Methanol → 4-Bromo-1-benzothiophene-2-carboxylic acid

A mixture of methyl 4-bromobenzo[b]thiophene-2-carboxylate (101 g), sodium hydroxide (63 g), methanol (1200 ml) and water (600 ml) was stirred at ambient temperature for 16 hours, the methanol was removed in vacuo, and the resulting suspension was cooled to 0° C. and acidified by dropwise addition of concentrated hydrochloric acid. The mixture was stirred for 20 minutes and the resulting solid was collected by filtration, washed with water (3×250 ml) and dried in vacuo at 110-120° C. to give 4-bromobenzo[b]thiophene-2-carboxylic acid (62 g) as a cream solid which was used without further purification.

1. customthe methanol was removed in vacuo
2. temperaturethe resulting suspension was cooled to 0° C.
3. additionacidified by dropwise addition of concentrated hydrochloric acid
4. stirringThe mixture was stirred for 20 minutes
5. filtrationthe resulting solid was collected by filtration
6. washwashed with water (3×250 ml)
7. customdried in vacuo at 110-120° C.

ORD record

ord-ed15c01f872b4d8d81cc4481d67bf288

Source dataset

uspto-grants-2005_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06900216B2