetate (25 ml twice)
6. extractionThe extract
7. customthe organic phase was separated
8. washwashed with saturated brine to pH=7
9. dry with materialdried over anhydrous Na2SO4 over night
10. concentrationThe organic layer was concentrated under reduced pressure

ORD record

ord-a1f7535c79e04bbcb9dbc0efbf0e3c0d

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09249154B2