Multicomponent Reaction

Small ring heterocycles, such as epoxides and aziridines, are present in several natural products and are also highly versatile building blocks, frequently involved in the synthesis of numerous bioactive products and pharmaceuticals. Because of the potential for increased efficiency and selectivity, along with the advantages of environmentally benign synthetic procedures, multicomponent reactions (MCRs) have been explored in the synthesis and ring opening of these heterocyclic units. In this review, the recent advances in MCRs involving the synthesis and applications of epoxides and aziridines to the preparation of other heterocycles are discussed emphasizing the stereoselectivity of the reactions...

A practical one-pot isoindolinone synthesis enabled by RhIII catalysis was developed. The advantage of this protocol is that it does not require pre-preparation of amide substrates, because RhIII participates in two reactions independently. This mild, operationally multicomponent process transforms a wide variety of commercially available aldehydes into the corresponding γ-lactams in good yields, thereby demonstrating that N-pyridin-2-yl benzamide is an effective directing group. Notably, the anxiolytic drugs pagoclone and pazinaclone can be directly prepared by this methodology...

Two metal-organic frameworks (MOFs) made of indium and 1,3,5-tris(4-carboxyphenyl)benzene (H3btb) and having a layered structure have been synthesized under solvothermal conditions: [In(btb)(H2O)(DMF)]·L (InPF-50) and [In2(btb)2Cl2]2-·[(CH3)2NH2]22+·L (InPF-51). The structures of both materials have been determined by single crystal X-ray diffraction. The synthetic study which has been carried out demonstrates the influence of the selected indium salt in obtaining each MOF. The structure of both materials consists of pairs of catenated layers, where the metal atoms display coordinated solvent ligands that provide potential open metal sites...

Activation of disulfides with N-halogen succinimide in the presence of TEMPO allows insertion reaction by an isocyanide, the product of which can further accept a wide range of nucleophiles for the generation of isothioureas and related molecular moieties. This new procedure overcomes previous methods that accept essentially only aryl amines as the third nucleophilic component. The diverse nucleophiles usable in our new protocol make this approach a general method for de novo synthesis of many S-containing heterocycles...

We report the synthesis and biological evaluation of two new series of 2-amino-6-benzyl-4-phenyl-4,6-dihydrobenzo[c]pyrano[2,3-e][1,2]thiazine-3‑carbonitrile 5,5-dioxides and 2-amino-6-methyl-4-phenyl-4,6-dihydrobenzo[c]pyrano[2,3-e][1,2]thiazine-3‑carbonitrile 5,5-dioxides. The synthetic methodology involves a multistep reaction starting with methyl anthranilate which was coupled with methane sulfonyl chloride. The product of the reaction was subjected to N-benzylation and N-methylation reactions followed by ring closure with sodium hydride resulting in the formation of respective 2,1-benzothiazine 2,2-dioxides...

The Biginelli multicomponent reaction has been used as an effective and model method to efficiently prepare a library of cellulose derivatives based on cellulose acetoacetate (CAA). Various cellulose derivatives containing 3, 4-dihydropyrimidin-2(1 H)-ones (DHPMs) with different functional groups (carboxyl, methoxyl, and nitro) are synthesized. The entire reaction process is followed using FT-IR, 1 H NMR. The results demonstrate that more than 80% of the acetoacetyl groups are converted within four hours...

The catalyst p-sulfonic acid calix[4]arene was effectively used in the three-component Povarov reaction between aromatic anilines and two equivalents of 2,3-dihydrofuran to obtain furano[3,2-c]-1,2,3,4-tetrahydroquinolines. These reactions proceeded efficiently using water as a green solvent and nontoxic catalysts that could be efficiently reused; the reactions were metal-free and used only inexpensive and easily available compounds. Together with a simple workup procedure, these advantages make this protocol a very efficient and green alternative to the traditional methods for constructing tetrahydroquinoline structures, through the formation of two new C-C bonds and one C-N bond...

Herein, a new Ugi multicomponent reaction strategy is described to enhance activity and solubility of the chemotherapeutic drug chlorambucil through its conjugation to poly(amidoamine) (PAMAM-NH₂) dendrimers with the simultaneous introduction of lipidic ( i -Pr) and cationic (⁻NH₂) or anionic (⁻COOH) groups. Standard viability assays were used to evaluate the anticancer potential of the water-soluble dendrimers against PC-3 prostate and HT-29 colon cancer cell lines, as well as non-cancerous mouse NIH3T3 fibroblasts...

We present a local free-energy functional-based generic continuum model for material interfaces with a specific emphasis on electrified solid/liquid interfaces. The model enables a description of multicomponent phases at interfaces and includes the effects of specific non-electrostatic interactions (specific adsorption), ion size disparity, and the explicit presence of neutral species. In addition to the optimization of electrostatic, non-electrostatic, and steric forces, the model can be easily modified to explore the effects of other channels for equilibration, including local chemical transformations driven by equilibrium constants and electrochemical reactions driven by the electrode potential...

Tetrazole derivatives are a prime class of heterocycles, very important to medicinal chemistry and drug design due to not only their bioisosterism to carboxylic acid and amide moieties but also to their metabolic stability and other beneficial physicochemical properties. Although more than 20 FDA-approved drugs contain 1 H- or 2 H-tetrazole substituents, their exact binding mode, structural biology, 3D conformations, and in general their chemical behavior is not fully understood. Importantly, multicomponent reaction (MCR) chemistry offers convergent access to multiple tetrazole scaffolds providing the three important elements of novelty, diversity, and complexity, yet MCR pathways to tetrazoles are far from completely explored...

4-Hydroxycoumarins are some of the most versatile heterocyclic scaffolds and are frequently applied in the synthesis of various organic compounds. 4-Hydroxycoumarin-based compounds are important among heterocyclic structures due to their biological and pharmaceutical activities. In this study, we provide an overview on the recent applications of 4-hydroxycoumarin in multicomponent reactions for the synthesis of various heterocyclic compounds during the time period of 2015-2018.

An efficient I2-DMSO reagent system-mediated multicomponent reaction strategy for the synthesis of C3-sulfenylated chromones from o-hydroxyaryl methyl ketones, rongalite, and dimethyl sulfoxide has been developed. Notably, the double C-S bond cleavages of rongalite and dimethyl sulfoxide served as key steps in this smooth transformation, affording the C1 unit and sulfur source for the assembly of C3-sulfenylated chromones. Preliminary mechanistic studies indicated that in situ generated HCHO and (2-(2-hydroxyphenyl)-2-oxoethyl)dimethylsulfonium iodine were probably the key intermediates in this transformation...

Aminoxanthones constitute a group of therapeutically promising compounds that so far have been synthetically challenging. Here, we report the synthesis of both aminodihydroxanthones and fully aromatized aminoxanthones by an easy to perform, one-step multicomponent reaction of isocyanides, 3-carbonylchromones and dienophiles. The mechanism of the reaction involves a sequence of a [4 + 1] cycloaddition, iminolactone-aminofuran tautomerization, [4 + 2] cycloaddition, oxygen ring opening and aromatization. Remarkably, DFT quantum chemical computations revealed that the iminolactone-aminofuran tautomerization requires the assistance of a water molecule and, contrary to intuition, it is the rate-determining step...

An air- and moisture-stable molybdenum Schiff base complexes immobilized on magnetic iron oxide nanoparticles with a core-shell structure was developed for utilization as a new heterogeneous catalyst. The surface, structural and magnetic characteristics of the nanomaterials were characterized by using Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and inductively coupled plasma atomic emission spectroscopy (ICP-AES)...

Understanding the structural and compositional sensitivities of the electrochemical CO2 reduction reaction (CO2RR) is fundamentally important for developing highly efficient and selective electrocatalysts. Here, we use Ag/Cu nanocrystals to uncover the key role played by the Ag/Cu interface in promoting CO2RR. Nanodimers including the two constituent metals as segregated domains sharing a tunable interface are obtained by developing a seeded growth synthesis, wherein pre-formed Ag nanoparticles are used as nucleation seeds for the Cu domain...

Racemic vinylallenes are found to be highly attractive substrates for catalytic multicomponent processes. Specifically, a method for diastereo-, and enantioselective 1,6-conjugate addition of multifunctional allyl moieties to easily accessible α,β,γ,δ-unsaturated diesters has been developed. Reactions were catalyzed by 5.0 mol % of a readily accessible NHC-Cu complex at ambient temperature, and involve a vinylallene, B2(pin)2, an α,β,γ,δ-unsaturated diester. Through just one operation, a variety of vinylallenes were converted to products bearing a Z-trisubstituted alkenyl-B(pin) moiety, a vinyl group, a β,γ-unsaturated diester unit, and vicinal stereogenic centers in up to 67% yield, 87:13 Z:E ratio, >98:2 d...

Malononitrile is a useful reagent for multicomponent reactions with hundreds of methods developed. In this paper, we suggest α-(cyano)- o -tolunitrile (homophtalonitrile) to work as a vinylogous malononitrile. Thus, a organocatalytic pseudo-three-component reaction of homopthalonitrile (2 equiv) and o -hydroxybenzaldehyde, leading to the diastereoselective formation of 5-amino-12 H -chromeno[2,3-c]isoquinolin-12-yl)(cyano)methyl)benzonitriles, was discovered. The possibility to employ other nucleophiles was demonstrated for indoles, and a sequential three-component reaction of homophtalonitrile, o -hydroxybenzaldehyde, and (aza)indole, giving 12-(1 H -Indol-3-yl)-12 H -chromeno[2,3- c ]isoquinolin-5-amines, was developed...

Controlling chemical reactions in porous heterogeneous catalysts is a tremendous challenge because of the difficulty in producing uniform active sites that can be tuned with precision. However, analogous to enzymes, when a catalytic pocket provides complementary close contacts and favorable intermolecular interactions with the reaction participants, the reaction efficiency and selectivity may be tuned. Here, we report an isoreticular family of catalysts based on the multicomponent metal-organic framework MUF-77...

Qiangshen tablet, an important prescription consisting of 14 kinds of Chinese herbal medicines, has been used for decades to treat kidney yang deficiency syndrome (KYDS) in China. Qiangshen tablet has been recorded in ChP (2015 edition) and possesses the effect of strengthening yang, invigorating qi and tonifying kidneys. In this research, a simple, reliable and specific method was established for simultaneous determination of stachydrine, psoralen, isopsoralen, morroniside, paeoniflorin and loganin in normal and KYDS rat plasma after intragastric administration of a Qiangshen tablet suspension by UPLC-MS/MS...

A new palladium(II)-catalyzed cyclization-radical addition cascade enables the direct construction of 1,3-dimethylene-substituted isobenzofuran derivatives containing vinyl aryl sulfone unit in good yields by treating with β-alkynyl ketones, aryl diazonium salt and DABCO•(SO2)2 (DABSO). The oxidant-free multicomponent reaction features good substrate scope and functional group tolerance, which proceeds through a sequence of by Heck coupling, oxo-cyclization and SO2 insertion.