- Acid- And base-switched palladium-catalyzed γ-C(sp3)-H alkylation and alkenylation of neopentylamine
-
The functionalization of remote unactivated C(sp3)-H and the reaction selectivity are among the core pursuits for transition-metal catalytic system development. Herein, we report Pd-catalyzed γ-C(sp3)-H-selective alkylation and alkenylation with removable 7-azaindole as a directing group. Acid and base were found to be the decisive regulators for the selective alkylation and alkenylation, respectively, on the same single substrate under otherwise the same reaction conditions. Various acrylates were compatible for the formation of C(sp3)-C(sp3) and C(sp3)-C(sp2) bonds. The alkenylation protocol could be further extended to acrylates with natural product units and α,β-unsaturated ketones. The preliminary synthetic manipulation of the alkylation and alkenylation products demonstrates the potential of this strategy for structurally diverse aliphatic chain extension and functionalization. Mechanistic experimental studies showed that the acidic and basic catalytic transformations shared the same six-membered dimer palladacycle.
- Zhang, Jinquan,Zhang, Shuaizhong,Zou, Hongbin
-
supporting information
p. 3466 - 3471
(2021/05/31)
-
- Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
-
The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
- Dong, Guangbin,Xu, Yan,Zhou, Xukai
-
supporting information
p. 20042 - 20048
(2021/12/03)
-
- Asymmetric Allylation Catalyzed by Chiral Phosphoric Acids: Stereoselective Synthesis of Tertiary Alcohols and a Reagent-Based Switch in Stereopreference
-
The substrate scope of the asymmetric allylation with zinc organyls catalyzed by 3,3-bis(2,4,6-triisopropylphenyl)-1,1-binaphthyl-2,2-diyl hydrogenphosphate (TRIP) has been extended to non-cyclic ester organozinc reagents and ketones. Tertiary chiral alcohols are obtained with ee's up to 94% and two stereogenic centers can be created. Compared to the previous lactone reagent the stereopreference switches almost completely, proving the fact that the nature of the organometallic compound is of immense importance for the asymmetry of the product. (Figure presented.).
- Lazzarotto, Mattia,Hartmann, Peter,Pletz, Jakob,Belaj, Ferdinand,Kroutil, Wolfgang,Payer, Stefan E.,Fuchs, Michael
-
supporting information
p. 3138 - 3143
(2021/04/28)
-
- Phosphine-Catalyzed Cascade Annulation of MBH Carbonates and Diazenes: Synthesis of Hexahydrocyclopenta[c]pyrazole Derivatives
-
A phosphine-catalyzed cascade annulation of Morita-Baylis-Hillman (MBH) carbonates and diazenes was achieved, giving tetrahydropyrazole-fused heterocycles bearing two five-membered rings in moderate to excellent yields. The reaction underwent an unprecedented reaction mode of MBH carbonates, in which two molecules of MBH carbonates were fully merged into the ring system.
- Guo, Hongchao,Li, Hongxiang,Liu, Hao,Shi, Wangyu,Wang, Chang,Wang, Wei,Wu, Yongjun
-
supporting information
p. 5571 - 5575
(2021/07/31)
-
- ISOTOPES OF ALPHA KETOGLUTARATE AND RELATED COMPOUNDS AND THEIR USE IN HYPERPOLARIZED IMAGING
-
A compound of the Formula I or a pharmaceutically acceptable salt thereof, wherein R1, Ca, Cb, Cd, and n are the same as described in the specification. Disclosed is a method of diagnosing or monitoring a patient suffering from cancer, the method comprising: administering a pharmaceutical composition comprising an effective amount of an active agent, wherein the active agent is the compound of Formula I, a pharmaceutically acceptable salt of any of the foregoing thereof, or a combination thereof, together with a pharmaceutically acceptable carrier to the patient; and diagnosing or monitoring the patient by hyperpolarized 13C-MRI. Also disclosed is a method of synthesizing 1-13C- 5-12C-diacid.
- -
-
Paragraph 0157-0159
(2021/07/24)
-
- Palladium-catalyzed regioselective synthesis of B(4,5)-or B(4)-substituted: O-carboranes containing α,β-unsaturated carbonyls
-
With the help of a carboxylic acid directing group, Pd-catalyzed regioselective synthesis of B(4,5)-or B(4)-substituted o-carboranes containing α,β-unsaturated carbonyls has been reported. The-COOH, removed during the course of the reaction, is responsible for controlling the regioselectivity. The desired products could be obtained in moderate to good yields.
- Li, Jiaoyi,Lu, Jian,Tian, Song,Wang, Qian,Zhang, Chuyi,Zhang, Jianwei,Zhou, Ling
-
p. 4723 - 4727
(2020/07/13)
-
- Palladium-catalyzed remote C-H functionalization of 2-aminopyrimidines
-
A straightforward strategy was developed for the arylation and olefination at the C5-position of the N-(alkyl)pyrimidin-2-amine core with readily available aryl halides and alkenes, respectively. This approach was highly regioselective, and the transformation was achieved based on two different (Pd(ii)/Pd(iv)) and (Pd(0)/Pd(ii)) catalytic cycles.
- Das, Animesh,Jana, Akash,Maji, Biplab
-
supporting information
p. 4284 - 4287
(2020/04/27)
-
- Method for synthesizing cisatracurium besilate
-
The invention discloses a method for synthesizing cisatracurium besilate. The method comprises the following steps of: reacting a compound shown as formula I, a compound shown as formula II and oxalicacid dihydrate to generate a compound shown as formula III; reacting the compound shown as formula III under the catalysis of Pd/C to generate a compound shown as formula IV; reacting the compound shown as formula IV with 1, 5-pentanediol to generate a compound shown as formula V; and reacting the compound shown as formula V with methyl benzenesulfonate to prepare cisatracurium besilate; whereinthe compounds shown as the formula I, the formula II, the formula III, the formula IV and the formula V are respectively represented as the specification. The synthesis method provided by the invention can significantly improve the yield and purity of cisatracurium besilate and reduce the synthesis cost of cisatracurium besilate.
- -
-
Paragraph 0027; 0034-0039
(2021/03/06)
-
- Synthesis of C-Glycosyl Amino Acid Building Blocks Suitable for the Solid-Phase Synthesis of Multivalent Glycopeptide Mimics
-
Five C-glycosyl functionalized lysine building blocks, featuring C-glycosidic derivatives of α-rhamnose, α-mannose, α-galactose, β-galactose, and β-N-acetyl glucosamine have been designed and synthesized. These derivatives, equipped with acid-labile protecting groups, are eminently suitable for solid-phase synthesis of multivalent glycopeptides. The lysine building blocks were prepared from C-allyl glycosides that underwent a Grubbs cross-metathesis with an acrylate, followed by a reduction of the C=C double bond in the resulting α,β-unsaturated esters, and liberation of the carboxylate to allow condensation with a lysine side chain. The thus obtained C-glycosides, five in total, were applied in the solid-phase peptide synthesis (SPPS) of three glycopeptides, showing the potential of the described building blocks in the assembly of well-defined mimics of homo- and heteromultivalent glycopeptides and glycoclusters.
- Reintjens, Niels R. M.,Koemans, Tony S.,Zilverschoon, Nick,Castelli, Riccardo,Cordfunke, Robert A.,Drijfhout, Jan Wouter,Meeuwenoord, Nico J.,Overkleeft, Herman S.,Filippov, Dmitri V.,van der Marel, Gijsbert A.,Codée, Jeroen D. C.
-
supporting information
p. 5126 - 5139
(2020/06/23)
-
- Ruthenium(II) Catalysed Highly Regioselective C-3 Alkenylation of Indolizines and Pyrrolo[1,2-a]quinolines
-
Discovered the Ruthenium(II) catalysed highly stereo- and regioselective protocol for the oxidative C-3 alkenylation of indolizines and pyrrolo[1,2-a]quinolines. The methodology represents the first example for the directing group assisted C–C bond formation reaction of the indolizines. Under mild reaction conditions, this method provides an ample substrate scope to produce C-3 alkenyl indolizines in excellent to moderate yields. However, pyrrolo[1,2-a]quinolines underwent alkenynation at elevated temperature to furnish C-3 alkenyl derivatives. The functionalized indolizines were selectively reduced to obtain their saturated derivatives.
- Jadhav, Pankaj Pandit,Kahar, Nilesh Machhindra,Dawande, Sudam Ganpat
-
supporting information
p. 7831 - 7835
(2019/12/24)
-
- Selective Conversion of Carbon Dioxide to Formaldehyde via a Bis(silyl)acetal: Incorporation of Isotopically Labeled C1 Moieties Derived from Carbon Dioxide into Organic Molecules
-
The conversion of carbon dioxide to formaldehyde is a transformation that is of considerable significance in view of the fact that formaldehyde is a widely used chemical, but this conversion is challenging because CO2 is resistant to chemical transformations. Therefore, we report here that formaldehyde can be readily obtained from CO2 at room temperature via the bis(silyl)acetal, H2C(OSiPh3)2. Specifically, formaldehyde is released from H2C(OSiPh3)2 upon treatment with CsF at room temperature. H2C(OSiPh3)2 thus serves as a formaldehyde surrogate and provides a means to incorporate CHx (x = 1 or 2) moieties into organic molecules. Isotopologues of H2C(OSiPh3)2 may also be synthesized, thereby providing a convenient means to use CO2 as a source of isotopic labels in organic molecules.
- Rauch, Michael,Strater, Zack,Parkin, Gerard
-
supporting information
p. 17754 - 17762
(2019/11/05)
-
- Ruthenium(II) oxidase catalysis for C-H alkenylations in biomass-derived γ-valerolactone
-
Ruthenium(ii) biscarboxylate oxidase catalysis is a powerful tool for the assembly of functionalized arenes with oxygen as a green oxidant, but this strategy was thus far limited to its use in traditional organic solvents. Herein, we report on a green procedure for the ruthenium(ii) biscarboxylate-catalysed C-H functionalisation in biomass-derived γ-valerolactone as the reaction medium. The oxidase catalysis was characterized by ample substrate scope and proceeded efficiently with oxygen as the sole oxidant. The overall green nature of this C-H-activation methodology is reflected by H2O being the only by-product.
- Bechtoldt, Alexander,Baumert, Marcel E.,Vaccaro, Luigi,Ackermann, Lutz
-
supporting information
p. 398 - 402
(2018/02/07)
-
- Formyloxyacetoxyphenylmethane and 1,1-diacylals as versatile O-formylating and O-acylating reagents for alcohols
-
Formyloxyacetoxyphenylmethane, symmetric 1,1-diacylals and mixed 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as moisture stable O-formylating and O-acylating reagents for primary and secondary alcohols, allylic alcohols and phenols under solvent/catalyst free conditions to afford their corresponding esters in good yield.
- Chapman, Robert S.L.,Francis, Molly,Lawrence, Ruth,Tibbetts, Joshua D.,Bull, Steven D.
-
p. 6442 - 6452
(2018/10/02)
-
- Cyanomethyl anion transfer reagents for diastereoselective Corey-Chaykovsky cyclopropanation reactions
-
A readily available and bench-stable cyanomethyl sulfonium salt was used in highly diastereoselective Corey-Chaykovsky cyclopropanation reactions of electron-poor olefins. This efficient method provides a rapid route to access densely functionalized cyclopropyl nitriles.
- Hommelsheim, Renè,Hock, Katharina J.,Schumacher, Christian,Hussein, Mohanad A.,Nguyen, Thanh V.,Koenigs, Rene M.
-
supporting information
p. 11439 - 11442
(2018/10/20)
-
- Synthesis method of terminal olefin type compound
-
The invention discloses a synthesis method of a terminal olefin type compound. The synthesis method comprises the following steps: taking a phosphorus ylide compound as a raw material and carbon dioxide as a C1 synthon in an organic solvent; reacting in the presence of a reducing agent to prepare the terminal olefin type compound, wherein the mole ratio of the phosphorus ylide compound to the reducing agent is 1 to (1 to 6) and the pressure of carbon dioxide is 1 to 3atm. The synthesis method disclosed by the invention has the advantages of convenience for operation, moderate conditions, widesubstrate applicable range and high efficiency; the defects in the prior art are filled; the synthesis method takes the carbon dioxide as synthon and carbon dioxide can be effectively absorbed so thata greenhouse effect is effectively prevented.
- -
-
Paragraph 0040; 0041; 0044; 0045; 0046; 0048; 0049
(2018/09/21)
-
- Transition-Metal-Free Reductive Deoxygenative Olefination with CO2
-
A new transition-metal-free reductive deoxygenative olefination of phosphorus ylides with CO2, an abundant and sustainable C1 chemical feedstock, is described. This catalytic CO2 fixation afforded β-unsubstituted acrylates and vinyl ketones in good yields with broad scope and good functional group tolerance under mild reaction conditions. Cost-effective and easily handled polymethylhydrosiloxane was used as a reductant. Bis(silyl)acetal was proved to be the key intermediate in this reductive functionalization of CO2.
- Zhu, Dao-Yong,Li, Wen-Duo,Yang, Ce,Chen, Jie,Xia, Ji-Bao
-
supporting information
p. 3282 - 3285
(2018/06/11)
-
- Enhanced Acrylate Production from 2-Acetoxypropanoic Acid Esters
-
Reaction conditions and reactor geometry for producing acrylates in high yield from lactic acid-derived 2-acetoxypropanoic acid (APA) esters are presented. An acrylate ester yield of 75% is achieved from methyl and benzyl APA esters at 550 °C in a fixed bed reactor filled with nonporous silica particles, carbon dioxide as a diluent gas, and acetic acid as a co-feed with the APA ester. The yield from methyl and benzyl APA esters is remarkably higher than from ethyl or butyl esters of APA, which have hydrogen atoms on the β-carbon of the ester functional group and thus can undergo alkene elimination, leading to reduced acrylate yield. Under optimum conditions, APA conversion to acrylates is stable over 30 h of continuous operation with little carbon deposition on the contact material.
- Nezam, Iman,Peereboom, Lars,Miller, Dennis J.
-
p. 715 - 719
(2017/05/29)
-
- PRODUCTION METHOD OF MONOFUNCTIONAL (METH)ACRYLATE
-
PROBLEM TO BE SOLVED: To provide a production method of monofunctional(meth)acrylate in which a monofunctional (meth)acrylate can be produced with low in color tone and good in yield by conducting transesterification of (meth)acrylate and monohydric alcohol. SOLUTION: In the production method of monofunctional (meth)acrylate, the following catalyst A and catalyst B are used together for the production of monofunctional (meth)acrylate by conducting transesterification of (meth)acrylate and monohydric alcohol. The catalyst A is one or more compound selected from the group consisting of a cyclic tertiary amine having an azabicyclo structure or a salt or complex thereof, an amidine or a salt or complex thereof, a compound having a pyridine ring or a salt or complex thereof, and a compound having a tertiary diamine structure or a salt or complex thereof. The catalyst B is one or more compounds selected from the group consisting of compounds containing zinc. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2017,JPO&INPIT
- -
-
Paragraph 0057; 0059; 0060
(2017/11/14)
-
- NOVEL SINGLE STEP ESTERIFICATION PROCESS OF ALDEHYDES USING A HETEROGENEOUS CATALYST
-
The present invention relates to a novel simple, efficient and single-step process for esterification of aldehydes using a heterogeneous catalyst with high yields. More particularly, the present invention relates to a novel simple, efficient and single-step process for esterification of aldehydes using Titanium superoxide with greater than 80% yields.
- -
-
Page/Page column 9; 14
(2016/06/20)
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- Chemoselective Transesterification of Acrylate Derivatives for Functionalized Monomer Synthesis Using a Hard Zinc Alkoxide Generation Strategy
-
A new practical method for the synthesis of functionalized acrylate derivatives with the view to prepare functional polymers was explored. Hard zinc alkoxide generation enabled the highly chemoselective transesterification of acrylate derivatives over the undesired conjugate addition, which caused polymerization. The combined use of the catalytic zinc cluster Zn4(OCOCF3)6O and 4-(dimethylamino)pyridine delivered various functionalized acrylate derivatives through the transesterification of commercially available methyl acrylate derivatives with functionalized alcohols under mild conditions.
- Nakatake, Daiki,Yazaki, Ryo,Ohshima, Takashi
-
supporting information
p. 3696 - 3699
(2016/08/20)
-
- Synthesis and Characterization of Poly(glyceric Acid Carbonate): A Degradable Analogue of Poly(acrylic Acid)
-
The synthesis and characterization of a degradable version of poly(acrylic acid), poly(glyceric acid carbonate), are reported. Specifically, atactic and isotactic poly(benzyl glycidate carbonate)s are obtained via the ring-opening copolymerization of rac-/(R)-benzyl glycidate with CO2 using a bifunctional rac-/(S,S)-cobalt salen catalyst in high carbonate linkage selectivity (>99%) and polymer/cyclic carbonate selectivity (~90%). Atactic poly(benzyl glycidate carbonate) is an amorphous material with a Tg (glass transition temperature) of 44 °C, while its isotactic counterpart synthesized from enantiopure epoxide and catalyst is semicrystalline with a Tm (melting temperature) = 87 °C. Hydrogenolysis of the resultant polymers affords the poly(glyceric acid carbonate). Poly(glyceric acid carbonate) exhibits an improved cell cytotoxicity profile compared to poly(acrylic acid). Poly(glyceric acid carbonate)s also degrade remarkably fast (t1/2 ≈ 2 weeks) compared to poly(acrylic acid). Cross-linked hydrogels prepared from poly(glyceric acid carbonate) and poly(ethylene glycol) diaziridine show significant degradation in pH 8.4 aqueous buffer solution compared to similarly prepared hydrogels from poly(acrylic acid) and poly(ethylene glycol) diaziridine.
- Zhang, Heng,Lin, Xinrong,Chin, Stacy,Grinstaff, Mark W.
-
supporting information
p. 12660 - 12666
(2015/10/20)
-
- 1,4-Diazabicyclo[2.2.2]octane-Promoted Aminotrifluoromethylthiolation of α,β-Unsaturated Carbonyl Compounds: N-Trifluoromethylthio-4-nitrophthalimide Acts as Both the Nitrogen and SCF3 Sources
-
A novel difunctionalization reaction is described. It uses N-trifluoromethylthio-4-nitrophthalimide as the reagent, which serves as both the nitrogen and SCF3 sources. In the presence of DABCO (1,4-diazabicyclo[2.2.2]octane), the nitrogen and SCF3 groups can be incorporated into α,β-unsaturated carbonyl compounds easily and give versatile β-amino ketones and esters in good yields. This difunctionalization reaction features mild reaction conditions, high atom-economy, and efficient access to α-SCF3 amino acids.
- Xiao, Qing,He, Qijie,Li, Juncheng,Wang, Jun
-
supporting information
p. 6090 - 6093
(2016/01/09)
-
- Titanium superoxide-a stable recyclable heterogeneous catalyst for oxidative esterification of aldehydes with alkylarenes or alcohols using TBHP as an oxidant
-
Titanium superoxide efficiently catalysed the oxidative esterification of aldehydes with alkylarenes or alcohols, under truly heterogeneous conditions, to afford the corresponding benzyl and alkyl esters in excellent yields. Mechanistic studies have established that this "one pot" direct oxidative esterification process proceeds through a radical pathway, proven by a FTIR spectral study of a titanium superoxide-aldehyde complex as well as spin trapping experiments with TEMPO. The intramolecular version of this protocol has been successfully demonstrated in the concise synthesis of 3-butylphthalide, an anti-convulsant drug.
- Dey, Soumen,Gadakh, Sunita K.,Sudalai
-
p. 10631 - 10640
(2015/11/17)
-
- PROCESS FOR PREPARING 4-HYDROXYBUTYL ACRYLATE
-
A process for preparing 4-hydroxybutyl acrylate by transesterifying an alkyl acrylate with 1,4-butanediol in the presence of a dialkyltin oxide such that each of the alkyl groups has 4 to 8 carbon atoms, characterized in that the amount of the dialkyltin oxide is adjusted to 0.00001 to 0.01 moles per one mole of the alkyl acrylate.
- -
-
Paragraph 0625; 0626; 0627; 0628; 0629
(2015/04/22)
-
- Highly stereoselective cyclopropanation of α,β-unsaturated carbonyl compounds with methyl (diazoacetoxy)acetate catalyzed by a chiral ruthenium(II) complex
-
Tantalizing triangles: The title reaction gives bicarbonyl cyclopropane products that can lead to versatile intermediates with high yields and stereoselectivities. This system was also applied to the enantioselective total synthesis of spiro cyclopropane oxindole, an HIV-1 nonnucleoside reverse transcriptase inhibitor. Copyright
- Chanthamath, Soda,Takaki, Suguru,Shibatomi, Kazutaka,Iwasa, Seiji
-
supporting information
p. 5818 - 5821
(2013/07/11)
-
- Macroscopic self-assembly based on molecular recognition: Effect of linkage between aromatics and the polyacrylamide gel scaffold, amide versus ester
-
The interactions of polyacrylamide- (pAAm-) based gels possessing cyclodextrin (CD) residues (CD-gels) with pAAm-based gels modified with aromatic residues through amide and ester linkages (ArA-gels and ArE-gels, respectively) were investigated to examine the effect of linkage (i.e., amide and ester) between aromatic residues and the pAAm gel scaffold. In the present study, benzyl (Bz), 2-naphthylmethyl (Np), 9-phenanthrylmethyl (Ph), and 1-pyrenylmethyl (Py) residues were chosen as a series of aromatic residues. αCD-gel did not interact notably with the ArA-gels and ArE-gels in water. βCD-gel interacted with the ArA-gels and ArE-gels possessing smaller aromatic residues (i.e., Bz and Np residues) in water to form gel assemblies. γCD-gel showed different tendencies of its interactions with the ArA-gels and with the ArE-gels; γCD-gel interacted with the ArA-gels carrying larger aromatic residues (i.e., Ph and Py residues), while γCD-gel formed stable gel assemblies only with NpE-gel among the ArE-gels examined. This is because γCD residues in γCD-gel included favorably dimeric aromatic residues in the ArA-gels and ArE-gels. Reflection fluorescence spectra for the ArA-gels and ArE-gels possessing fluorescent aromatic residues (i.e., Np, Ph, and Py residues) in the presence of 10 mM γCD were indicative of weak selectivities of γCD toward NpE, PhA, and PyA residues. Such weak selectivities may be largely enhanced in the macroscopic observation of interaction of CD-gels with the ArA-gels and ArE-gels presumably because of multivalency.
- Hashidzume, Akihito,Zheng, Yongtai,Takashima, Yoshinori,Yamaguchi, Hiroyasu,Harada, Akira
-
p. 1939 - 1947
(2013/04/24)
-
- A lewis acid-promoted pinner reaction
-
Carbonitriles and alcohols react in a Lewis acid-promoted Pinner reaction to carboxylic esters. Best results are obtained with two equivalents of trimethylsilyl triflate as Lewis acid. Good yields are achieved with primary alcohols and aliphatic or benzylic carbonitriles, but the straightforward synthesis of acrylates and benzoates starting with acrylonitrile and benzonitrile, respectively, is similarly possible. Phenols are not acylated under these reaction conditions. The method has been used for the first total synthesis of the natural product monaspilosin. In the reaction of benzyl alcohols variable amounts of amides are formed in a Ritter-type side reaction.
- Pfaff, Dominik,Nemecek, Gregor,Podlech, Joachim
-
supporting information
p. 1572 - 1577
(2013/10/22)
-
- A new method using 2-chloro-4,6-dimethoxy-1,3,5-triazine for facile elimination of dimethylamino group in Eschenmoser's methylenation for synthesis of α,β-unsaturated esters
-
A facile one-step method for the elimination of the dimethylamino group in Eschenmoser's methylenation has been developed using a combination of 2-chloro-4,6-dimethoxy-1,3,5-triazine and triethylamine. The chemoselective elimination of the dimethylamino group occurred in compounds possessing either a diethylamino group or an alkylsulfanyl group.
- Yamada, Kohei,Masaki, Kazumasa,Hagimoto, Yuri,Kamiya, Seina,Kunishima, Munetaka
-
p. 1758 - 1760
(2013/03/29)
-
- Radical mechanism in the elimination of 2-arylsulfinyl esters
-
The mechanism of the dehydrosulfenylation of 2-arylsulfinyl esters was investigated. The reaction was found to follow a homolytic cleavage mechanism as verified by electrospray ionization tandem mass spectrometry and experimental work. Rearranged sulfoxides are obtained as byproduct during the elimination reaction.
- Latorre, Antonio,Lopez, Irakusne,Ramirez, Victoria,Rodriguez, Santiago,Izquierdo, Javier,Gonzalez, Florenci V.,Vicent, Cristian
-
p. 5191 - 5197
(2012/07/27)
-
- Use of diethoxymethane as a solvent for phase-transfer esterification of carboxylic acids
-
The esterification of carboxylic acids with selected primary alkyl halides in diethoxymethane (DEM) utilizing solid-liquid phase-transfer catalysis has been studied. The use of DEM as the solvent simplifies the process in that a single solvent can be used for both reaction and workup.
- Coleman, M. Todd
-
scheme or table
p. 1911 - 1913
(2012/06/04)
-
- Nickel-catalyzed synthesis of 1,3,5-trisubstituted hydantoins from acrylates and isocyanates
-
One molecule of acrylate reacts with two molecules of isocyanate in the presence of a nickel(0)/SIPr catalyst to give a 1,3,5-trisubstituted hydantoin. Two processes operate in sequence, the first, regioselective formation of N-substituted fumaramate from acrylate and isocyanate and, the second, ring closure of the fumaramate with incorporation of another molecule of isocyanate.
- Miura, Tomoya,Mikano, Yusuke,Murakami, Masahiro
-
supporting information; experimental part
p. 3560 - 3563
(2011/09/16)
-
- Synthesis of water-soluble first generation janus-type dendrimers bearing Asp oligopeptides and naproxen
-
To construct a water-soluble and bone-targeting non-steroidal anti-inflammatory dendritic drug carrier, a series of Asp oligopeptides and naproxen based poly amido-ester Janus dendrimers were synthesized using a conventional method and their water solubility was preliminary evaluated. The corresponding small dendritic linkers contain two or three drug moieties on the surface and two or three oligopeptides groups at the focal terminus. This design provided an effective entry for the synthesis of multiple drug carriers with water-soluble and bone-targeting.
- Ouyang, Liang,Ma, Lifang,Li, Yanhua,Pan, Junzhu,Guoa, Li
-
scheme or table
p. 256 - 266
(2010/08/07)
-
- Synthesis and biological evaluation of pyrazoline analogues with β-amino acyl group as dipeptidyl peptidase IV inhibitors
-
A series of pyrazoline derivatives with β-amino acyl group were synthesized and evaluated for their ability to inhibit dipeptidyl peptidase IV. Several pyrazoline derivatives exhibited submicromolar inhibitory activities against DPP-IV. X-ray co-crystal structure of initial hit compound 1h was determined. Among this series, carboxylic acid substituted pyrazoline derivative 2u was the most active and greatly decreased the inhibitory activity toward CYP3A4 enzyme.
- Jun, Mi Ae,Park, Woul Seong,Kang, Seung Kyu,Kim, Ki Young,Kim, Kwang Rok,Rhee, Sang Dal,Bae, Myung Ae,Kang, Nam Sook,Sohn, Sang-Kwon,Kim, Sung Gyu,Lee, Jie Oh,Lee, Duck Hyung,Cheon, Hyae Gyeong,Kim, Sung Soo,Ahn, Jin Hee
-
p. 1889 - 1902
(2008/12/22)
-
- Ni-catalyzed mild arylation of α-halocarbonyl compounds with arylboronic acids
-
A simple yet powerful Ni catalyst can be used to promote direct arylations of α-halocarbonyl compounds, including a range of esters, amides, and ketones, with various arylboronic acids under mild conditions. The method tolerates β-hydrogens and functional groups in the substrates and offers reactivity and selectivity profiles that are complementary to those found in the well-established Buchwald-Hartwig approach.
- Liu, Chao,He, Chuan,Shi, Wei,Chen, Mao,Lei, Aiwen
-
p. 5601 - 5604
(2008/09/17)
-
- Convergent synthesis of internally branched PAMAM dendrimers
-
(Chemical Equation Presented) A series of aliphatic internally branched poly(amido amine) dendrons and dendrimers has been synthesized. The internal branching unit was 1,2-propanediamine and a series of PAMAM-type dendrons of the types AB2, AB4, and AB8 were built. These were anchored on a core molecule containing four carboxylic acid moieties and the 1,2-propanediamine unit resulted in PAMAM dendrimers with 4, 8, 16, and 32 end groups.
- Pittelkow, Michael,Christensen, Jorn B.
-
p. 1295 - 1298
(2007/10/03)
-
- Antimicrobial activity of p-hydroxyphenyl acrylate derivatives
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To estimate the antimicrobial effect of p-hydroxyphenyl acrylate (H5) derivatives on the basis of their molecular structure, the hydroxy and acryl groups of p-hydroxyphenyl acrylate were modified. The antimicrobial activity of the resulting compounds was assessed against a Gram-positive bacterium (Staphylococcus aureus), a Gram-negative bacterium (Pseudomonas aeruginosa), and fungi (Aspergillus fumigatus and Penicillium pinphilum) by the halo zone and the shake flask test. The antimicrobial activity of H5 was ascribed mainly to the acryl group. Compounds with acryl or acryloxy groups bound to the phenyl moiety were found to exhibit particularly high antimicrobial activities. The activities of phenyl acrylate and phenyl vinyl ketone were excellent as compared to aliphatic acrylates such as cyclohexyl acrylate and hexyl acrylate, indicating that the stereoelectronic effect of the phenyl group was important to the antimicrobial activity.
- Jung, Hee Kim,Park, Eun-Soo,Jae, Hun Shim,Kim, Mal-Nam,Moon, Woong-Sik,Chung, Kyoo-Hyun,Yoon, Jin-San
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p. 7480 - 7483
(2007/10/03)
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- Zn-promoted regioselective and sequence-selective one-pot joining reaction of three components: Alkyl iodides, α,β-unsaturated esters (or nitriles), and acylating agents
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One-pot treatment of alkyl iodides, α,β-unsaturated esters (or nitriles), and acylating agents such as nitriles or acid anhydrides in the presence of Zn metal at room temperature in the same reaction system brought about a regioselective and sequence-selective three-component joining reaction involving first C-alkylation at the β-position and second C-acylation at the α-position of α,β-unsaturated esters (or nitriles) to afford the corresponding α,α-dialkylketoesters (or α,α-dialkylketonitriles) in moderate to good yields.
- Yamamoto, Yoshimasa,Nakano, Seiji,Maekawa, Hirofumi,Nishiguchi, Ikuzo
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p. 799 - 802
(2007/10/03)
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- PROCESS FOR MAKING ORGANIC PRODUCTS FROM NON-PRODUCT STREAMS USING A CATALYST
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A method for preparing a product from non-product streams, such as waste or byproduct liquid streams, uses a phase transfer catalyst to enhance the reaction between two or more constituents each from a separate non-product stream. Since the non-product streams have different phases, a phase transfer catalyst may be used to transfer a chemical species from the aqueous phase to the organic phase where it will react. In one embodiment, the aqueous solution is contacted with an electrophile and a phase transfer catalyst and, optionally, a pH adjusting agent in the event that the chemical species in the aqueous solution needs to be ionized. A method for continuously preparing a product involves carrying out two processes providing two non-product streams, then contacting the two non-product streams in the presence of a phase transfer catalyst, then separating the aqueous phase from the organic phase, and then dividing the organic phase into the product and the phase transfer catalyst, which is then recycled or discarded. The catalyst can also remain in the aqueous phase and be discarded from there.
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Page/Page column 16
(2008/06/13)
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- Efficient transesterification/acylation reactions mediated by N-heterocyclic carbene catalysts
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Imidazol-2-ylidenes, a family of N-heterocyclic carbenes (NHC), are efficient catalysts in the transesterification involving numerous esters and alcohols. Low catalyst loadings of aryl- or alkyl-substituted NHC catalysts mediate the acylation of alcohols with enol acetates in short reaction times at room temperature. Commercially available and more difficult to cleave methyl esters react with primary alcohols in the presence of alkyl-substituted NHC to efficiently form the corresponding esters. While primary alcohols are selectively acylated over secondary alcohols with use of enol esters as acylating agents, methyl and ethyl esters can be employed as protective agents for secondary alcohols in the presence of the more active alkyl-substituted NHC catalysts. The NHC-catalyzed transesterification protocol was simplified by generating the imidazol-2-ylidene catalysts in situ.
- Grasa, Gabriela A.,Gueveli, Tatyana,Singh, Rohit,Nolan, Steven P.
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p. 2812 - 2819
(2007/10/03)
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- Asymmetric synthesis of the cis- and trans-3,4-dihydro-2,4,8-trihydroxynaphthalen-1(2H)-ones
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A short and efficient protocol for the asymmetric synthesis of cis- and trans-3,4-dihydro-2,4,8-trihydroxynaphthalen-1(2H)-one (1 and 2, resp.) is described, with a phthalide annulation as the key step. Introduction of a OH substituent at position 2 was performed by Sharpless dihydroxylation of a silyl enol ether or by means of an N-sulfonyloxaziridine. The absolute configuration of each isomer was determined via Mosherester derivatives. By comparison with previously recorded CD spectra of our natural sample, we established that the natural trans- and cis-isomers from Ceratocystis fimbriata sp. platani were the (-)-(2S,4S)-isomer (-)-2 and the (+)-(2S,4R)-isomer (+)-1, respectively.
- Couche, Emmanuel,Fkyerat, Abdellatif,Tabacchi, Raffaele
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p. 210 - 221
(2007/10/03)
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- Diacid-substituted heteroaryl derivatives as matrix metalloproteinase inhibitors
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The invention provides dicarboxylic acid-substituted heteroaryl derivatives of the formula G1-(C(R1)R2)n-Q1-B-Q2-(C(R3)R4)m-G2??I or a pharmaceutically acceptable salt thereof, wherein G1, G2, R1, R2, R3, R4, n, m, Q1, Q2, and B are as defined in the specification. The invention compounds are inhibitors of matrix metalloproteinase enzymes, including MMP-13. This invention also provides pharmaceutical compositions and methods of treating diseases mediated by MMP-13, including arthritis, asthma, heart disease, atherosclerosis, and osteoporosis, or a pharmaceutically acceptable salt thereof.
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- Triphenylphosphine-catalysed conversion of maleic anhydride into acrylate esters
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Maleic anhydride has been converted into a range of acrylate esters on treatment with a suitable alcohol using triphenylphosphine as a catalyst.
- Adair, Gareth R. A.,Edwards, Michael G.,Williams, Jonathan M. J.
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p. 5523 - 5525
(2007/10/03)
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- N-heterocyclic carbenes as versatile nucleophilic catalysts for transesterification/acylation reactions
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(graph presented) Imidazol-2-ylidenes, a family of N-heterocyclic carbones (NHC), are efficient catalysts in the transesterification between esters and alcohols. Low catalyst loadings of aryl-or alkyl-substituted NHC catalysts mediate the acylation of alcohols with vinyl acetate in convenient reaction times at room temperature. Commercially available and more difficult to cleave methyl esters react with numerous alcohols in the presence of alkyl-substituted NHC to form efficiently the corresponding esters in very short reaction times.
- Grasa, Gabriela A.,Kissling, Rebecca M.,Nolan, Steven P.
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p. 3583 - 3586
(2007/10/03)
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- Diastereoselective Diels-Alder reactions of α-fluorinated α,β-unsaturated carbonyl compounds: Chemical consequences of fluorine substitution. 2
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Two α-fluoro α,β-unsaturated carbonyl compounds, i.e., benzyl 2-fluoroacrylate (3) and 2-fluorooct-1-en-3-one (4), as well as the corresponding nonfluorinated parent compounds, were synthesized and subjected to Diels-Alder reactions with cyclopentadiene. The cycloadditions were conducted thermally, microwave-assisted, and Lewis acid-mediated (TiCl4). The fluorinated dienophiles exhibited a lower reactivity and exo diastereoselectivity, while the corresponding nonfluorinated parent compounds reacted endo selectively. DFT calculations suggest that kinetic effects of fluorine determine the stereoselectivity rather than higher thermodynamic stability of the exo products.
- Essers, Michael,Mueck-Lichtenfeld, Christian,Haufe, Guenter
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p. 4715 - 4721
(2007/10/03)
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- Direct ester condensation from a 1:1 mixture of carboxylic acids and alcohols catalyzed by hafnium(IV) or zirconium(IV) salts
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To promote atom efficiency in synthesis and to avoid the generation of environmental waste, the use of stoichiometric amounts of condensing reagents or excess substrates should be avoided. In esterification, excess amounts of either carboxylic acids or alcohols are normally needed. We found that the direct condensation of equimolar amounts of carboxylic acids and alcohols could be achieved using hafnium(IV) or zirconium(IV) salts. These metal salts are highly effective as catalysts for the selective esterification of primary alcohols with carboxylic acids in the presence of secondary alcohols or aromatic alcohols. The present methods can be applied to direct polyesterification and may be suitable for large-scale operations.
- Ishihara, Kazuaki,Nakayama, Masaya,Ohara, Suguru,Yamamoto, Hisashi
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p. 8179 - 8188
(2007/10/03)
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- Intramolecular C-H insertion reactions of (η5-Cyclopentadienyl)dicarbonyliron carbene complexes: Scope of the reactions and application to the synthesis of (±)-sterpurene and (±)-pentalenene
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(η5-Cyclopentadienyl)dicarbonyliron carbene complexes, [(η5C5H5) (CO)2Fe=CHR]+BF4-, are generated as reactive intermediates from thioether derivatives, (η5-C5H5)(CO)2FeCH(R)SPh, by S-alkylation with trimethyloxonium tetrafluoroborate and loss of thioanisole. The carbene complexes undergo intramolecular C-H insertion into appropriately situated side chains to form cyclopentane derivatives. The reaction has been developed into a general procedure employing cycloalkanones as scaffolds bearing the iron carbene moieties and the side chains at C(2) and C(3), respectively. The products of the intramolecular insertion reactions are substituted bicyclo[n.3.0]alkanones. The scope and limitations of the reaction are described. The reaction is applied to a total synthesis of sterpurene and to a formal synthesis of pentalenene. Overall, this approach to cyclopentane annulation complements the related metal-catalyzed insertion reactions of diazocarbonyl compounds, which are also believed to occur via metal carbene complexes.
- Ishii,Zhao,Mehta,Knors,Helquist
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p. 3449 - 3458
(2007/10/03)
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- Highly Selective Acylation of Alcohols Using Enol Esters Catalyzed by Iminophosphoranes
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The iminophosphorane bases PhCH2N=P(MeNCH2CH2)3N and PhCH2N=P(NMe2)3 catalyze the acylation of primary alcohols with enol esters in excellent yields and in high selectivity. It was found that acid labile groups such as acetal and epoxide survive under the reaction conditions. Groups such as TBS and disulfide, which undergo cleavage in the presence of Ac2O and the Lewis acid Sc(OTf)3, are also unaffected. Diene, conjugated acetylene, oxazoline, nitro, and benzodioxane groups are also compatible with our catalyst/reagent system. Because secondary alcohols do not react under our conditions, our methodology is attractive for the selective acylation of primary alcohols. Polymer-supported iminophosphorane catalysts are also shown to be useful in these reactions, thus opening the possibility of wider applications.
- Ilankumaran, Palanichamy,Verkade, John G.
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p. 9063 - 9066
(2007/10/03)
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- Auxiliary accelerated reactions: Towards the use of catalytic chiral auxiliaries
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In competition experiments, the acceleration of reactivity of alkenes tethered to pyridyl groups compared with the corresponding alkenes tethered to phenyl groups in the presence of transition metals was demonstrated for two reaction types: Diels-Alder cycloaddition of enoate esters and catalytic hydrogenation of allylic and homoallylic ethers. The rate accelerations observed are of crucial importance in the development of a new concept for asymmetric catalysis: chiral auxiliaries which can function in a catalytic manner.
- Westwell, Andrew D.,Williams, Jonathan M. J.
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p. 13063 - 13078
(2007/10/03)
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- New methodology for the synthesis of unsaturated 8-, 9- and 10-membered lactams
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Unsaturated 8-, 9- and 10-membered medium ring lactams 1 (n = 1, 2, 3) have been prepared in good yield by the Claisen rearrangement of the vinyl-substituted precursors 3 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).
- Evans, P. Andrew,Holmes, Andrew B.,McGeary, Ross P.,Nadin, Alan,Russell, Keith,O'Hanlon, Peter J.,Pearson, Neil D.
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p. 123 - 138
(2007/10/03)
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- Radical cycloaddition by nickel(II) complex-catalyzed electroreduction. A method for preparation of pyrrolopyridine and pyrrolopyrrole derivatives
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Cycloalkano[a]pyrroles were obtained by reductive radical cycloaddition of 1-(2-iodoethyl)pyrrole and activated olefins or by cyclization of 1-(ω- iodoalkyl)pyrroles, through electroreduction of the iodides using nickel(II) complex as an electron-transfer catalyst.
- Ozaki, Shigeko,Mitoh, Shizue,Ohmori, Hidenobu
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p. 2020 - 2024
(2007/10/03)
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