- A Straightforward Conversion of Activated Amides and Haloalkanes into Esters under Transition-Metal-Free Cs 2 CO 3 /DMAP Conditions
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The esterification of activated amides, N -acylsaccharins, under transition-metal-free conditions with good functional group tolerance has been developed, resulting in C-N cleavage leading to efficient synthesis of a variety of esters in moderate to good yields. This work demonstrates that esterification may proceed by using simple N -acylsaccharins, haloalkanes, and Cs 2 CO 3 as oxygen source.
- Chen, Liuqing,Gu, Ying,Jian, Junsheng,Liu, Yueping,Miao, Liqiong,Wang, Zijia,Zeng, Zhuo
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supporting information
p. 4078 - 4084
(2019/10/28)
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- Structure–activity relationships of vanillic acid ester analogs in inhibitory effect of antigen-mediated degranulation in rat basophilic leukemia RBL-2H3 cells
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Methyl vanillate (1) showed strong degranulation inhibitory activity among vanillin derivatives tested. In order to find structure–activity relationships for developing anti-allergic agents with simple structures and potent activity, we synthesized several vanillic acid (VA) ester derivatives with C1–C4and C8alkyl chains and evaluated their degranulation inhibitory activities. The most active compound of VA ester derivatives was derivative 5 with a C4straight alkyl chain, and derivative 5 exhibited approximately three-fold greater inhibitory activity than that of 1. Moreover, we designed 8 types of analogs based on 5, and we found that the minimum structure for potent degranulation inhibitory activity requires direct connection of the butyl ester moiety on the benzene ring and at least one hydroxyl group on the benzene ring. Butyl meta or para hydroxyl benzoate (10 or 11) has a simpler structure than that of 5 and exhibited more potent degranulation inhibitory activity than that of 5.
- Ishimata, Nao,Ito, Hideyuki,Tai, Akihiro
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supporting information
p. 3533 - 3536
(2016/07/22)
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- Fe-Catalyzed Aerobic Oxidative C-CN Bond Cleavage of Arylacetonitriles Leading to Various Esters
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Fe-catalyzed aerobic oxidative esterifications of arylacetonitriles with alcohols, tri alkoxsilanes, silicate esters, or borate esters have been developed. The acyl groups which were in situ generated via chemoselective C(CO)-CN bond cleavage were directly used as electrophiles, leading to corresponding aryl esters in good to excellent yields under molecular oxygen when attacked by alcohols or alcohol surrogates. Dioxygen serves as both oxidant and reactant in this protocol. The reaction has a very broad substrate scope. Cheap starting materials as well as environmentally benign and inexpensive iron catalyst and ideal oxidant O2 feature this transformation and make it a practical and sustainable protocol to afford esters.
- Kong, Weiguang,Li, Bingnan,Xu, Xuezhao,Song, Qiuling
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p. 8436 - 8443
(2016/09/28)
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- Generally applicable and efficient esterification of aldehydes with alcohols catalyzed by cyclopalladated ferrocenylimine
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The palladacycle-catalyzed esterification of a variety of aldehydes with alcohols was developed. This reaction allows formation of esters in moderate to excellent yields not only for various aldehydes but also alcohols. In addition, the esterification could proceed well under mild conditions with a low catalyst loading of 0.0625 mol%. Copyright
- Ma, Gaizhi,Leng, Yuting,Qiao, Huijie,Yang, Fan,Wang, Shiwei,Wu, Yangjie
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- Mechanistic investigation of oxidation of some substituted aromatic acetals with N-bromosuccinimide in acetonitrile medium - A kinetic approach
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The oxidation of meta- and para-substituted aromatic acetals by N-bromosuccinimide (NBS) to the corresponding esters and alkyl bromide, is first-order in [NBS] and [acetal]. The effect of substituents in the aromatic ring of some aromatic acetals [X-C6H4CH(OBu-B) 2] {X = H, p-OMe, p-Me, p-Cl, p-NO2, m-OMe, m-CI, m-NO2} on the kinetics of above oxidation has been studied in acetonitrile medium at various temperatures by iodometric method. The rate of the reaction increases with the increase in the dielectric constant of the medium. The stoichiometry of the reaction is found to be 1 : 1. A primary kinetic isotopic effect kH/kD of 1.8 is observed, which indicates the C-H bond cleavage of the aldehydic carbon in the rate determining step. The Hammett reaction constant (a) for the reaction is found to be -1.38 and -1.42 at 313 K and 323 K respectively. The Exner plot is found to be linear with the isokinetic temperature 132 K. The kinetic and activation parameters Ea, A, ΔH≠, ΔG≠ and ΔS≠ have been calculated. A mechanism involving simultaneous loss of H+ from the aldehydic carbon and expulsion of bromide ion with the formation of carbonium ion intermediate is proposed.
- Mathiyalagan
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p. 1499 - 1506
(2013/02/23)
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- Efficient carbonylation of aryl and heteroaryl bromides under atmospheric pressure of CO
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In the presence of Et and n-BuOH, efficient alkoxycarbonylation of (hetero)aromatic bromides was achieved under atmospheric pressure of carbon monoxide with in situ generated palladium/rac-BINAP as catalyst. Georg Thieme Verlag Stuttgart - New York.
- Yang, Weizhun,Han, Wei,Zhang, Weidong,Shan, Lei,Sun, Jiansong
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supporting information; experimental part
p. 2253 - 2255
(2011/10/19)
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- Correlation analysis in the study of oxidation kinetics of aromatic acetals with N-bromosuccinimide in acetonitrile medium
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An attempt has been made to correlate the rate constants of substituted acetals with the chemical shifts of the benzylic proton of the acetals (log k2 vs δ). This correlation is similar to that of which is obtained between σ vs δ. The benzylic proton chemical shift in acetals is found to be the characteristics of acetals. The benzylic proton does not couple with other protons and hence appears as a singlet, which would ensure effective correlation.
- Mathiyalagan
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scheme or table
p. 865 - 868
(2012/04/10)
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- General and selective palladium-catalyzed oxidative esterification of alcohols
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Selectively esterified: Primary alcohols react with dioxygen as a benign oxidant in a palladium-catalyzed oxidative esterification (see scheme). The corresponding aldehydes and esters are formed highly selectively depending on the catalyst system. The reactions take place in the presence of commercially available ligands without the need for additional organic hydrogen acceptors. Copyright
- Gowrisankar, Saravanan,Neumann, Helfried,Beller, Matthias
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supporting information; experimental part
p. 5139 - 5143
(2011/06/25)
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- Palladium-catalyzed aerobic oxidative carbonylation of arylboronate esters under mild conditions
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(Figure Presented) "CO"n Air: The title reaction was carried out using [PdCl2(PPh3)2 ] as the catalyst precursor under very mild conditions (balloon pressure of CO and air, at 40- 50°C), and produced a wide range of aryl carboxyl esters 2 in good to excellent yields. Remarkable selectivity between oxidative carbonylation and homocoupling of arylboronate esters l was also achieved.
- Liu, Qiang,Li, Gang,He, Jun,Liu, Jing,Li, Peng,Lei, Aiwen
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supporting information; experimental part
p. 3371 - 3374
(2010/07/06)
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- New cyclopentadienyl, indenyl or fluorenyl substituted phosphine compounds and their use in catalytic reactions
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The invention is directed to a phosphine compound represented by general formula (1) wherein R' and R" independently are selected from alkyl, cycloalkyl and 2-furyl radicals, or R' and R" are joined together to form with the phosphorous atom a carbon-phosphorous monocycle comprising at least 3 carbon atoms or a carbon-phosphorous bicycle; the alkyl radicals, cycloalkyl radicals, and carbon-phosphorous monocycle being unsubstituted or substituted by at least one radical selected from the group of alkyl, cycloalkyl, aryl, alkoxy, and aryloxy radicals; Cps is a partially substituted or completely substituted cyclopentadien-1-yl group, including substitutions resulting in a fused ring system, and wherein a substitution at the 1-position of the cyclopentadien-1-yl group is mandatory when the cyclopentadien-1-yl group is not part of a fused ring system or is part of an indenyl group. Also claimed is the use of these phosphines as ligands in catalytic reactions and the preparation of these phosphines.
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Page/Page column 64; 65; 66
(2008/06/13)
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- Efficient carbonylation of aryl and heteroaryl bromides using a palladium/diadamantylbutylphosphine catalyst
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A general palladium-catalyzed alkoxycarbonylation of aryl and heteroaryl bromides has been developed in the presence of bulky monodentate phosphines. Studies of the butoxycarbonylation of three model substrates revealed the advantages of di-1-adamantyl-n-butylphosphine compared to other ligands. In the presence of this catalyst system various bromoarenes provided the corresponding benzoic acid derivatives (ester, amides, acids) in excellent yield at low catalyst loadings (0.5 mol% Pd or below).
- Neumann, Helfried,Brennfuehrer, Anne,Gross, Peter,Riermeier, Thomas,Almena, Juan,Beller, Matthias
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p. 1255 - 1261
(2007/10/03)
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- Development of new palladium catalysts for the alkoxycarbonylation of aryl chlorides
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The alkoxycarbonylation of different aryl chlorides was studied. Studies of the butoxycarbonylation of 4-chlorobenzotrifluoride and chlorobenzene using chelating ferrocenylphosphines reveal the advantages of these ligands compared to the well-known tricyc
- M?gerlein, Wolfgang,Indolese, Adriano F,Beller, Matthias
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- Advances in the carbonylation of aryl halides using palladium catalysts
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The palladium-catalyzed carbonylation of aryl halides is shown to be a versatile tool for the synthesis of various benzoic and heteroaromatic acid derivatives. Recent developments from our laboratories in this area are presented.
- Beller, Matthias,Indolese, Adriano F.
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p. 684 - 687
(2007/10/03)
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- A more efficient catalyst for the carbonylation of chloroarenes
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The right ligand enables the efficient carbonylation of unactivated chloroarenes. A general synthesis of benzoic acid derivatives is possible with the palladium - Ferrocenylphosphane catalysts (see scheme).
- Maegerlein, Wolfgang,Indolese, Adriano F.,Beller, Matthias
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p. 2856 - 2859
(2007/10/03)
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- Substituents Effect on the Reaction of Aromatic Acetals Over Aluminium Phosphate and Aluminium Sulphate Catalyst
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Aromatic acetals in the presence of aluminium phosphate (AP) catalyst at elevated temperatures yield the corresponding esters (b), ethers (c) and the parent aldehydes (d).These substrates over aluminium sulphate (AS) catalyst give only the esters (b) and aldehydes (d).The products distribution varies with temperature.Substituents in the ring also play a part in the reaction.
- Xavier, N.,Arulraj, S. J.
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p. 775 - 777
(2007/10/02)
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- REARRANGEMENT OF SUBSTITUTED AROMATIC ACETALS CATALYSED BY γ-ALUMINA
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Aromatic acetals over γ-alumina undergo rearrangement to give the corresponding esters (b) and ethers (c) in good yield.The product distribution varied unusually over the range of reaction temperatures.The effect of substituents has also been felt much in the study.Probable mechanisms have been suggested for the reaction.The catalyst has been characterized by various studies and the specific poisoning of the catalyst has been done with NH3, CO2 and H2S.
- Xavier, N.,Arulraj, S. J.
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p. 2875 - 2878
(2007/10/02)
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