نتایج جستجو برای: 4h chromene

تعداد نتایج: 7259  

2013
Zeenat Fatima Thothadri Srinivasan Jonnalagadda Naga Siva Rao Raghavachary Raghunathan Devadasan Velmurugan

In the title compound, C20H18O7, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap, and its mean plane makes a dihedral angle of 73.25 (2)° with the pyran ring mean plane. The furan ring makes dihedral angles of 67.43 (12) and 6.20 (11)° with the mean plane of the dioxolane and pyran rings, respectively. The O atom attached to the pyran ring dev...

1999
A. H. ABDEL-RAHMAN A. M. KHALIL S. I. EL-DESOKY E. M. KESHK

The reaction of 6-formyl-7-hydroxy-5-methoxy-2-methylbenzopyran-4-one with dimethyl acetylenedicarboxylate and benzil gave the respective 4H,6H-pyrano[3,2-g]chromene and imidazolylbenzopyran derivatives. Treatment of the imidazolylbenzopyran with hydrazine hydrate or hydroxylammonium chloride yielded imidazolylpyrazolylor imidazolylisoxazolylbenzenes, while the alkaline hydrolysis of imidazolyl...

Journal: :iranian journal of catalysis 2014
esmayeel abbaspour-gilandeh seyyedeh cobra azimi

the ionic liquid li(ohch2ch2nh2)(cf3oac) was found to efficiently catalyze the three-component reaction between different enols, aldehydes, and malononitrile , leading to rapid synthesis of 2-amino-4h-chromene derivatives in fairly high yields. the catalyst is easily prepared, highly stable, simple to handle and recycled for several times without significant loss of activity. the method is simp...

Journal: :IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 2018

Journal: :Acta Crystallographica Section E Structure Reports Online 2012

2008
Bin Liu Bo-Lun Yang

In the title compound, [Ca(C(15)H(9)O(7)S)(H(2)O)(6)](C(15)H(9)O(7)S)·3H(2)O, the Ca centre has a distorted deca-hedral geometry, coordinated by six O atoms from water mol-ecules and one sulfonate O atom. The crystal structure is stabilized by aromatic π-π inter-actions, with centroid-centroid distances of 3.765 (5) and 3.896 (5) Å between the phenyl ring and the benzene ring of the chromene un...

2010
Xian Zhang Yueqing Li Pingping Chen Tianjiao Han Weijie Zhao

The organic anion of the title compound, {[Na(C(15)H(9)O(10)S)(H(2)O)(2)]·H(2)O}(n) {systematic name: poly[[diaqua-[μ-2-(3,4-dihy-droxy-phen-yl)-3,5,7-trihy-droxy-4-oxo-4H-chromene-8-sulfon-ato]-sodium] monohydrate]}, has a nearly planar structure. The Na atom is six-coordinated by O atoms, two from water mol-ecules and four from the anion. The dihedral angle between the ring systems in the ani...

Journal: :Acta Crystallographica Section E Crystallographic Communications 2015

Sucrose is applied as an efficient catalyst for the three-component reaction consisting of aromatic aldehydes, malononitrile and resorcinol in a mixture of water and ethanol media as green solvents. The advantages of this method are excellent yeild, inexpensive catalyst and more environmentally friendly. Mechanistic insight into the synthesis of 2-amino-4H-chromene included spectral kinetics ap...

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