Hydrochloric Acid → 2-{4'-[(3aR,6aR)-5-Methylhexahydropyrrolo[3,4-b]pyrrol-1(2H)-yl]-1,1'-biphenyl-4-yl}pyridazin-3(2H)-one HCl

2-{4′-[(3aR,6aR)-5-Methylhexahydropyrrolo[3,4-b]pyrrol-1(2H)-yl]-1,1′-biphenyl-4-yl}pyridazin-3(2H)-one (372 mg) was suspended in dichloromethane (1.5 mL). The suspension was heated to about 50° C. A 1 M HCl (1.1 mL) solution was added to the suspension in dichloromethane dropwise. Throughout the process the suspension is stirred using a magnetic stirrer and temperature maintained at about 50° C. Most of the solid dissolved leaving a light suspension when about one third of the HCl solution was added. Upon further addition of the HCl solution, crystallization was observed. The resulting suspension was agitated at ambient temperatures overnight before the crystals were harvested.