Enaminones as building blocks in heterocyclic syntheses: A new approach to polyfunctionally substituted cyclohexenoazines

Abstract

A variety of polyfunctionally substituted condensed pyridines and pyrazolotetrahydroquinazolines have been synthesized utilizing cyclic enaminones as starting materials.

Pyrimidine‐based pyrazoles as cyclin‐dependent kinase 2 inhibitors: Design, synthesis, and biological evaluation

“…The synthetic methodology for the pyrimidine‐pyrazole hybrid molecules is shown in Scheme . Synthesis of Enaminone intermediate through N , N ‐Dimethylformamide dimethyl acetal (DMF‐DMA) approach was a primary step toward the formation of key scaffold that is, ethyl 1‐(6‐chloropyrimidin‐4‐yl)‐5‐methyl‐1 H ‐pyrazole‐4‐carboxylate (Intermediate‐ A ). Reaction of 1 with Intermediate‐ A under refluxing condition in ethanol afforded ethyl 1‐(6‐chloropyrimidin‐4‐yl)‐5‐methyl‐1 H ‐pyrazole‐4‐carboxylate ( 2 ) by a facile formation of pyrazole ring, which then underwent nucleophilic substitution using by benzylamine to afford ethyl 1‐(6‐(benzylamino)pyrimidin‐4‐yl)‐5‐methyl‐1 H ‐pyrazole‐4‐carboxylate ( 3 ).…”

Chemistry of Pyrazole-3(5)-Diazonium Salts (Review)*

“…The pentacyclic system 112 was also formed by azo coupling of compound 1 (R = R 1 = H) with the enaminone 113 under standard conditions [185]. Analogous Yapp-Klingemann reaction was possible by using benzosuberone derivative 114 [186].…”

Dimethylformamide dimethyl acetal as a building block in heterocyclic synthesis

“…These compounds are also potentially valuable for the preparation of different types of heterocycles (61-67) as outlined in Scheme 12 [36,37,[48][49][50]. Microwave irradiation of 1,3-cyclohexanedione (59a) with hydrazine hydrate and its derivatives afforded the corresponding pyrazole derivatives (68) [51].…”