Er-Yan Xia

Synthesis of Polysubstituted Dihydropyridines by Four-Component Reactions of Aromatic Aldehydes, Malononitrile, Arylamines, and Acetylenedicarboxylate

A practical and efficient procedure for the preparation of the polysubstituted dihydropyridines was developed through a unique four-component reaction of aromatic aldehydes, malononitrile, arylamines, and acetylenedicarboxylate in ethanol in the presence of triethylamine as a base promoter. This four-component reaction is atom-efficient, high-yielding, and applicable to a wide variety of four-component reactions.

Synthesis of 3,4-Dihydropyridin-2(1H)-ones and 3,4-Dihydro-2H-pyrans via Four-Component Reactions of Aromatic Aldehydes, Cyclic 1,3-Carbonyls, Arylamines, and Dimethyl Acetylenedicarboxylate

A protocol has been developed for the efficient synthesis of structurally diverse 3,4-dihydropyridin-2(1H)-ones and 3,4-dihydro-2H-pyrans via four-component reactions of arylamines, acetylenedicarboxylate, aromatic aldehydes and cyclic 1,3-diketones. The selective formation of the very different pyridinone or pyran derivatives depends on the structure of cyclic 1,3-diketone. The key steps are proposed to involve Michael addition of the enamino ester formed in situ from the reaction of arylamine with dimethyl acetylenedicarboxylate to arylidine cyclic 1,3-diketones.

Synthesis of Functionalized 2-Aminohydropyridines and 2-Pyridinones via Domino Reactions of Arylamines, Methyl Propiolate, Aromatic Aldehydes, and Substituted Acetonitriles

An efficient and practical synthetic method for the functionalized 2-amino hydropyridines and 2-pyridinones was successfully developed via the domino reactions of arylamines, methyl propiolate, aromatic aldehydes and the substituted acetonitriles with triethylamine as base catalyst. Reactions involving malononitrile and cyanoacetamide gave exclusively the 2-aminohydropyridines. On the other hand ethyl cyanoacetate resulted in the 2-pyridinones as main products.

Synthesis of dihydrothiophenes or spirocyclic compounds by domino reactions of 1,3-thiazolidinedione.

The domino reactions of 1,3-thiazolidinedione, malononitrile, and aromatic aldehydes in the presence of different organic amines were studied. Secondary amines such as pyrrolidine, piperidine, morpholine, and dimethylamine and primary amines such as benzylamine yield dihydrothiophene derivatives through a domino ring-opening/recyclization reaction of 1,3-thiazolidinedione. Bulky diethylamine, diisopropylamine, and 1,4-diazabicyclo[2.2.2]octane give spirocyclohexano-1,3-thiazole through a double Michael addition/spirocyclization reaction.

Syntheses and structures of Mn(II), Co(II), and Zn(II) complexes of 1,3-diterpyridyl-substituted p-tert-butylcalix[4]arene

The calix[4]arene-based podand which incorporates two terpyridine functions in 1,3-alternate positions with flexible propylene spacers at lower rim has been prepared and subjected to complexation studies with some transition metal ions. Single-crystal structures of Mn(II), Co(II), and Zn(II) complexes were determined by X-ray diffraction. These metal complexes are formed with a 2 : 1 ratio of metal and ligand. Coordination of each metal is five-coordinate distorted trigonal-bipyramidal geometry by three nitrogen atoms from a terpyridyl unit and two chloride atoms.

Convenient synthesis of polyfunctional dihydrothiophenes with tandem reaction of 1,3-thiazolidinedione, aldehyde, arylamine and ethyl cyanoacetate.

New, highly-functionalized dihydrothiophenes are conveniently synthesized from the novel tandem, four-component reactions of 1,3-thiazolidinedione, aldehyde, arylamine, and ethyl cyanoacetate, catalyzed by triethylamine. The reaction mechanism involves the use of Knoevenagel condensation, Michael addition, and ring-opening of 1,3-thiazolidinedione, followed by intramolecular ring closure process. The reaction is diastereoselective and only trans-2,3-dihydrothiophenes were produced in moderate yields. The functionalized dihydrothiophenes can be converted efficiently to the corresponding thiophenes by DCC dehydrogenation reaction.Graphical Abstract

Synthesis of Ammonium 3,5-Dicyano-4-aryl-2,6-pyridinedionates with One-Pot Reaction of Aromatic Aldehydes, Amines, and Cyanoacetamide

Abstract A simple and efficient synthesis of ammonium 3,5-dicyano-4-aryl-2,6-pyridinedionates was accomplished via one-pot, three-component reaction of aromatic aldehydes, amines, and cyanoacetamide. This unprecedented methodology had some potential advantages such as the common available starting material, short reaction time, good yield, broad substrate scope, and convenient operation. GRAPHICAL ABSTRACT