ChemInform Abstract: Heterocyclic Ring-Closure Reactions. Part 9. Reactions of Trimethylsilyl Isocyanate and Isothiocyanate with 3-(Dialkylamino)-2H-azirines. A Facile Synthesis of 1-Unsubstituted 4-(Dialkylamino)imidazolin-2-ones and 4-(Dialkylamino)imidazoline-2-thiones.

ChemInform Abstract

The azirines (I) are treated with trimethylsilyl isothiocyanate (II) or trimethylsilyl isocyanate (IV) to yield the imidazolinethiones (III) or the imidazolinones (V). In contrast, the azirine (VI) react with the isothiocyanate (II) to give the crotonamidinium thiocyanate (VII). Oxidation of (IIIa) and (IIIc) with hydrogen peroxide yields the imidazolinones (Va) and (Vc). Hydrolysis of (IIIa) produces the dimethylthiohydantoin (VIII). Further reactions in this series are described in the original paper.