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91.
A short and new synthesis of the non-phenolic azafluoranthene alkaloid triclisine utilizing the photocyclization of 1-(2-halophenyl)-3,4-dihydro-6,7-dimethoxyisoquinolines as a key step has been described. 相似文献
92.
Alexandre Drouin 《Tetrahedron letters》2006,47(25):4285-4288
Upon photolysis in methylene chloride at −78 °C, different N-chlorolactams underwent a novel ring contraction to the corresponding carbamoyl chlorides, which were converted to the methyl carbamates. The rearrangement is 100% stereoselective, occurring with retention of configuration at the migrating carbon center. The yields of isolated carbamates ranged from 40% to 57%, the other product being the parent lactam, 18% to 38%. 相似文献
93.
Magdalena Zyder 《Journal of organometallic chemistry》2009,694(13):2110-631
The germane intermediate σ-complexes, characterized by high-field resonances in the region from −6 to −8 ppm, have been detected during the 1H NMR spectroscopy monitoring of the photochemical reaction of Et3GeH with Mo(CO)6, [Mo(CO)4(η4-cod)], and [Mo(CO)4(η4-nbd)] in the NMR tube. The activation of the Ge-H bond of germane in photochemical reaction of the norbornadiene (nbd) complex [Mo(CO)4(η4-nbd)] has been applied in the hydrogermylation of norbornadiene, which leads to the formation of triethylgermylnorbornene. 相似文献
94.
低密度聚乙烯光引发交联机理Ⅴ.光引发剂二苯甲酮光解产物的NMR研究 总被引:1,自引:1,他引:0
用NMR技术对光引发剂二苯甲酮(BP)引发低密度聚乙烯模型化合物正二十四烷、正十二烷、鲨烷(异三十烷)、异辛烷和乙烯-1紫外光交联过程中的光解产物进行了检测和研究.井首次确定了BP在光引发交联体系中光解的主要产物为苯并哪醇(1,1,2,2-四苯基-1,2-乙二醇),为BP光引发聚乙烯交联的机理提供了直接的实验证据. 相似文献
95.
拟除虫菊酯光解产物的红外图谱研究 总被引:4,自引:0,他引:4
本文研究了胺菊酯、甲醚菊酯、丙烯菊酯和氯氰菊酯在液相中的光解作用,并用离心薄层层析方法对光解混合物进行了分离。对光解产物的FTIR红外光谱谱图和标样的FTIR红外光谱谱图的研究表明,光解产物的FTIR红外光谱图发生了较大变化,有羟基和环氧化结构产生,即有氧化产物生成;甲醚菊酯和丙烯酯光解产物的元素分析结果与表明产物中氧的含量有明显提高、证实氧参与了拟除虫菊酯的光解过程。 相似文献
96.
Two selected benzoylhydrazones I and II were subjected to thermolysis by reflux at 200 °C. Benzil, benzoic acid, biphenyl, benzanilide together with the corresponding ketones, nitriles and imines were isolated. Similar treatment of the third hydrazone III at 250 °C afforded, in addition to the previous products, bibenzyl, stilbene, and 2-phenylindole. Photolysis of the same hydrazones I-III in acetonitrile gave the previously reported products but in different ratios along with azine derivatives and substituted methanes. A free radical mechanism involving homolysis of the N-N and C-N bonds is suggested, substantiated by trapping of phenyl radical with isoquinoline, to account for the formation of the identified products. 相似文献
97.
Uncaging of several neuroactive amino acids, namely β-alanine, tyrosine, 3,4-dihydroxyphenylalanine (DOPA) and glutamic acid from the corresponding 5,6-benzocoumarinyl conjugates was carried out by irradiation at different wavelengths and in different solvent systems. The release of the various amino acids was faster in ACN/HEPES buffer mixtures and for the tyrosine conjugate, an increase in the photolysis reaction rates and the quantitative uncaging of the amino acid was associated with increasing water content in the solvent mixture. 相似文献
98.
Juri Ugolotti 《Journal of organometallic chemistry》2011,696(6):1184-1188
Treatment of R2Si(CC-SiMe3)2 [1a (Me), 1b (Ph)] with HB(C6F5)2 at low temperature (253 K (a), 273 K (b)) gives the -B(C6F5)2 substituted silacyclobutene products (4a,b) under kinetic control. Upon warming to room temperature they disappear to form the thermodynamically favoured isomeric silole derivatives (2a,b). Similar treatment of Me2Si(CC-R1)2 [5a (R1 = Ph), 5b (R1 = tert-butyl) with HB(C6F5)2 at room temperature gave the stable -B(C6F5)2 substituted silacyclobutene derivatives 6 and 7, respectively. Subsequent photolysis resulted in a Z- to E-isomerization of the substituted exocyclic CC double bonds in these products. The silacyclobutene derivative E-6 was characterized by an X-ray crystal structure analysis. 相似文献
99.
100.
Cocrystallization has evolved as an attractive prospect to broaden the chemical landscape of a drug entity, expand its therapeutic scope, and address physicochemical deficiencies of an active pharmaceutical ingredient (API). The non-covalent approaches to address the solubility and bioavailability of BCS Class-II and Class-IV drugs is an archetypal example and is a prolific topic. The present review highlights various supramolecular methods employed in addressing the photoinstability in drugs, emphasizing crystal engineering approaches. Because a greater proportion of the drugs are formulated in the solid-state, the structural factors—crystal packing, intermolecular interactions, packing density—remain a critical determinant in the observed extent of stability. Comprehending and amending these structural determinants using crystal engineering concepts proposes to address the photoinstability in drugs. Also, we highlight the pros and cons of the different adopted strategies in terms of formulation and the underlying challenges and put in prospect. The review provides a correlative assessment of the structure-property relations that could further augment the foundations of factual knowledge in drug stability. 相似文献