Ternary condensation of Biginelli thiones, chloroacetic acid, and aldehydes as an effective approach towards thiazolo[3,2‐a]pyrimidines and 5‐arylidenethiazolidine‐2,4‐diones

Abstract

At the process of ethyl 6‐methyl‐4‐aryl‐2‐thioxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carboxylates condensation with aryl aldehydes and chloroacetic acid the unexpected formation of 5‐arylidenethiazolidine‐2,4‐diones was determined in high yields as the reaction time was increased to 20 h. The latter represent the products of destructive hydrolyzes of ethyl 2‐benzylidene‐7‐methyl‐3‐oxo‐5‐aryl‐2,3‐dihydro‐5H‐[1,3]thiazolo[3,2‐a]pyrimidine‐6‐carboxylates which have been proved by independent synthesis. J. Heterocyclic Chem., (2010).

Green and catalyst-free synthesis of olsalazine analogs

“…Water was used as the reaction medium because it offers several advantages such as: (i) it is cheap, noninflammable, non-toxic and safe for use; (ii) it eliminates the additional efforts required to make the substrates/ reagents dry before use and thus reduces/eliminates the consumption of drying agents, energy and time; (iii) the unique physical and chemical properties of water often increase the reactivity or selectivity unattainable in organic solvents; and (iv) the product may be easily isolated by filtration (18,19).…”

Behavior of 2-cyano-3-(dimethylamino)-N-(4-phenylthiazol-2-yl)acrylamide towards some nitrogen nucleophiles

“…In view of the growing biological importance of fused thiazoles, particularly thiazolo[3,2-a]pyrimidines, 32,33 it was of interest to synthesize 5-oxo-3-phenyl-N-(4-phenylthiazol-2-yl)-5H-thiazolo[3,2-a]pyrimidine-6-carboxamide. This bicyclic system is considered as a thia-analogue of the natural purine bases, adenine and guanine.…”

Transformations of Di‐ and Tetrahydropyrimidine Derivatives into Condensed Heterocycles with Retention of their Partially Saturated Structure

“…For example, approach, which is based on bromination and a subsequent nucleophilic replacement reaction, is well documented. 6‐Bromo‐ and 6‐dibromomethyl‐3,4‐dihydropyrimidines are a versatile, readily accessible building blocks for the synthesis of furo[3,4‐ d ]pyrimidines , pyrrolo[3,4‐ d ]pyrimidines , pyrimido[4,5‐ d ]pyridazines , thiazolo[3,4‐ c ]pyrimidine , and cyclopenta[d]pyrimidine .…”