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41.
The mass spectra of a series of N-substituted cantharidinimides were examined. The feature of this series compounds is a sequential double hydrogen transfer from the oxabicycloheptane unit to either the carbonyl group of the succinimide unit or the nitrogen atom of the pyridyl or thiazolyl substituent through space. The ability of the N-substituent to accept a hydrogen atom possibly leads to the different fragmentation pathway. 相似文献
42.
In the frame of a more complete study on the tautomery of the pyrazolines-5-ones, the authors determined the normal vibration modes of pyrazole. They calculate the interatomic force constants by means of a “simplex” optimisation procedure (1). 相似文献
43.
Vadapalli Chandrasekhar Palani Sasikumar Puja Singh Ramalingam Thirumoorthi Tapas Senapati 《Journal of Chemical Sciences》2008,120(1):105-113
Organostannoxane cages and aggregates of well-defined composition and structure can be prepared by the reactions of organotin
oxides or organotin oxide-hydroxides with protic acids. The utility of this strategy for the preparation of dendrimer-like
molecules containing a stannoxane core and a functional periphery is described. 相似文献
44.
Sanjib Gogoi 《Tetrahedron letters》2009,50(19):2252-1652
The first enantioselective synthesis of biologically active 6-amino-5-cyanodihydropyrano[2,3-c]pyrazoles has been achieved through a cinchona alkaloid-catalyzed tandem Michael addition and Thorpe-Ziegler type reaction between 2-pyrazolin-5-ones and benzylidenemalononitriles. The reaction may also be carried out in a three-component or a four-component fashion via the in situ formation of these two components from simple and readily available starting materials. The desired products were obtained in excellent yields with mediocre to excellent enantioselectivities (up to >99% ee). 相似文献
45.
46.
Yakup Budak Meliha Burcu Gürdere Kezban Özcan Parham Taslimi İlhami Gülçin 《合成通讯》2017,47(24):2313-2323
Novel 4,5-dihydropyrazole derivatives (3a–i), 3-(4-((3aR,4S,7R,7aS)-1,3-dioxo-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindol-2(3H)-yl)phenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbothio amide, were obtained by the addition of thiosemicarbazide (2) to the chalcones (1a–i). The addition–cyclization of 2,4′-dibromoacetophenone (4) to pyrazole derivatives (3a–i) gave the new pyrazolyl-thiazole derivatives (5a–i), (3aR,4S,7R,7aS)-2-(4-(1-(4-(4-bromophenyl)thiazol-2-yl)-5-phenyl-4,5-dihydro-1H-pyrazol-3-yl)phenyl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione. Antibacterial and acetylcholinesterase (AChE) enzyme and human carbonic anhydrase (hCA) I, and II isoform inhibitory activities of the compounds 3a–i and 5a–i were investigated. Some of the compounds showed promising antibacterial activity. In addition, the hCA II and I were effectively inhibited by the lately synthesized derivatives, with Ki values in the range of 18.90?±?2.37 ?58.25?±?13.62?nM for hCA II and 5.72?±?0.98 ?37.67?±?5.54?nM for hCA I. Also, the Ki parameters of these compounds for AChE were obtained in the range of 25.47?±?11.11???255.74?±?82.20?nM. Also, acetazolamide, clinical molecule, was used as a CA standard inhibitor that showed Ki value of 70.55?±?12.30?nM against hCA II, and 67.17?±?9.1?nM against hCA I, and tacrine inhibited AChE showed Ki value of 263.67?±?91.95. 相似文献
47.
Kinsuk Das Tarak Nath Mandal Somnath Roy Samik Gupta Anil Kumar Barik Partha Mitra Arnold L. Rheingold Susanta Kumar Kar 《Polyhedron》2010
The varying coordination modes of the title ligand, L [5-methyl-1-(pyridin-2-yl)-N′-[pyridin-2-ylmethylidene]pyrazole-3-carbohydrazide] towards the different metal centers is reported by preparation and characterization of Cu(II), Zn(II) and Cd(II) complexes, [Cu(L)NO3.H2O](NO3) (1) [Zn(L)2](ClO4)2·2DMF (2) and [Cd(L)(I)2] (3) respectively. In 1, the neutral ligand serves as tetradentate 4 N donor where both pyridine and pyrazole nitrogen atoms of pyridyl–pyrazole part are coordinatively active, leaving the carbonyl oxygen of the carbohydrazide part inactive. The same pyridine and pyrazole N atoms remain abstained from the coordination process towards the Zn(II) and Cd(II) metal centers. For 2 and 3 the ligand behaves as a tridentate NNO donor where the two nitrogen atoms come from azomethine, pyridine of pyridine-2-carbaldehyde parts and O from carbonyl oxygen atoms (carbohydrazide part). The complex 1 and 2 are distorted octahedral while complex 3 adopts distorted square pyramidal geometry. All the complexes are X-ray crystallographically characterized. 相似文献
48.
以3-( 4-氟苯基) -1H-吡唑-5-甲酸乙酯为原料,与H2NNH2?H2O发生肼解生成3-( 4-氟苯基) -1H-吡唑-5-甲酰肼,再与CS2环化生成2-巯基噁二唑中间体,最后在巯基上进行烷基化反应合成了一系列新型的2-硫醚-5-吡唑基-1,3,4-噁二唑类化合物,并利用IR、1H NMR、HRMS等波谱技术对目标化合物结构进行了表征。该合成方法具有原料易得,后处理简便,收率较高的优点。 相似文献
49.
加速溶剂萃取-气相色谱-串联质谱法测定茶叶中10种吡唑和吡咯类农药的残留量 总被引:3,自引:0,他引:3
建立了加速溶剂萃取(ASE)-气相色谱-串联质谱(GC-MS/MS)法用于测定茶叶中10种吡唑和吡咯类农药残留。ASE萃取压力为1.03×107 Pa,萃取温度为100 ℃,萃取时间为5 min,萃取溶剂为乙酸乙酯-正己烷(1:1, v/v)。萃取循环1次,萃取液浓缩后用Envi-Carb/PSA固相萃取小柱净化,乙酸乙酯-正己烷(1:1, v/v)洗脱。洗脱液浓缩后,用正己烷定容,供GC-MS/MS测定,外标法定量。方法的准确度和精密度均符合残留分析要求。方法的定量限(LOQ)分别为唑螨酯0.003 mg/kg、氟虫腈硫化物0.001 mg/kg、氟虫腈0.002 mg/kg、氟虫腈砜化物0.005 mg/kg、溴虫腈0.002 mg/kg、氟硅唑0.006 mg/kg、野燕枯0.001 mg/kg、吡草醚0.001 mg/kg、吡螨胺0.0003 mg/kg、唑虫酰胺0.005 mg/kg。方法的灵敏度能满足各国有关农药的残留限量要求。 相似文献
50.
A new photochromic organic compound of thiosemicarbazone, 4-(p-bromo-α-methylaminothiocarbonyl hydrazonobenzal)-2,5-dihydro-3-mcthyl-5-oxo-1-phcnyl pyrazolc, was synthesized and characterized by elemental analyses, IR, ^1H NMR spectra, and X-ray single-crystal diffraction analysis. The compound exhibited an interesting photochromism in the solid state when irradiated by ultraviolet light at 365 nm. The photochromic kinetics was studied by the time-dependent powder UV-Vis reflectance spectra. The intcrmolecular and intramolecular hydrogcn-bonding interactions may be responsible for the photochromic phenomenon. 相似文献