[NH2:1][C:2]1[CH:7]=[CH:6][C:5]([Cl:8])=[CH:4][C:3]=1[CH2:9][N:10]1[CH:14]=[C:13]([CH3:15])[CH:12]=[C:11]1[C:16]([O:18]CC)=O.CC(C)([O-])C.[K+].O>CS(C)=O>[Cl:8][C:5]1[CH:6]=[CH:7][C:2]2[NH:1][C:16](=[O:18])[C:11]3=[CH:12][C:13]([CH3:15])=[CH:14][N:10]3[CH2:9][C:3]=2[CH:4]=1To a solution of ethyl 1-[(2-amino-5-chloro-phenyl)methyl]-4-methyl-pyrrole-2-carboxylate (20 g, 68.3 mmoles) in dimethyl sulfoxide (60 mL) add potassium t-butoxide (8.4 g, 74.9 mmoles) in DMSO (40 mL) and heat the reaction mixture to 75-80° C. for 1-2 hr. Add water (200 mL) slowly, cool to room temperature, and stir for 1-2 hr. Filter the solids, wash the filtercake with water (75 mL), and transfer the solids to a clean reaction vessel. Add THF (100 mL) and heat the reaction mixture to 30-35° C. until the solids dissolve. Add DCM (350 mL) and continue to stir at 30-35° C. for 1-2 hr. Add 1N hydrochloric acid (250 mL) and continue to stir at 30-35° C. for 1-2 hr. Separate the layers, wash the organic layer with 1N hydrochloric acid (250 mL) followed by a 25% aqueous solution of sodium chloride (50 mL), and concentrate the solution, at below 50° C., to arrive at a volume of approximately 25 mL. Add ethanol (50 mL), concentrate the solution, at below 50° C., to arrive at a volume of approximately 25 mL, and add additional ethanol (50 mL). Concentrate the solution, at below 50° C., to arrive at a volume of approximately 25 mL, heat the reaction mixture to 45-50° C., and stir for 1-2 hr. Cool the reaction mixture to 5-10° C. with stirring for 2-3 hr., and filter the resulting solids. Rinse the filtercake with ethanol (25 mL) and dry in an oven at less than 50° C. under reduced pressure to give 7-chloro-2-methyl-5,10-dihydro-11H-pyrrolo[2,1-c][1,4]benzodiazepin-11-one as an off-white solid (14.9 g, 99.9% purity, 88.5% yield).
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