Acetyl chloride → 1-[8-Chloro-1-(3,4,5,6-tetrahydro-2h-[1,2']bipyridinyl-4-yl)-4h,6h-2,3,5,10b-tetraaza-benzo[e]azulen-5-yl]-ethanone dihydrochloride

Acetyl chloride (0.1 ml, 1.4 mmol) was added to an ice cooled solution of the amine of example 4 (200 mg, 0.53 mmol) in dichloromethane (5 ml) and stirred at room temperature for 20 hours. Dichloromethane was evaporated off under reduced pressure and the residue purified by chromatography on silica gel using methanol in dichloromethane (5:95) as eluant. The residue was dissolved in dichloromethane (2 ml) and hydrochloric acid (1M in diethyl ether, 2 ml) was added, and the solvents evaporated under reduced pressure to give the title compound as a brown foam (110 mg).