Benzophenone imine → 3-(Benzhydrylidene-amino)-1-methyl-pyrrolidin-2-one

Participants

Reaction Conditions

Reaction Steps

Benzophenone imine (200.04 g, 1103.8 mmol) was added dropwise over 20 minutes to a stirred solution of 3-amino-1-methylpyrrolidine-2-one (120 g, 1051.2 mmol) in DCE (1000 mL) at ambient temp under nitrogen in a 2 L flask fitted with a magnetic stirrer bar. The reagent was washed with further DCE (100 mL). The stirred solution was heated at reflux on a heat-on block at a block temp of 95° C. for 7 h, using a N2 bubbler with exhaled gas passing through a safety trap then into 2 L of water via an upturned funnel (for scrubbing NH3 gas, estimated to be approx 23 L). The reaction was left to stand at ambient temp overnight under N2. The mixture was evaporated to a thick, off-white oil. To this was added Et2O (700 ml) and to this stirred solution, as it began to crystallize, was added iso-hexane (700 ml) over 2 minutes. The mixture was stirred for 1 h then filtered under suction and washed with Et2O/iso-hexane (1:1) (500 ml). The white solid was dried at 35° C. under vacuum for 3 h to afford 3-(benzhydrylidene-amino)-1-methyl-pyrrolidin-2-one (D1) (259.4 g, 88.6%). The NMR was consistent with pure material.

Provenance & Evidence