- Iron(II) and Copper(I) Control the Total Regioselectivity in the Hydrobromination of Alkenes
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A new method that allows the complete control of the regioselectivity of the hydrobromination reaction of alkenes is described. Herein, we report a radical procedure with TMSBr and oxygen as common reagents, where the formation of the anti-Markovnikov product occurs in the presence of parts per million amounts of the Cu(I) species and the formation of the Markovnikov product occurs in the presence of 30 mol % iron(II) bromide. Density functional theory calculations combined with Fukui's radical susceptibilities support the obtained results.
- Cruz, Daniel A.,Sinka, Victoria,De Armas, Pedro,Steingruber, Hugo Sebastian,Fernández, Israel,Martín, Víctor S.,Miranda, Pedro O.,Padrón, Juan I.
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supporting information
p. 6105 - 6109
(2021/08/18)
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- Cobalt-Catalyzed Decarboxylative Methylation and Ethylation of Aliphatic N-(Acyloxy)phthalimides with Organoaluminum Reagents
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A cobalt-catalyzed decarboxylative methylation of aliphatic redox-active esters [ N-(acyloxy)phthalimides; RAEs] with trimethylaluminum under mild conditions was developed, providing a method for transforming a carboxylate group into a methyl group without redox fluctuation. Primary and secondary RAEs were both amenable substrates, whereas a tertiary RAE delivered an elimination product. Triethylaluminum was also used to deliver a decarboxylative ethylation product.
- Wang, Ze-Zhong,Wang, Guang-Zu,Zhao, Bin,Shang, Rui,Fu, Yao
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supporting information
p. 1221 - 1225
(2020/08/17)
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- Method for decarboxylation and in-situ methylation of alkyl active carboxylic ester
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The invention relates to a method for decarboxylation and in-situ methylation of alkyl active carboxylic ester. The method comprises the following step: in the presence of a cobalt catalyst, a phosphine ligand and an organic solvent, reacting alkyl active carboxylic ester with a trimethyl aluminum reagent to obtain a target methylated product. According to the provided method, trimethyl aluminum is used as a methylation reagent, so that a series of important secondary carbon and tertiary carbon centers are commercially and conveniently constructed successfully; the used carboxylate substrate is rich in source and simple to synthesize; compared with a traditional synthesis method reported before, the method avoids the use of a noble metal catalyst, and meets the requirements of green environment-friendly chemistry; the functional group compatibility is wide, the method is successfully applied to gram-scale reaction, the conversion rate is high, and the method has an important syntheticchemical value.
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Paragraph 0047-0054; 0159-0165; 0203
(2020/06/20)
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- PROCESS FOR THE PREPARATION OF ORGANIC HALIDES
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The present invention provides a halo-de-carboxylation process for the preparation of organic chlorides, organic bromides and mixtures thereof, from their corresponding carboxylic acids, using a chlorinating agent selected from trichloroisocyanuric acid (TCCA), dichloroisocyanuric acid (DCCA), or combination thereof, and a brominating agent.
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Paragraph 00162
(2017/08/01)
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- PROCESS FOR THE PREPARATION OF ORGANIC BROMIDES
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The present invention provides a process for the preparation of organic bromides, by a radical bromodecarboxylation of carboxylic acids with a bromoisocyanurate.
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Paragraph 00165
(2017/07/28)
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- Copper-catalyzed reduction of alkyl triflates and iodides: An efficient method for the deoxygenation of primary and secondary alcohols
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We describe an effective method for catalytic reduction of 1°alkyl sulfonates, and 1°and 2°iodides in the presence of a wide range of functional groups. This Cu-catalyzed reaction provides a means for the effective deoxygenation of alcohols, as demonstrated by the highly selective reduction of 1°alcohols using a triflation/reduction sequence. A preliminary study of the reaction mechanism suggests that the reduction does not involve free-radical intermediates. Primarily reduced: The copper-catalyzed reduction of 1°alkyl sulfonates, and 1°and 2°iodides, which is effective in the presence of a wide range of functional groups, provides a means for the effective deoxygenation of alcohols. A preliminary study of the reaction mechanism suggests that the reduction does not involve free-radical intermediates. Copyright
- Dang, Hester,Cox, Nick,Lalic, Gojko
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supporting information
p. 752 - 756
(2014/01/23)
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- NHC-copper hydrides as chemoselective reducing agents: Catalytic reduction of alkynes, alkyl triflates, and alkyl halides
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The NHC-copper-catalyzed Z-selective semi-reduction of terminal and internal alkynes, as well as the NHC-copper-catalyzed reduction of primary alkyl triflates and primary and secondary alkyl iodides and bromides are described. The high chemoselectivity demonstrated in these examples illustrates the mild nature of copper hydride complexes as reducing agents, which have applications in synthetic chemistry beyond their traditional role in the reduction of activated alkenes and carbonyl compounds.
- Cox, Nick,Dang, Hester,Whittaker, Aaron M.,Lalic, Gojko
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supporting information
p. 4219 - 4231
(2014/06/09)
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- Rhodium-catalyzed tandem isomerization/hydroformylation of the bio-sourced 10-undecenenitrile: Selective and productive catalysts for production of polyamide-12 precursor
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The hydroformylation of 10-undecenenitrile (1) - a substrate readily prepared from renewable castor oil - in the presence of rhodium-phosphane catalysts systems is reported. The corresponding linear aldehyde (2) can be prepared in high yields and regioselectivities with a (dicarbonyl)rhodium acetoacetonate-biphephos [Rh(acac)(CO)2-biphephos] catalyst. The hydroformylation process is accompanied by isomerization of 1 into internal isomers of undecenenitrile (1-int); yet, it is shown that the Rh-biphephos catalyst effectively isomerizes back 1-int into 1, eventually allowing high conversions of 1/1-int into 2. Recycling of the catalyst by vacuum distillation under a controlled atmosphere was demonstrated over 4-5 runs, leading to high productivities up to 230,000 mol (2)×mol (Rh)-1 and 5,750 mol (2)×mol (biphephos)-1. Attempted recycling of the catalyst using a thermomorphic multicomponent solvent (TMS) phase-separation procedure proved ineffective because the final product 2 and the Rh-biphephos catalyst were always found in the same polar phase. Auto-oxidation of the linear aldehyde 2 into the fatty 10-cyano-2-methyldecanoic acid (5) proceeds readily upon exposure to air at room temperature, opening a new effective entry toward polyamide-12. Copyright
- Ternel, Jeremy,Couturier, Jean-Luc,Dubois, Jean-Luc,Carpentier, Jean-Francois
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p. 3191 - 3204
(2013/12/04)
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- Synthesis of [14C] acids from their unlabeled counterparts and application toward a novel [14C] labeled hepatitis C virus polymerase inhibitor
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A strategy has been developed for the rapid construction of a [ 14C] acid from either an aromatic or an alkyl acid via a decarboxylation-carboxylation sequence. A [14C] labeled heptatitis C virus polymerase inhibitor was prepared. Other examples and the limitations of this methodology are discussed. Copyright
- Ho, Jonathan Z.,Wallace, Michael A.,Tang, Yui S.,Zhang, Andy S.,Braun, Matthew P.
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scheme or table
p. 251 - 253
(2011/05/02)
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- A photoirradiative phase-vanishing method: Efficient generation of HBr from alkanes and molecular bromine and its use for subsequent radical addition to terminal alkenes
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A triphasic phase-vanishing (PV) system comprised of an alkane, perfluorohexanes, and bromine was successfully combined by photoirradiation to efficiently generate hydrogen bromide, which underwent radical addition with 1-alkenes in the hydrocarbon layer to afford terminal bromides in high yields. Georg Thieme Verlag Stuttgart.
- Matsubara, Hiroshi,Tsukida, Masaaki,Ishihara, Daisuke,Kuniyoshi, Kenji,Ryu, Ilhyong
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experimental part
p. 2014 - 2018
(2010/10/02)
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- A facile synthesis of high specific activity sodium [1-14C] lauryl sulphate under microwave irradiation
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A highly efficient and optimized synthesis of sodium[1-14C] lauryl sulphate having high specific activity (50 mCi/mmol) is described. Lauric acid was converted to undecyl bromide using a modified Hunsdiecker reaction. This was treated with potassium 14C cyanide (specific activity 50 mCi/mmol) using phase transfer catalysis to yield [1-14C] lauronitrile, which was subsequently hydrolysed with a mixture of concentrated hydrochloric acid:propionic acid (1:2 v/v) under microwave irradiation for 2 min to obtain [1-14C] lauric acid in quantitative yield. The latter on reaction with chlorosulphonic acid and subsequent neutralization with sodium bicarbonate yielded the title compound. Copyright
- Ravi,Mathew,Unny,Sivaprasad
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p. 1055 - 1058
(2007/10/03)
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- Syntheses of [14C]-detergents: Octaethyleneglycol-[1-14C]-dodecylether, [1-14C]-dodecylβ-D-maltoside and dibromo-analogues
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Octaethylene-glycol-dodecylether and dodecyl-β-D-maltoside are two widely used detergents in membrane protein studies. We describe here the synthesis of the 14C-labelled brominated analogues, and of the 14C-labelled forms. [1-14C]5,6-Dibromo-dodecylether was prepared by coupling [1-14C]-(Z)-1-bromododec-5-ene with octaethylene glycol followed by bromination. [1-14C]-5,6-Dibromo-dodecyl-β-D-maltoside was synthesised from [1-14C]-(Z)-dodec-5-en-1-ol via a coupling with α-bromohepta-O-acetyl-maltose followed by a deprotection step and bromination. Following similar methods, octaethyleneglycol-[1-14C]-dodecylether and [1-14C]-dodecyl-β-D-maltoside were also obtained. Copyright
- Georgin, Dominique,Maire, Marc Le,Noel, Jean Pierre
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p. 575 - 585
(2007/10/03)
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- Intramolecular homolytic displacements. 30. Functional decarbonylative transformations of aldehydes via homolytically induced decomposition of unsaturated peroxyacetals
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Homolytically induced decompositions of unsaturated peroxyacetals, synthesized from aldehydes, gave alkoxyalkoxyl radicals that yielded alkyl radicals by rapid β-scission. The latter radicals could react with several types of "transfer agents" to smoothly bring about homolytic decarbonylative functional group transformations of aldehydes into halides, hydrocarbons, xanthates, alkanenitriles, 2-alkyl-3-chloromaleic anhydrides, 1-phenylalk-1-ynes, and ethyl 2-alkylpropenoates.
- Degueil-Castaing, Marie,Moutet, Laurent,Maillard, Bernard
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p. 3961 - 3965
(2007/10/03)
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- Hunsdiecker-type bromodecarboxylation of carboxylic acids with iodosobenzene diacetate
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Carboxylic acids are bromodecarboxylated in moderate to good yields on reaction with iodosobenzene diacetate and bromine under irradiation with a tungsten lamp. The reaction works very well with carboxylic acids having a primary, secondary or tertiary α-carbon atom, although diphenylacetic acid gives benzophenone. Benzoic acid derivatives are bromodecarboxylated in moderate yields if electron-withdrawing substituents are present in the benzene ring, while they are recovered mostly unchanged if the substituents are electron-donating. Partially iodinated products have been isolated in low yield from the bis-bromodecarboxylation of dicarboxylic acids having two bridgehead α-carbon atoms. (C) 2000 Elsevier Science Ltd.
- Camps, Pelayo,Lukach, Andrés E.,Pujol, Xavier,Vázquez, Santiago
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p. 2703 - 2707
(2007/10/03)
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- Calamitic organometallic liquid crystals with terminal metal. Syntheses and liquid crystal properties of dicarbonylrhodium(I) β-diketonate complexes
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A series of novel organometallic complexes based on γ-substituted β-diketone ligands with terminal metal Rh(I) have been prepared by reaction of the ligands with [Rh(CO)2(μ-Cl)]2. The mesomorphism of the ligands and complexes has been investigated using DSC and polarizing microscope. It is found that non-mesogenic ligands with n=7, 8, 9, 10, 11 can form liquid crystalline phase by direct coordination to metal. The effect of the terminal carbon number on the mesomorphism has also been discussed.
- Wan, Wen,Guang, Wen-Jie,Zhao, Ke-Qin,Zheng, Wei-Zhong,Zhang, Liang-Fu
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p. 157 - 161
(2007/10/03)
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- Scavenger assisted combinatorial process for preparing libraries of tertiary amine compounds
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This invention relates to a novel solution phase process for the preparation of tertiary amine combinatorial libraries. These libraries have utility for drug discovery and are used to form wellplate components of novel assay kits.
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- Desulfurization with Nickel and Cobalt Boride: Scope, Selectivity, Stereochemistry, and Deuterium-Labeling Studies
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A variety of organosulfur compounds containing alkylthio and arylthio groups underwent reductive desulfurization under notably mild conditions when treated with nickel boride, generated in situ from nickel chloride hexahydrate and sodium borohydride in methanol-THF (3:1).Phenyl, chloro, and ester groups are not reduced under these conditions, while iodo, bromo, nitrile, aldehyde, ketone, cyclopropane, and olefinic functions are reduced either completely or partially.Deuterium-labeling studies indicate that the hydrogen that is incorporated into the product originates from both the sodium borohydride and the protic solvent, suggesting the intermediacy of dihydrogen.The epimers 3α- and 3β-(phenylthio)cholestane afforded 3α- and 3β-deuteriocholestane, respectively, demonstrating that the reaction proceeds with retention of configuration.The method may thus be employed for the stereospecific preparation of deuterated products from organosulfur compounds.Arguments are presented in support of a tentative mechanism involving an oxidative addition-reductive elimination sequence via a nickel hydride intermediate.
- Back, Thomas G.,Baron, Denise L.,Yang, Kexin
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p. 2407 - 2413
(2007/10/02)
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- Rate Constants for Halogen Atom Transfer from Representative α-Halocarbonyl Compounds to Primary Alkyl Radicals
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Rate constants for halogen atom transfer from diethyl methyliodomalonate (7a), iodoacetonitrile (7b), ethyl 2-methyl-2-iodopropanoate (7c), ethyl iodoacetate (7d), diethyl methylbromomalonate (7e), and ethyl bromoacetate (7f) to simple primary alkyl radicals have been studied by a variety of competition reactions.The Arrhenius functions for halogen atom transfer to the undecyl radical from halides 7d and 7f are log (kI, M-1 s-1) = 10.4 - 4.4/θ and log (kBr, M-1 s-1) = 10.4 - 8.2/θ, respectively.The rate constants for halogen atom transfer to a primaryradical from the series of compounds 7a-7f at 50 deg C are 1.8 x 109, 1.7 x 109, ca. 6 x 108, 2.6 x 107, 1.0 x 106, and 7.0 x 104 M-1 s-1, respectively.The kinetic values are useful for the planning of synthetic methods that incorporate an atom transfer-cyclization process.
- Curran, Dennis P.,Bosch, Eric,Kaplan, Jere,Newcomb, Martin
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p. 1826 - 1831
(2007/10/02)
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- Pheromones
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Compounds of formula STR1 in which R represents hydrogen, formyl or an alkanoyl group of two to twenty-five carbon atoms and R' represents an alkyl group of one to thirty-five carbon atoms are of value as mosquito attractants, mosquitoes being attracted to a location where they and/or their eggs or larvae are then destroyed.
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- SELECTIVE MIXED COUPLING OF CARBOXYLIC ACIDS (II). -PHOTOLYSIS OF UNSYMMETRICAL DIACYLPEROXIDES WITH ALKENYL-, HALO-, KETO-, CARBOXYL-GROUPS AND A CHIRAL α-CARBON. COMPARISON WITH THE MIXED KOLBE ELECTROLYSIS.
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- Alkenoyl and functionalized alkanoyl dodecanoyl peroxides are prepared in 70 to 97 percent yield and photolyzed at -78 deg C.Thereby 4- to 10-alkenoyl and 4-alkynoyl peroxides afford good yields (56 - 68 percent) of unsymmetrical coupling products.Similarly α- to δ-haloalkanoyl, cholanoyl or 3- and 4-carboxyalkanoyl peroxides can be coupled (40 - 70 percent).The α-chiral diacyl peroxide 1s undergoes the photochemical coupling reaction with 80 percent retention of its configuration.The photolysis of diacyl peroxides at -78 deg C proves to be a favorable supplement of the Kolbe-electrolysis in cases, where the electrolysis fails or produces low yields.
- Feldhues, Michael,Schaefer, Hans J.
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p. 4213 - 4236
(2007/10/02)
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- LIQUID CRYSTALLINE PROPERTIES OF 4-N-ALKOXYPHENYL 4-NITROBENZOATES.
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Twelve 4-alkoxyphenyl esters of 4-nitrobenzoic acid were synthesized. The mesophases were identified and the transition temperatures and enthalpies determined. The above series shows considerable similarity to the reverse analogues, i. e. , the 4-nitro-phenyl 4-n-alkoxybenzoates.
- Galewski,Sobczyk
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- PREPARATION OF ALKYL HALIDES VIA ORGANOTELLURIUMS
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The conversion of phenyltelluroalkanes to haloalkanes was studied in connection with the homologation of alkyl halides.Similar reactions of 1,1-bis(phenyltelluro)alkanes provided a new synthetic method of aldehydes.
- Chikamatsu, Kiyofumi,Otsubo, Tetsuo,Ogura, Fumio,Yamaguchi, Hachiro
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p. 1081 - 1084
(2007/10/02)
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- Thallium(I) Carboxylate Modification of the Hunsdiecker Reaction
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Treatment of a thallium(I) carboxylate with 1 molar equivalent of bromine gives the corresponding thallium(III) carboxylate dibromide.High yields of primary alkyl bromides are obtained if the thallium(III) carboxylate dibromide is treated with 0.5 mol equiv. of bromine in refluxing carbon tetrachloride.Pyrolysis of the thallium(III) derivative in the absence of added bromine gives a low yield of the corresponding alkyl bromide.The use of thallium(I) carboxylates for the preparation of alkyl bromides in high yields is limited to the salts of primary carboxylic acids.A simple procedure for the preparation of alkyl bromides from carboxylic acids using thallium(I) carbonate has been developed.
- Cambie, Richard C.,Hayward, Rodney C.,Jurlina, Jeffrey L.,Rutledge, Peter S.,Woodgate, Paul D.
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p. 2608 - 2614
(2007/10/02)
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- Insect Juvenile Hormone Analogues: Part VII - Synthesis of Long Chain Aromatic Ethers & Nitrogen Analogues
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Syntheses of various aromatic ethers of undecenyl bromide and thio ethers of undecenyl and undecanyl bromides with 2-benzothiazolethiol are described.The preparation of a few amides and their corresponding amines from undecenoic acid and different aromatic amines and benzyl amine are also reported.The bromo derivatives of a few amides have also been prepared.These compounds have been tested on common Indian red cotton bug for their juvenile hormone activity.
- Vig, O. P.,Trehan, I. R.,Kad, G. L.,Dhawan, R. K.,Grewal, M. S.
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p. 688 - 691
(2007/10/02)
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- Remarkable Solvent Control of Functional Group Selectivity in Complex Metal Hydride Reductions
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Lithium aluminium hydride in ethyl ether reduces alkyl tosylates to the corresponding alkanes rapidly and selectively in the presence of alkyl iodides and bromides without concurrent attack on halogen, whereas in diglyme the reactivity order is reversed, alkyl iodides and bromides being reduced selectively without significant attack on alkyl tosylates.
- Krishnamurthy, S.
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p. 2550 - 2551
(2007/10/02)
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