Multicomponent synthesis of chromophores – The one-pot approach to functional π-systems

Multicomponent reactions, conducted in a domino, sequential or consecutive fashion, have not only considerably enhanced synthetic efficiency as one-pot methodology, but they have also become an enabling tool for interdisciplinary research. The highly diversity-oriented nature of the synthetic concept allows accessing huge structural and functional space. Already some decades ago this has been recognized for life sciences, in particular, lead finding and exploration in pharma and agricultural chemistry. The quest for novel functional materials has also opened the field for diversity-oriented syntheses of functional π-systems, i.e. dyes for photonic and electronic applications based on their electronic properties. This review summarizes recent developments in MCR syntheses of functional chromophores highlighting syntheses following either the framework forming scaffold approach by establishing connectivity between chromophores or the chromogenic chromophore approach by de novo formation of chromophore of interest. Both approaches warrant rapid access to molecular functional π-systems, i.e. chromophores, fluorophores, and electrophores for various applications.

Recent Developments on Five-Component Reactions

Multicomponent reactions (MCRs) have inherent advantages in pot, atom, and step economy (PASE). This important green synthetic approach has gained increasing attention due to high efficiency, minimal waste, saving resources, and straightforward procedures. Presented in this review article are the recent development on 5-compoment reactions (5CRs) of the following six types: (I) five different molecules A + B + C + D + E; pseudo-5CRs including (II) 2A + B + C + D, (III) 2A + 2B + C, (IV) 3A + B + C, (V) 3A + 2B, and (VI) 4A + B. 5CRs with more than five-reaction centers are also included.

5-Oxo-hexahydroquinoline: an attractive scaffold with diverse biological activities

5-Oxo-hexahydroquinoline (5-oxo-HHQ) represents a biologically attractive fused heterocyclic core. Various synthetic analogs of 5-oxo-HHQ have been synthesized and assessed for different biological activities. Some derivatives have exhibited myorelaxant, analgesic, anticancer, antibacterial, antifungal, antitubercular, antimalarial, antioxidant, anti-inflammatory, multidrug resistance reversal, anti-Alzheimer, neuroprotective, antidiabetic, antidyslipidemic and antiosteoporotic activities. This review provides a comprehensive report regarding the preparation and pharmacological characterization of 5-oxo-HHQ derivatives that have been reported so far. This information will be beneficial for medicinal chemists in the field of drug discovery to design and develop new and potent therapeutical agents bearing the 5-oxo-HHQ nucleus.

An efficient, green synthesis of novel regioselective and stereoselective indan-1,3-dione grafted spirooxindolopyrrolizidine linked 1,2,3-triazoles via a one-pot five-component condensation using PEG-400

An efficient synthesis of highly diversified novel functionalized indan-1,3-dione grafted spirooxindolopyrrolizidine linked 1,2,3-triazole conjugates is reported using Cu(i) as a catalyst in PEG-400.

A green, multicomponent, regio- and stereo-selective 1,3-dipolar cycloaddition of azides and azomethine ylides generated in situ with bifunctional dipolarophiles using PEG-400

A series of novel dispiropyrrolidine-linked 1,2,3-triazole derivatives have been prepared by one-pot, four-component protocol that employed 5-arylidene-3-(prop-2-ynyl)thiazolidine-2,4-dione, isatin, sarcosine and substituted azides using Cu(I) generated in situ as catalyst in PEG-400 as a highly efficient and green media. This is the first report of a four-component reaction involving a classical Huisgen reaction, in which the two dipolar moieties (substituted azides and in situ generated azomethine ylides) react with acetylenic and olefinic dipolarophiles, respectively. The 1,3-dipolar cycloaddition proceeds in a highly regio- and stereo-selective manner. This methodology can be an ideal tool for the preparation of biologically important five-membered heterocyclic compounds in one pot.