a simple, efficient, and high yielding one-pot protocol has been developed for the synthesis of 4h-benzo[b]pyrans scaffolds installing a three-component tandem knoevenagel-cyclocondensation reaction of an aldehyde, malononitrile and dimedone using guanidinium chloride as polyfunctional organocatalyst under solvent-free conditions in high to excellent yields. various aromatic aldehydes were util...

In the title mol-ecule, C(17)H(20)O(8), the two pyran rings form a dihedral angle of 61.2 (2)°. The two hy-droxy-methyl groups are each disordered over two sets of sites in a 0.764 (3):0.236 (3) ratio. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into layers parallel to the ac plane.

The title compound, C(19)H(18)O(7) [systematic name 5-hy-droxy-3,6,7-tri-meth--oxy-2-(4-meth-oxy-phen-yl)-4H-1-benzopyran-4-one], is a flavonoid which was isolated from the traditional Chinese medicine Laggera alata. The benzene ring of the benzopyran-one unit forms dihedral angles of 1.72 (3) and 37.39 (5)° with the pyran ring and the substituent benzene ring, respectively. The mol-ecular conf...

We designed a ceria-vanadia/silica (Ce-V/SiO2) heterogeneous catalyst and used it for the green and efficient synthesis of 2-amino-3-cyano-4H-pyran derivatives. The green reaction was a multicomponent one-pot condensation of 5,5-dimethylcyclohexane-1,3-dione, aromatic aldehyde, and malononitrile in an eco-compatible solvent (ethanol). The catalyst was synthesized and fully characterized by powd...

In this work, a simple and economical procedure for the synthesis of spiro-4H-pyranderivatives has been found through the three-component, one-pot condensation of isatin/acenaphthequinone, malononitrile and different reagents including 1, 3-dicrbonyl compounds, naphthol and 4-hydroxycumarin under thermal and solvent-free conditions in the presence ofFe2O<su...