Hydrochloric Acid → 1,3,4,5-tetrahydro-1-{1-[(4-methyl-4H,6H-pyrrolo[1,2-a][4,1]benzoxazepin-4-yl)-methyl]-4-piperidinyl}-2H-imidazol-2-one

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Reaction Steps

To a solution of 4.5 g of 4-formyl-4-methyl-4H,6H-pyrrolo[1,2-a][4,1]benzoxazepine in 50 ml of methanol is added 3.6 ml of 5.5N methanolic HCl and 3.4 g of 1,3,4,5-tetrahydro-1-(4-piperidinyl)-2H-imidazol-2-one followed by 900 mg of sodium cyanoborohydride. The reaction mixture is allowed to stir at room temperature for 8 days. 2 ml of conc. HCl is added to the reaction mixture and the solvent is removed by evaporation under reduced pressure. The residue is dissolved in 150 ml water and washed with 150 ml of 1:1 ethyl acetate-ether mixture. The aqueous phase is separated, basified with dilute sodium hydroxide to pH 9 and extracted with 2×150 ml of ethyl acetate. The combined ethyl acetate extracts are dried over anhydrous MgSO4, filtered, and the solvent is removed by evaporation under reduced pressure to yield 1,3,4,5-tetrahydro-1-{1-[(4-methyl-4H,6H-pyrrolo[ 1,2-a][4,1]benzoxazepin-4-yl)-methyl]-4-piperidinyl}-2H-imidazol-2-one which is characterized as its maleate salt, m.p. 197°-199°.

Provenance & Evidence