Hydrochloric Acid → 5-Amino-2,3-dichloropyridine

A solution of 2,3dichloro-5-nitropyridine (prepared as described in Rocz. Chem. (1968), 42 (12), 2079–2088; CAN 70:106327; 2.83 g) in propan-2-ol (40 ml) was added over 10 minutes to a stirred mixture of reduced iron powder (2.96 g), propan-2-ol (25 ml), water (15 ml) and concentrated hydrochloric acid (0.24 ml) at 70° C. The mixture was heated to reflux for 1 hour then sodium hydroxide (0.13 g) in water (1 ml) was added and the reaction filtered whilst hot through kieselguhr. The insoluble material was washed with ethyl acetate and water and the filtrates were combined and evaporated under reduced pressure to a small volume. The residue was extracted with dichloromethane (three times) and the extracts were combined, washed with water, dried over magnesium sulphate and evaporated under reduced pressure to give the required product, 2.11 g, as a pale yellow solid, m.p. 117–119° C.

1. temperatureThe mixture was heated
2. temperatureto reflux for 1 hour
3. filtrationthe reaction filtered whilst hot through kieselguhr
4. washThe insoluble material was washed with ethyl acetate and water
5. customevaporated under reduced pressure to a small volume
6. extractionThe residue was extracted with dichloromethane (three times)
7. washwashed with water
8. dry with materialdried over magnesium sulphate
9. customevaporated under reduced pressure

ORD record

ord-5eb2700212484625ad1e6d179efe955f

Source dataset

uspto-grants-2007_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07166621B2