SYNTHESIS AND PROPERTIES OF PYRROLO(3,4-DEXTRO)IMIDAZOLES. A NEW FLUORESCENT HETEROCYCLIC SYSTEM

Pyrrolo 3,4-d imidazoles, "stretched-up" pyrimidine analogues, have been prepared by a two-step procedure from the corresponding pyrrolo 3,4-d imidazolines. The new heterocyclic system displays exceptional fluorescence properties. Large Stokes shifts are observed in both polar and nonpolar solvents, and the emission maxima are sensitive to solvent. The planarity of the substituted pyrrolo 3,4-d imidazole ring system has been established by X-ray crystallographic analysis. The problem of a suitable protecting group for the system has been addressed and N-ribosyl derivatives of both pyrrolo 3,4-d imidazolines and pyrrolo 3,4-d imidazoles have been prepared.