共查询到20条相似文献,搜索用时 15 毫秒
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Diarylamines in the benzo[b]thiophene series bearing electron donating or withdrawing groups, were prepared by Buchwald-Hartwig C-N coupling in moderate to high yields. The conditions used were Pd(OAc)2 (3 mol%), BINAP as ligand (4 mol%) and Cs2CO3 as base (1.4 equiv.), in toluene at 100°C, being 6-bromo or amino benzo[b]thiophenes coupled, respectively, with substituted anilines or phenylbromides. The 6-aminobenzo[b]thiophene derivatives were also prepared by palladium catalyzed C-N coupling of the corresponding 6-bromo compounds with benzophenone imine, followed by acidic hydrolysis of the imino derivatives. When 4-nitrobromobenzene and 4-bromobenzonitrile were used as coupling components, triarylamines were also isolated in small amounts. The presence of a fluorine atom on the phenylbromide highly increases the diarylamine yields. 相似文献
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Ana S. AbreuNatália O. Silva Paula M.T. FerreiraMaria-João R.P. Queiroz 《Tetrahedron letters》2003,44(32):6007-6009
Several benzo[b]thienyldehydroamino acids were prepared by one-pot palladium-catalyzed borylation and Suzuki coupling (BSC) from bromobenzo[b]thiophenes containing EDG (OMe or Me), as the component to be borylated with pinacolborane, and pure stereoisomers of β-bromodehydroamino acid derivatives. To our knowledge it is the first time that the BSC reaction involves a non aromatic system. 相似文献
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A new method was adopted for the synthesis of benzo[b]carbazoles by Claisen condensation followed by Fischer indole cyclization. Newly synthesized benzo[b]carbazoles were treated with ethanol amine in the presence of polyphosphoric acid which leads to the formation of pyrazino carbazoles. All the synthesized compounds were characterized by all spectral means. 相似文献
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Lidiya G. FedenokNataliya A. Zolnikova 《Tetrahedron letters》2003,44(29):5453-5455
Cyclization of ortho-(phenylethynyl)benzene diazonium salts containing groups of +C character at the para-position of the phenyl ring proceeds with closure to a pyrazole, but not to a pyridazine as is the case in the presence of neutral or −C groups. 相似文献
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The secondary homoallylic alcohol derived from d-glucose undergoes smooth coupling with aldehydes in the presence of molecular iodine under mild reaction conditions to produce 7-iodofurano[3,2-b]pyrans in good yields. This method is highly stereoselective, affording cis-tetrahydropyrans exclusively. 相似文献
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Isabel C.F.R. FerreiraMaria-João R.P. Queiroz Gilbert Kirsch 《Tetrahedron letters》2003,44(23):4327-4329
Substituted 2-methyl-2′-nitro diaryl compounds in the benzo[b]thiophene series were prepared by palladium-catalyzed, two-step, one-pot borylation/Suzuki coupling (BSC) reaction in good to high yields. The borylation reaction was performed on methylated 6-bromobenzo[b]thiophenes using pinacolborane and was followed by in situ Suzuki coupling with substituted (CF3, OMe) 2-bromonitrobenzenes. The compounds obtained were cyclized to the corresponding ring A substituted thienocarbazoles which can have biological activity or/and be used as biomarkers due to their fluorescence properties and possible DNA intercalation. 相似文献
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Shengqiang Xiao Yongjun Li Yuliang Li Huibiao Liu Junpeng Zhuang Fushen Lu Deqing Zhang 《Tetrahedron letters》2004,45(20):3975-3978
[60]Fulleropyrrolidines were used as secondary amines to react with aldehydes through reductive aminations to afford N-alkylated derivatives. In spite of the very weak base activity of the nitrogen atom of N-unsubstituted [60]fulleropyrrolidines, this method was found to be efficient at the aid of sodium triacetoxyborohydride. Several N-alkylated derivatives were synthesized and fully characterized. 相似文献
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A new efficient synthesis of indolo[3,2,1-jk]carbazoles by the palladium-catalyzed cyclization of N-(2-bromoaryl)carbazoles is described. The reaction involves intramolecular C-C bond formation, coupled with the cleavage of a C-X bond and a C-H bond on carbazole ring. Substitutions on N-aryl core with either electron-donating or electron-withdrawing groups are introduced, and different reaction factors for cyclization are evaluated. 相似文献
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A simple method has been developed for the efficient synthesis of naphtho[b]furans from allyl bromonaphthyl ethers. The approach utilizes a novel photochemical process involving sequential radical cyclization and dehydrohalogenation. Because light is a readily available, environmentally friendly reagent that produces no by-products, the new process serves as a green synthetic method. 相似文献
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A convenient method for the preparation of 2-aryl(or methyl)sulfanylbenzo[b]thiophenes has been developed. Thus, aryl 2-aryl(or methyl)sulfanylmethylsulfanylphenyl ketones, easily prepared from readily available aryl 2-sulfanylphenyl ketones or 2-chloro-5-nitrophenyl phenyl ketone, are treated with LDA in 1,2-dimethoxyethane (DME) to give 3-aryl-2-aryl(or methyl)sulfanylmethylsulfanyl-2,3-dihydrobenzo[b]thiophen-3-ols, which in turn were dehydrated with thionyl chloride to afford 3-aryl-2-aryl(or methyl)sulfanylbenzo[b]thiophenes in reasonable overall yields. 相似文献
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Maria L. Kondratieva Natalia P. Belskaia Alexandr V. Koksharov Koen Robeyns Wim Dehaen Vasiliy A. Bakulev 《Tetrahedron》2007,63(14):3042-3048
The systematic study of oxidative cyclization of 3-hydrazono-1,3-dihydroindole-2-thiones has been carried out and a series of new 2H-[1,2,3]thiadiazolo[5,4-b]indoles has been prepared. The elaborated reaction represents an efficient method for the synthesis of fused 1,2,3-thiadiazoles. 相似文献
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Ramendra Pratap 《Tetrahedron letters》2007,48(27):4715-4718
An elegant approach to the synthesis of 2,3,6,7-tetrahydrophenanthro[4,3-b]thiophenes has been described through base catalyzed ring transformation of 4-sec-amino-2-oxo-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles with tetrahydrothiophen-3-one in very good yields. 相似文献
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We describe the straightforward synthesis of 6-substituted-2-aminopyrazolo[1,5-a]pyridines from 2-pyridineacetonitriles by N-amination with O-(mesitylsulfonyl)hydroxylamine and subsequent base-promoted cyclization. This N-amination/intramolecular cyclization reaction allows access to a variety of 6-substituted-2-aminopyrazolo[1,5-a]pyridines in a one-pot procedure, in moderate to good yields. 相似文献