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排序方式: 共有136条查询结果,搜索用时 15 毫秒
1.
Rok Frlan 《Tetrahedron》2007,63(43):10698-10708
All three isomers of ethyl 3-(hydroxyphenoxy)benzyl butylphosphonates as potential antigen 85C inhibitors were synthesized from 3-bromobenzoic acid using Ullman diaryl ether synthesis combined with benzyl- and trityl protection strategy for the phenol hydroxyl groups. 相似文献
2.
A new synthetic route for biologically interesting benzochromenes was developed starting from naphthalenols and α,β‐unsaturated aldehydes in the presence of ethylenediamine diacetate. This methodology was applied for the total synthesis of the biologically important natural products lapachenole, dihydrolapachenole, and mollugin with a benzochromene moiety. 相似文献
3.
Rhodium(II)-catalyzed reactions of cyclic diazodicarbonyl compounds with a variety of halides have been examined. With acid halides, β-acyloxy α-haloenones are produced in good yields. With benzyl halides, β-benzyloxy α-haloenones are obtained in good yields. Reactions with methylene halides yield β-halomethoxy α-haloenones in good yields, whereas reactions with ethyl halides and ethylene dihalides result in β-hydroxy α-haloenones in high yields. These reactions provide a useful and rapid entry to β-substituted α-haloenones. The mechanistic pathway for the formation of these products has been also described in terms of halonium ylides. 相似文献
4.
5.
Tomasz Rok Eugeniusz Rokita Grzegorz Tatoń Tomasz Guzik Tomasz Śliwa 《Journal of Thermal Analysis and Calorimetry》2017,127(2):1163-1170
Allergen sensitization is being diagnosed by commonly available methods in clinical practice—skin prick tests (SPTs) and specific immunoglobulin E test (sIgE). Recently, a new thermographic (TH) method for the assessment of SPT was developed, and it was demonstrated that the TH measurements of forearm temperature distribution during SPT, supported by a mathematical model, offer a new quantification method of allergen-induced skin reactions. The aim of this study is a comprehensive comparison of the TH method with SPT and sIgE techniques. The studies were performed for a group of 51 patients. The SPT and sIgE examinations were done in a routine way. For TH analyses, set of thermograms of both forearms were acquired after prick and analyzed with the use of developed software. All results were converted into categorized scale for comparison. The collected results indicate high correlation coefficients between methods equal to 0.76–0.99. Sensitivity and accuracy of TH assessment in respect of both SPT and sIgE methods is at good level (0.72–0.93). Acceptable level of specificity 0.60–0.88 was also achieved for most allergic responses. Excellent agreement between SPT and sIgE methods was observed which makes the TH assessment competitive. Due to higher precision and sensitivity of digital infrared technology, possibility of making error in diagnosis is significantly reduced. Additional advantage of the TH method relies on an estimation of the skin reactivity which allows highlighting the hypersensitivity patients and automatic correction of the diagnosis. 相似文献
6.
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
7.
An efficient and facile green synthesis of spirooxindole derivatives bearing pyrano[2,3-c]pyrazole moiety has been achieved via a \(\mathrm{CeO}_{2}\)-NPs catalyzed four-component reaction in water. The protocol offers an environmentally benign and effective approach to highly functionalized and biologically interesting spiro[indoline-3,4\(^\prime \)-pyrano[2,3-c]pyrazole] derivatives. The synthesized compounds exhibit potent antioxidant and antibacterial activities. 相似文献
8.
9.
Zajc B Grahek R Kocijan A Lakshman MK Kosmrlj J Lah J 《The Journal of organic chemistry》2003,68(8):3291-3294
The enantiomeric resolution and the elution order of (+/-)-trans-7,8-dihydrodiols of benzo[a]pyrene and its 6-fluoro and 6-bromo derivatives were analyzed on three polysaccharide-based columns: Daicel Chiralcel CA-I (cellulose triacetate), OF, and OG [cellulose tris(4-chloro- and 4-methylphenylcarbamate)]. For comparison, the separation of (+/-)-1,1'-bi-2-naphthol was evaluated on the OG and OF columns. Possibly similar interactions of (S)-1,1'-bi-2-naphthol and (7S,8S)-isomers of 6-halo-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene with the chiral sorbent are suggested. 相似文献
10.
A. S. Moskalenko D. A. Rok S. Ya. Umanskii 《Russian Journal of Physical Chemistry B, Focus on Physics》2011,5(1):8-15
For a model molecular system with one vibrational degree of freedom and three electronic states coupled by pump and probe
laser pulses in a condensed medium, the response signal in a femtosecond pump-probe experiment is calculated. The potential
curves of all three states are described by the Morse potential. Calculations are performed using two qualitatively different
approaches to describing the medium-induced relaxation: with memory of the relaxation process and without memory (Markovian
approximation). The temporal evolution of the vibrational wave packet in the intermediate electronically excited state is
described using a master equation for the density matrix of the molecular system, which is derived within the framework of
the Nakajima-Zwanzig formalism. It is demonstrated that, at short delay times, when the proposed approach is applicable, taking
into account memory effects can substantially change the form of the pump-probe experiment signal in comparison with the signal
calculated in the Markovian approximation. 相似文献