نتایج جستجو برای: chromene derivatives
تعداد نتایج: 105503 فیلتر نتایج به سال:
Na2SO4 as an inexpensive and effective catalyst has provided a green protocol for the synthesis of tetrahydrobenzo[b]pyran, pyrano[2,3-d]pyrimidinone and dihydropyrano[3,2c]chromene derivatives from the three-component domino reaction of aromatic aldehydes and malononitrile with 4-hydroxycoumarin/ dimedone/ barbituric acid in ethanol/water as a mixture of solvent that, this mixture entirely is ...
Chromanone derivatives demonstrate remarkable cytotoxity against a varieties of cancer cell lines. Novel 9-[hydroxy(substitutedphenyl)methyl]-2,2-dimethyl-2,3,8,9- tetrahydro-4H,10H-pyrano[2,3-f]chromene-4,10-diones as Glyasperin analogues were synthesized in four steps from known 4-chromone 1. The key step was the preparation of chromane dione 5a by regioselective intramolecular c...
A series of 2-amino-4-(nitroalkyl)-4H-chromene-3-carbonitriles were synthesized by an efficient multicomponent reaction in aqueous media using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) as a catalyst at room temperature. Mild condition, environment friendly procedure and excellent yields are the main advantages of this procedure. The cytotoxic activity of target compounds were evaluated against t...
A novel catalytic synthesis of 3,3'-(arylmethylene)-bis-(4-hydroxy-2H-chromene-2-one) derivatives from a tandem condensation reaction of 4-hydroxycoumarin and aromatic aldehydes has been developed. The reaction occurs in water in the presence of Melamine trisulfonic acid as catalyst to give the corresponding products in good to high yields. This green approach has several advantages such as sho...
Na2SO4 as an inexpensive and effective catalyst has provided a green protocol for the synthesis of tetrahydrobenzo[b]pyran, pyrano[2,3-d]pyrimidinone and dihydropyrano[3,2c]chromene derivatives from the three-component domino reaction of aromatic aldehydes and malononitrile with 4-hydroxycoumarin/ dimedone/ barbituric acid in ethanol/water as a mixture of solvent that, this mixture entirely is ...
The crystal structures of two chromone derivatives, viz. ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate, C19H16O4, (1), and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate C18H13FO4, (2), have been determined: (1) crystallizes with two mol-ecules in the asymmetric unit. A comparison of the dihedral angles beween the mean planes of the central chromone core with those of...
A new efficient enantioselective conjugate addition strategy has been disclosed to rapidly construct 2-amino-3-nitrile-chromene complexes via a multi-hydrogen-bond cooperative activation model.
Abstract 4-(2-Pyridylazo)resorcinol (PAR) sodium salt reacts with aromatic aldehydes and malononitrile in aqueous ethanol to form 2-amino-4-aryl-5-hydroxy-6-(2-pyridylazo)-4 H -chromene-3-carbonitriles.
In the title compound, C17H19NO3S2, the maximum deviation of atoms in the 2H-chromene ring system is 0.0097 (14) Å and the piperidine ring adopts a chair conformation. The dihedral angle between the 2H-chromene ring and the piperidine ring (all atoms) is 87.59 (8)°. In the crystal, inversion dimers linked by pairs of C-H⋯O inter-actions generate R 2 (2)(22) loops. Further C-H⋯O hydrogen bonds l...
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