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排序方式: 共有113条查询结果,搜索用时 15 毫秒
61.
《Tetrahedron letters》2019,60(22):1501-1504
A divergent synthesis of new oxacyclophenylpropanoids from the readily available and biomass-derived starting material eugenol is reported. The synthetic routes feature two important steps, including (i) DDQ-mediated selective oxidation of an allyl group and subsequent Claisen-rearrangement for the formation of key intermediates 1 and 11, and (ii) five-membered or six-membered ring formation via either palladium-catalyzed cyclization or ring-closing metathesis (RCM) strategies. 相似文献
62.
An efficient synthesis of indolo[1,2-c]isoindolo[2,1-a]quinazolin-5(16aH)-one derivatives through palladium-catalyzed cyclocarbonylation reaction of 6-(2-bromoaryl)-5,6-dihydroindolo[1,2-c]quinazolines with the use of CO as a carbonyl source under atmospheric pressure has been disclosed. More intriguingly, the above-mentioned products can also be obtained directly from a one-pot two-step tandem reaction of 2-(1H-indol-2-yl)anilines and 2-bromobenzaldehydes, which are the precursors of 6-(2-bromoaryl)-5,6-dihydroindolo[1,2-c]quinazolines, under an atmospheric CO pressure in modest yields. 相似文献
63.
Ali Keivanloo Atena Soozani Mohammad Bakherad Mahdi Mirzaee Hadi Amiri Rudbari Giuseppe Bruno 《Tetrahedron》2017,73(12):1633-1639
1,2,4-trisubstituted pyrrolo[1,2-a]quinoxalines are synthesized through the multi-component reaction of 3-substituted 2-chloroquinoxalines, propargyl bromide, and excess secondary amines in the presence of a palladium copper catalytic system. This one-pot process provides an unexpected synthesis of new trisubstituted pyrrolo[1,2-a]quinoxalines by the introduction of two amine substituents onto the fused pyrrole rings in a single reaction procedure. The compounds formed are fully characterized by the analytical spectral data and X-ray analysis. A number of synthesized pyrrolo[1,2-a]quinoxaline derivatives are also screened against the three bacterial strains Micrococcus luteus, Pseudomonas aeruginos, and Bacillus subtilis. According to the results obtained, compounds 3b, 3c, and 3e are active against M. luteus, compounds 3b and 3e are active against Ps. Aeruginos, and only compound 3f is active against all the three bacterial strains. 相似文献
64.
Piotr Pomarański Piotr Roszkowski Jan K. Maurin Armand Budzianowski Zbigniew Czarnocki 《Tetrahedron letters》2017,58(5):462-465
The first synthesis of sterically demanding, stable at room temperature atropisomeric derivatives of penta-(ortho-substituted phenyl)pyridines is described. The Suzuki-Miyaura cross-coupling reaction of pentabromopyridine and selected meta- and ortho-tolylboronic acids afforded a series of pentaarylpyridine derivatives. The structures of two room temperature stable atropisomeric derivatives of penta-(o-tolyl)pyridines were confirmed by single-crystal X-ray analysis. Racemic atropisomers were examined by 1H NMR spectroscopy with a chiral solvating agent in order to visualize the presence of individual enantiomers. 相似文献
65.
The regioselective one-pot synthesis of ortho-acylphenols via the palladium-catalyzed addition of phenols to nitriles and subsequent hydrolysis is reported. The acylation reaction proceeded smoothly using the Pd(OAc)2/DMSO system and TFA as the additive. This method also provides a direct strategy for the synthesis of a salicylketoxime scaffold. 相似文献
66.
《中国化学快报》2020,31(12):3263-3266
Pd-catalyzed oxidative homocoupling of 2-arylquinazolinones was successfully developed for the direct construction of biaryls via CH bond activation. New well-defined structure that possessed two quinazolinone units was obtained with high efficiency and atomic economy. The protocols offer an efficient approach to the synthetically useful and functionalized biaryls in good yields using quinazolinone as a directing group. 相似文献
67.
Triarylstibines react with iodobenzene diacetate in dichloromethane to afford triarylantimony(V) diacetates. The cross-coupling and carbonylative cross-coupling of triarylantimony(V) diacetates and dichlorides with organostannanes was accomplished in the presence of PdCl2 (5 mol%) in CH3CN at room temperature. 相似文献
68.
Ricardo C. Calhelha 《Tetrahedron letters》2010,51(2):281-283
Two methyl 3-aminothieno[3,2-b]pyridine-2-carboxylates were prepared from 3-fluoro or 3-nitropicolinonitriles and methyl thioglycolate in DMF/KOH(aq). From the unsubstituted precursor in the pyridine ring, di(hetero)arylamines were obtained by C-N Buchwald-Hartwig coupling with bromonitrobenzenes and with 2-bromopyridine. In the latter case a tetracyclic compound was formed by intramolecular cyclization. Using a brominated derivative in the pyridine ring as a coupling component, it was possible to synthesize C-C (Suzuki and Sonogashira) and C-N (Buchwald-Hartwig) coupling products and a tetracyclic compound obtained by bifunctionalization of the thienopyridine system. 相似文献
69.
Adewale O. AdeloyePeter A. Ajibade 《Tetrahedron letters》2011,52(2):274-277
We report the synthesis, characterization and preliminary investigation of the electro redox properties of soluble bromoterpyridine ligand precursors L1, L2 and L3 having one to three anthracenyl modules. The synthetic protocol is based on sequential palladium cross-coupling reactions between 9,10-dibromoanthracene and bromoterpyridine, 9-bromoanthracene-terpyridine or 9-bromo-dianthraceneterpyridine synthons. With increasing numbers of anthracene units on the terpyridine ligand, common absorption wavelengths at the near visible region and enhanced molar absorptivity coefficients were recorded. However, the luminescence intensity decreases with increasing length of π-conjugation relating to aggregation effects in the molecules. The cyclic voltammograms of L1 and L2 display good electro redox activity, being better than that of L3. 相似文献
70.
A novel Pd(II)-catalyzed dehydrogenative cross-coupling reaction of thiazolo[5,4-d]pyrimidine with unactivated (hetero)arenes via C–H bond activation was achieved. This protocol provides a straightforward and operationally simple method for the synthesis of 2-arylsubstituted thiazolo[5,4-d]pyrimidines of interest in pharmaceutical sciences. 相似文献