The reaction of 1-azirines with 2-pyridyl isothiocyanate: Possible approaches to benzodiazepine and benzodiazepine derivatives

The structure of the dimer ( 5 ) from 2-pyridyl isothiocyanate ( 1 ) has been confirmed by ¹³C nmr spectral studies. The cycloaddition of 2-pyridyl isothiocyanate with 1-azirines results in the formation of thiazoles ( 10 ). Thermal decomposition of the vinyl azide ( 14 ) gives the pyrrole ( 15 ) and the pyridazine ( 16 ) instead of 2-(2-pyridyl)-1-azirine ( 12 ).