Cycloaddition reactions of 2,3‐dihydro‐1H‐1,4‐diazepines with nitrile oxides and imines. Synthesis of bis[1,2,4]oxadiazolo‐and bis[1,2,4]triazolo[1,4]diazepine derivatives

Abstract

AbstractNew heterotricyclic systems, 6,10a,11,11a‐tetrahydro‐5H‐bis[1,2,4]oxadiazolo[4,5‐d:5′,4′‐g][1,4]diazepines 6,7,9‐11 and 5,6,10,10a,11,11a‐hexahydro‐1H‐bis[1,2,4]triazolo[4,3‐d:3′,4′‐g][1,4]diazepines 8,12 have been obtained by double site‐ and regie‐specific 1,3‐dipolar cycloaddition of mesitylnitrile oxide (1) or diphenylnitrile imine (2) to 5,7‐disubstituted 2,3‐dihydro‐1H‐1,4‐diazepines 3‐5. The structure of the synthesized bis‐adducts 6‐12 shows that the hetero double bonds are much more reactive than the olefinic ones in the dipolarophiles under study. No evidence for the formation of mono‐adducts was obtained.