共查询到20条相似文献,搜索用时 15 毫秒
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The mechanism of formation of 1,3-dioxolanes is considered in the light of Baldwin's rule for ring-closure. 相似文献
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《Journal of fluorine chemistry》1986,31(3):247-253
The reaction of 1,1,2,3,3,3-hexafluoropropyldiethylamine (PPDA) with hydroxy esters having PhC(H)(OH)-groups gave their corresponding secondary fluorides. Fluorination of (R)-(-)-mandelic acid ethylester ([α]29D −106.46) gave ethyl (S)-(+)-2-fluoro-2-phenyl acetate ([α]29D +6.57). The value of the enantiomeric excess (% ee) was 74.1. The reaction mechanism of the fluorination by PPDA is suggested to be the SN2 type. 相似文献
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Selective monofluorination of 1,2- and 1,3-diols was achieved by reaction with DFMBA. The method is applicable for the synthesis of optically-active fluorohydrin derivatives. 相似文献
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1,4-Butanediol, 2,5-hexanediol and 1,5-pentanediol were selectively converted to tetrahydrofuran and tetrahydropyran in the presence of LaHY, CaHY and H-ZSM-6 zeolites. The advantage of these zeolites is in their high stability and faster regeneration. 相似文献
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《Journal of fluorine chemistry》1987,36(3):361-372
By reaction with 1,1,2,3,3,3-hexafluoropropyldiethylamine (PPDA), various monoesters of ethylene glycol gave a mixture of corresponding monofluorides and 2,3,3,3-tetrafluoropropionate esters. The antimicrobial properties of these fluorine compounds for a spent coolant were examined. 相似文献
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A one-pot cascade approach to 4-alkylidene-beta-lactams and N, N'-diarylamidines from aryl azides and aryloxyacetyl chlorides has been developed. The chemical outcome of the reaction can be controlled selectively by an appropriate choice of the stoichiometric ratio of different substrates and reagents. The products should find use in pharmaceutical discovery, especially in the development of new antimicrobial agents against multidrug-resistant pathogens. 相似文献
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《Journal of Inorganic and Nuclear Chemistry》1981,43(5):957-961
Cu(II) complexes have been prepared with N,N-diethyl-2-picolinamine N-oxide (DEA) employing the perchlorate, tetrafluoroborate, nitrate, chloride and bromide salts. A single unique solid was isolated for each Cu(II) salt with the following stoichiometries: Cu(DEA)2X2(XClO4 and BF4) and Cu(DEA)X2(XNO3, Cl and Br). Characterization has been accomplished primarily by IR, electronic and ESR spectral measurements of the solid state complexes. Significant, though not as great as with lighter ligands of the same series, changes occurred when spectral measurements of acetonitrile or nitromethane solutions were attempted. DEA was found to bind to Cu(II) exclusively as a bidentate ligand via the N-oxide oxygen and the amine nitrogen. 相似文献
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Tamotsu Hashimoto Michio Urushisaki 《Journal of polymer science. Part A, Polymer chemistry》2007,45(21):4855-4866
The living cationic polymerization of 5‐ethyl‐2‐methyl‐5‐(vinyloxymethyl)‐1,3‐dioxane ( 1 ), a vinyl ether with a cyclic acetal unit, was investigated with various initiating systems in toluene or methylene chloride at 0 to ?30 °C. With initiating systems such as hydrogen chloride (HCl)/zinc chloride (ZnCl2), isobutyl vinyl ether–acetic acid adduct [CH3CH(OiBu)OCOCH3]/tin tetrabromide (SnBr4)/di‐tert‐butylpyridine (DTBP), and CH3CH(OiBu)OCOCH3/ethylaluminum sesquichloride (Et1.5AlCl1.5)/ethyl acetate (CH3COOEt), the number‐average molecular weights (Mn's) of the obtained poly( 1 )s increased in direct proportion to the monomer conversion and produced polymers with relatively narrow molecular weight distributions [MWDs; weight‐average molecular weight/number‐average molecular weight (Mw/Mn) = 1.2–1.3]. To investigate the living nature of the polymerization with CH3CH(OiBu)OCOCH3/SnBr4/DTBP, a second monomer feed was added to the almost polymerized reaction mixture. The added monomer was completely consumed, and the Mn values of the polymers showed a direct increase against the conversion of the added monomer, indicating the formation of a long‐lived propagating species. The glass transition temperature and thermal decomposition temperature of poly( 1 ) (e.g., Mn = 13,600, Mw/Mn = 1.30) were 29 and 308 °C, respectively. The cyclic acetal group in the pendants of the polymer of 1 could be converted to the corresponding two hydroxy groups in a 65% yield by an acid‐catalyzed hydrolysis reaction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4855–4866, 2007 相似文献
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With use of diol, alkoxysilane, and a catalytic amount of trimethylsilyl trifluoromethanesulfonate (TMSOTf), carbonyl compounds are converted to acetals in good yields under mild conditions. This procedure, which was carried out without synthesizing the silylated diols, is a more convenient adaptation of Noyori's method. This acetalization applies to not only simple but also conjugated carbonyl compounds. Moreover, various TMS compounds, including solid supported compounds, are effective for this method instead of alkoxylsilane. 相似文献
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The reaction of 3-methyl-2-methylene-1,3-oxazolidine ( 1a ) and phenylisothiocyanate (PhNCS) gives 3-methyl-2-(phenylthiocarbamoyl)methylene-1,3-oxazolidine ( 3 ) whereas that of 2-isopropylidene-3-methyl-1,3-oxazolidine ( 1b ) and PhNCS gives 1:1 alternating copolymers. It is assumed that the reaction of 1b and PhNCS forms a zwitterionic intermediate ( 2b ), followed by the successive combination of 2b to give 1:1 alternating copolymers 4 and/or 5 . Consequently, it was demonstrated that the copolymerization of 1b and PhNCS proceeds via a zwitterionic mechanism with complete ring-opening to afford the 1:1 alternating copolymer 5 . 相似文献
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Summary Dimerization of the cyclic acetal of crotonaldehyde takes place in accordance with the scheme studied previously, leading to the formation of a 1,4-dioxepan ring. 相似文献
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Fluoroalkylation of aliphatic diols, tetrahydrofuran and 1,3-dioxolanes with perfluoroolefins under photochemical initiation was studied. The aim of the study was the preparation of fluoroalkylated diols as intermediates for special fluorinated monomers. Fluoroalkylation was only partly successful in the case of 1,4-butanediol and quite successful with tetrahydrofuran and 2,2-dimethyl-1,3-dioxolane. The fluoroalkyl diols obtained were converted to monomethacrylates that are amphiphilic monomers. 相似文献
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N,N′-亚乙基二(2-羟基-4-甲氧基二苯酮缩亚胺)Schiff碱的合成及抑菌活性 总被引:2,自引:0,他引:2
本文将 2 羟基 4 甲氧基二苯酮与乙二胺缩合成Schiff碱 ,发现该Schiff碱对紫外光的UV -A、UV-B区都有较强吸收 ,对多种细菌有抑制作用。1 实验部分1 1 合成称取 2 羟基 4 甲氧基二苯酮 6 848g( 30mmol)于圆底烧瓶内 ,加 30ml 95 %乙醇 ,水浴加热至 5 0℃ ,磁力搅拌溶解 ,滴加 0 90 0g( 1 5mmol)乙二胺溶液 ,磁力搅拌 ,5 0~ 60℃回流反应 4h ,析出黄色固体 ,冷却 ,过滤 ,用热的 95 %乙醇 ( 30~40℃ )溶液洗三次 ,再用乙醚洗一次 ,抽干。 40℃真空干燥 5h ,得黄色粉末 ,产率 94%。1 2 表征Schi… 相似文献
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Advait S NagleRalph N Salvatore Richard M CrossElona A Kapxhiu Suma SahabCheol Hwan Yoon Kyung Woon Jung 《Tetrahedron letters》2003,44(30):5695-5698
Efficient synthetic methods were developed for the synthesis of mono xanthates, as well as mono dithiocarbamates of diamines and amino alcohols. This protocol utilizes the three component coupling of diols, diamines, and amino alcohols using alkyl bromides and carbon disulfide in the presence of a cesium base and tetrabutylammonium iodide (TBAI). 相似文献
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Amide nitrogens open episulfonium ions to form pyrrolidines or piperidines selectively, depending on the nitrogen substituent, in either reversible or irreversible reactions. 相似文献