Synthesis of indolo- and benzothieno[3,2-c]quinolines via POCl3 mediated tandem cyclization of o-alkynylisocyanobenzenes derived from o-alkynyl-N-phenylformamides

A synthesis of indolo[3,2-c]quinolines and benzothieno[3,2-c]quinolines has been developed employing o-alkynyl-N-phenylformamide derivatives as the substrates. The reaction proceeded via a tandem process involving POCl3‒assisted intramolecular cyclization of the firstly formed...

Chiral Phosphoric Acid-Catalyzed Pictet-Spengler Reactions for Synthesis of 5',11'-Dihydrospiro[indoline-3,6'-indolo[3,2-c]qui-nolin]-2-ones Containing Quaternary Stereocenters

Chiral phosphoric acid-catalyzed Pictet-Spengler reactions of 2-(1H-indolyl)aniline derivatives and isatins by the condensation/cyclization process have been realized. A series of enantioenriched 5',11'-dihydrospiro[indoline-3,6'-indolo[3,2-c]quinolin]-2-ones bearing quaternary stereogenic centers were obtained with excellent yields and up to >99% ee. This protocol was suitable for the Pictet-Spengler reactions of 2-(1-benzyl-5-methyl-1H-pyrrol-2-yl)aniline, and a variety of 1',5'-dihydro-spiro[indoline-3,4'-pyrrolo[3,2-c]quinolin]-2-ones could also be obtained in good yields and up to 88% ee.

Advancements in the synthesis of fused tetracyclic quinoline derivatives

Fused tetracyclic systems containing a quinoline nucleus represent an important class of heterocyclic bioactive natural products and pharmaceuticals because of their significant and wide-spectrum biological properties. Several of these compounds have been obtained with diverse pharmacological and biological activities, such as antiplasmodial, antifungal, antibacterial, potent antiparasitic, antiproliferative, anti-tumor and anti-inflammatory activities. This information will be beneficial for medicinal chemists in the field of drug discovery to design and synthesize new fused tetracyclic quinolines as potent therapeutical agents. This review article provides a comprehensive report regarding the methods developed for the synthesis of fused tetracyclic quinolines reported so far (till October 2019). The article includes synthesis by one-pot domino reaction, microwave synthesis using a catalyst, using ionic liquids, photocatalytic synthesis (UV radiation), Pfitzinger reaction, I2-catalyzed cyclization reaction, Wittig reaction, cascade reaction, imino Diels-Alder reaction, Friedel-Crafts reaction, CDC reaction, solvent-free reactions and using small chiral organic molecules as catalysts. To the best of our knowledge, this is the first review focused on the synthesis of fused tetracyclic quinolines along with mechanistic aspects.

To each his own: isonitriles for all flavors. Functionalized isocyanides as valuable tools in organic synthesis

The term functionalized isocyanides refers to all those isocyanides in which a neighbouring functional group can finely tune the reactivity of the isocyano group or can be exploited in post-functionalization processes. In this manuscript, we have reviewed all the isocyanides in which the pendant functional group causes either deviation from or reinforces the normal reactivity of the isocyano group and categorized them to highlight their common features and differences. An analysis of their synthetic potential and the possible unexplored directions for future research studies is also addressed.