A suspension of 7-chloro-6-phenyl-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine-8-carboxylic acid amide trifluoroacetic acid salt (100 mg, Reference Example 1) in dry dichloromethane (2 mL) under a blanket of nitrogen was treated with dry triethylamine (35 μL), then with a 2M solution of trimethylaluminum in toluene (0.30 mL) dropwise. After stirring at room temperature for a further 30 minutes the reaction mixture was treated with N-4-methoxyphenyl-N′-cyano-O-phenylisourea (64 mg, Reference Example 46) and then further stirred at room temperature for 3 hours. The reaction mixture was then heated overnight at 50° C. and then allowed to cool to room temperature. The reaction mixture was further treated with dichloromethane and then washed with a 0.5M aqueous solution of sodium carbonate. The organic phase was dried over magnesium sulfate and evaporated. The residue was subjected to column chromatography on silica eluting with a mixture of pentane and ethyl acetate (1:1, v/v) then ethyl acetate to give 2-[(cyanoimino)(4-methoxyphenylamino)methyl]-7-chloro-6-phenyl-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine-8-carboxylic acid amide (10 mg) as a white solid, m.p. 170° C. MS: 451 [MH]+, 449 [MH]+.
