Carbon Dioxide → 6a,7,8,9-tetrahydro-6H-pyrido[3,2-e]pyrrolo[1,2-a][1,4]diazepine-6,11(5H)-dione

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Reaction Steps

36 g (0.26 mol) of 3-aminopyridine-2-carboxylic acid, 46.6 g (0.29 mol) of N,N'-carbonyldiimidazole and 200 ml of dimethylformamide are stirred at room temperature until the carbon dioxide evolution has finished, then the mixture is treated with 26.3 g (0.26 mol) of triethylamine and 43.1 g (0.26 mol) of methyl L-prolinate and stirred at room temperature for a further 1.5 hours. Subsequently, the solution is poured into water, extracted four times with chloroform, the combined chloroform extracts are dried over magnesium sulphate and then evaporated in vacuo. The oily residue is treated with 500 ml of glacial acetic acid, heated to boiling under reflux for 1 hour and then evaporated to dryness. By recrystallization from ethanol there is obtained 6a,7,8,9-tetrahydro-6H-pyrido[3,2-e]pyrrolo[1,2-a][1,4]diazepine-6,11(5H)-dione of melting point 249°-250°.

Provenance & Evidence