ACTIVATED NITRILES IN HETEROCYCLIC SYNTHESIS NOVEL SYNTHESES OF IMIDAZO (2,1-b)-1,3-THIAZINE DERIVATIVES

Synthesis, reactions, and biological activity of 4,5-diarylimidazole-2-thiones (Review)

“…of 4,5-diphenylimidazole-2-thione (1) with acryloyl chloride (R = H), crotonyl chloride (R = Me), and 3-aryl-2-propenoyl chlorides in pyridine and acetone afforded 7-substituted 6,7-dihydro-5H-imidazo[2,1-b][1,3]thiazin-5-ones 100 [74imidazo[2,1-b][1,3]thiazine derivatives 101 (R = H, MeO, Cl) and 102 were synthesized via the reaction of thione 1 with α,β-unsaturated nitriles (R 1 = CN, COPh, R 2 = NH 2 , Ph)[75]…”

New Regioselective Synthesis of 7H-Imidazo[2,1-b][1,3]thiazine and 2H,6H-Pyrimido[2,1-b][1,3]thiazine Derivatives

“…4 Furthermore, Bózsing et al have reported anti-inflammatory and antipyretic properties of pyrimido [2,1-b] [1,3]thiazine derivatives. 5 Although many potent biological activities have been published, few syntheses of imidazothiazines and pyrimidothiazines have been proposed, most of them using imidazoline-2-thiones, [6][7][8] imidazolidine-2-thiones, 9,10 or 2-thioxopyrimidines [11][12][13] as starting materials inducing the formation of two regioisomers in certain cases. Therefore, the purpose of this work was to investigate an alternative, convenient and versatile preparation of these heterocyclic ring systems.…”