Friedländer synthesis of poly-substituted quinolines in the presence of dodecylphosphonic acid (DPA) as a highly efficient, recyclable and novel catalyst in aqueous media and solvent-free conditions

Organocatalyzed Synthesis of Functionalized Quinolines

As one of the most widely investigated compound skeleton, quinolines possess important medicinal and biological activities. As such, a great number of literatures, including reviews, have reported various methodologies to construct quinolines. Recently, organocatalyzed reactions have attracted the attention of organic chemists due to its being "green" because the reactions avoid the use of toxic metals. In this review, various distinctive contributions are surveyed with specific emphasis on organocatalyzed reactions for quinoline core constructions.

A NbO type Cu(ii) metal-organic framework showing efficient catalytic activity in the Friedländer and Henry reactions

A three-dimensional NbO type porous metal-organic framework 1 containing both tertiary amine groups and paddle wheel dinuclear Cu₂(COO)₄ secondary building units as the active centre was synthesized at room temperature. The activated framework 1' can be used as an efficient heterogeneous catalyst for the synthesis of quinoline derivatives by the Friedländer reaction and for the synthesis of β-nitroalcohols by the Henry (nitroaldol) reaction. This MOF-based heterogeneous catalyst is easily recycled and reused further without losing its structural integrity and catalytic activity.

Ionic Liquid as an Efficient Medium for the Synthesis of Quinoline Derivatives via α-Chymotrypsin-Catalyzed Friedländer Condensation

An efficient, convenient, and eco-friendly biocatalytic approach was developed for the synthesis of quinoline derivatives via the α-chymotrypsin-catalyzed Friedländer reaction. Interestingly, α-chymotrypsin exhibited higher catalytic activity in an ionic liquid (IL) aqueous solution as compared to that observed in our previous relevant study, which was conducted using an organic solvent, and a series of substrates gave similar excellent yields at lower reaction temperature and under reduced enzyme-loading conditions.

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

An efficient new strategy for the green synthesis of a variety of polysubstituted quinolines, using the Friedländer approach is reported, employing malic acid as a catalyst in organic synthesis for the first time.

Friedländer annulation: scope and limitations of metal salt Lewis acid catalysts in selectivity control for the synthesis of functionalised quinolines

In(OTf)₃ is the most effective catalyst among metal halides, tetrafluoroborates, perchlorates, and triflates for Friedländer quinoline synthesis in 75–92% yields.

Synthesis, and the antioxidant, neuroprotective and P-glycoprotein induction activity of 4-arylquinoline-2-carboxylates

An efficient synthesis of 4-arylquinoline-2-carboxylates and their antioxidant, neuroprotective and P-glycoprotein induction activity have been described.

Quinoline: A versatile heterocyclic

Quinoline or 1-aza-naphthalene is a weak tertiary base. Quinoline ring has been found to possess antimalarial, anti-bacterial, antifungal, anthelmintic, cardiotonic, anticonvulsant, anti-inflammatory, and analgesic activity. Quinoline not only has a wide range of biological and pharmacological activities but there are several established protocols for the synthesis of this ring. The article aims at highlighting these very diversities of the ring.

Cerium(IV) ammonium nitrate is an excellent, general catalyst for the Friedländer and Friedländer-Borsche quinoline syntheses: very efficient access to the antitumor alkaloid luotonin A

The use of cerium(IV) ammonium nitrate as a catalyst of the Friedländer reaction allows the synthesis of polysubstituted quinoline derivatives in excellent yields, avoiding the traditional harshly basic or acidic conditions. Unlike most other previously known reagents, CAN allows double condensations and is also an excellent catalyst for the Borsche variation of the Friedländer reaction, which has been applied to the very efficient synthesis of the antitumor alkaloid luotonin A.