Mandavi Singh

Visible light promoted synthesis of dihydropyrano[2,3-c]chromenes via a multicomponent-tandem strategy under solvent and catalyst free conditions

The development of unique, mild and efficient one pot, multicomponent-tandem synthesis of highly functionalized dihydropyrano[2,3-c]chromenes under photochemical activation is reported. The key feature of the present work is the utilization of visible light which is a ubiquitous, inexpensive and eco-sustainable reagent for catalysing the reaction. The reported methodology is the first example of visible light induced synthesis of dihydropyrano[2,3-c]chromenes and includes several advantages like solvent and catalyst free, environmentally benign reaction conditions, operational simplicity, cost effectiveness, short reaction times, high atom economy, and excellent yields, making it a genuinely green protocol.

Catalyst free, multicomponent-tandem synthesis of spirooxindole-indazolones and spirooxindole-pyrazolines: a glycerol mediated green approach

The development of a versatile new one pot, catalyst free, multicomponent-tandem strategy for assembly of spirooxindole-indazolones and spirooxindole-pyrazolines is described. The reported protocol includes several advantages like environmental friendliness, cost effectiveness, high atom economy, short reaction times and high yields. The reported method is the first green synthesis of spirooxindole-indazolones and spirooxindole-pyrazolines.

A catalyst free, multicomponent-tandem, facile synthesis of pyrido[2,3-d]pyrimidines using glycerol as a recyclable promoting medium

A clean and efficient, multicomponent-tandem strategy for the synthesis of pyrido[2,3-d]pyrimidines is reported in glycerol, a biodegradable and reusable promoting medium. The advantages of the present methodology includes a one-pot catalyst free environmentally friendly approach, 100% atom economy, cost effectiveness, broad substrate scope, operational simplicity, short reaction times, easy workup procedure and high yields.

Nucleophilic heterocyclic carbene promoted one pot multicomponent synthesis of new 6-(1H-indol-3-yl)-2-oxo-4-aryl-1,2,3,4 tetrahydropyrimidine-5-carbonitriles: an eco-compatible approach with PEG as a biodegradable medium

A three-component, one-pot, simple, direct and highly efficient cyclocondensation method has been developed for the synthesis of fourteen 6-(1H-indol-3-yl)-2-oxo-4-aryl-1,2,3,4-tetrahydropyrimidine-5-carbonitriles by combining an arylaldehyde with 3-(cyanoacetyl)-indoles and urea in the presence of the PEG-400 and a catalytic amount of the thiazolium anion. A short reaction time, simple reaction conditions, ease of product isolation, use of a cheap and readily available and reusable catalyst make this method very attractive from an environmental and economic perspective.

Development of five membered heterocyclic frameworks via [3+2] cycloaddition reaction in an aqueous micellar system

A series of novel dihydropyrrolo[2,1-a]isoquinolines and dihydropyrrolo[1,2-a]quinolines have been synthesized from isoquinolines/quinolines, various substituted phenacyl bromides and substituted dialkylacetylenedicarboxylates via [3+2] cycloaddition reaction. The reaction proceeds in aqueous micellar medium with DBU as a catalyst. The present protocol offers a simple one pot sequential reaction affording products in excellent yields.

Bioorganopromoted green Friedländer synthesis: a versatile new malic acid promoted solvent free approach to multisubstituted quinolines

The discovery of a new, malic acid promoted, eco-friendly Friedlander approach to varied multisubstituted quinolines is disclosed. To the best of our knowledge, this is the first report on the use of malic acid, classified as one of the 12 biobased hot molecules by the US Department of Energy, as an organopromoter in organic synthesis and includes many benefits like wide substrate scope, solvent free ambient reaction conditions, short reaction times, operational simplicity, cost effectiveness, high atom economy, good to excellent yields, and recylability of the organopromoter, making it a valuable green alternative to the existing methods. The versatility and practicability of the developed method was further established by its successful application towards the targeted synthesis of some important quinoline molecules and successful scale up.

Nucleophilic, Heterocyclic, Carbene-Catalyzed, Solvent-Free, One-Pot Synthesis of Polyhydroquinolines via Multicomponent Hantzsch Reaction: An Efficient and Ecofriendly Approach

Abstract A simple, efficient, and ecofriendly one-pot method has been reported for the synthesis of polyhydroquinolines in excellent yield using nucleophilic heterocyclic carbene as catalyst. The generalized approach is the Hantzsch four-component reaction of aromatic aldehyde, ethyl acetoacetate, cyclic 1,3-diketone, and ammonium acetate. GRAPHICAL ABSTRACT

Supramolecular catalysis in the synthesis of polyfunctionalised pyrroles

An efficient sequential one pot three component reaction involving anilines, DEAD/DMAD and glyoxal in aqueous media is reported. The protocol is environmentally benign and provides a new synthetic route to access polyfunctionalised pyrrole derivatives in high yield. The reaction proceeded via supramolecular catalysis.

Triphenylphosphine-Catalyzed, Novel, One-Pot, Multicomponent Synthesis of Functionalized β-Acetamido Carbonyls

Abstract An efficient triphenylphosphine-catalyzed synthesis of β-acetamido carbonyls via multicomponent reaction of aromatic aldehydes, enolizable ketones or β-keto esters, acid chlorides and acetonitrile at room temperature is described. The process is remarkably simple, environmentally benign, and uses Lewis base for the first time in such type of reaction. GRAPHICAL ABSTRACT