Dimethyl Sulfoxide → Methyl 4-chloro-1-benzothiophene-2-carboxylate

A 100 ml 3-necked round-bottomed flask, reflux condenser, thermometer adapter, gas inlet, and Teflon stirrer were oven-dried for 12 hours at 160° C. The apparatus was rapidly assembled, fitted with a thermometer, flushed with dry nitrogen gas, sealed with rubber septa, and allowed to cool to room temperature. The cooled reaction flask was charged with anhydrous dimethyl sulfoxide (40 ml), 2-fluoro-6-chlorobenzaldehyde (5 g, 31.53 mmole), anhydrous triethylamine (2.5 equivalents, 78.83 mmole, 7.976 g, 11 ml) and methyl thioglycolate (1.1 equivalents, 3.681 g, 3.10 ml, 34.68 mmole). The reaction mixture was heated to 75° C. with rapid stirring. The progress of the reaction was monitored by thin-layer chromatography (TLC, silica, 10% dichloromethane-hexane developing solution and UV visualization). After 3 hours the reaction mixture was allowed to cool to room temperature and poured into an ice/water mixture (250 ml). The resulting slurry was stirred for 20 minutes, filtered, washed with cold water (2×100 ml) and dried in vacuo to give 6.07 g (85%) of methyl 4-chlorobenzo[b]thiophene-2-carboxylate. See, A. J. Bridges, A. Lee, E. C. Madukor, and C. E. Schwartz, Tetrahedron Letters, 33:7499 (1992).

1. temperatureA 100 ml 3-necked round-bottomed flask, reflux condenser, thermometer adapter, gas inlet, and Teflon stirrer
2. customwere oven-dried for 12 hours at 160° C
3. customfitted with a thermometer
4. customflushed with dry nitrogen gas
5. customsealed with rubber septa
6. customThe cooled reaction flask
7. temperatureThe reaction mixture was heated to 75° C. with rapid stirring
8. temperatureto cool to room temperature
9. filtrationfiltered
10. washwashed with cold water (2×100 ml)
11. customdried in vacuo

ORD record

ord-fd02a35b140c4878add4f47e0beb3248

Source dataset

uspto-grants-1999_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05863936