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

Participants

Reaction Steps

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.

Provenance & Evidence