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941.
Total synthesis of biologically interesting natural and unnatural pyranoflavones has been accomplished starting from readily available 2,4‐dihydroxyacetophenone or 2,4‐dihydroxy‐6‐methoxyacetophenone in three steps, i.e., benzopyran formation, condensation, and cyclization reaction. 相似文献
942.
Jun‐Ju Xu Da‐Ke Zhao Hong‐Lian Ai Li‐Mei Zhang Shi‐Qing Xie Shu‐Hui Zi Sheng‐Chao Yang Yong Shen 《Helvetica chimica acta》2013,96(11):2155-2159
A further study of the alkaloid constituents of Aconitum forrestii led to the isolation of three new C19‐diterpenoid alkaloids, named 14‐acetoxy‐8‐O‐methylsachaconitine ( 1 ), 14‐acetoxyscaconine ( 2 ), and 8‐O‐ethylcammaconine ( 3 ). Their structures were determined by UV, IR, and MS, 1D‐ and 2D‐NMR analyses. 相似文献
943.
Ting‐Ting Zhang Xiao‐Xia Qi Jianfeng Jia Hai‐Shun Wu 《International journal of quantum chemistry》2013,113(7):1010-1017
Quantum chemistry methods are applied to investigate the electronic structures, injection and transport properties, absorption and phosphorescence mechanism of a series of Iridium (III) complexes [Ir(C∧N)2(L)2]+ (L = 4‐pyCO2Et; C∧N = 2‐phenylpyridine, 1 ; 2‐(4‐tolyl)pyridine, 2 ; 2‐(4,6‐difluorophenyl)pyridimato, 3 ; benzoquinoline, 4 ), which may be used as emitters on organic light emitting diodes (OLEDs). Calculations of ionization potentials and electron affinities are used to evaluate the injection abilities of holes and electrons into these complexes. The reorganization energy (λ) calculations show that the four complexes are suitable as emitters in OLEDs. The absorptions and emissions can be tuned by adding substituent to the ppy ligand or extending the π‐conjugation effect of the C∧N ligand, and quantum yields of 1 – 4 are investigated. In addition, no solvent effect is observed in the absorption and emission spectra. © 2012 Wiley Periodicals, Inc. 相似文献
944.
Qiong Wu Hui Feng Dong‐Dong Guo Mian‐Shuai Yi Xing‐Han Wang Bo Jiang Shu‐Jiang Tu 《Journal of heterocyclic chemistry》2013,50(3):599-602
A green and highly efficient method for the synthesis of polyfunctionalized indoline‐spiro fused pyran derivatives has been established. This reaction was conducted by reacting readily available and inexpensive starting materials, such as isatins, cyclic‐1,3‐dicarbonyl compounds, and malononitrile in aqueous media without any catalysts under microwave irradiation. The present green synthesis shows fascinating properties such as the use of water as the reaction solution, concise one‐pot conditions, short reaction periods (8–14 min), and easy purifications. The synthesis could also set a good example to GAP (Group‐Assistant‐Purification) chemistry in which purification via chromatography can be avoided and the pure products can be easily acquired only by washing the crude products with 95% EtOH. 相似文献
945.
An efficient one‐pot synthesis of spiro[indoline‐3,1′‐pyrazolo[1,2‐b]phthalazine] derivatives via three‐component reaction of phthalhydrazide, isatin, and malononitrile (cyanoacetic ester) is described. This new protocol has the advantages of high efficiency, mild reaction conditions, one‐pot procedure, and convenient operation. 相似文献
946.
A series of novel 5‐aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole 3a – 3n were synthesized by the annulation of 2‐aryloxyacetohydrazides with 3‐aryl‐1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)prop‐2‐en‐1‐ones ( 2 ) in the presence of a catalytic amount of acetic acid. Compounds 2 were obtained by the Knoevenagel reactions of 1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanone ( 1 ) with aromatic aldehydes in the presence of piperidine. Their structures were confirmed by IR, 1H‐NMR, ESI‐MS, and elemental analyses. The preliminary bioassay indicated that some compounds displayed moderate to excellent fungicidal activity. For example, compounds 3l , 3m , and 3n possessed 100% inhibition against Cercospora arachidicola Hori at the concentration of 50 mg/L. 相似文献
947.
Dengxue Ma Qiying Xia Guangfu Ji 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(12):2047-2053
To look for the single-source precursors, density functional theory calculations were performed to study structures, IR spectra, and stabilities of the possible isomers for the clusters (I2GaN3) n (n = 1–4). It is found that the optimized (I2GaN3) n (n = 2–4) clusters all possess cyclic structure containing Ga-Nα-Ga linkages, and azido group in azides has linear structure. Trends in geometrical parameters with the oligomerization degree n are discussed. The IR spectra are obtained and assigned by vibrational analysis. Thermodynamic properties are linearly correlated with the oligomerization degree n as well as the temperature. Mean-while, the oligomerizations can occur spontaneously at 298.2 K. 相似文献
948.
Air oxidation of N-cyclopropylanilines was shown to occur under either ambient conditions or accelerated conditions (warming or shining light) in an open container. A subsequent fragmentation resulted in formation of the corresponding acetamide. While potential mechanisms have been previously proposed, simple aerobic oxidation to β-hydroxy-propionamides in the absence of a radical promoter has not been previously reported. 相似文献
949.
A facile and efficient synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes has been accomplished by treatment of β-naphthol with aryl or alkyl aldehydes catalyzed by 2-1′-methylimidazolium-3-yl-1-ethyl sulfate in ionic liquid [BMIM][BF4] at 80°C. The luminescence of products was studied in detail. 相似文献
950.
Mediated by samarium diiodide, 1-(benzotriazole-1-yl)alkyl esters 1 underwent cross-coupling with aldehydes or ketones to afford β-(benzotriazole-1-yl)alcohols 2 exclusively with the selective removal of acyloxy over benzotriazolyl. 相似文献