- Synthesis method of 4-chloro-2-butanone
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The invention provides a synthesis method of 4-chloro-2-butanone. The synthesis method comprises main steps as follows: (1) cooling an organic solution of butyl ketone to 0-30 DEG C; (2) adding hydrogen chloride, and then, conducting a thermal insulation reaction at room temperature for 1-5 h; (3) washing a product with a washing liquid to be neutral; and (4) performing reduced pressure distillation to obtain a finished product of 4-chloro-2-butanone. The synthesis method of 4-chloro-2-butanone directly conducts an anti-Markovnikov addition reaction with butyl ketone and hydrogen chloride gasto produce the product synthesis method of 4-chloro-2-butanone, and the process produces little sewage and is suitable for industrial production.
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Paragraph 0027-0034
(2020/02/19)
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- Palladium/Copper-catalyzed Oxidation of Aliphatic Terminal Alkenes to Aldehydes Assisted by p-Benzoquinone
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The development of an anti-Markovnikov Wacker-type oxidation for simple aliphatic alkenes is a significant challenge. Herein, a variety of aldehydes can be selectively obtained from various unbiased aliphatic terminal alkenes using PdCl2(MeCN)2/CuCl in the presence of p-benzoquinone (BQ) under mild reaction conditions. Isomerization of the terminal alkene to the internal alkene was suppressed via slow addition of the starting material to the reaction mixture. In addition to the Pd catalyst, CuCl and BQ were essential in order to obtain the anti-Markovnikov product with high selectivity. Terminal alkenes bearing a halogen substituent afforded their corresponding aldehydes with high anti-Markovnikov selectivity. The halogen acts as a directing group in the reaction. DFT calculations indicate that a μ-chloro Pd(II)?Cu(I) bimetallic species with BQ coordinated to Cu is the catalytically active species in the case of a terminal alkene without a directing group.
- Komori, Saki,Yamaguchi, Yoshiko,Murakami, Yuka,Kataoka, Yasutaka,Ura, Yasuyuki
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p. 3946 - 3955
(2020/07/06)
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- Photolysis of Tp′Rh(CNneopentyl)(PhNCNneopentyl) in the presence of ketones and esters: Kinetic and thermodynamic selectivity for activation of different aliphatic C-H bonds
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The active fragment [Tp′Rh(CNneopentyl)], generated from the precursor Tp′Rh(CNneopentyl)(PhNCNneopentyl), underwent oxidative addition of substituted ketones and esters resulting in Tp′Rh(CNneopentyl)(R)(H) complexes (Tp′ = tris-(3,5-dimethylpyrazolyl)borate). These C-H activated complexes underwent reductive elimination at varying temperatures (24-70 °C) in C6D6 or C6D12. Using previously established kinetic techniques, the relative Rh-C bond strengths were calculated. Analysis of the relative Rh-C bond strengths vs. C-H bond strengths shows a linear correlation with slope RM-C/C-H = 1.22 (12). In general, α-substituents increase the relative Rh-C bond strengths compared to the C-H bond that is broken.
- Jones, William D.,Parsons, Astrid M.
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supporting information
p. 10945 - 10952
(2019/08/01)
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- PHARMACOLOGICALLY ACTIVE QUINAZOLINEDIONE DERIVATIVES
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Compounds of formula (I), wherein R1-8 are as defined in the claims, exhibit a positive allosteric GABAB modulator effect and are thus useful as positive allosteric modulators of the GABAB receptor.
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Page/Page column 63
(2015/11/27)
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- Regio- and stereoselective monoamination of diketones without protecting groups
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Hitting the right target: Differentiation between two keto moieties was accomplished by a regio- and enantioselective bioamination employing ω-transaminases. Using 1,5-diketones as substrates gave access to the optically pure 2,6-disubstituted piperidine scaffold. The approach allowed the shortest synthesis of the alkaloid dihydropinidine, as well as its enantiomer, by choosing an appropriate ω-transaminase. Copyright
- Simon, Robert C.,Grischek, Barbara,Zepeck, Ferdinand,Steinreiber, Andreas,Belaj, Ferdinand,Kroutil, Wolfgang
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supporting information; experimental part
p. 6713 - 6716
(2012/09/22)
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- The reactions of 4-chloro-2-butanol and 3-chloro-1-butanol with aqueous sodium hydroxide, and 1-chloro-2-propanol and 2-chloro-1-propanol with isopropyl amine
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The total reaction of 4-chloro-2-butanol 1 with NaOH(aq) is dominated (74%) by intramolecular substitution (SNi), besides which bimolecular substitution (SN2, 12%) and 1,4-elimination (i.e. fragmentation, contrary to earlier arguments) exhibit a significant contribution (11%). The total reaction of 3-chloro-1-butanol 2 instead is dominated by 1,4-(72%) and 1,2-elimination (25%), the substitution reactions being just observable (SNi 2% and SN2 1%). In 1 both the +I-effect and the conformational factors in the intermediate γ-chloroalkoxy anion favour the SNi-reaction, whereas in 2 the situation is opposite and the location of Cl on a secondary carbon also makes the SNi-reaction less favourable. The relative proportions of 1,4-and 1,2-eliminations for 2 can be explained by thermodynamic basis since the consequent products are more stable than the corresponding products from 1. 1-chloro-2-propanol 3 and 2-chloro-1-propanol 4 both react with isopropyl amine giving the same product, namely 1-isopropylamino-2-propanol, which indicates that the reaction proceeds through the propylene oxide intermediate. Compound 1 also reacted with isopropyl amine predominantly via SNi-reaction, giving first 2-methyloxetane which then further gave 4-isopropylamino-2-butanol, whereas 2 gave 3-isopropylamino-1-butanol through a direct S N2-reaction. ARKAT-USA, Inc.
- Pihlaja, Kalevi,Aaljoki, Kari,Lyytinen, Maija-Riitta,Huusko, Marja-Liisa,Hotokka, Marjut
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experimental part
p. 188 - 199
(2011/07/07)
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- Ruthenium-lewis acid catalyzed asymmetric diels-alder reactions between dienes and α,β-unsaturated ketones
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The complex [Ru(Cp)(R,R-BIPHOP-F)(acetone)][SbF6],(R,R)-1a. was used as catalyst for asymmetric Diels-Alder reactions between dienes (cyclopentadiene, methylcyclopentadienc, isoprene, 2,3-dimethylbutadiene) and α,β-unsaturated ketones (methyl vinyl ketone (MVK). ethyl vinyl ketone, divinyl ketone, α-bromovinyl methyl ketone and α-chlorovinyl methyl ketone). The cycloaddition products were obtained in yields of 50-_90% and with enantioselectivities up to 96% ee. Ethyl vinyl ketone, divinyl ketone and the halogenated vinyl ketones worked best and their reactions with acyclic dienes consistently provided products with >90% ee. α-Chlorovinyl methyl ketone performed better than α-bromovinyl methyl ketone. The reaction also provided a [4.3.1]bicyclic ring system in 95% ee through an intramolecular cycloaddition reaction. Crystal structure determinations of [Ru(Cp)((S,S)-BIPHOP-F)(mvk)]-[SbF6], (S,S)-1b, and [Ru(Cp)((R,R)-Me4BIPHOP-F)(acrolein)][SbF6], (R,R)-2b, provided the basis for a rationalization of the asymmetric induction.
- Rickerby, Jenny,Vallet, Martial,Bernardinelli, Gerald,Viton, Florian,Kuendig, E. Peter
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p. 3354 - 3368
(2008/03/27)
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- Tetrabutylammonium peroxydisulfate in organic synthesis; VII. A facile and efficient method for the regeneration of carbonyl compounds from semicarbazones by tetrabutylammonium peroxydisulfate
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Semicarbazones of aldehydes and ketones are oxidized to the corresponding carbonyl compounds in excellent yields by tetrabutylammonium peroxydisulfate in dichlorlethane under mild conditions.
- Chen, Fen-Er,Liu, Ji-Dong,Fu, Han,Peng, Zuo-Zhong,Shao, Lan-Ying
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p. 2295 - 2299
(2007/10/03)
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- Reexamination of products and the reaction mechanism of the chalcogeno- Baylis-Hillman reaction: Chalcogenide-TiCl4-mediated reactions of electron- deficient alkenes with aldehydes
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Reactions of p-nitrobenzaldehyde (4) with methyl vinyl ketone (5) were conducted in the presence of TiCl4 and dimethyl sulfide (3) or selenopyranone 6. When the raw product was purified by column chromatography on silica gel, α-chloromethyl aldol 8 was obtained as a mixture of diastereoisomers 8a and 8b. In contrast, purification of the raw product by preparative TLC on silica gel gave α-methylene aldol 7. The mechanism for the formation of α-chloromethyl aldol 8 and diasteroselection for the syn- isomer 8a and anti-isomer 8b are discussed. (C) 2000 Elsevier Science Ltd.
- Kataoka, Tadashi,Kinoshita, Hironori,Iwama, Tetsuo,Tsujiyama, Shin-Ichiro,Iwamura, Tatsunori,Watanabe, Shin-Ichi,Muraoka, Osamu,Tanabe, Genzoh
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p. 4725 - 4731
(2007/10/03)
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- Trimethylchlorosilane and water. Convenient reagents for the regioselective hydrochlorination of olefins
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The hydrochlorination of a series of simple and functionalized olefins in high yields was readily accomplished using a mixture of trimethylchlorosilane and water. Hydrochlorination by this procedure is chemoselective and regioselective.
- Boudjouk, Philip,Kim, Beon-Kyu,Han, Byung-Hee
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p. 3479 - 3484
(2007/10/03)
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- Yeast Reduction of Some Four-Carbon Chlorinated Ketones. A Convenient Synthesis of (S)-(+)-But-3-en-2-ol
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The action of fermenting yeast on various four-carbon chlorinated ketones has been studied. (S)-(+)-But-3-en-2-ol is conveniently prepared from (+/-)-3-chlorobutan-2-one which yields a 1:1 mixture of (2S,3S)- and (2S,3R)-3-chlorobutan-2-ols.Conversion of the mixture into the dimethyl-methoxymethyl ethers followed by dehydrohalogenation and hydrolysis then gives (S)-(+)-but-3-en-2-ol.
- Ibrahim, Tuncel,Grattan, Timothy J.,Whitehurst, John Stanley
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p. 3317 - 3319
(2007/10/02)
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- CHIMIE ORGANOMETALLIQUE SOUS HAUTE PRESSION: REACTION DES CHLOROCETONES AVEC L'HYDRURE DE TRIBUTYLETAIN
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High-pressure reaction of tributyltin hydride with several chloroketones (3-chloro-2-butanone, 4-chloro-2-butanone, 5-chloro-2-pentanone, 6-chloro-2-hexanone and 7-chloro-2-heptanone) led to the formation of chloroalkoxytins or cyclic ethers.An ionic mechanism, starting with nucleophilic attack at the carbonyl group, is proposed to explain the formation of the reaction products.
- Degueil-Castaing, M.,Maillard, B.,Rahm, A.
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- A SIMPLE AND CONVENIENT SYNTHESIS OF β-HALOKETONES.
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A new rapid quantitative method to synthesize β-halo-ketones is described (eqn 2) wich utilizes the reaction of an enone with a tetraalkyl ammonium halide in anhydrous trifluoro acetic acid.The method is especially convenient for the preparation of β-iodoketones.
- Marx, John N.
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p. 1529 - 1532
(2007/10/02)
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- Total Synthesis of the Spirans of Cannabis: Cannabispiradienone, Cannabispirenone-A and -B, Cannabispirone, α- and β-Cannabispiranols and the Dihydrophenanthrene Cannithrene-1
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O-Methylcannabispirenone has been synthesised (57percent overall from 3,5-dimethoxycinnamic acid) via 5,7-dimethoxyindanone, p-tolylsulphonylmethyl isocyanide conversion into the 1-nitrile, alkylation with 1-iodo-3,3-ethylenedioxybutane, deacetalisation, and spirocyclisation. 5,7-Dimethoxyindanone is 7-deprotected by boron trichloride with high selectivity, and re-protected as the methoxyethoxymethyl ether: following the above route, finally deprotecting by boron trichloride, gives cannabispirenone-A (2) in 21percent overall yield.O-Methylcannabispirenone can be demethylated to give (2) by lithium 1,1-dimethylethanethiolate: demethylation with boron tribromide gives cannabispirenone-B (3).Hydrogenation of synthetic cannabispirenone-A gives cannabispirone (4), reduced by borohydride to the epimeric α-(6) and β-(5) cannabispiranols, separated by h.p.l.c.Dehydrogenation of O-methylcannabispirenone with dichlorodicyanobenzoquinone, followed by lithium 1,1-dimethylethanethiolate demethylation, gives cannabispiradienone (1).Under acidic conditions, the latter undergoes dienone-phenol rearrangement to give cannithrene-1 (8), thus completing the total synthesis of the spiro-cannabinoid group of natural products discussed in the preceding paper.The unsubstituted cannabispirenone parent has also been synthesised.
- Crombie, Leslie,Tuchinda, Patoomratana,Powell, Michael J.
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p. 1477 - 1484
(2007/10/02)
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- REACTION OF HALOGENS WITH SOME α,β-UNSATURATED ALDEHYDES AND KETONES
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Mechanisms are proposed to acconunt for evidence indicating that some simple α,β-unsaturated aldehydes and ketones do not react with halogens by the expected attack on the C=C bond.
- Heasley, Victor L.,Shellhamer, Dale F.,Carter, Tom L.,Gipe, Daphne E.,Gipe, Robert K.,et al.
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p. 2467 - 2470
(2007/10/02)
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- Oxidation products of arachidonic acid. IV. Model studies on the attachment of the C(13)-C(20) side-chain in the synthesis of tetrahydrofurans and pyrans 1, 2, and 3
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The synthesis of methyl 15-hydroxy-8(R)-methoxy-11(R)-p-nitrobenzoyloxy-9(S),12(R)-oxy-eicosa-13-ynoate, an arachidonic acid metabolite derivative, is described.As well, methods for the attachment of the C(13)-C(20) prostaglandin side-chain to furanosides were studied and the results are described.The reduction of the C-15 keto group on a model compound was performed and was found to have the same behavior as in the prostaglandins.A partial structure proof of Pace-Asciak's compound, 9,12-oxy-8,11,15-trihydroxy-13-enoic acid is given.
- Just, George,Crosilla, Danilo
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p. 2349 - 2357
(2007/10/02)
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