共查询到20条相似文献,搜索用时 15 毫秒
1.
Noriaki Moriyama Yoshihiro Matsumura Masami Kuriyama Osamu Onomura 《Tetrahedron: Asymmetry》2009,20(23):2677-2687
A new method using electrochemical oxidation and/or OsO4 oxidation has been used for the stereoselective synthesis of 2,3,6-trihydroxylated (5S)-piperidine derivatives. The electrochemical method was successively used for the conversion of N-protected piperidines to N-protected 1-methoxypiperidines and for the conversion of 2,3-didehydro-1-methoxypiperidine derivatives to 2,3-trans-1,2,3-triacetoxypiperidine derivatives. These triacetates were easily transformed into (2S,3S)-6-triacetoxy-(5S)-methylpiperidine and (2R,3R)-6-triacetoxy-(5S)-methylpiperidine. In addition, the 2,3-cis-dihydroxylation of 2,3-didehydro-1-methoxypiperidine derivatives with OsO4 afforded (2R,3S)-6-triacetoxy-(5S)-methylpiperidine and (2S,3R)-6-triacetoxy-(5S)-methylpiperidine. 相似文献
2.
J.S. Yadav B.V.S. ReddyG. Satheesh A. PrabhakarA.C. Kunwar 《Tetrahedron letters》2003,44(10):2221-2224
2-Methylindole and its N-substituted derivatives react smoothly with 2,3-dihydrofuran (DHF) in the presence of a catalytic amount of InCl3 under mild conditions to afford the corresponding 2-methyl-3-perhydrofuro[2,3-b]oxepin-4-yl-1H-indole derivatives in fairly good yields with high diastereoselectivity, while 3,4-dihydro-2H-pyran (DHP) affords exclusively 5,5-di(1H-3-indolyl)-1-pentanol derivatives in high yields under similar reaction conditions. 相似文献
3.
Hamid Reza Shaterian Morteza Aghakhanizadeh 《Research on Chemical Intermediates》2014,40(4):1655-1668
A simple and facile method for the green synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives by direct three-component cyclo-condensation of isatoic anhydride, ammonium acetate (or primary amines), and arylaldehydes using different Brønsted acidic ionic liquids, for example 2-pyrrolidonium hydrogensulfate ([hnmp][HSO4]), N-methyl-2-pyrrolidonium hydrogensulfate ([NMP][HSO4]), and N-methyl-2-pyrrolidonium dihydrogenphosphate ([NMP][H2PO4]), as reusable catalysts under solvent-free conditions is described. In addition, reaction of anthranilamide and arylaldehydes for synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives was investigated. 相似文献
4.
Weizhi Geng Hanliu Wang Zitao Wang Shaoguang Zhang Wen-Xiong Zhang Zhenfeng Xi 《Tetrahedron》2012,68(26):5283-5289
Benzothieno[2,3-b]thiophenes, [2,3-b:3′,2′-d]-dithienothiophenes, and their selenium derivatives were synthesized in good yields from readily available 3-ethynyllithio-benzo[b]thiophenyllithio compounds, sulfur or selenium, and 2 equiv of acid chlorides. Two heteroarene rings were constructed by a twofold cyclization via an acid chloride-induced electrophilic ring closing and the McMurry cyclization using Zn/TiCl4 reagents. 相似文献
5.
Sigitas Tumkevicius Jelena Dodonova Viktoras Masevicius Saulius Jursenas 《Tetrahedron letters》2010,51(30):3902-339
The palladium-catalyzed Suzuki-Miyaura reaction of 2,4-dichloropyrrolo[2,3-d]pyrimidine with aryl boronic acids has been studied. Pd(OAc)2/dicyclohexyl(2-biphenyl)phosphine/K3PO4 was found to be an efficient catalyst system to prepare 4-aryl-2-chloro- and 2,4-diarylpyrrolo[2,3-d]pyrimidines. Novel non-linear molecules consisting of a pyrrolo[2,3-d]pyrimidine core and aryl branches have been elucidated as blue light-emitters with fluorescence quantum yields ranging from 4% to 67% in THF solution. The impact of an electron-withdrawing t-BuOCO group attached to the pyrrole ring of pyrrolopyrimidine derivatives on optical properties is discussed. 相似文献
6.
Seyedeh Yasaman Afsar Ghodsi Mohammadi Ziarani Hoda Mollabagher Parisa Gholamzadeh Alireza Badiei Ali Abolhasani Soorki 《Journal of the Iranian Chemical Society》2017,14(3):577-583
An efficient one-pot synthesis of 2,3-dihydroquinazoline-4(1H)-one derivatives 4a–l is described using SBA-Pr-SO3H as a heterogeneous acid catalyst. The present methodology resulted in various derivatives of 2,3-dihydroquinazoline-4(1H)-one in good yield via a three-component reaction of isatoic anhydride, aldehydes and ammonium acetate. SBA-Pr-SO3H played a significant role as an efficient mesoporous catalyst due to its pore size of 6 nm. Additionally, UV–Vis spectrum of the products was studied in order to investigate their application as UV absorbers. 相似文献
7.
O. V. Shitikova N. A. Ivanova Z. R. Valiullina M. S. Miftakhov L. V. Spirikhin 《Russian Journal of Organic Chemistry》2007,43(6):812-816
1H NMR study showed the possibility for intramolecular hydrogen bonding in 5(4)-hydroxy derivatives of 2,3-O-isopropylidene-β-D-ribofuranose in CDCl3. The obtained data were used to interpret differences in the 1H NMR spectra of structurally related 5-halo-2,3-O-isopropylidene-D-ribofuranosides and four newly synthesized diastereoisomeric 5-bromo-5-deoxy-4-hydroxy-2,3-O-isopropylidene-D-ribofuranosides. 相似文献
8.
A simple method for the synthesis of pyrrolo[2,3-c]carbazoles from N-alkylated-3-aminocarbazole derivatives and ethylene glycol has been developed via heteroannulation reaction using RuCl3/SnCl2 system. Moreover indolo[2,3-c]carbazoles were prepared from various pyrrolo[2,3-c]carbazoles in good yields. 相似文献
9.
Nikita A. Kazin Nadezhda S. Demina Roman A. Irgashev Ekaterina F. Zhilina Gennady L. Rusinov 《Tetrahedron》2019,75(33):4686-4696
The effective approaches for regioselective double formylation and acetylation of 5,12-dialkyl-6,7-diaryl-substituted 5,12-dihydroindolo[3,2-a]carbazoles by their treatment with dichloromethyl methyl ether in the presence of SnCl4 or with acetyl chloride in the presence of AlCl3 to afford the 2,9-diformyl or 2,9-diacetyl derivatives, respectively, were developed. Furthermore, new 2,9-bis(2,2-dicyanovinyl) derivatives were synthesized by the Knoevenagel condensation of diformyl-containing substrates with malononitrile, when new 2,9-bis(quinoxaline-2-yl)- and 2,9-bis(benzo[g]quinoxaline-2-yl) derivatives were formed via microwave-promoted oxidation of diacetyl-containing substrates with SeO2 to the corresponding diglyoxals, followed by the reaction of these intermediates with o-phenylendiamine or 2,3-diaminonaphthalene, respectively. The basic optical and electrochemical properties of some 5,12-dihydroindolo[3,2-a]carbazoles were investigated. 相似文献
10.
V. N. Odinokov R. G. Savchenko R. V. Shafikov S. R. Afon'kina L. M. Khalilov V. V. Kachala A. S. Shashkov 《Russian Journal of Organic Chemistry》2005,41(9):1296-1305
The 6-oxo group in 2,3:20,22-di-O-isopropylidene derivatives of 20-hydroxyecdysone and its 24,25/25,26-anhydro analog is reduced with NaBH4-CeCl3 in a stereoselective fashion to afford the corresponding 6α-alcohols. In the first case, the reaction is accompanied by dehydration to give Δ14-bond. Reduction of the same substrates with NaBH4 or LiAlH4 in the absence of CeCl3 leads to mixtures of 6α- and 6β-hydroxy derivatives, the latter prevailing. In all cases, epimerization at C5 occurs. 相似文献
11.
Denis N. Bazhin Dmitry L. Chizhov Gerd-Volker Röschenthaler Yulia S. Kudyakova Yanina V. Burgart Pavel A. Slepukhin Victor I. Saloutin Valery N. Charushin 《Tetrahedron letters》2014
1,1,1-Trifluoro-4,5,5-trimethoxyhex-3-en-2-one and lithium (2Z)-1,1,1-trifluoro-5,5-dialkoxy-4-oxohex-2-en-2-olate were synthesized for the first time via direct trifluoroacetylation of 2,3-butanedione acetal derivatives. A simple and effective approach to acetal or acyl substituted CF3-pyrazoles, 5,5′-bis(trifluoromethyl)-3,3′-bipyrazole, and, to 5-trifluoromethylfuran-3-ones is presented. 相似文献
12.
Benjamin E. Blass Keith Coburn Neil Fairweather Mark Sabat Laura West 《Tetrahedron letters》2006,47(18):3177-3180
A series of functionalized pyrido[2,3-d]pyrimidin-7(8H)-ones were prepared by a KF/Al2O3 mediated condensation of 4-(alkylamino)-2-(methylthio)pyrimidine-5-carbaldehydes and phenyl acetic acid ester derivatives. 相似文献
13.
The reaction between 5,7-dihydroxy-4-substituted coumarin, malononitrile, and aromatic aldehydes in the presence of a catalytic amount of K2CO3 as a basic catalyst leads to new pyrano[2,3-h]coumarin derivatives in good to excellent yields. 相似文献
14.
Omer Tahir Gunkara Bilgesu Onur Sucu Nuket Ocal Dieter E. Kaufmann 《Chemical Papers》2013,67(6):643-649
Tandospirone (I), developed as an anxiolytic drug, is an aryl-piperazine compound that binds to both 5-HT1A and dopamine D4 receptors. Palladium-catalysed hydroarylation reactions of tandospirone analogues containing an oxygen bridge and 3-(trifluoromethyl)phenyl or 2,3-dichlorophenyl groups were studied in order to find a new stereoselective access to a series of new exo-aryl(hetaryl)-substituted derivatives with potential biological activity. 相似文献
15.
A bio-supported solid acid catalyst, cellulose-SO3H, was used for three-component reactions to synthesize 2-amino-4-aryl-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitriles, spirooxindoles, 2,3-dihydroquinazolin-4(1H)-ones, 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones, α-amidoalkyl-β-naphthols, and α-carbamato-alkyl-β-naphthols derivatives under solvent-free conditions. 相似文献
16.
E. S. Kelbysheva L. N. Telegina E. A. Ershova T. V. Strelkova M. G. Ezernitskaya E. V. Nosova A. F. Smol´yakov F. M. Dolgushin N. M. Loim 《Russian Chemical Bulletin》2017,66(2):327-335
The synthesis of new quinazoline derivatives with 2,3- and 4-positioned cymantrenyl fragment is described. Alkylation of 2-substituted quinazolin-4-ones with cymantrenylalkyl bromides on using K2CO3, potassium tert-butoxide, and sodium hydride as bases has been studied. It is established for the first time that condensation of 2-methylquinazolin-4-ones with aldehydes can cause elimination of the substituent at the nitrogen atom in position 3. The new cymantrene derivatives possess fluorescence properties. 相似文献
17.
V. P. Kruglenko V. P. Gnidets N. A. Klyuev M. V. Povstyanoi 《Chemistry of Heterocyclic Compounds》2002,38(5):598-606
By reaction of 1,2-diaminobenzimidazole with 1,3-diketones, acetoacetic ester and its derivatives, we have synthesized substituted 1,2,4-triazepino[2,3-a]benzimidazole and 5H-1,2,4-triazepino[2,3-a]benzimidazol-4-one. By reaction of 5H-2-methyl-1,2,4-triazepino[2,3-a]benzimidazol-4-one with aromatic aldehydes or phenyldiazonium chloride, we have obtained 3-arylidene(phenylazo) derivatives of this compound, and by reaction with P2S5 we have obtained 5H-2-methyl-1,2,4-triazepino[2,3-a]benzimidazole-4-thione. We have shown that when reacted with ammonia, primary or secondary amines, the latter forms 4-amino-substituted 2-methyl-1,2,4-triazepino[2,3-a]benzimidazole. 相似文献
18.
Reactions of two isomers—2-chloro-1-(oxiran-2-ylmethyl)-1H-indole-3-carbaldehyde or 2-(chloromethyl)-2,3-dihydro[1,3]oxazolo[3,2-a]indole-9-carbaldehyde with aromatic amines lead to the same products in both cases—hydrochlorides of pyrimido[1,2-a]indole derivatives containing two fragments of an amine per one part of the indole nucleus. Its structure was confirmed by X-ray analysis of the crystals base, obtained by alkali treatment of the reaction product (when aryl is 4-MeOC6H4). 相似文献
19.
Ekambaram Ramesh 《Tetrahedron letters》2008,49(16):2583-2587
The intramolecular aza Diels-Alder cyclization reaction of aldimines derived from aromatic amines and N-prenyl/cinnamyl derivatives of pyrrolo[2,3-d]pyrimidine were efficiently catalyzed by InCl3 to afford the corresponding tetrahydroquinoline derivatives in good yields. 相似文献
20.
A novel method for the oxidative degradation of the side-chain of 3-(3-haloisoxazol-5-yl) propionic acids has been developed. The E-3-(3-chloroisoxazol-5-yl) propenoic acid 13a obtained by treatment of the striazolo [2,3-c] quinazolin-4-ium iodide 11a with PhI(OAc)2 and Bz2O2, respectively, and subsequent hydroxysis, has been used for the synthesis of numerous 3-haloisoxazole derivatives. 相似文献