Regioselective Synthesis of Imidazo[4,5‐ e ][1,3]Thiazino[3,2‐ b ][1,2,4]Triazines as New Heterocyclic System Derivatives

• Published in: Journal of heterocyclic chemistry
• Main Authors: Izmest'ev, Alexei N., Baranov, Vladimir V., Kolotyrkina, Natalya G., Kravchenko, Angelina N., Gazieva, Galina A.
• Format: Journal Article
• Language: English
• Published: 21-10-2024
• ISSN: 0022-152X; 1943-5193
• DOI: 10.1002/jhet.4925

ABSTRACT A series of new 4a,7a‐diarylperhydroimidazo[4,5‐ e ][1,2,4]triazine‐3‐thiones were synthesized from 4,5‐diaryl‐4,5‐dihydroxyimidazolidin‐2‐ones and thiosemicarbazide in high yields, and their interaction with ethyl phenylpropiolate was studied. An effective method for the regioselective synthesis of imidazo[4,5‐ e ][1,3]thiazino[3,2‐ b ][1,2,4]triazines as new heterocycic system derivatives was proposed based on the reaction of aforementioned imidazotriazinethiones with ethyl phenylpropiolate in the presence of MeONa in methanol. The reaction is initiated by a Michael‐type addition of the imidazotriazinethiones to the triple bond of ethyl phenylpropiolate followed by intramolecular cyclization.