Interaction of 3-(2-Aminophenyl)-6-R1-1,2,4-triazin-5-ones with Acylating Reagents: An Efficient Method for Preparation of 6-Substituted 3-R1-2H-[1,2,4]triazino[2,3-c]quinazolin-2-ones

The series of 6‐substituted 3‐R1‐2H‐[1,2,4]triazino[2,3‐c]quinazolin‐2‐one was prepared via condensation of 3‐(2‐aminophenyl)‐6‐R1‐1,2,4‐triazin‐5‐ones with acylating reagents. Particularities of 1H NMR spectra have been also discussed based on the comparison of experimental and theoretical results for 3‐methyl‐6‐phenyl‐2H‐[1,2,4]triazino[2,3‐c]quinazolin‐2‐one and its 4,3‐isomer.