4-Thiazolidinones in Heterocyclic Synthesis: Synthesis of Novel Enaminones, Azolopyrimidines and 2-Arylimino-5-arylidene-4-thiazolidinones

Abstract

The 4-thiazolidinones 3a–d were used as a key intermediates for the synthesis of 2-arylimino-5-arylidene-4-thiazolidinones derivatives 7a–p via nucleophilic addition reactions with the arylidene malononitrile. Moreover the 4-thiazolidinones 3a and 3c condensed with the DMF-DMA to form the corresponding enamines 8 and 9 depending on the reaction conditions. Otherwise the 4-thiazolidinone 3b reacts regioselectively with DMF-DMA to afford the enaminones 10 and 11, respectively. The latter reacts with many heterocyclic amines affording polyfunctionally substituted fused pyrimidine derivatives 13–18. The enamine 8b was also reacted with the 3-amino-1,2,4-triazole to afford the acyclic product 19, which could not be further cyclized to the corresponding tricyclic system 20. Moreover the 4-thiazolidinone 3c reacted with the benzenediazonium chloride to afford the arylhydrazones 12. The X-ray single crystal technique was employed in this study for structure elucidation and Z/E potential isomerism configuration determination. The X-ray crystallographic analyses of eight products could be obtained, thus establishing with certainty the structures proposed in this work.

Organocatalysis in heterocyclic synthesis: DABCO as a mild and efficient catalytic system for the synthesis of a novel class of quinazoline, thiazolo [3,2-a]quinazoline and thiazolo[2,3-b] quinazoline derivatives

“…Moreover conducting the reaction between the methyl-2-(2-chloroaceta-mido) benzoate ( 3 ) and the ammonium thiocyanate in absolute methanol afford two products depending on the refluxing time, 4 was formed after 6h while the methyl-2-[(4-oxo-3,4-dihydroquinazolin-2-yl)thio]acetate ( 5 ) was formed after 12 h and not compound 6 or 7 [43,44]. Also compound 5 can be obtained by refluxing the formed methyl-2-(2-thiocyanatoacetamido)benzoate ( 4 ) in methanol [45] (cf.…”

“…However, after detailed literature survey it was observed that there were only limited publications devoted to the synthesis of especially thiazolo[3,2- a ]quinazoline which involved reaction of 2-mercaptopropargyl quinazolin-4-one with various aryl iodides catalyzed by Pd-Cu [39] or by condensation of 2-mercapto-4-oxoquinazoline with chloroacetic acid [40], inspite of this procedure was also reported in the literature to afford the thiazolo[2,3- b ]quinazoline. So the multistep synthesis of thiazoloquinazolines especially thiazolo[3,2- a ]quinazoline suffered from some flaws and in continuation of our research program on the synthesis of nitrogen and sulphur containing novel heterocycles [41-43] of pharmaceutical interest and in view of the operational simplicity in this study we have synthesized a novel class of thiazoloquinazolines by a simple and convenient method involving catalysis by DABCO. The X-ray single crystal technique as an advanced tool of analysis was employed in this study for structure elucidation and for determination the regioselectivety of the reactions.…”

Chloroquinoline–acetamide hybrids: a promising series of potential antiprotozoal agents

“…The product formed was recrystallized in ethanol (1-15). These compounds have already been reported in the following literature [24][25][26][27][28][29][30][31][32] For aliphatic (2-Chloro-acetamides): To a stirring solution of amine in 10 ml dichloromethane, triethylamine was added.…”

Ionic Liquids-Prompted Synthesis of Biologically Relevant Five- and Six-Membered Heterocyclic Skeletons

“…The 4-thiazolidinone ring system is a core structure in various synthetic compounds and an important scaffold known to be associated with several biological activities such as hypnotic activity, antitubercular, anticonvulsant, antibacterial, anticancer, antihistaminic, antifungal, anti-inflammatory, antiviral, and cardiovascular effects [174]. Generally, these heterocycles are synthesized easily by a three-component condensation of a primary amine, an aldehyde, and a mercaptoacetic acid.…”