Thioglycolic Acid → 4-Bromo-1-benzothiophene-2-carboxylic acid

HRID 250239Notes

Reaction equation

[OH-].[K+].[Br:3][C:4]1[CH:11]=[CH:10][CH:9]=[C:8](F)[C:5]=1[CH:6]=O.[SH:13][CH2:14][C:15]([OH:17])=[O:16]>CN(C)C=O>[Br:3][C:4]1[C:5]2[CH:6]=[C:14]([C:15]([OH:17])=[O:16])[S:13][C:8]=2[CH:9]=[CH:10][CH:11]=1

Participants

Conditions

Temperature: 136 °C

Procedure

Potassium hydroxide (415.1 g, 7.40 mol) is added to a stirred solution of 2-bromo-6-fluorobenzaldehyde (1.00 Kg, 4.93 mol) and mercaptoacetic acid (453.8 g, 4.93 mol) in dimethylformamide (5.0 L). The resultant solution is brought to and maintained at reflux (136° C.) for 90 min. The reaction mixture is allowed to cool to room temperature and is quenched by the slow addition of hydrochloric acid (2.25 M, 5.90 L) over 5 min. The mixture is cooled to 10° C., stirred for 1 h and the observed solid material is collected by filtration. The filter cake is washed with water (1.00 L) and hexanes (2.00 L) and dried in vacuo at 40 to 45° C. to constant weight to yield the title compound (990.0 g, 78.2%). 1H NMR (DMSO, d6): δ 13.8 (bs, 1H), 8.10 (d, 1H, J=8.2 Hz), 7.97 (s, 1H), 7.72 (d, 1H, J=7.6 Hz), 7.45 (t, 1H, J=8.0 Hz).

Workup

temperaturemaintained
temperatureto cool to room temperature
customis quenched by the slow addition of hydrochloric acid (2.25 M, 5.90 L) over 5 min
temperatureThe mixture is cooled to 10° C.
filtrationthe observed solid material is collected by filtration
washThe filter cake is washed with water (1.00 L) and hexanes (2.00 L)
customdried in vacuo at 40 to 45° C. to constant weight

Sources & evidence

ORD record: ord-becba6a3619744ad992ffafd399bacf5
Source dataset: uspto-grants-2011_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07863302B2

Reaction notes

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