A New Method for the Synthesis of -Monosubstituted 1,3-Diaminopropanes

A new method for the synthesis of N-monosubstituted diamines has been developed. On the first step 1,3-diaminopropane is protected with phthalic anhydride to form a heterocyclic system - 3,4-dihydropyrimidino[2,1-]isoindol-6(2)-one, which is then subjected to selective alkylation followed by removal of the protective phthalyl group, that leads to the target diamines with a total yield of up to 66% without formation of excessively alkylated diaminopropanes. The paper presents the X-ray data of new compounds - 1-methyl-6-oxo-2,3,4,6-tetrahydropyrimido[2,1-]isoindol-1-ium iodide and 3-(1,3-dioxoisoindoline-2-yl)--methylpropan-1-aminium iodide.