One-Pot Synthesis of 3,4-Dihydropyrimidino[2,1-a]isoindol-6(2H)-one

One-pot synthesis of 3,4-dihydropyrimidino[2,1-a]isoindol-6(2H)-one, an analog of the promising anti-cancer drug batracilin, has been developed. Both acylation of 1,3-diaminopropane with phthalic anhydride and followed by cyclocondensation took place while heating in toluene or ortho-xylene. The highest yield 76% of the target isoindolone was obtained by adding 1,3-diaminopropane to phthalic anhydride in toluene, while reverse order of mixing the reagents, decreases the yield to 60%. The reaction proceeds stepwise, through the formation of 2-(3-aminopropyl)carbamoyl)benzoic acid, which is converted to isoindolone upon heating with 68% yield.