- Decarboxylative Hydroxylation of Benzoic Acids
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Herein, we report the first decarboxylative hydroxylation to synthesize phenols from benzoic acids at 35 °C via photoinduced ligand-to-metal charge transfer (LMCT)-enabled radical decarboxylative carbometalation. The aromatic decarboxylative hydroxylation is synthetically promising due to its mild conditions, broad substrate scope, and late-stage applications.
- Ritter, Tobias,Su, Wanqi,Xu, Peng
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supporting information
p. 24012 - 24017
(2021/10/06)
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- Cobalt-Catalyzed Esterification of Amides
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The first cobalt-catalyzed amide activation of N-Boc-amides, and their conversion into esters, is reported here. This new methodology presents a very practical process that does not require an inert atmosphere, uses an inexpensive cobalt catalyst, and proceeds under mild reaction conditions. This catalytic system has a broad substrate scope and has been shown to be highly efficient, with catalyst loadings as low as 1 mol %.
- Bourne-Branchu, Yann,Gosmini, Corinne,Danoun, Grégory
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supporting information
p. 10043 - 10047
(2017/08/01)
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- Rhodium-catalyzed synthesis of esters from aryl iodides and alcohols: use of alcohols with/without the assistance of aldehydes as carbon monoxide and nucleophile sources
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A CO-gas-free rhodium-catalyzed alkoxycarbonylation of aryl iodide with alcohols has been developed. Alcohols, with/without the aid of an aldehyde, were used as a carbon monoxide and nucleophile source. The former synthesis afforded better yields of the alkoxycarbonylated products. Moreover, phenols also afforded phenoxycarbonylation products with high yields.
- Kim, Ju Hyun,Park, Hawon,Chung, Young Keun
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p. 190 - 194
(2017/01/12)
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- Direct synthesis of symmetrical azines from alcohols and hydrazine catalyzed by a ruthenium pincer complex: Effect of hydrogen bonding
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Azines (2,3-diazabuta-1,3-dienes) are a widely used class of compounds with conjugated CN double bonds. Herein, we present a direct synthesis of azines from alcohols and hydrazine hydrate. The reaction, catalyzed by a ruthenium pincer complex, evolves dihydrogen and can be run in a base-free version The deh dro enative cou lin of benz lic and aliphatic alcohols led to good conversions and yields. Spectroscopic evidence for a hydrazine-coordinated dearomatized ruthenium pincer complex was obtained. Isolation of a supramolecular crystalline compound provided evidence for the important role of hydrogen bonding networks under the reaction conditions.
- Bauer, Jonathan O.,Leitus, Gregory,Ben-David, Yehoshoa,Milstein, David
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p. 8415 - 8419
(2018/05/23)
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- K2CO3-promoted formation of aryl esters from primary aryl amides by the acyl-acyl exchange process
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A new acyl-acyl exchange reaction has been developed for the formation of aryl esters from primary aryl amides. The reaction could occur under mild reaction conditions with catalytic quantities of K2CO3, and could afford moderate to good yields of the desired products.
- Bian, Yongjun,Qu, Xingyu
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supporting information
p. 3869 - 3872
(2016/05/24)
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- Pd/Cu-cocatalyzed aerobic oxidative carbonylative homocoupling of arylboronic acids and CO: A highly selective approach to diaryl ketones
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A highly selective Pd/Cu-cocatalyzed aerobic oxidative carbonylative homocoupling of arylboronic acids has been developed. This method employs a simple catalytic system, readily available boronic acids as the substrates, molecular oxygen as the oxidant, and 1 atm of CO/O2, which makes this method practical for further applications.
- Ren, Long,Jiao, Ning
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p. 2411 - 2414
(2014/10/15)
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- Aryl formate as bifunctional reagent: Applications in palladium-catalyzed carbonylative coupling reactions using in situ generated CO
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After decades of development, carbonylation reactions have become one of the most powerful tools in modern organic synthesis. However, the requirement of CO gas limits the applications of such reactions. Reported herein is a versatile and practical protocol for carbonylative reactions which rely on the cooperation of phenyl formate and nonaflate, and the generation of CO in situ. This protocol has a high functional-group tolerance and could be applied in carbonylations with C, N, and, O nucleophiles. The corresponding amides, alkynones, furanones, and aryl benzoates were synthesized in good yields. Transformers: A versatile and practical protocol for carbonylation reactions involve the cooperation of phenyl formate and nonaflate with generation of CO in situ. This protocol has a high functional-group tolerance and could be applied in carbonylative couplings with C, N, and O nucleophiles. The corresponding amides, alkynones, furanones, and aryl benzoates were synthesized in good yield.
- Li, Haoquan,Neumann, Helfried,Beller, Matthias,Wu, Xiao-Feng
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supporting information
p. 3183 - 3186
(2014/04/03)
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- Facile esterification of alcohols with 2-Acyl-4,5-dichloropyridazin-3(2 H)-ones under Friedel-Crafts conditions
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This paper describes the esterification of aromatic and aliphatic alcohols by using 2-acyl-4,5-dichloropyridazin-3(2H)-ones as an acyl source under Friedel-Crafts conditions. Twelve alcohols were reacted with four 2-acyl-4,5-dichloropyridazin-3(2H)-ones in the presence of AlCl3 in tetrahydrofuran at room temperature to give the corresponding esters in moderate to excellent yields. Thus, 2-acylpyridazin-3(2H)-ones serve as good and atom-economic acyl sources for the esterification of aromatic alcohols under Friedel-Crafts conditions, representing a rapid, practical, and efficient method of esterification. Georg Thieme Verlag Stuttgart. New York.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Yoon, Hyo Jae,Lee, Sang-Gyeong,Yoon, Yong-Jin
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p. 1909 - 1915
(2014/08/18)
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- Catalyst-free esterification of alcohols using 2-acyl-4,5- dichloropyridazinones under microwave conditions
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Efficient and green esterification is of great importance. In this work, we demonstrate the catalyst-free esterification of alcohols by their reaction with 2-acyl-4,5-dichloropyridazin-3(2H)-ones under microwave irradiation. Aliphatic and aromatic alcohols were converted into the corresponding esters in good to excellent yields under microwave irradiation in solvent or solvent-free conditions. It is noteworthy that the reaction is catalyst-free, atom-economic, and rapid and that the process is inexpensive.
- Kim, Bo Ram,Sung, Gi Hyeon,Lee, Sang-Gyeong,Yoon, Yong Jin
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supporting information
p. 3234 - 3237
(2013/04/24)
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- Rapid and Ecofriendly Esterification of Alcohols with 2-Acylpyridazinones
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Atom-economical esterification is of great importance in green chemistry. In this work, we demonstrated the catalyst and additive free esterification of alcohols by their reaction with 2-acyl-4,5-dichloropyridazin-3(2H)- ones without solvent at 100 oC. Aliphatic and aromatic alcohols were converted into the corresponding esters in good to excellent yields. It is noteworthy that the reaction is solvent-free, atom-economic, easy-workup, and rapid and that the process is inexpensive.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Kim, Jeum-Jong,Yoon, Yong-Jin
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p. 3410 - 3414
(2014/01/06)
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- Preparation of esters and amides from carboxylic acids and N-formylation of amines promoted by 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-hexachloride (TAPC)
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A new method is described for the preparation of esters and amides promoted by TAPC from carboxylic acids using a solvent-free grinding technique. The solvent-free N-formylation of amines is also reported.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Targhan, Homa,Sheikh Arabi, Mehdi
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supporting information
p. 5064 - 5068
(2013/09/02)
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- Significant promoting effects of Lewis acidity on Au-Pd systems in the selective oxidation of aromatic hydrocarbons
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An unprecedented synergistic effect, obtained for rationally designed Au-Pd alloy nanoparticles supported on an acidic metal-organic framework (MOF), in the aerobic oxidation of the primary C-H bonds in toluene and derivates is reported.
- Liu, Hongli,Li, Yingwei,Jiang, Huanfeng,Vargas, Carolina,Luque, Rafael
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supporting information
p. 8431 - 8433
(2012/10/29)
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- Preparation of benzoyloxy benzophenone derivatives and their inhibitory effects of ICAM-1 expression
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Benzoyloxy benzophenone derivatives were prepared in 3 steps including DCC coupling, Fries rearrangement and esterification from benzoic acids in 24-89% total yields. Among the prepared 12 benzophenone analogues 1a-1l, the compound 1b having three chloro groups at the para position showed maximum inhibitory effects of ICAM-1 expression but, 1a which have no substituents at all showed no inhibitory activity. This study provides the evidences that benzoyloxy benzophenone derivative, 1b may exert its anti-inflammatory activity by suppressing IFN-γ-induced ICAM-1 expression.
- Kwon, Eun Mi,Kim, Cheol Gi,Goh, Ah Ra,Park, Jinseu,Jun, Jong-Gab
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experimental part
p. 1939 - 1944
(2012/08/07)
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- N-heterocyclic carbene-catalyzed aerobic oxidative direct esterification of aldehydes with organoboronic acids
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A simple procedure affording benzoates through a NHC-catalyzed aerobic oxidative esterification of aldehydes with organoboronic acids has been disclosed. This process allows access to a wide variety of aromatic esters in good to excellent yields under simple, efficient, and sustainable reaction conditions (see scheme).
- Meng, Jing-Jing,Gao, Min,Wei, Yu-Ping,Zhang, Wen-Qin
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experimental part
p. 872 - 875
(2012/07/03)
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- A general and efficient palladium-catalyzed alkoxycarbonylation of phenols to form esters through in situ formed aryl nonaflates
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Esters made easy! A general and efficient methodology for the palladium-catalyzed alkoxycarbonylation of in situ formed aryl nonaflates has been developed (see scheme). Both homo- and cross-esterifications are possible. DPPF=1,1′-bis(diphenylphosphino)ferrocene. Copyright
- Wu, Xiao-Feng,Neumann, Helfried,Beller, Matthias
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supporting information; experimental part
p. 3831 - 3834
(2012/05/20)
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- Equilibrium shift in the rhodium-catalyzed acyl transfer reactions
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Rhodium/phosphine complexes catalyze equilibrium acyl transfer reactions between acid fluorides, aryl esters, acylphosphine sulfides, and thioesters. The use of appropriate co-substrates to accept heteroatom groups shifted the equilibrium to desired products. Acylphosphine sulfides and aryl esters were converted to acid fluorides using benzoylpentafluorobenzene as the fluoride donor, and the fluorination reaction of thioesters employed (4-tolylthio) pentafluorobenzene. Acid fluorides were converted into acylphosphine sulfides and thioesters using diphosphine disulfides and disulfides/triphenylphosphine, respectively. Aryl esters were obtained from acid fluorides and phenols in the presence of triphenylsilane. Aryl esters, acylphosphine sulfides, and thioesters were also interconverted in the presence of rhodium complexes. These rhodium-catalyzed acyl transfer reactions proceeded under neutral conditions without using acid or base. The involvement of acyl rhodium intermediates in these reactions was suggested by the carbothiolation reaction of thioesters and alkynes.
- Arisawa, Mieko,Igarashi, Yui,Kobayashi, Haruki,Yamada, Toru,Bando, Kentaro,Ichikawa, Takuya,Yamaguchi, Masahiko
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supporting information; experimental part
p. 7846 - 7859
(2011/10/12)
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- Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation of aromatic carboxylic acids
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Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation reactions of aromatic carboxylic acids are reported. The new reactions may provide alternative routes for the synthesis of some biaryls and aromatic carboxylic esters. The Royal Society of Chemistry 2011.
- Dai, Jian-Jun,Liu, Jing-Hui,Luo, Dong-Fen,Liu, Lei
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supporting information; experimental part
p. 677 - 679
(2011/03/22)
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- Practical and chemoselective reduction of acyl chloride to alcohol by borohydride in aqueous dichloromethane
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A simple methodology for the reduction of acid chlorides to their corresponding alcohols has been developed. Various carboxylic acids were converted to alcohols in excellent yields using NaBH4-K2CO3 in a mixed solvent system of dichloromethane and water (1:1) in the presence of a phase-transfer catalyst at low temperature. The importance of the work is its simplicity, selectivity, excellent yield, and very short reaction time. This new reduction condition has proved to be an excellent chemoselective method for a range of acid chlorides in the presence of various functional groups.
- Rajan, Ramya,Badgujar, Sachin,Kaur, Kamaljit,Malpani, Yashwardhan,Kanjilal, Pranab R.
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experimental part
p. 2897 - 2907
(2010/11/18)
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- Radical 1,2-o→c transposition for conversion of phenols into benzoates by o-neophyl rearrangement/fragmentation cascade
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Figure Presented Radical merry-go-round! Diaryl thiocarbonates, available in a single step from phenols, can be directly transformed into benzoates by a new radical cascade that transposes O and C atoms at the aromatic core. The cascade bypasses the common Barton McCombie fragmentation in favor of the usually unfavorable O-neophyl rearrangement, which is rendered irreversible and efficient by a highly exothermic C-S bond scission in the O-centered radical (see scheme; FG = functional group).
- Baroudi, Abdulkader,Alicea, Jeremiah,Alabugin, Igor Y.
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experimental part
p. 7683 - 7687
(2010/08/22)
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- Evidence of substituent-induced electronic interplay. Effect of the remote aromatic ring substituent of phenyl benzoates on the sensitivity of the carbonyl unit to electronic effects of phenyl or benzoyl ring substituents
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Carbonyl carbon 13C NMR chemical shifts δC(C=O) measured in this work for a wide set of substituted phenyl benzoates p-Y-C 6H4CO2C6H4-p-X (X = NO2, CN, Cl, Br, H, Me, or MeO; Y = NO2, Cl, H, Me, MeO, or NMe2) have been used as a tool to study substituent effects on the carbonyl unit. The goal of the work was to study the cross-interaction between X and Y in that respect. Both the phenyl substituents X and the benzoyl substituents Y have a reverse effect on δC(C=O). Electron-withdrawing substituents cause shielding while electron-donating ones have an opposite influence, with both inductive and resonance effects being significant. The presence of cross-interaction between X and Y could be clearly verified. Electronic effects of the remote aromatic ring substituents systematically modify the sensitivity of the C=O group to the electronic effects of the phenyl or benzoyl ring substituents. Electron-withdrawing substituents in one ring decrease the sensitivity of δC(C=O) to the substitution of another ring, while electron-donating substituents inversely affect the sensitivity. It is suggested that the results can be explained by substituent-sensitive balance of the contributions of different resonance structures (electron delocalization, Scheme 1).
- Neuvonen, Helmi,Neuvonen, Kari,Pasanen, Paavo
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p. 3794 - 3800
(2007/10/03)
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- Efficient method for the preparation of inverted alkyl carboxylates and phenyl carboxylates via oxidation-reduction condensation using 2,6-dimethyl-1,4-benzoquinone or simple 1,4-benzoquinone
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Oxidation-reduction condensation using in situ formed alkoxydiphenylphosphines, 2,6-dimethy-1,4-benzoquinone, and carboxylic acids provides a useful method for the preparation of inverted tertiary alkyl carboxylates from the corresponding chiral tertiary alcohols under mild and neutral conditions. Similarly, it has afforded alkyl carboxylates successfully in good-to-high yields by the combined use of alkoxydiphenylphosphines having primary, secondary, or tertiary alkoxy groups, carboxylic acids, and simple 1,4-benzoquinone. When chiral secondary or tertiary alcohols are used, the corresponding inverted secondary or tertiary alkyl carboxylates are also obtained in good-to-high yields. In addition, a convenient method for the preparation of phenyl carboxylates in high yields has been established by utilizing oxidation-reduction condensation in toluene at 110 °C using phenoxydiphenylphosphines in situ-formed from phenols and chlorodiphenylphosphine, 2,6-dimethyl-1,4-benzoquinone, and carboxylic acids.
- Shintou, Taichi,Fukumoto, Kentaro,Mukaiyama, Teruaki
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p. 1569 - 1579
(2007/10/03)
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- Ozonation of 1,1,2,2-tetraphenylethene revisited: Evidence for electron- transfer oxygenations
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Ozonolyses of 1,1,2,2-tetraphenylethene (TPE, 1) have been described many times in the literature, but the reports are contradictory. This reaction is particularly important for understanding the mechanism of alkene ozonolysis, in view of possible stabilization of reactive intermediates by aryl groups. Thus, systematic investigations of ozonolysis in both aprotic solvents and in protic solvents are reported here. Attention is directed to the following details that have been underestimated in the past: i) the actual electronic structure of ground-state ozone (O3), ii) differentiation between strained and unstrained alkenes, iii) the significance of both the O3 concentration and the TPE concentration, iv) the influence of various solvents, including pyridine, v) the influence of the reaction temperature, vi) the role of electron-transfer catalysis (ETC) and, yii) the effect of structural modifications. Our results suggest that ozonolysis of TPE (1) does not include a 1,3-dipolar reaction step, but represents a particularly interesting example of electron-donor (TPE)/electron-acceptor (O3) redox chemistry. The present investigations include several crucial results. First, pure 3,3,6,6-tetraphenyltetroxane (3, m.p. 221°(dec.)) and pure tetraphenylethylene ozonide (4, m.p. 153°(dec.)) are prepared for the first time, although 3 and 4 have long been known. Second, the singlet diradical character of O3, lessened by means of hypervalent-electron interaction and predicted by different calculations, is evidenced via reaction with the spintrap galvinoxyl (2,6-bis(1-1-dimethylethyl)-4-{[3,5-bis(1,1- dimethylethyl)-4-oxocyclohexa-2,5-dien-1-ylidene]methyl}phenoxy; 8), and the zwitterionic reaction behavior of ground-state O3 is ruled out. Third, the electronacceptor ability of O3 is evidenced by reactions with suitable tetraaryl ethylenes: it is enhanced by addition of catalytic amounts of protons or Lewis acids. Fourth, the observed distribution of the O3 O-atoms to the two different olefinic C-atoms of the unsymmetric alkene 27b is in full agreement with an initial single-electron transfer (SET) step, followed by a radical mono-oxygenation to cause the crucial C,C cleavage. Final dioxygenation should lead to the generally known products (ozonides, tetroxanes, hydroperoxides). The regioselectivity is found to be inconsistent with the expected decay of an intermediate primary ozonide. Finally, the treatment of 1,2-bis(4-methoxyphenyl)acenaphthylene (36) with O3 (simultaneous transfer of three O-atoms) leads to the same experimental result as a stepwise transfer of one O-atom followed by a transfer of two O- atoms.
- Schank, Kurt,Beck, Horst,Buschlinger, Michael,Eder, Joerg,Heisel, Thomas,Pistorius, Susanne,Wagner, Christiane
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p. 801 - 826
(2007/10/03)
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- Studies on Mixed Liquid Crystal. Part-I. Nemetic Mesophase induced by Mixing Two Non-liquid Crystalline Components and Determination of Latent Transition Temperature
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Eight binary systems consisting of both non-liquid crystalline components, viz. p-methoxyphenyl-p''-methoxy benzoate and Schiff base have been studied.One of the eight binary systems involving Schiff base p-tolual-p-phenetidine was found to give monotropi
- Doshi, A.V.,Joshi, N.N.
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p. 807 - 810
(2007/10/02)
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- Electrochemical generation and reactions of acyloxytriphenylphosphonium ions
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Constant-current electrolysis, in an undivided cell, of Ph3P in the presence of a carboxylic acid in CH2Cl2 containing 2,6-lutidinium perchlorate as the supporting electrolyte was shown to generate the corresponding acyloxyphosphonium ion, Ph3P+-OCOR, which was converted in situ to esters, amides, and β-lactams under mild conditions.
- Ohmori, Hidenobu,Maeda, Hatsuo,Kikuoka, Masayuki,Maki, Toshihide,Masui, Masaichiro
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p. 767 - 776
(2007/10/02)
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