Pyrrole is widely known as a biologically active scaffold which possesses a diverse nature of activities. The combination of different pharmacophores in a pyrrole ring system has led to the formation of more active compounds. Pyrrole containing analogs are considered as a potential source of biologically active compounds that contains a significant set of advantageous properties and can be found in many natural products. The marketed drugs containing a pyrrole ring system are known to have many biological properties such as antipsychotic, β-adrenergic antagonist, anxiolytic, anticancer (leukemia, lymphoma and myelofibrosis etc.), antibacterial, antifungal, antiprotozoal, antimalarial and many more. Due to the diversity of these analogs in the therapeutic response profile, many researchers have been working to explore this skeleton to its maximum potential against several diseases or disorders. In this review, attempts have been made to disclose various tactical approaches to synthesize pyrrole and pyrrole containing analogs. The structure–activity relationship studies have been discussed along with their therapeutic applications which have been reported during last decade. Some molecules as the main components of the market and clinical trials have also been discussed.

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Pyrrole: a resourceful small molecule in key medicinal hetero-aromatics

Coumarin heterocyclic derivatives: chemical synthesis and biological activity

Synthesis of indazole motifs and their medicinal importance: an overview.

Quinoline is one of the most widely investigated scaffolds by synthetic chemists because of its medicinal importance. A wide range of metal-catalyzed, metal-free, multi-step or domino one-pot protocols are reported in the literature for construction of this scaffold. Several reviews have appeared on synthetic aspects of this scaffold, however there is no focused review on metal-free domino one-pot protocols. Domino one-pot protocols offer an opportunity to access highly functionalized final products from simple starting materials. Because of this unique feature of domino protocols, in recent years their utility for generation of molecular libraries has been widely appreciated. In this review, all contributions till March 2015 are surveyed with particular emphasis on metal-free domino reactions for quinoline ring construction and are discussed herein along with mechanistic aspects.

Metal-free domino one-pot protocols for quinoline synthesis

Push–pull alkenes, which bear electron-donating and -accepting group(s) at both termini of a C═C double bond, respectively, are of interest not only for their unique electronic properties but also for their importance as versatile building blocks in organic synthesis. In the world of ketene acetals having the push–pull alkene skeleton, ketene N,S-acetal is most likely the biggest family according to the number and types of these compounds. The first ketene N,S-acetal compound was reported in 1956. As a cyclic ketene N,S-acetal compound, nithiazine, the first lead structure of neonicotinoid insecticides, was reported in 1978. The characteristics of ketene N,S-acetals, which have the structural feature of ketene S,S-acetals and enaminones, make them versatile and easy to use, especially in cyclization and multicomponent reactions for the synthesis of various heterocyclic systems and related natural products. There has been an increasing wealth of information about the synthesis and synthetic applications of...

Chemistry of Ketene N,S-Acetals: An Overview.

Highly efficient synthesis of polysubstituted pyrroles via four-component domino reaction.

GAP chemistry for pyrrolyl coumarin derivatives: a highly efficient one-pot synthesis under catalyst-free conditions

An efficient synthesis of novel functionalized 1,8-naphthyridine and chromeno[2,3-b]quinoline derivatives via cascade reaction of 2-chloroquinoline-3-carbaldehyde and enaminones or cyclic 1,3-dicarbonyl compounds was developed. All of the 1,8-naphthyridine derivatives synthesized were evaluated for their antiproliferative properties in vitro against cancer cells and several compounds were found to have high activities.

Efficient synthesis and evaluation of antitumor activities of novel functionalized 1,8-naphthyridine derivatives.

A simple and efficient one-pot construction of pyrazolo[3,4-e]indolizine derivatives via a diethylamine-catalyzed three-component domino reaction of arylglyoxals, cyclic 1,3-diones, and 5-aminopyrazoles under microwave irradiation is described. In this one-pot transformation, seven bonds and two new rings are efficiently formed. This synthesis was confirmed to follow the group-assisted-purification (GAP) chemistry process, which can avoid traditional recrystallization or chromatography purification methods.

Xian Feng

Papers

Highly efficient synthesis of polysubstituted pyrroles via four-component domino reaction.

GAP chemistry for pyrrolyl coumarin derivatives: a highly efficient one-pot synthesis under catalyst-free conditions

Efficient synthesis and evaluation of antitumor activities of novel functionalized 1,8-naphthyridine derivatives.

Multicomponent Strategy to Pyrazolo[3,4-e]indolizine Derivatives under Microwave Irradiation.

An efficient synthesis of 2H-indazoles via reductive cyclization of 2-nitrobenzylamines induced by low-valent titanium reagent