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1.
Márta Porcs-Makkay Balázs Volk Rita Kapiller-Dezsófi Tibor Mezei Gyula Simig 《Monatshefte für Chemie / Chemical Monthly》2004,26(5):697-711
A new, practical synthesis of the antirheumatic oxindole derivative, tenidap, has been elaborated. The new approach has initiated studies on the mechanism of the acylation reactions of oxindoles. Methods have been developed for the synthesis of 1-[alkoxy(or aryloxy)carbonyl]- and 1,3-di[alkoxy(or aryloxy)carbonyl]oxindoles starting from oxindoles. The route designed for tenidap has provided a facile access to several analogues, too.On another front, new reaction conditions are described, which turn Wenkerts synthesis of 3-alkyloxindoles (by Raney nickel induced alkylation of oxindoles with alcohols) into a highly efficient synthetic tool. The method has been extended to the synthesis of 3-alkyloxindoles from isatins and to the preparation of 3-(-hydroxyalkyl)oxindoles from oxindoles and isatins. 相似文献
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Jun‐Fei Wang Ning Ding Wei Zhang Peng Wang Ying‐Xia Li 《Helvetica chimica acta》2011,94(12):2221-2230
Baicalein, an important active constituent of the traditional Chinese herb Scutellaria baicalensis, exhibited antitumor activity and inhibitory activity against P‐gp 170. The syntheses of 25 baicalein derivatives, 2 – 26 (Table), are described here (Scheme 1). These compounds were systematically modified with O‐alkylation and O‐acylation at HO? C(5), HO? C(6), and HO? C(7), singly or in combination, on the ring A of baicalein in order to evaluate the effects of such modifications on their inhibitory activities against multidrug‐resistant tumor cell lines and P‐gp 170. Highly selective and efficient alkylations at HO? C(7) of peracetylated baicalein were the key to the distinction between HO? C(6) and HO? C(7) of baicalein. 相似文献
4.
A. A. Elagamey F. M. A. El-Taweel R. A. N. Abu El-Enein 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):2155-2176
Different new 1,3,4-thiadiazolopyridine derivatives (6, 8, 20, 28, and 42) were synthesized from 5-cyanomethyl-1,3-4-thiadiazole (1) and activated nitriles. Also, spiro indolono-thiadiazolopyridine (12) was obtained from the reaction of (1) with 2-(2-oxoindolin-3-ylidene)malononitrile (10). Other heterocyclic derivatives at position-5 in the thiadiazole ring were obtained for possible use as antimicrobial agents. 相似文献
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The one-pot synthesis of spirooxindoles via three-component reaction of urea, isatin, and 1,3-dicarbonyl compounds in the presence of a catalytic amount of p-toluenesulfonic acid in acetonitrile has been carried out.
6.
New quinoxaline derivatives were prepared by the reaction of 2-hydroxyquinoxaline 1 and alkyl or alkylaminoalkyl halides in dimethylformamide using potassium carbonate as a base. The hydroxyl group was readily converted into a thiol function by treatment with phosphorus pentasulfide and/or Lawesson's reagent in pyridine, and the subsequent alkylation of the thiol group was carried out under phase-transfer catalyst conditions. Chlorination of 1 was carried out with phosphorus oxychloride. Branching of alkylamino side chains to the 2-OH, 2-SH, and 2-Cl quinoxalines resulted in the synthesis of several compounds. Synthesis and alkylation of 2-hydroxy 7-nitroquinoxaline are also reported. 相似文献
7.
Per Wiklund 《Tetrahedron letters》2004,45(5):969-972
The O-nucleophilicity of basic anthranilic acid salts was documented, analyzed, and utilized in synthesis. Specifically substitutions leading to esters instead of secondary amines, and formation of anthranilic acid anhydrides were studied. 相似文献
8.
Wataru Muramatsu 《Tetrahedron letters》2007,48(29):5031-5033
Regioselectivity of acylation of 6-O-protected octyl β-d-glucopyranosides was investigated. Treatment of octyl 6-O-methyl-β-d-glucopyranoside with isobutyric anhydride in the presence of DMAP in toluene at −40 °C gave 3-O-isobutyryl derivative in >99% regioselectivity. Similar treatment of octyl 6-O-TBS-β-d-glucopyranoside at −20 °C also gave 3-O-isobutyryl derivative in >99% regioselectivity. 相似文献
9.
Glenn C. Condie 《Tetrahedron》2005,61(21):4989-5004
The reactivity of some 5,7-dimethoxyindoles with respect to electrophiles has been investigated. The favoured sites for reaction are C3 and C4 and regioselectivity can be controlled by the judicious arrangement of electron-withdrawing substituents. Results of formylation, acylation, the Mannich reaction, bromination and nitration are described. 相似文献
10.
Janusz Lewiński Pawe? Horeglad Iwona Justyniak Zbigniew Ochal 《Journal of organometallic chemistry》2005,690(16):3697-3699
Several control experiments were designed to optimize the reaction of 2,3-epoxy-1-propanol with R3Al (R = Me, Et or iBu) and to probe for the nature of aluminium-bound alkyl groups that influence the reactivity and selectivity. The reported studies revealed that the Et3Al mediated reaction leads to the C-2 product in contrast to the well-known C-3 substitution promoted by Me3Al. 相似文献
11.
<正>A series of monosubstituted troxerutin esters have been synthesized by enzyme-catalyzed regioselective acylation of troxerutin in nonaqueous medium.Using divinyl dicarboxylates(CH_2=CH-OOC-(CH_2)_n-COO-CH=CH_2,n = 2,3,4,7,8,11) featuring different chain length as acyl donors and alkaline protease from Bacillus subtilis as catalyst,troxerutin was regioselective acylated at B' ethoxyl group.The results indicated that the regioselectivity of the enzyme-catalyzed acylation was not affected by the chain length of the acyl donor. 相似文献
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《Journal of heterocyclic chemistry》2017,54(1):789-793
An efficient and rapid procedure for the synthesis of novel oxindole derivatives is described. The process employs a condensation reaction of 3‐(bis(methyl thio)methylene)indolin‐2‐one and dinucleophiles such as 1,2‐phenylene diamine, propylene diamine, 2‐aminoethanol, ethylene‐1,2‐dithiol, 2‐mercaptoethanol, (1S,2S)‐cyclohexane‐1,2‐diamine, 2‐aminoethanthiol, 2,3‐diaminomaleonitrile, 2‐aminobenzenethiol, (3,4‐diaminophenyl)(phenyl)methanone, and ethane‐1,2‐diole in the presence of triethylamine under solvent‐free conditions at 60°C. 相似文献
14.
Esráa S. Abu-Sheaib Jalal A. Zahra Mustafa M. El-Abadelah Roland Boese 《Monatshefte für Chemie / Chemical Monthly》2008,139(9):1061-1066
Cyclocondensation reaction of ethyl 7,8-diamino-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate with 1-methylisatin produced a separable mixture of the corresponding indolo[3,2-b]- and [2,3-b]pyrido[2,3-f]quinoxaline-3-carboxylates, of which the latter isomer predominates. On the other hand, interaction with 1H-isatin or 5-chloroisatin gave the respective indolo[2,3-b]pyrido[2,3-f]quinoxaline-3-carboxylates as the sole regiospecific products. The structures of these new pentacyclic derivatives are based on microanalytical, spectral (IR, MS, and NMR) and X-ray crystal structure data. 相似文献
15.
Runze Mao Lifeng Sun Yong-Shi Wang Min-Min Zhou De-Cai Xiong Qin Li Xin-Shan Ye 《中国化学快报》2018,29(1):61-64
A light-promoted approach to the synthesis of N-9 alkylated purine nucleoside derivatives has been developed. 相似文献
16.
Orthogonally diprotected l-glyceraldehyde was efficiently prepared from readily available starting materials, allowing to obtain a highly stable and synthetically versatile chiral building block compared to known symmetrically protected derivatives. 相似文献
17.
M Markert 《Tetrahedron》2004,60(4):993-999
Aldehydes undergo an unusual and very mild alkylation by LiClO4-activation in the presence of acids. This new methodology enables the inclusion of a broad range of aldehydes as well as tertiary alcohols. Regio- and stereoselectivity observed during this reaction will be discussed. 相似文献
18.
Kana M. Sureshan 《Tetrahedron》2009,65(13):2703-5526
A metal mediated unusual 1-3 acyl migration from C4-O to C2-OH of myo-inositol 1,3,5-orthoformate was observed during the alkylation of racemic 4-O-benzoyl-myo-inositol 1,3,5-orthoformate. This has been exploited for the selective esterification of either the C4(6)-OH or the C2-OH of myo-inositol by varying the amount of the base used. While the use of 1 equiv of the base (sodium hydride or potassium tert-butoxide) for the acylation of myo-inositol orthoesters gives the corresponding C4-ester exclusively, the use of two or more equivalents of base for the same reaction gives the C2-ester exclusively. The relatively higher stability of the alkoxide of racemic 2-O-acyl-myo-inositol 1,3,5-orthoester as compared to the alkoxide of 4-O-acyl-myo-inositol 1,3,5-orthoester is suggested to be responsible for the observed isomerization. 相似文献
19.
René Dicke 《Cellulose (London, England)》2004,11(2):255-263
The topic of this contribution ID a novel method for regioselective esterification of starch, similar polysaccharides and cyclodextrines avoiding protecting or activating groups. A broad spectrum of polysaccharides could be acylated selectively at the C-2 position of the AGU. The reaction principle ID based on a transesterification of a carboxylic acid vinyl ester with the hydroxyl groups of the polymer ID the presence of a low molecular salt. The interaction of the reaction participants and the solution state of the polysaccharides enable this selective functionalization. The structure characterization of the new polysaccharide derivatives ID carried out by NMR spectroscopy, especially the HMBC technique, after a complete esterification of the free hydroxyl groups with a suitable carbon acid anhydride. 相似文献
20.
EnasM. Awad NehalM. Elwan HamdiM. Hassaneen Anthony Linden Heinz Heimgartner 《Helvetica chimica acta》2002,85(1):320-332
Treatment of 6,7‐diethoxy‐3,4‐dihydroisoquinoline ( 8 ) and its 1‐methyl derivative 12 with hydrazonoyl halides 10 in the presence of Et3N in THF under reflux afforded the corresponding 5,6‐dihydro‐1,2,4‐triazolo[3,4‐a]isoquinolines 11 and 13 , respectively, in high yield (Schemes 2 and 3). The products are formed via regioselective 1,3‐dipolar cycloaddition of the intermediate nitrilimines 9 with the isoquinoline C=N bond. Reaction of 6,7‐diethoxy‐3,4‐dihydroisoquinoline‐1‐acetonitrile ( 4a ) with ethyl α‐cyanocinnamates 15 in the presence of piperidine in refluxing MeCN yielded benzo[a]quinolizin‐4‐ones 16 (Scheme 4). Under the same conditions, 12 and arylidene malononitriles 19 reacted to give benzo[a]quinolizin‐4‐imines 20 (Scheme 5). Instead of 15 and 19 , mixtures of an aromatic aldehyde, and ethyl cyanoacetate or malononitrile, respectively, can be used in a one‐pot reaction. 相似文献