A new one-pot three-component synthesis of 2,4-diamino-5H-chromeno[2,3-b]pyridine-3-carbonitrile derivatives

The Chromenopyridine Scaffold: A Privileged Platform in Drug Design

The chromenopyridine scaffold represents an important class of heterocyclic compounds exhibiting a broad spectrum of biological properties. This review describes novel and efficient procedures for the synthesis of this scaffold. Herein, several methods were detailed and grouped according to their starting material (e.g., salicylaldehydes, chromones, chromanones and coumarins) and respective biological activity, when reported. This review highlights the potential of the reported synthetic strategies for preparing chromenopyridine derivatives with promising biological activity, paving the way for further developments in drug discovery.

Multicomponent design of chromeno[2,3-b]pyridine systems

The review summarizes and systematizes data on the methods for the preparation of chromeno[2,3-b]pyridines. Both multicomponent and pseudo-multicomponent synthetic approaches and one-pot transformations based on the reactions of carbonyl compounds, malononitrile or its derivatives, and CH-acids are considered. Examples of the use of various catalysts, microwave and ultrasonic radiation, as well as electric current for the implementation of multicomponent transformations of this type are given. Characteristic features of the course and mechanisms of reactions are discussed. Data on the biological activity of the obtained compounds and on other fields of application of such heterocyclic systems are presented.

The bibliography includes 109 references.

Unravelling the anticancer potential of functionalized chromeno[2,3-b]pyridines for breast cancer treatment

A selection of new chromeno[2,3-b]pyridines was prepared from chromenylacrylonitriles and N-substituted piperazines, using a novel and efficient synthetic procedure. The compounds were tested for their anticancer activity using breast cancer cell lines MCF-7, Hs578t and MDA-MB-231 and the non-neoplastic cell line MCF-10A for toxicity evaluation. In general, compounds showed higher activity towards the luminal breast cancer subtype (MCF-7), competitive with the reference compound Doxorubicin. The in vivo toxicity assay using C. elegans demonstrated a safe profile for the most active compounds. Chromene 3f revealed a promising drug profile, inhibiting cell growth and proliferation, inducing cell cycle arrest in G₂/M phase, apoptosis and microtubule destabilization. The new compounds presented exciting bioactive features and may be used as lead compounds in cancer related drug discovery.

Zn(OTf)2-Catalyzed Formal [3 + 3] Cascade Annulation of Propargylic Alcohols with 2-Aminochromones: Accessing the Chromeno[2,3-b]pyridines

A Zn(OTf)₂-catalyzed formal [3 + 3] cascade annulation strategy for the synthesis of functionalized chromeno[2,3-b]pyridines has been developed using propargylic alcohols and 2-aminochromones as the substrates. The protocol provides a convenient and atom-economical method of accessing a broad range of chromeno[2,3-b]pyridine derivatives in excellent yields with good functional-group tolerance. The method is also effective on the gram scale, which highlights the inherent practicality of this synthetic transformation.

Three-component bicyclization providing an expedient access to pyrano[2',3':5,6]pyrano[2,3-b]pyridines and its derivatives

A new three-component bicyclization for the efficient synthesis of a fused pyrano[2,3-b]pyridine library has been developed. The syntheses were achieved by reacting diverse C,O-containing nucleophiles, aldehydes, and 2-aminoprop-1-ene-1,1,3-tricarbonitrile under microwave irradiation, providing 50 examples of chemically and biomedically significant pyrano[2,3-b]pyridine analogues with the concomitant formation of two new rings and four σ bonds. This procedure features short reaction times, low-cost, and easily available starting materials, reliable scalability and mild reaction conditions, as well as operational simplicity.