Phosgene → 5,10-Dihydro-5-{[(1-methyl-4-piperidinyl)oxy]carbonyl}-11H-dibenzo[b,e][1,4]diazepin-11-one

Participants

Reaction Steps

A quantity of 4.9 gm (0.0425 mol) of 1-methyl-4-piperidinol was added dropwise to a mixture of 22.5 ml of a 20% solution of phosgene in toluene, 100 ml of dioxane, and 4.75 gm (0.045 mol) of anhydrous sodium carbonate while external cooling with ice was carried out. The mixture was stirred for a further 60 minutes at ambient temperature, 9.0 gm (0.0428 mol) of 5,10-dihydro-11H-dibenzo[b,e][1,4]diazepin-11-one were added to the reaction mixture, and this was then refluxed for four hours. The mixture was filtered, the filtrate was concentrated by evaporation in vacuo, and the crude product obtained was purified by column chromatography on 500 gm of silica gel [eluant: ethyl acetate/methanol (volume ratio of 10:1)]. After recrystallization from ethyl acetate, the resulting colorless crystals melted at 203°-204° C. and were identical--according to the mixed melting point, thin layer chromatogram, and IR spectrum--to a product prepared according to Example 4. Yield: 7.6 gm (51% of theory).

Provenance & Evidence