The Study On The Green Synthesis Of Six-membered Heterocyclic Compounds Of Pyridine And Pyran Derivatives

It is well known that pyridine and pyran derivatives are important six-membered heterocyclic compounds which exist in many natural products,pharmaceuticals and functional materials.They possess a wide range of physiological activity and application value.Therefore,the development of new strategies to synthesize them with lower impact on the environment is one of the most important objectives in modern synthetic organic and green chemistry.In this paper,the green and efficient synthesis of acridine-1,8-dione,polyhydroquinoline compounds which containing 1,4-dihydropyridine nucleoside?1,4-DHPs?and 4H-pyran compounds were studied.Two synthesis methods of acridine-1,8-dione and polyhydroquinoline based on Hantzsch reaction via multi-component one-pot reactions were developed.An effective and facile method for the synthesis of 4H-pyran derivatives was also developed.The specific contents are as follows:1.The environment-friendly and benign methodology for the synthesis of acridine-1,8-dione and polyhydroquinoline compounds in recent years are summarized.2.Mild and nontoxic KH₂PO₄ is an efficient catalyst and aqueous ethanol is the valid solvent for the one-pot multi-component Hantzsch type condensation.A series of acridine-1,8-dione?up to 97%yield?and polyhydroquinoline derivatives via reaction of various aromatic aldehydes with ammonium acetate and 1,3-dicarbonyl compounds were prepared smoothly with good to excellent yields.Structures of all the products were characterized by IR and NMR.3.A total of 16 kinds of acridine-1,8-dione derivatives were synthesized by a three-component one-pot approach of aromatic aldehydes with dimethanone and ammonium acetate.Choline chloride was demonstrated to be a suitable catalyst for this reaction to get a satisfactory result.The products were characterized by IR and NMR.4.On the basis of the previous synthesis of 1,4-DHPs derivatives,a series of 4H-pyran derivatives were synthesized by one-pot procedure of 4-hydroxycoumarin with malononitrile and aromatic aldehyde employing PEG-400 and water as solvent.The yield was 85-93%and the products were characterized by IR and NMR.