Synthesis of 6-R-3-(2-Aminophenyl)-2Н-1,2,4-Thriazin-5-ones: Resources and Limitations
The novel methods of 6-R-3-(2-aminophenyl)-2Н-1,2,4-triazin-5-ones synthesis by 2-R-[(3H-quinazoline-4-yliden)hydrazono]--carboxylic acid esters hydrazinolysis and nucleophylic cleavage of 3-R-2H-[1,2,4]triazino[2,3-c]quinazoline-2-ones are worked out. It is shown that 2-R-[(3H-quinazoline-4-yliden)–hydrazono]--carboxylic acid esters under hydrazinolysis form (3Н-quinazoline-4-yliden)hydrazine or 6-R-3-(2-aminophenyl)-2Н-1,2,4-triazin-5-ones. The reaction direction depends on geometric isomerism of corresponding esters.