Double heteroannulation reactions of 1-naphthol with alkyl- and arylmethylidene derivatives of malononitrile dimer

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.

Catalyst-Solvent System for PASE Approach to Hydroxyquinolinone-Substituted Chromeno[2,3-b]pyridines Its Quantum Chemical Study and Investigation of Reaction Mechanism

The Pot, Atom, and Step Economy (PASE) approach is based on the Pot economy principle and unites it with the Atom and Step Economy strategies; it ensures high efficiency, simplicity and low waste formation. The PASE approach is widely used in multicomponent chemistry. This approach was adopted for the synthesis of previously unknown hydroxyquinolinone substituted chromeno[2,3-b]pyridines via reaction of salicylaldehydes, malononitrile dimer and hydroxyquinolinone. It was shown that an ethanol-pyridine combination is more beneficial than other inorganic or organic catalysts. Quantum chemical studies showed that chromeno[2,3-b]pyridines has potential for corrosion inhibition. Real time ¹H NMR monitoring was used for the investigation of reaction mechanism and 2-((2H-chromen-3-yl)methylene)malononitrile was defined as a key intermediate in the reaction.

One-pot synthesis of annulated 1,8-naphthyridines

Annulated 1,8-naphthyridines were synthesized by one-pot reaction of aromatic aldehyde, malononitrile dimer and enehydrazinoketone.

Diastereoselective Cascade Assembly of Functionalized Pyrano[3,4-c]pyrrole Derivatives

A novel convenient approach for the synthesis of densely functionalized pyrano[3,4-c]pyrrole derivatives was developed. Cascade transformation of the simple adducts of tetracyanoethylene (TCNE) and ketones (4-oxoalkane-1,1,2,2-tetracarbonitriles) in the presence of aldehyde under the action of acetic acid led to the diastereoselective formation of targeted pyrano[3,4-c]pyrroles. The reaction pathway was thoroughly investigated, and proposed intermediates were shown to be consistent with experiment.