Synthesis of 4H,5H-pyrano[3,2-c][1]benzopyran-5-ones in aqueous media

One-Pot Synthesis of 4H-Pyrano[3,2-c]coumarin Derivatives Catalyzed by Deep Eutectic Solvent

4H-Pyrano[3,2-c]coumarin derivatives are an important class of pharmaceutical compounds that are expensive to prepare by previously reported methods. An efficient and green method was developed to obtain these derivatives using the deep eutectic solvent (DES) zinc chloride/acetamide (n:n = 1:4), which acted as both the catalyst and the solvent for the reaction. An aromatic aldehyde, 4-hydroxycoumarin, and cyanoacetate were used as the substrates. The DES, substrate molar ratio, diluent type, temperature, and reaction time were optimized to obtain the 4H-pyrano[3,2-c]coumarin derivatives from a range of aromatic aldehydes in a single step in moderate to high yields and under mild reaction conditions.

A Convenient and Clean Procedure for the Synthesis of Pyran Derivatives in Aqueous Media Catalysed by Tebac

A clean and simple synthesis of 6-amino-5-cyano-4-aryl-2-methyl-4 H-pyran-3-carboxylate derivatives was accomplished in high yields via the reaction of arylmethylidenemalononitriles with acetoacetate in aqueous media catalysed by triethylbenzylammonium chloride (TEBAC). The structures were established by spectroscopic data and further confirmed by X-ray analysis.

A green one-pot three-component synthesis of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives using a Fe3O4@SiO2–imid–PMAn magnetic nanocatalyst under ultrasonic irradiation or reflux conditions

Green synthesis of tetrahydrobenzo[b]pyran and dihydropyrano[3,2-c]chromene derivatives.

N,2-Dibromo-6-chloro-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazine-7-sulfonamide 1,1-dioxide: an efficient and homogeneous catalyst for one-pot synthesis of 4H-pyran, pyranopyrazole and pyrazolo[1,2-b]phthalazine derivatives under aqueous media

DCDBTSD was successfully applied in the synthesis of 4H-pyran, pyranopyrazole and pyrazolo[1,2-b]phthalazine derivatives by a one-pot multi-component reaction in water.

Synthesis of 5,5′-(arylmethylene)bis(pyrimidinone) derivatives in aqueous media

The condensation and addition reactions of aromatic aldehydes and 4,6-dihydroxypyrimidine or 2,4-dihydroxy-6-aminopyrimidine in water in the presence of triethylbenzylammonium chloride (TEBAC) afford a one-pot synthesis of 5,5′-(arylmethylene)bis[6-hydroxypyrimidine-4(3H)-one]s and 5,5′-(arylmethylene)bis[6-aminopyrimidine-2,4 (1H,3H)-dione]s. These compounds were characterised by elemental analysis and IR and 1H NMR spectra and further confirmed by a single crystal X-ray diffraction analysis.

Synthesis of 2-Amino-4-Aryl-5-Oxo-4,5-Dihydropyrano[3,2-c] Chromene Derivatives Catalysed by KF-Montmorillonite

A series of 2-amino-4-aryl-5-oxo-4,5-dihydropyrano[3,2- c]chromene derivatives has been synthesised by the reaction of 4-hydroxycoumarin and substituted cinnamonitriles catalysed by KF-montmorillonite. The structures were characterised by IR and 1H NMR spectroscopic data and confirmed by X-ray diffraction analysis.

An efficient synthesis of 3,3′-arylmethylenebis(4-hydroxy-6-methyl-2H-pyran-2-one)s in aqueous media

The condensation reactions of aromatic aldehydes and 4-hydroxy-6-methyl-2H-pyran-2-one in water in the presence of sodium 1-dodecanesulfonate affords a one-pot synthesis of 3,3′-arylmethylene bis(4-hydroxy-6-methyl-2H-pyran-2-one)s.