نتایج جستجو برای: chromene

تعداد نتایج: 842  

2011
Zhen Qiao Li Liu Dong Wang

In the title compound, C(21)H(16)O(4), the dihedral angle between the phenyl ring and the 2H-chromene ring system is 59.8 (2)°. The crystal packing is stabilized by weak π-π stacking inter-actions [centroid-centroid distances = 3.667 (2) Å] and inter-molecular C-H⋯O hydrogen-bonding inter-actions.

2013
Zeinab H. Ismail

α-Enone 1, reacts with hydrazines, hydroxylamine hydrochloride, thiourea, diethylmalonate, malononitrile ethyl cyanoacetate to give the corresponding indazole, oxime, isoxazole, quinazoline, chromene and quinoline derivatives. The structures of all the synthesized compounds were confirmed by micro analytical and spectral data. The antimicrobial and the antitumor activities of some of the synthe...

2010
Bingjing Liu Guangying Chen Changchun Cen Xinming Song Changri Han

The title chromene, C(14)H(16)O(4), was isolated from the stems of Polyalthia plagioneura Diels. The mol-ecular structure is stabilized by an intra-molecular O-H⋯O hydrogen bond, which generates an S(6) ring. In the crystal, the mol-ecules are linked by C-H⋯O inter-actions, generating [010] chains.

Journal: :Catalysis Today 2023

The synthesis of 2-amino-chromene with excellent yields (82%) was achieved by utilizing basic hierarchical zeolites prepared surfactant-templating as catalysts in a multicomponent reaction under solvent-free conditions. use these more than doubles the activity their microporous counterparts. These results highlight superior diffusivity and performance zeolites, which can be attributed to well-d...

Journal: :Applied and environmental microbiology 1979
S Otten J P Rosazza

Microbial transformation of lapachol, a naturally occurring naphthoquinone, was carried out by Curvularia lunata (NRRL 2178). The fungus brings about oxidative cyclization of the substrate to dehydro-alpha-lapachone, which was isolated and characterized by nuclear magnetic resonance and mass spectral analyses; its structure was verified by chemical synthesis. The metabolite is a naturally occur...

2012
Renata Gašparová Ján Titiš Filip Kraic

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.

2015
Danielle L Paterson David Barker

The synthesis of the unique furo[2,3-b]chromene ring system found in hyperaspidinols A and B, acylphloroglucinols from Hypericum chinense has been achieved in twelve steps. By comparison of the NMR spectra of the synthesized compounds with those of the natural products, a relative stereochemistry is suggested, especially that of the ketal carbon.

Journal: :Chemical communications 2014
Hai Xiao Siyang Xu Rui Wu Xiao Yue Ji Xin Yan Wu Pei Nian Liu

A copper(ii) perchlorate-promoted tandem reaction of internal alkynol and salicyl N-tosylhydrazone provides a novel, concise method for constructing isochromeno[3,4-b]chromene in 35-94% yields. The tandem reaction involves cycloisomerization, formal [4+2] cycloaddition and an elimination process.

Journal: :International journal of advanced research 2022

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...

Journal: :Catalysts 2022

An organocatalytic [4 + 2] cascade annulation of salicylaldehydes and 1,3-bisarylsulfonylpropenes has been developed. This protocol enables the efficient straightforward synthesis a new series 3-sulfonyl-2-sulfonylmethyl-2H-chromenes that are useful for exploring pharmacologically valued compounds. Further reductive modifications result in 3-desulfonylated chromene or chromane derivatives. can ...

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