نتایج جستجو برای: chromene
تعداد نتایج: 842 فیلتر نتایج به سال:
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.
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...
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.
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...
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...
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.
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.
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.
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...
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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