An efficient telescoped method for synthesis of 3-phenyl-10-(2,3,4-trimethoxyphenyl)-9,10-dihydro-4H,8H-pyrano[2,3-f]chromene-4,8-dione was elaborated. The presented protocol includes the one-pot multicomponent reaction 7-hydroxy-3-phenyl-4H-chromen-4-one, 2,3,4-trimethoxybenzaldehyde and Meldrum’s acid. Advantages this are application readily available starting reagents, atom economy easy proc...

The treatment of β,γ-unsaturated α-ketoesters with phenols in the presence of trityl chloride and 4 Å molecular sieves in refluxing trifluoroacetic acid afforded 4-aryl-2H-chromenes in high yields, in which a reverse of the regiochemistry of Jørgensen-Rutjes chromane synthesis was observed. The isolation of 4H-chromene intermediates, confirmed by single-crystal X-ray analysis, indicates that th...

The mol-ecular conformation of the title compound, C(10)H(8)O(4), isolated from Laretia acualis, is stabilized by a strong intra-molecular hydrogen bond between the hydroxyl and carbonyl groups. The crystal packing shows π-π stacking inter-actions. The chromene (4H-1-benzopyran-4-one) unit is essentially planar.

Carboxhydrazides 3 were synthesized by reaction of substituted furo[3,2-b]pyrrole-5-carboxhydrazides 1 with 4-oxo-4H-chromene-2-carboxaldehyde 2 in the presence of 3-methyl-benzenesulfonic acid in ethanol. Carboxhydrazides 3 were used as ligands for synthesis of Cu, Co, and Ni complexes 4.

ABSTRACT A simple and efficient approach has been developed to synthesise novel functionalised 5H-chromeno[2,3-d] pyrimidines derivatives (4a-h). This entails treating 2-amino-3-cyano-4H-chromenes (3a-h) with formamidine acetate under microwave irradiations solvent-free conditions. All structures of new compounds obtained in this study were characterised by IR, MS, 1H 13C NMR analysis. Addition...

Silica-bonded n-propyltriethylene-tetramine (SBNPTT) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes. Chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oC under solvent-free conditions. The heterogeneous solid base showed much the same efficiency when u...

silica-bonded n-propyltriethylene-tetramine (sbnptt) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4h-chromenes. chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oc under solvent-free conditions. the heterogeneous solid base showed much the same efficiency when u...

A newsynthetic route has been developed for the total synthesis of ozenoxacin. In this avoided toxic heavy metals and synthesised key intermediate_7-bromo-1-cyclopropyl-8-methyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid by simply insertion Cyclopropyl amine into 4-oxo-4H-chromene-3-carboxylic intermediate, Then intermediate carboxylic acidundergoesSuzuki coupling with boronated ester deacety...

In(OTf)3 catalyzed microwave-assisted alkenylation of methoxyphenols was investigated. Exclusive formation of either indenes or chromenes was observed depending on the position of the methoxy group on phenol. The structures of 1H-inden-4-ol derivatives (4a-e) and 4H-chromene derivatives (5a-j) were established by NMR ((1)H & (13)C) and high-resolution mass spectra, which were further supported ...