Bromine → Methyl 5-bromo-4-methyl-3-(4-sulfamoylphenyl)thiophene-2-carboxylate

Temperature

25 °C

To a stirred suspension of methyl 4-methyl-3-(4-sulfamoylphenyl)thiophene-2-carboxylate (compound 7b, 8.80 g, 27.0 mmol) in DCM (150 ml), bromine (5.19 g, 1.67 ml, 32.0 mmol) was added at 0° C. in a drop wise manner. The reaction mixture was stirred at 25° C. for 2 hr and the progress of the reaction was monitored by TLC. The reaction mixture was then concentrated completely and again dissolved in DCM (250 ml). The organic layer so obtained was washed with water (2×50 ml), brine (1×50 ml) and dried over sodium sulfate and concentrated under reduced pressure to obtain crude product as semi-solid (10.2 g), which was then purified by column chromatography over silica gel (100-200 mesh) using 50% ethyl acetate in hexanes as an eluent to obtain the title compound (20% ethyl ester as trans esterified product was observed) (9.0 g, 82.34%).

1. additionwas added at 0° C. in a drop wise manner
2. concentrationThe reaction mixture was then concentrated completely
3. dissolutionagain dissolved in DCM (250 ml)
4. customThe organic layer so obtained
5. washwas washed with water (2×50 ml), brine (1×50 ml)
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated under reduced pressure
8. customto obtain crude product as semi-solid (10.2 g), which
9. customwas then purified by column chromatography over silica gel (100-200 mesh)

ORD record

ord-b1076ce20fe8486c9c2fdb32513e585f

Source dataset

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09072731B2