- Preparation method of 5- bromo-n-valeryl bromide
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The invention relates to a preparing method of 5-bromine pivaloyl bromide normal, belonging to the field of synthesizing methods of compounds. The preparing method of the 5-bromine pivaloyl bromide normal comprises the following steps: (1) synthesis of a midbody I: adding raw materials, i.e. m-chloroperoxybenzoic acid and drying chloroform, into a reaction kettle, and slowly adding a drying chloroform solution containing raw material cyclopentanone at room temperature so as to obtain a crude product of the midbody I; (2) synthesis of a midbody II: adding the raw material midbody I, hydrobromicacid and sodium bromide into the reaction kettle, reacting to obtain the midbody II and directly carrying out the reaction of a next step without purification; (3) synthesis of the 5-bromine pivaloylbromide normal: adding triphenylphosphine and dichloromethane into the reaction kettle, reducing the temperature to about 0 DEG C, starting to slowly add a dichloromethane solution containing bromine, adding the raw material midbody II to react, and purifying to obtain a target product, i.e. the 5-bromine pivaloyl bromide normal. The prepared product prepared by the method has higher purity and ideal yield coefficient and is suitable for being applied to industrialized production.
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Paragraph 0017; 0019; 0021; 0028; 0032
(2019/12/25)
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- Organocatalyzed Aerobic Oxidation of Aldehydes to Acids
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The first example organocatalyzed aerobic oxidation of aldehydes to carboxylic acids in both organic solvent and water under mild conditions is developed. As low as 5 mol % N-hydroxyphthalimide was used as the organocatalyst, and molecular O2 was used as the sole oxidant. No transition metals or hazardous oxidants or cocatalysts were involved. A wide range of carboxylic acids bearing diverse functional groups were obtained from aldehydes, even from alcohols, in high yields.
- Dai, Peng-Fei,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 1393 - 1396
(2019/02/26)
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- A aldehyde or mellow directly converted into the carboxylic acid (by machine translation)
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The invention discloses a aldehyde or mellow oxidation can be directly transformed into carboxylic acid, is characterized in that the pure oxygen environment, in N - hydroxy imide compound under the catalysis of the imide compound or N - hydroxy and nitrous acid ester compound common under the catalysis, the CH2 OH and CHO oxidation directly converted into the carboxylic acid compounds. The invention using oxygen as the oxidizing agent, does not add any metal catalyst, environment-friendly, high catalytic efficiency, simple and convenient operation. With the previous metal catalytic system complex and different catalytic system, has some metal catalytic system in the process, the use of transition metal will cause the transition metal of the residual, the invention adopts the non-metallic catalytic system, environmental protection, preventing the metal residue problem, this to the solution of the drug in the synthesis of transition metal residue problem and provides a new method of thinking. (by machine translation)
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Paragraph 0044-0046
(2018/08/03)
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- Unusual Adsorption at the Air-Water Interface of a Zwitterionic Carboxybetaine with a Large Charge Separation
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The structures of layers of three different dodecylcarboxybetaine surfactants adsorbed at the air-water interface have been determined by neutron reflection. The zwitterionic compounds differed in the length of the spacer separating the quaternary ammonium and carboxylate groups, which was (CH2)1, (CH2)4, or (CH2)8. The limiting area per molecule was found to be 45, 52, or 84 ?2, respectively, and compared reasonably with results from surface tension showing that the Gibbs prefactor is 1 in each case. Isotopic labeling was used to distinguish between the position of the alkyl and spacer groups in the layer. The spacer was found to be well-immersed in water for the (CH2)1 and (CH2)4 spacers but significantly above water for the (CH2)8 spacer. The distribution of the (CH2)8 spacer along the surface normal was found to be similar to that of the dodecyl group; i.e., it projects out of the water, contrary to an earlier hypothesis that it forms a loop. Comparison of the overlap of water with dodecyl and spacer groups also indicates that the (CH2)8 spacer is well out of the water. This in turn suggests that the anionic carboxylic acid group, which is dissociated in solution, is not ionized in the adsorbed layer. A further observation is that the dodecylcarboxybetaine with the (CH2)8 spacer reaches surface saturation at one-tenth of the critical micelle concentration. This is highly unusual and is attributed to the long spacer destabilizing the micelle relative to the surface layer.
- Ma, Kun,Li, Pei Xun,Dong, Chu Chuan,Thomas, Robert K.,Penfold, Jeffrey
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p. 3340 - 3347
(2016/05/10)
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- Preparation method of 5-bromo-valeric acid
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The invention relates to a preparation method of 5-bromo-valeric acid. The preparation method particularly includes: subjecting 5-chlorine-3-pentenoic acid ester to hydrolysis reaction, hydrogenation reaction and bromination reaction to obtain 5-bromo-valeric acid, wherein 5-chlorine-3-pentenoic acid ester is one of or multiple of 5-chlorine-3-pentenoic acid methyl ester, 5-chlorine-3-pentenoic acid ethyl ester, 5-chlorine-3-pentenoic acid propyl ester and 5-chlorine-3-pentenoic acid butyl ester. The preparation method is high in finished product yield, low in production cost, simple and easy to control and easy for industrial production, and using of high-toxicity substances like benzene and sodium cyanide is avoided, so that safety is high.
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Paragraph 0097; 0098; 0099; 0100
(2016/11/28)
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- Sequence-specific base pair mimics are efficient topoisomerase IB inhibitors
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Topoisomerase IB controls DNA topology by cleaving DNA transiently. This property is used by inhibitors, such as camptothecin, that stabilize, by inhibiting the religation step, the cleavage complex, in which the enzyme is covalently attached to the 3'-phosphate of the cleaved DNA strand. These drugs are used in clinics as antitumor agents. Because three-dimensional structural studies have shown that camptothecin derivatives act as base pair mimics and intercalate between two base pairs in the ternary DNA- topoisomerase-inhibitor complex, we hypothesized that base pairs mimics could act like campthotecin and inhibit the religation reaction after the formation of the topoisomerase I-DNA cleavage complex. We show here that three base pair mimics, nucleobases analogues of the aminophenyl-thiazole family, once targeted specifically to a DNA sequence were potent topoisomerase IB inhibitors. The targeting was achieved through covalent linkage to a sequencespecific DNA ligand, a triplex-forming oligonucleotide, and was necessary to position and keep the nucleobase analogue in the cleavage complex. In the absence of triplex formation, only a weak binding to the DNA and topoisomerase I-mediated DNA cleavage was observed. The three compounds were equally active once conjugated, implying that the intercalation of the nucleobase upon triplex formation is the essential feature for the inhibition activity.
- Vekhoff, Pierre,Duca, Maria,Guianvarc'h, Dominique,Benhida, Rachid,Arimondo, Paola B.
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experimental part
p. 43 - 51
(2012/05/20)
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- A new one-pot synthetic method for selenium-containing medium-sized α,β-unsaturated cyclic ketones
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The reaction of tetrahydroselenopyran-2-one (7) with ethynyllithiums 20a-h, followed by treatment with aqueous 5% H2SO4 successfully led to a two-carbon ring expansion to give the 2-substituted 5,6,7,8-tetrahydroselenocin-4-ones 21a-h in 43-95% yields. Seven- to nine-membered γ-selena-α,β-unsaturated cyclic ketones 22-26 and a 5,6,7,8-tetrahydrotellurocin-4-one 27 were also prepared from the corresponding selenolactones or tellurolactone in a one-pot reaction.
- Sashida, Haruki,Nakayama, Akemi,Kaname, Mamoru
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experimental part
p. 3229 - 3236
(2009/05/07)
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- Functional group transformations of diols, cyclic ethers, and lactones using aqueous hydrobromic acid and phase transfer catalyst under microwave irradiation
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Synthesis of bromoalkanols has been achieved from diols, ethers, and lactones using aq HBr (48%) and tetrabutylammonium iodide/bromide as phase transfer catalyst under microwave irradiation. This environmentally benign route provides enhanced yields of products and does away with the use of benzene as compared to existing conventional methods.
- Kad, Goverdhan L.,Kaur, Irvinder,Bhandari, Monica,Singh, Jasvinder,Kaur, Jasamrit
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p. 339 - 340
(2013/09/06)
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- Labelling colors for detecting cocaine or methamphetamine, method of preparing the same and detector for cocaine or methamphetamine
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A labelling color for detecting cocaine of Formula (I) STR1 wherein X represents a halogen, and a method of detecting methamphetamine, including the steps of adding a labelling color of Formula (II) STR2 wherein X represents an anion to a first solution of methamphetamine antibody to form a labelling color-methamphetamine antibody complex, measuring the fluorescence of the first solution, adding a sample containing an unknown amount of methamphetamine to the first solution to form a second solution, measuring the fluorescence of the second solution, and correlating any change in the fluorescence between the first and second solutions to the concentration of methamphetamine in the sample.
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- MECHANISM OF THE ADDITION OF TRIBUTYLTIN IODOACETATE TO ALKENES
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The mechanism of the formation of lactones by free radical additions of tri-n-butyltin iodoacetate to alkenes occurs through a two-step process: a homolytic addition of the ester (addition of .CH2-CO2SnBu3, iodine transfer), followed by a fast ionic cyclization with elimination of tri-n-butyltin iodide.
- Degueil-Castaing, M.,Jeso, B. De,Kraus, G. A.,Landgrebe, K.,Maillard, B.
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p. 5927 - 5930
(2007/10/02)
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- SYNTHESIS OF 4-VALEROLACTONE AND 4-BROMOVALERIC ACID.
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4-Valerolactone has been obtained by the liquid-phase oxidation of 2,3-dihydropyran with pyridinium chlorochromate. The yields of 4-valerolactone at the liquid-phase oxidation stage reach 90-96% at 90% conversion of the starting material. The isolation of 4-valerolactone is complicated by resinification and condensation. Yields of up to 54% of valerolactone were obtained. 4-Bromovaleric acid was obtained by hydrobrominating 4-valerolactone in dioxane solution, yields of up to 64% of 4-bromovaleric acid being obtained. A by-product of the reaction was beta -( beta prime -bromoethoxy)ethyl 4-bromovalerate.
- Slavinskaya,Brezhnev,Sile,Kreile,Eglite,Tomsons,Liepin'sh,Karakhanov
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p. 348 - 352
(2007/10/02)
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- Unidirectional Dieckmann Cyclizations on a Solid Phase and in Solution
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Dieckmann cyclization of 2percent divinylbenzene-copolystyrene resin alkyl pimelates and analogous benzyl alkyl pimelates is reported.The use of uniquely single-labeled dioate esters has allowed analysis of the direction of closure via decarboxylation of the keto ester products.The influence of steric factors on the competition between enolate condensation and transesterification and upon the direction of closure of the cyclization has been evaluated, and the conditions for achieving >99percent regioselective closure are described.Modifications in the conditions of solid-phase peptide synthesis required for successful high-temperature enolate cyclization have been developed and the results are compared to solution reactions of benzyl alkyl esters under similar conditions.The resin attachment afforded a clear benefit over the benzyl models and greatly simplified isolation and purification of the resulting β-keto esters.
- Crowley, John I.,Rapoport, Henry
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p. 3215 - 3227
(2007/10/02)
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