4-Methylmorpholine → cis-4-[(4,6-Dihydro-4-oxo-3-phenylpyrido-[2,1-a]isoindol-1-yl)carbonyl]-2,6-dimethylmorpholine

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Reaction Steps

A suspension of 2.0 g of 4,6-dihydro-4-oxo-3-phenylpyrido[2,1-a]isoindole-1-carboxylic acid in 25 ml of N,N-dimethylformamide was treated under argon with 0.91 ml of cis-2,6-dimethylmorpholine and then with 0.81 ml of N-methylmorpholine and 2.8 g of 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate and stirred at room temperature for a further 4.5 hours. The reaction mixture was then poured into a mixture of 50 ml of saturated sodium hydrogen carbonate solution and 250 ml of water. The crystallized-out crude product was filtered under suction and dried. After chromatography on silica gel with toluene and toluene/acetone (9:1) recrystallization was carried out twice from ethyl acetate. There was obtained 1.19 g of cis-4-[(4,6-dihydro-4-oxo-3-phenylpyrido-[2,1-a]isoindol-1-yl)carbonyl]-2,6-dimethylmorpholine as yellow crystals with a m.p. of 226°-228°.

Provenance & Evidence