Multicomponent Mannich Reaction Research Articles

A simple and convenient method for synthesis of new aminonaphthoquinones derived from lawsone by catalytic multicomponent Mannich reaction

A clean, efficient and facile one-pot protocol was developed for the synthesis of a series of new aminonaphthoquinones derived from 2-hydroxy-1,4-naphthoquinone (lawsone) by three-component Mannich reaction using catalytic amount of p-TsOH in CH3CN, at room temperature. At the present work, we improved the yield and significantly reduced the reaction time for several Mannich reactions with different amine and aromatic aldehydes using a non-expensive, mild catalyst and suitable solvent.

Synthesis of novel bis(β-aminocarbonyl) compounds and some β-aminocarbonyls by catalyst-free multicomponent Mannich reactions

A highly diastereoselective catalyst-free multicomponent Mannich reaction between cyclohexanone, aromatic aldehydes and amines in cyclohexane is described. The double Mannich reaction of diamines and two equivalents of aldehydes and cyclohexanone gave the novel bis(β-aminocarbonyl) compounds. Reactions proceeded in good to high yields with an excellent diastereoselectivity. The best selectivity was obtained where there are weak electron donating and electron-withdrawing groups on the aldehyde. The rate formation of Mannich product is decreased when strong electron-withdrawing groups and/or electron-releasing groups are present on aldehyde. In these cases only the corresponding imines are obtained in moderate to high yields. Aromatic diamines are more suitable than aliphatic diamines in this reaction. Usually, aliphatic diamines only produce the corresponding imines albeit in high yields. .

A Facile Microwave-Assisted Solution Combustion Synthesis of Highly Stable Magnesium Oxide for Multicomponent Mannich Reaction

A green and robust solid base MgO has been synthesized by a rapid microwave-assisted solution combustion synthesis method and evaluated for multicomponent Mannich reaction under solvent-free conditions at ambient temperature in the liquid phase. The synthesized catalyst was characterized by various techniques to ascertain its phase composition and thermal stability. Catalyst characterization studies revealed that magnesium oxide synthesized by microwaveassisted solution combustion synthesis method offers stable nanosized MgO crystallites. Good to excellent yields of β-amino carbonyl compounds were achieved with aromatic aldehydes bearing an electron withdrawing group.

ChemInform Abstract: Hydride Adducts of Dinitroquinolines in Multicomponent Mannich Reaction.

AbstractδH‐Adducts, generated by reduction of dinitro derivatives of 8‐oxyquinoline, 8‐oxyquinaldine, and 3,4‐dihydroquinolin‐2‐one with NaBH4 enter in multicomponent Mannich reactions furnishing pyridoazabicyclo[3.3.1]nonane derivatives in good yield.

Hydride adducts of dinitroquinolines in multicomponent Mannich reaction

Dinitro derivatives of 8-oxyquinoline, 8-oxyquinaldine, and 3,4-dihydroquinolin-2-one when reacted with NaBH4 form hydride σH-adducts that are involved into a multicomponent Mannich reaction affording pyridoazabicyclo[3.3.1]nonane.

ChemInform Abstract: Multicomponent Mannich Reactions with Boron Enolates Derived from Diazo Esters and 9‐BBN.

AbstractThe reaction leads to isocyanate Mannich products, which can be trapped in situ by alcohols.

Multicomponent Mannich Reactions with Boron Enolates Derived from Diazo Esters and 9-BBN

Diazo esters, arylboranes, and carbamoyl imines undergo a 3-component Mannich condensation reaction. Catalyzed by Cu(II) salts, the reaction affords the corresponding isocyanate Mannich product: one that can be easily trapped in situ by other nucleophiles. The Mannich condensation corresponds to an α,α-disubstituted enolate addition to imines. The reaction was rendered asymmetric by using the (-)-phenylmenthol ester in good yield and selectivities.

ChemInform Abstract: Chiral Broensted Acid Catalyzed Enantioselective Multicomponent Mannich Reaction: Synthesis of anti‐1,3‐Diamines Using Enecarbamates as Nucleophiles.

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