Comprehensive experimental investigation of mechanically induced 1,4-diazines synthesis in solid state

Abstract Compared mechanosynthesis of two condensed 1,4-diazines were investigated in ball milling conditions from o-phenylenediamine. 13 C CP-MAS NMR revealed a hemiaminal intermediate for dibenzo[a,c]phenazine synthesis accumulated under mechanical action, as confirmed by calorimetry. Such intermediate, which is not detected in the case of 2,3-diphenylquinoxaline synthesis, provides experimental evidence of a concerted reaction between highly reactive mechanically-excited diamine and 9,10-phenanthrenequinone.