Ammonia → 3-Chloroquinolin-6-ol

Temperature

150 °C

3-Bromo-6-hydroxyquinoline (2.75 g) and cuprous chloride (9 g) in dry N-methylpyrrolidin-2-one (25 ml) were stirred and heated at 150° C. under an atmosphere of nitrogen for 2 hours. The dark red suspension was cooled to ambient temperature, poured into water then treated with sufficient aqueous ammonia to dissolve the solid material. The blue solution was taken to pH 5-6 with hydrochloric acid (2M) then ethyl acetate was added. The mixture was filtered and the insoluble solids washed with ethyl acetate. The organic component of the filtrate was separated and the aqueous phase was further extracted with ethyl acetate. The ethyl acetate fractions were combined, washed with brine, dried over magnesium sulphate then evaporated under reduced pressure to give a solid. The solid was fractionated by chromatography (silica; hexane/ethyl acetate, 2:1 by volume) to give 3-chloro-6-hydroxyquinoline as a pale yellow solid, 0.95 g. (M+ 179, 1×Cl). 1H NMR (CDCl3) δ: 7.06(1H, d); 7.35(1H, dd); 7.91(1H, d); 7.96(1H, d); 8.59(1H, d); 9.55(1H, s).

1. temperatureThe dark red suspension was cooled to ambient temperature
2. dissolutionto dissolve the solid material
3. filtrationThe mixture was filtered
4. washthe insoluble solids washed with ethyl acetate
5. customThe organic component of the filtrate was separated
6. extractionthe aqueous phase was further extracted with ethyl acetate
7. washwashed with brine
8. dry with materialdried over magnesium sulphate
9. customthen evaporated under reduced pressure
10. customto give a solid

ORD record

ord-a4e1a0dded164bad9334f51d8ec62624

Source dataset

uspto-grants-2008_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07371764B2