Sodium Nitrite → HCID 68660365, compound

Temperature

0 °C

A dispersion of 7-chloro-benzo[b]thiophen-5-ylamine (2.3 g, 0.012 mol) in dil. sulphuric acid (14 ml conc. H2SO4 in 400 ml water) was heated to obtain the clear solution and it was cooled to 0° C. A cold solution of NaNO2 (0.9 g in 5 mL of water, 0.013 mol) was added dropwise and the mixture was stirred at same temperature for 1 h and then warmed to 10° C. over 30 min. Excess nitrite was then quenched with urea. The reaction mixture was then added to dil. sulphuric acid (8 mL conc. Sulphuric acid in 115 mL water) maintained at 90° C. and the mixture was further refluxed for 1 h. The reaction mixture was filtered hot and the filtrate was stirred overnight at room temperature. The mixture was extracted with ethyl acetate and the combined organic extracts were washed with water, brine, dried and concentrated. The residue was purified by column chromatography (silica gel, hexane:ethyl acetate/9:1) to give 0.4 g of 7-chloro-benzo[b]thiophene-5-ol.

1. customto obtain the clear solution and it
2. temperaturewarmed to 10° C. over 30 min
3. customExcess nitrite was then quenched with urea
4. additionThe reaction mixture was then added to dil. sulphuric acid (8 mL conc. Sulphuric acid in 115 mL water)
5. temperaturemaintained at 90° C.
6. temperaturethe mixture was further refluxed for 1 h
7. filtrationThe reaction mixture was filtered hot
8. stirringthe filtrate was stirred overnight at room temperature
9. extractionThe mixture was extracted with ethyl acetate
10. washthe combined organic extracts were washed with water, brine
11. customdried
12. concentrationconcentrated
13. customThe residue was purified by column chromatography (silica gel, hexane:ethyl acetate/9:1)

ORD record

ord-1505183159114019b78ce201465bd497

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08507509B2