- Preparation method of methyl 4-chlorobutyrate
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The invention discloses a preparation method of methyl 4-chlorobutyrate and belongs to the field of synthesis of compounds. The preparation method using gamma-butyrolactone as a raw material comprisesthe steps of adding the gamma-butyrolactone into dichloromethane mixed liquid of triphenyl dichlorophosphate to carry out chlorination; adding methanol to carry out esterification to obtain methyl 4-chlorobutyrate. The preparation method is simple to perform, good in product quality, high in yield and green, produces nearly no three wastes and is suitable for industrial production.
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Paragraph 0020-0029
(2018/05/01)
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- Conversion of levulinate into succinate through catalytic oxidative carbon-carbon bond cleavage with dioxygen
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Grand Cleft Oxo: Levulinate, available from biomass, is oxidized into succinate through manganese(III)-catalyzed selective cleavage of C-C bonds with molecular oxygen. In addition to levulinate, a wide range of aliphatic methyl ketones also undergo oxidative C-C bond cleavage at the carbonyl group. This procedure offers a route to valuable dicarboxylic acids from biomass resources by nonfermentive approaches. Copyright
- Liu, Junxia,Du, Zhongtian,Lu, Tianliang,Xu, Jie
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p. 2255 - 2258
(2014/01/06)
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- Stereocontrolled construction of 1, 7-dimethyl A.B.C.[6.6.6] tricycles. Part I. transannular Diels-Alder reactions of 14-membered macrocycles containing frans-dienophiles
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Transannular Diels-Alder reactions of 14-membered macrocyclic trienes possessing a methyl substituent on both the diene and dienophile moiety have been investigated. Macrocyclic structures la, lb, and lc having cis-trans-trans (CTT), trans-cis-trans (TCT), and trans-trans-trans (TTT) geometries could be stereoselectively constructed by coupling appropriately functionalized dienes 5 and dienophile 4 following an intramolecular displacement of an allylic halide by the anion of an appropriately located dimethyl malonate unit. The transannular Diels-Alder reaction performed on la led to a mixture of four major tricyclic products, including 34 possessing the unexpected trans-anti-cis (TAC) stereochemistry. When heated at 300°C, macrocycle lb underwent an unique conversion via an ene-retroene, Diels-Alder process, producing the unexpected tricycle 41 (racemic form) containing five contiguous chiral centers. A rationale for the above experimental facts is presented. In contrast to the previous results, the transannular Diels-Alder reaction of macrocycle lc was straightforward, producing a 95% isolated yield of trans-anti-cis (TAC) tricycle 34. This investigation demonstrates a general methodology for the stereocontrolled synthesis of 1, 2-dimethyl A.B.C[6.6.6] tricyclic compounds, which are potential precursors to polycyclic natural products such as steroids and terpenes.
- Xu, Yao-Chang,Roughton, Andrew L.,Plante, Raymond,Goldstein, Solo,Deslongchamps, Pierre
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p. 1152 - 1168
(2007/10/02)
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- Transannular Diels-Alder reactions on 14-membered macrocyclic trienes. Part I: stereoselective syntheses of the macrocyclic trienes precursors
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Transannular Diels-Alder reactions on 14-membered macrocycles containing properly located diene and methyl-substituted dienophile units lead to A.B.C. tricycles related to steroids.To study the influence of the olefin and diene geometry on the stereochemical outcome of the Diels-Alder reaction it was necessary to prepare macrocyclic trienes of well-defined stereochemistry.Eight different types of macrocyclic trienes might be obtained by the coupling of appropriate dienophiles and dienes, namely, TTC, TTT, TCC, TCT, CTC, CTT, CCC, and CCT.In this paper (first in a series of two), the synthesis of appropriately functionalized dienophile and diene synthons, as well as their coupling reaction affording macrocyclic triene precursors, is described.
- Ndibwami, Alexis,Lamothe, Serge,Guay, Daniel,Plante, Raymond,Soucy, Pierre,et al.
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p. 695 - 713
(2007/10/02)
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- MECHANISMS OF FREE-RADICAL REACTIONS. XXIV. QUANTITATIVE DESCRIPTION OF THE POLAR EFFECTS OF SUBSTITUENTS ON THE KINETICS OF THE FREE-RADICAL CHLORINATION OF ALIPHATIC COMPOUNDS BY N-CHLOROPIPERIDINE
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The free-radical chlorination of 1-substituted alkanes with electron-withdrawing substituents by N-chloropiperidine in trifluoroacetic acid was studied by the method of competing reactions, and the relative rate constants were obtained for all positions of the substrates.The data on the position selectivity can be described satisfactorily by means of an electrostatic model of the polar effect of the substituent, calculated according to the Kirkwood-Westheimer equation.The obtained characteristics of the electrostatic effect can be successfully applied to calculation of the substrate selectivity and the intermolecular relative rate constants for all the positions, beginning with the third.The Taft equation is unsuitable for description of the effect of substituents on the reaction rate.
- Dneprovskii, A. S.,Mil'tsov, S. A.,Arbuzov, P. V.
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p. 1826 - 1835
(2007/10/02)
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- SIMPLE PREPARATION OF ω-gem-DISUBSTITUTED HOMOALLYL CHLORIDES
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The synthesis of the title compounds, starting from γ-butyrolactone, is described.
- Biernacki, Wladyslaw,Gdula, Andrzej
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p. 849 - 852
(2007/10/02)
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- Chlorination of Esters. I. Chlorination of Methyl Esters of Propanoic, Butanoic, Pentanoic and Hexanoic Acids. The Isomer Distribution of Monochloro Esters Formed
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The chlorination of methyl ester with chlorine in the liquid and vapor phase and with sulfuryl chloride in the liquid phase has been investigated.The chlorination yields all possible monochloro esters isomers with the 2-chloro isomer in the smallest amount.The products were identified by NMR and mass spectrometry.The isomer distribution and mass spectra of products were studied in detail.
- Korhonen, Ilpo O.O.,Korvola, Jorma N.J.
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p. 139 - 142
(2007/10/02)
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- Interaction of Cyclopropane with Platinum-Metal Chlorides under Carbon Monoxide Pressure in Benzene
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The six platinum-metal chlorides were reacted with cyclopropane in benzene under carbon monoxide pressure to produce propyl benzenes and, in three instances, chlorobutyrates.The isomer of propylbenzene obtained ranged from pure n-propylbenzene from PdCl2 to pure isopropylbenzene for OsCl3 and IrCl3.The other three platinum-metal chlorides gave mixture of the two propylbenzenes.The reaction was shown to be specific for benzene and cyclopropane as chlorobenzene and toluene failed to enter into the reaction.Likewise, methylcyclopropane did not react with benzene to produce butylbenzenes.
- Johnson, Thomas J.,Baldwin, Thomas F.
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p. 140 - 142
(2007/10/02)
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- Analysis of drugs by pyrolysis. I. Selected ion monitoring combined with a pyrolysis method for the determination of carpronium chloride in biological samples.
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In order to establish an analytical method for carpronium chloride, a parasympathomimetic agent, the pyrolysis reaction of carpronium chloride was examined in a g.c.m.s. system, which revealed that gamma-butyrolactone was produced directly from the drug as the main pyrolysis product. In the case of conversion of [2,2,3,3-2H4]carpronium chloride into the deuterated gamma-butyrolactone, 2H/1H scrambling was observed and confirmed to occur during the pyrolysis process of the deuterated compound. The proportion of gamma-[2H4]butyrolactone among the pyrolysis products was almost independent of the operating conditions, so [2,2,3,3-2H4]carpronium chloride was of practical use as an internal standard for selected ion monitoring. By incorporation of the pyrolysis reaction of carpronium chloride with selected ion monitoring and the use of [2,2,3,3-2H4]carpronium chloride as an internal standard, a rapid, sensitive and selective method was devised for the determination of the drug in biological samples. The method was utilized successfully for the biopharmaceutical studies of carpronium chloride in ma.
- Ohya,Sano
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p. 241 - 247
(2007/10/05)
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- Process for the production of even series ω-amino acids
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The invention relates to a process for the production of even-series ω-amino acids of the general empirical formula NH2 (CH2 CH2)n CH2 COOH /I/, where N = 1 or 2. The process of the invention comprises telomerizing ethylene with methyl esters of halogen acetic acids of the general empirical formula Xm CH3-m COOCH3 /II/, where X = Br and m = 1 or X = Cl and m = 2 or 3, at a temperature of from 100 to 145° C. and under ethylene pressure of from 25 to 40 gage atmospheres in the presence of initiators of free-radical reactions. The telomerization procedure gives telomers of the general empirical formula CH3 OOCCH3-m Xm-1 (CH2 CH2)n X /III/, where X, n and m are as in formulas /I/ and /II/. In case X = Br and m = 1, the telomers described by formula /III/ are subjected to ammonolysis with ammonia at a temperature of about 100° C to yield ammonolysis products; whereas, in case X = Cl and m = 2 or 3, the telomers described by formula /III/ are reduced to telomers of the same general formula, where X = Cl and m = 1, and the latter are subjected to ammonolysis with ammonia at a temperature from 135° to 140° C to yield ammonolysis products. Then the ammonolysis products are hydrolyzed with hydrochloric acid at a temperature of from 80° to 90° C., and the desired product is recovered from the resultant hydrolyzate by use of a styrene-divinylbenzene sulfocationite resin in the H form. The foregoing process uses widely available industrial raw materials, proceeds by a straightforward route and requires simple equipment; it is further characterized by high yields at all steps; all unreacted feedstocks can be completely recycled; and no non-utilizable wastes are produced.
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