نتایج جستجو برای: 4h chromene

تعداد نتایج: 7259  

Journal: :Acta Crystallographica Section E Structure Reports Online 2008

Journal: :Acta Crystallographica Section E Crystallographic Communications 2016

Journal: :Acta Crystallographica Section E Crystallographic Communications 2015

2014
Yoshinobu Ishikawa

In the title compound, C10H5ClO3, a chlorinated 3-formyl-chromone derivative, all atoms are essentially coplanar (r.m.s. deviation = 0.032 Å for the non-H atoms), with the largest deviation from the least-squares plane [0.0598 (14) Å] being for a pyran-ring C atom. In the crystal, mol-ecules are linked through stacking inter-actions along the b axis [shortest centroid-centroid distance between ...

2014
Yoshinobu Ishikawa

In the title compound, C10H4ClFO3, a chlorinated and fluorinated 3-formyl-chromone derivative, all atoms are essentially coplanar (r.m.s. = 0.0336 Å for the non-H atoms), with the largest deviation from the least-squares plane [0.062 (2) Å] being for a benzene-ring C atom. In the crystal, mol-ecules are linked through stacking inter-actions [centroid-centroid distance between the benzene and py...

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...

2013
Hamid-Reza Adhami Johannes Lutz Hanspeter Kählig Martin Zehl Liselotte Krenn

The use of herbal medicinal preparations in dementia therapy has been studied based on experience from traditional medicine. A dichloromethane extract of gum ammoniacum, the gum-resin from Dorema ammoniacum D. Don had shown acetylcholinesterase (AChE) inhibitory activity in a previous study. The aim of this study was the isolation and characterization of the active compounds from this resin. Th...

2016
Ligia R. Gomes John Nicolson Low Carlos Fernandes Alexandra Gaspar Fernanda Borges

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...

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