Mannich Reaction in the Synthesis of N,S‐Containing Heterocycles. Part 1. Synthesis of Novel Derivatives of Imidazo[2,1‐b][1,3,5]thiadiazine.

Abstract

2,1-b][1,3,5]thiadiazine. -The aminomethylation of 5-arylidene-2-thiohydantoins (I) offers a simple and convenient route to novel substituted imidazothiadiazines (III), which are promising starting material and objects for bioscreening. -(FROLOV, K. A.; DOTSENKO, V. V.; KRIVOKOLYSKO, S. G.; LITVINOV*, V. P.; Russ.

Design and Synthesis of Pyrido[2,1-b][1,3,5]thiadiazine Library via Uncatalyzed Mannich-Type Reaction

“…One of the most effective approaches to 1,3,5-thiadiazines is based on the double Mannich-type reaction of thioamides, dithiocarbamates or related S , N -binucleophilic species with primary amines and formaldehyde. − Cyclic thioamides (γ- and δ-thiolactams, 2-mercaptoazoles, -azines, or their 2-thioxotautomers) can also be successfully employed in this reaction, giving rise to a variety of ring-condensed 1,3,5-thiadiazines. In fact, the related syntheses of 1,2,4-triazolo[3,4- b ][1,3,5]thiadiazines, − imidazo[2,1- b ][1,3,5]thiadiazines, , 1,2,4-triazino[3,2- b ][1,3,5]thiadiazines, thiazolo[3′,4′:1,5][1,2,4]triazolo[3,4- b ][1,3,5]thiadiazines, 1,3,5-thiadiazino[3,2- a ]benzimidazoles, cyclopenta[ g ]pyrido[2,1- b ][1,3,5]thiadiazines, bis (pyrido[2,1- b ][1,3,5]thiadiazin-7-yl)methanes, pyrimido[2,1- b ][1,3,5]thiadiazines, and pyrimido[4,3- b ][1,3,5]thiadiazines − have been reported (Scheme ).…”