Morpholine Catalyzed One‐pot Multicomponent Synthesis of Compounds Containing Chromene Core in Water

A series of dihydropyrano[c]chromene was obtained via condensation of aldehyde, malononitrile and 4‐hydroxycoumarin in water catalyzed by morpholine, as a one‐pot reaction. The significance of our findings relates to reducing the use of organic solvents, potentially toxic and hazardous materials, as well as its simplicity, good yields, mild conditions, and lower costs.     

Acid Catalyzed Multicomponent Reaction to Access Functionalized N-Benzhydryl Amides: A Tandem Ritter Reaction

Acid catalyzed multicomponent reaction (MCR) for the synthesis of N-benzhydryl amide derivatives from aldehydes, N,N-disubstituted arylamines and nitriles is reported. The reaction is compatible with electronically differentiating aryl/heteroaryl aldehydes/acetals, different nucleophiles (cyclic and acyclic N,N-disubstituted arylamines,β-naphthols, 1,3 dicarbonyl, 1,3,5-trimethoxy benzene), alkyl nitriles, aryl/heteroaryl nitriles in catalytic TFA/TfOH through tandem Ritter reaction. The one-pot MCR with broad substrate scope generated a wide variety of sterically hindered N-substituted amides and is successfully applied for the synthesis of isoindolinone.     

Silica‐supported Perchloric Acid Catalyzed One‐pot Synthesis of 1,4‐Dihydropyridines

An environmentally friendly and highly efficient procedure for the preparation of 1,4‐dihydropyridines by the reaction between α,β‐unsaturated aldehydes, aromatic amines and β‐keto esters in the presence of silica supported perchloric acid is described.     

A Palladium(II)‐Catalyzed Synthesis of Spiroacetals through a One‐Pot Multicomponent Cascade Reaction

Functionalized spiroacetals have been easily prepared in a one‐pot three‐component coupling process that involves the reaction of pentynol derivatives, salicylaldehydes, and amines in the presence of catalytic amounts of a palladium(II) complex (see scheme). Alternatively, oxygen‐substituted spiroacetals can be obtained by using orthoesters as the third component.

     

An Eco‐friendly Catalytic System for One‐pot Multicomponent Synthesis of Diverse and Densely Functionalized Pyranopyrazole and Benzochromene Derivatives

An external base‐free, efficient, cost‐effective, and environmentally benign protocol has been developed for the one‐pot multicomponent synthesis of highly functionalized pyranopyrazoles and benzochromenes using water extract of Agave americana (century plant) leaf ash, a waste‐derived catalyst, at room temperature. Mild reaction conditions, high yield, easy isolation of products, eco‐friendly standards, and no chromatographic separation are the salient features of this protocol.     

Green Synthesis of 1,2,4,5‐Tetrasubstituted and 2,4,5‐Trisubstituted Imidazole Derivatives Involving One‐pot Multicomponent Reaction

Sodium lauryl sulfate has been found convenient, versatile, and eco‐friendly catalyst for the synthesis of 1,2,4,5‐tetrasubstituted and 2,4,5‐trisubstituted imidazole derivatives by one‐pot multicomponent reactions at 80°C using water as solvent. This protocol afforded advantages, that is, the metal‐free reaction, purification of products by non‐chromatographic method, and excellent yields.     

Palladium‐Catalyzed Oxidative Synthesis of Highly Functionalized Ortholactones

A palladium‐catalyzed oxidative reaction is reported which converts dihydropyrans to their corresponding ortholactone. The products are formed in good to excellent yields with a very high level of chemoselectivity and functional group tolerance. Mechanistic studies confirm that the reaction proceeds by a Wacker‐type mechanism.     

Multicomponent One‐pot Reactions Towards the Synthesis of Stereoisomers of Dipicolylamine Complexes

Reported are multi‐component one‐pot syntheses of chiral complexes [M(L^ROR′)Cl₂] or [M(L^RSR′)Cl₂] from the mixture of an N‐substituted ethylenediamine, pyridine‐2‐carboxaldehyde, a primary alcohol or thiol and MCl₂ utilizing in‐situ formed cyclized Schiff bases where a C?O bond, two stereocenters, and three C?N bonds are formed (M=Zn, Cu, Ni, Cd; R=Et, Ph; R′=Me, Et, nPr, nBu). Tridentate ligands L^ROR′ and L^RSR′ comprise two chiral centers and a hemiaminal ether or hemiaminal thioether moiety on the dipicolylamine skeleton. Syn‐[Zn(L^PhOMe)Cl₂] precipitates out readily from the reaction mixture as a major product whereas anti‐[Zn(L^PhOMe)Cl₂] stays in solution as minor product. Both syn‐[Zn(L^PhOMe)Cl₂] and anti‐[Zn(L^PhOMe)Cl₂] were characterized using NMR spectroscopy and mass spectrometry. Solid‐state structures revealed that syn‐[Zn(L^PhOMe)Cl₂] adopted a square pyramidal geometry while anti‐[Zn(L^PhOMe)Cl₂] possesses a trigonal bipyramidal geometry around the Zn centers. The scope of this method was shown to be wide by varying the components of the dynamic coordination assembly, and the structures of the complexes isolated were confirmed by NMR spectroscopy, mass spectrometry, and X‐ray crystallography. Syn complexes were isolated as major products with Zn^II and Cu^II, and anti complexes were found to be major products with Ni^II and Cd^II. Hemiaminals and hemiaminal ethers are known to be unstable and are seldom observed as part of cyclic organic compounds or as coordinated ligands assembled around metals. It is now shown, with the support of experimental results, that linear hemiaminal ethers or thioethers can be assembled without the assistance of Lewis acidic metals in the multi‐component assembly, and a possible pathway of the formation of hemiaminal ethers has been proposed.     

A Simple and Ecofriendly One‐Pot Synthesis of Highly Substituted 3‐Cyanopyridine‐Quinoline Hybrids via a Triphenyphosphine‐Catalyzed Multicomponent Reaction Under Mild Conditions

A simple and convenient one‐pot method has been used for the synthesis of new polycyclic compounds articulated around 3‐cyanopyridine derivatives from 2‐chloroquinolin‐3‐carbaldehydes, acetophenone derivatives, active methylene compounds, and ammonium acetate as a source of ammonia in the presence of catalytic amounts of PPh₃ at room temperature. The salient features of the protocol used are mild reaction conditions, good yields, short reaction time, safety, and high atom economy. No column chromatographic was needed, and pure products were obtained by simple filtration and washing with Et₂O.     

A Facile One‐pot Synthesis of Highly Functionalized Isoxazolyl Imidazo[1,2‐a] Pyridines Through CuI‐Promoted Cyclization

A copper iodide‐promoted cyclization for the synthesis of isoxazolyl imidazo[1,2‐a] pyridines 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j in a one‐pot procedure has been investigated by interaction of 2‐aminopyridines 1a , 1b , 1c , 1d , 1e with nitrostyrylisoxazoles 2a , 2b , 2c , 2d , 2e , 2f under aerial oxidation condition. Similarly, the one‐pot reaction of 2‐amino pyridines 1a , 1b , 1c , 1d , 1e with 4‐bromonitrostyrylisoxazole 2d in the presence of copper iodide under aerial oxidation condition, followed by reaction with phenyl acetylenes in situ afforded highly functionalized imidazo[1,2‐a]pyridines 10a , 10b , 10c , 10d , 10e , 10f , 10g , 10h , 10i , 10j by the Sonogashira coupling.     

A Highly Modular One‐Pot Multicomponent Approach to Functionalized Benzo[b]phosphole Derivatives

Benzo[b]phosphole derivatives have attracted significant attention for their unique optoelectronic properties with potential for application in materials science. Herein we report a modular approach to a benzo[b]phosphole derivative based on a one‐pot sequential coupling of an arylzinc reagent, an alkyne, dichlorophenylphosphine (or phosphorus trichloride and a Grignard reagent), and an oxidant (for example H₂O₂, S, or Se). The approach allows for the construction of a library of previously inaccessible, structurally diverse benzo[b]phosphole derivatives with unprecedented ease.     

A One‐pot Green Synthesis of Alkylidenesuccinimides

A mild and facile Wittig reaction between N‐substituted maleimides and aldehydes has been developed. Various synthetically valuable alkylidenesuccinimides were obtained from this one‐pot reaction in high yields (up to 99%). The product was obtained by simple filtration and no extra purification was necessary. Ethanol, an environment‐benign solvent, was found to be a suitable reaction medium.     

A Facile One‐Pot Synthesis of Substituted Quinolines via New Multicomponent Reaction

An efficient synthesis of quinoline derivatives is described via the reaction between ethyl chloropyruvate or alkyl 4‐chloroacetoacetate and activated acetylenic compounds in the presence of nucleophilic form of isatin in water as the solvent. Nucleophilic form of isatin is produced from the reaction of isatin and triethylamin.     

Isocyanide‐Based Multicomponent Reaction: One‐Pot Synthesis of New Derivatives of Iminofuranone

The one‐pot multicomponent reaction of alkyl isocyanide, alkylidene‐substituted Meldrum's acid, and arylcarboxylic acids affords new derivatives of iminofuranone in fair yields. The structure of the products was deduced from their spectroscopic data. Two equivalents of the respective isocyanides participate in this reaction.     

Synthesis of Novel Chromene,Pyridine, Pyrazole,Pyrimidine, and Imidazole Derivatives via One‐pot Multicomponent Reaction

New series of chromenes 2 – 4 , pyridines 5 – 8 , and pyranopyrazoles 9a,b were synthesized via one‐pot multicomponent reaction of 4‐tosyloxybenzaldehyde ( 1 ) and malononitrile with phenols, amines or hydrazines, and ethyl acetoacetate, respectively. Compound 9a was reacted with acetic anhydride, formic acid, or formamide to afford N ‐acetyl derivative 10 and pyrazolopyranopyrimidines 11 – 13 , respectively. Imidazole derivatives 14 and 15a – d were obtained by multicomponent reaction between compound 1 with ammonium acetate and benzil or aromatic amines in (1:2:1) or (1:1:1:1) ratio, respectively. The structures of new compounds were elucidated by elemental and spectral analyses.     

One‐pot Green Synthesis of Pyrrole Derivatives Catalyzed by Nano Sulfated Zirconia as a Solid Acid Catalyst

A new and efficient method for the preparation of N‐substituted pyrroles from one‐pot Paal‐Knorr condensation has been accomplished using nano‐crystalline sulfated zirconia (SZ) as the catalyst in ethanol at moderate temperature. This new protocol has the advantages of easy availability, stability, reusability and eco‐friendliness of the catalyst, high to excellent yields, simple experimental and work‐up procedure. The synthesized compounds were confirmed through spectral characterization using IR, ¹H NMR, ¹³C NMR and mass spectra.