Unexpected nitrilimine cycloaddition of thiazolo[3,2-a]pyrimidine derivatives

Highly regioselective 1,3-dipolar cycloaddition of diphenylnitrilimine to Sc3N@Ih-C80 affording a very stable, unprecedented pyrazole-ring fused derivative of endohedral metallofullerenes

“…[9][10][11] This is also a powerful tool for the synthesis of various fullerene derivatives with pyrazole rings. 12,13 Since pyrazoles are also a major class of five-membered nitrogen heterocycles in a wide variety of natural products and drug molecules, such structures have received great interest as a result of their broad range of biological activities.…”

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

“…2‐Arylidene‐6,7‐dihydrothiazolo[3,2‐ a ]pyrimidine‐3(5 H )‐ones 35 which contain C═C, C═N as well as C═O bonds could be involved in 1,3‐dipolar cycloadditions with nitrilimine . Reaction of 35 with diphenylnitrilimine (generated in situ from N ‐phenyl benzhydrazidoyl chloride) under gently conditions (Scheme ) led to the tricyclic derivatives 36 , containing fully saturated pyrimidine moiety.…”

Synthesis of Spiro[Pyrrolo[2,1-b][1,3]Benzothiazole-3,2′-[1,3]Thiazolo[3,2-a] Pyrimidine] via Cycloaddition Reactions

“…[8][9][10] Thiazolo[3,2-a]pyrimidine derivatives are found in many synthetic derivatives due to their broad spectrum of biological activities, including as antagonists of 5HT2 serotonin receptors and dopamine D2 receptors, 11-12 antifungal 13 and antiinflammatory properties 14 and CDC25 phosphatase inhibitor activity. 15 In continuation of our work on the study of the cycloaddition reaction [16][17][18][19] , we now report the synthesis of spiro [thiazolo[3,2-a] pyrimidine] derivatives by the 1,3-dipolar cycloaddition reactions of azomethine ylide generated in situ by the reaction of 3-(4-methoxyphenacyl)benzothiazolium bromides and triethylamine with ethyl-5-aryl-2-[(Z)-2-methoxy-2oxoethylidene]-7-methyl-3-oxo-3,5-dihydro-2H-thiazolo[3,2-a] pyrimidine-6-carboxylates (Scheme 1).…”