Synthesis of Multifunctionalized 2,3-Dihydro-4-pyridones and 4-Pyridones via the Reaction of Carbamoylated Enaminones with Aldehydes

Abstract

The novel and effective diastereoselective synthesis of multifunctionalized dihydropyridones, including CF3-substituted derivatives, has been developed on the basis of the piperidine-promoted domino reaction of carbamoylated enaminones with aldehydes. The products have been prepared in 38–90% yields and can be easily isolated by crystallization. Tautomerism, epimerization, and atropisomerism of dihydropyridones have been studied. The use of the resulting dihydropyridones in the synthesis of 1,2,6-trisubstituted 4-pyridone-3-carboxamides has been demonstrated via oxidative aromatization initiated by iodine.

Synthesis of γ-Pyrones and N-Methyl-4-pyridones via the Au Nanoparticle-Catalyzed Cyclization of Skipped Diynones in the Presence of Water or Aqueous Methylamine

“…As the core skeleton of 4-pyridone appears in a series of bioactive compounds, several synthetic approaches for the synthesis of this class of compounds have been developed so far. The most prominent include the treatment of γ-pyrones with amines, which is a slow process but can be promoted on certain types of pyrones (maltols) by boronic acids, via 4-alkoxy pyridinium salts under basic conditions; the Cu­(I)-catalyzed reaction of 4-hydroxypyridines with propargylic acetates, via the dehydrogenation of 2,3-dihydro-4-pyridones; the three-component cascade reaction of anilines, ethoxymethyl enemalonates, and acetylenedicarboxylates; the [4 + 2] cycloaddition between 3-aminocyclobutenones and electron-deficient alkynes; and the transition-metal-catalyzed N -allylation of parent 4-pyridone with allenes . We emphasize that the catalyzed approach for the synthesis of 4-pyridones using skipped diynones as precursors is practically underexamined.…”

The Construction of Polycyclic Pyridones via Ring-Opening Transformations of 3-hydroxy-3,4-dihydropyrido[2,1-c][1,4]oxazine-1,8-diones

“…The chemistry of these heterocycles is actively developed not only for the design of biologically important compounds [ 7 , 8 , 9 ], but also for effective preparation in the industry [ 1 , 2 , 3 , 10 , 11 , 12 , 13 , 14 , 15 ]. At the same time, there is a need to search for new multifarious pyridone building blocks [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] and convenient synthetic tools for the construction of polycyclic pyridones [ 1 , 2 , 3 , 15 ], including CH functionalization [ 26 ].…”

Enaminone, Enaminoesters, and Related Compounds in the Metal‐Free Synthesis of Pyridines and Fused Pyridines

“…Recently, several comprehensive reviews have appeared describing the preparation of many heterocyclic systems, among others of fused pyridinones …”

“…[24][25][26] Recently, several comprehensive reviews have appeared describing the preparation of many heterocyclic systems, among others of fused pyridinones. [27][28][29] The intention of this minireview is to show the metal-free syntheses of pyridines and fused paridines have been developed.…”