Isopropanol → Ammonia

Participants

Reaction Steps

A mixture of 1-(6-bromo-3-pyridyl)-4-tert-butoxycarbonylpiperazine (1.0 g, 2.9 mmol), phenyl boronic acid (1.06 g, 8.8 mmol), aqueous potassium carbonate (4.3 ml, 8.7 mmol), water (4.3 ml), isopropanol (0.66 ml, 8.7 mmol), 1.2-dimethoxyethane (10 ml) and palladium (0) tetrakis triphenylphosphine (66 mg, 0.058 mmol) was stirred at reflux for 4 days. Aqueous sodium hydroxide (50 ml) was added and the mixture was extracted with methylene chloride (3×50 ml). Chromatography of this crude mixture on silica gel with dichloromethane, methanol and conc. ammonia (89:10:1) gave 1-(6-phenyl-3-pyridyl)-4-tert-butoxycarbonylpiperazine. The intermediate (0.80 g, 2.4 mmol), trifluoroacetic acid (1.8 ml, 23.6 mmol) and dichloromethane (10 ml) was stirred for 1.5 hour. The mixture was evaporated. Aqueous sodium hydroxide (50 ml, 1 M) was was added and the mixture was extracted with diethyl ether (3×50 ml). The corresponding salt was obtained by addition of a diethyl ether and methanol mixture (9:1) saturated with fumaric acid. Mp 203-204° C.

Provenance & Evidence