Hydrazinolysis of 3-R-[1,2,4]Triazino[2,3-c]quinazolin-2-ones. Synthetic and Theoretical Aspects

Abstract

It has been shown that heating of 3-R-[1,2,4]triazino[2,3-c]quinazolin-2-ones with 5-fold excess of hydrazine hydrate in propanol-2 gave the corresponding 3-(2-aminophenyl)-6-R-1,2,4-triazin-5-ones with high yields. The mechanism of the reaction has been proposed based on the results of theoretical investigation at B3LYP and MP2 levels of theory. According to calculations, an attack of the hydrazine molecule on the C6═N7 double bond leads to ring-opening with N5-C6 bond cleavage. The process continues by addition of the second nucleophile molecule and elimination of the formazan fragment through a series of transformations that yield the target product.

Dimethyl Acetylenedicarboxylate in Reactions with Substituted 3‐(2‐aminophenyl)‐6‐R1‐1,2,4‐triazin‐5‐(2H)‐ones: Structure and Properties of the Products

“…3‐(2‐Amino‐3‐R 4 ‐4‐R 3 ‐5‐R 2 ‐phenyl)‐6‐R 1 ‐1,2,4‐triazin‐5(2 H )‐ones 1a–1m were used as starting compounds. Earlier, we have described them as promising 1,5‐binuclephiles leading to [1, 2, 4]triazino[2,3‐ c ]quinazolines .…”

“…3‐(2‐Amino‐3‐R 2 ‐4‐R 3 ‐5‐R 4 )‐6‐R 1 ‐1,2,4‐triazin‐5(2 H )‐ones ( 1a–1m ) have been prepared according to described synthetic protocols .…”

Design, Synthesis and Anti-inflammatory Activity of Derivatives 10-R-3-Aryl-6,7-dihydro-2H-[1,2,4] triazino[2,3-c]quinazolin-2-ones of Spiro-fused Cyclic Frameworks

“…Substances 1.1-1.5 were synthesized according to the reported procedures. 12 Other starting materials and solvents were obtained from commercially available sources and were used without additional purification.…”

Hydrolytic cleavage of the pyrimidine ring in 2-aryl-[1,2,4]triazole[1,5-c]quinazolines: physico-chemical properties and the hypoglycemic activity of the compounds synthesized

“…Recent publication describes hydrolytic cleavage of azole and azine condensed cycles under the action of nucleophiles [1,3,6,4,9,11,12,15,17,20,25,26,28,29]. It is known that kinetics of the reactions mentioned depends on basic properties of nucleophilic reagents.…”

“…It is known that kinetics of the reactions mentioned depends on basic properties of nucleophilic reagents. Strong nucleophiles (hydroxides and alkoxides of alkaline metals, hydrazine hydrate) easily react with the given substrates in the water or alcohol-water medium for 1 h and form products with high yields [4, 15,20,25,26,28,29]. Moreover, water may play the role of a nucleophile in hydrolytic cleavage reactions.…”