- Synthesis and tautomerism of substituted pyrazolo[4,3-c]pyrazoles
-
Fused five-membered nitrogen heterocycles comprise a very important group of compounds frequently utilized in pharmaceutical applications. In this study, we report the first systematic synthesis of substituted pyrazolo[4,3-c]pyrazoles and three regioisomers of their N-methyl derivatives. All compounds were fully characterized by NMR spectroscopy in solution and selected compounds also were studied by X-ray diffraction in the solid state. 1H, 13C, and 15N NMR spectroscopic data for all isomers were interpreted by DFT calculations of nuclear shielding constants and indirect spin-spin coupling constants. The N-methyl isomers were used in the following steps as model compounds to investigate a potential N1-H/N4-H, N2-H/N4-H, and N1-H/N5-H tautomerism of 3,6-substituted pyrazolo[4,3-c]pyrazoles by using low-temperature NMR spectroscopy. All bases were shown to occur predominantly in the N1-H/N4-H tautomeric form and the structure of minor form was governed by the substituents at positions 3 and 6. Stabilities of individual tautomeric forms are calculated by DFT methods and discussed. A relationship between the tautomeric populations and the ratios among N-methyl isomers obtained upon methylation of selected bases in solution are investigated. The stability of various tautomeric forms of substituted pyrazolo[4,3-c]pyrazoles characterized by low-temperature NMR spectroscopy can be qualitatively explained by electronic and steric effects of substituents in positions 3 and 6 in individual tautomers, as revealed by the DFT calculations. Copyright
- Kadam, Shivaji S.,Maier, Lukas,Kostakis, Ioannis,Pouli, Nicole,Tousek, Jaromir,Necas, Marek,Marakos, Panagiotis,Marek, Radek
-
-
Read Online
- REFORMATSKY INTERMEDIATE. A C-METALLED SPECIES.
-
13C-NMR and 1H-NMR spectra of the Reformatsky reagent from t-butylbromoacetate, evidence a C-metalled species: within the limits of detectability of the methods, no O-metallated species can be detected in solution.
- Orsini, F.,Pelizzoni, F.,Ricca, G.
-
-
Read Online
- UV-Vis spectroscopic studies of solute-solvent and solute-cosolvent interactions in supercritical carbon dioxide
-
The keto-enol tautomeric equilibria of ethyl acetoacetate in supercritical (SC) CO2 with and without ethanol cosolvent were investigated over the pressure range from 75.9 to 185 bar at 308.2 K using UV-Vis spectroscopy. In order to obtain the local densities of solvent and cosolvent about the solute, we correlated the standard Helmholtz free energy of the tautomerization with a solvent parameter based on the Onsager reaction field theory. In both SC CO2 and SC CO2-ethanol, the local density enhancement of CO2 in the vicinity of the solute is most remarkable at the reduced density close to unity. The highest degree of aggregation of cosolvent about the solute takes place at the lowest pressure investigated, which is slightly above the critical pressure. Moreover, the clustering of ethanol with the solute competes with that of CO2. In addition, the local concentration enhancement of ethanol was studied in the concentration range of 0 to 6 mol%. It was found that the local concentration of ethanol is enhanced significantly at lower cosolvent concentrations.
- Lu, Jie,Han, Buxing,Yan, Haike
-
-
Read Online
- Palladium-catalyzed synthesis of N-vinyl pyrroles and indoles
-
A stereospecific palladium-catalyzed N-vinylation of aza-heterocycles with vinyl inflates is described. Cyclic and acyclic vinyl triflates along with nonnucleophilic azaheterocycles were found to be substrates for this palladium-catalyzed synthesis of N-vinyl pyrrole and indole derivatives.
- Movassaghi, Mohammad,Ondrus, Alison E.
-
-
Read Online
- Diastereoselective Formal Synthesis of Polycyclic Meroterpenoid (±)-Cochlearol A
-
A formal synthesis of (±)-cochlearol A was accomplished. The synthesis features Suzuki coupling and Friedel-Crafts cyclization as a convergent strategy to the functionalized tetralone ring and an intramolecular construction of the C/D ring involving seque
- Venkatesh, Telugu,Mainkar, Prathama S.,Chandrasekhar, Srivari
-
-
Read Online
- Revisiting ageless antiques; synthesis, biological evaluation, docking simulation and mechanistic insights of 1,4-Dihydropyridines as anticancer agents
-
The historic DHP nucleus was serendipitously discovered by Arthur Hantzsch about 130 years ago and is still considered a hidden treasure for various pharmacological activities. Twenty-one DHP analogues were synthesized using the expedient one pot Hantzsch synthesis for screening as anticancer agents. Initially, the in vitro anti-proliferative single dose against a panel of 18 cancer cell lines showed that compounds 11b and 8f were the superlative candidates regarding their antitumor effect (GI% mean = 66.40% and 50.42%, correspondingly) compared to cisplatin (GI% mean = 65.58%) and doxorubicin (GI% mean = 74.56%). Remarkably, compound 11b showed a remarkable MDA-MB-468 anticancer activity (GI%=80.81%), higher than cisplatin (64.44%) and doxorubicin (76.72%), as well as strong antitumor activity against lung cancer A549 (GI%= 83.02%), more powerful than both cisplatin and doxorubicin. Compound 11b exhibited an exceptional anticancer activity against lung cancer cell line (A549) as its GI50 in nanomolar was (540 nM) with a 9-fold increase greater than cisplatin (GI50 = 4.93 μM) and with a selectivity index = 131 to cancer cells over normal cells. Further mechanistic investigations proved that DHPs anticipate simultaneously TOPI and RTKs (VEGFR-2, HER-2 and BTK) which can stimulate BAX/BAK and the executioner caspases via rtPCR studies.
- Sidhom, Peter A.,El-Bastawissy, Eman,Salama, Abeer A.,El-Moselhy, Tarek F.
-
supporting information
(2021/06/21)
-
- Electrochemical Oxidative Cyclization: Synthesis of Polysubstituted Pyrrole from Enamines
-
A conceptually novel method for the preparation of pyrrole is described by electrochemical-oxidation-induced intermolecular annulation via enamines. In a simple undivided cell, based on a sodium acetate-facilitated, polysubstituted pyrrole derivations has been facilely synthesized under external oxidant-free condition. This electrosynthetic approach providing an environmentally benign protocol for C?C bond cross-coupling and oxidative annulation, which features unparalleled broad scope of substrates and practicality.
- Chen, Zhiwei,Shi, Guang,Tang, Wei,Sun, Jie,Wang, Wenxing
-
supporting information
p. 951 - 955
(2021/02/03)
-
- A straightforward synthesis of 5-sulfonamidomethyl substituted 4,7-dihydroazolo[1,5-a]pyrimidines
-
4,7-Dihydroazolo[1,5-a]pyrimidin-5-ylmethanesulfonamides are side-products of the three-component Biginelli-like reaction of aminoazoles, aldehydes and N,N-dialkyl-2-ketomethanesulfonamides. Herein, we report a straightforward synthesis of 5-sulfonamidomethyl substituted 4,7-dihydroazolo[1,5-a]pyrimidines by a two-component condensation of aminoazoles and N,N-dialkyl(cinnamoyl)methanesulfonamides in DMF at reflux. The starting N,N-dialkyl-2-ketomethanesulfonamides can be obtained by either lithiation of N,N-dialkylmethanesulfonamides and reaction with aldehydes followed by oxidation of the resulting alcohols or by Claisen condensation of N,N-dialkylmethanesulfonamides with the corresponding esters. The chemical structures of all synthesized compounds are supported by 1H and 13C NMR-spectroscopy, mass spectrometry and elemental analysis.
- Shvets, Elena H.,Pidvorotnia, Anastasiia V.,Kulyk, Olesia G.,Mazepa, Alexander V.,Kolosov, Maksim A.
-
p. 114 - 122
(2020/10/02)
-
- Amide/Ester Cross-Coupling via C-N/C-H Bond Cleavage: Synthesis of β-Ketoesters
-
Activated primary, secondary, and tertiary amides were coupled with enolizable esters in the presence of LiHMDS to obtain good yields of β-ketoesters at room temperature. Notably, this protocol provides an efficient, mild, and high chemoselectivity method
- Chen, Jiajia,Joseph, Devaneyan,Xia, Yuanzhi,Lee, Sunwoo
-
p. 5943 - 5953
(2021/04/02)
-
- Nimodipine impurity IV reference substance as well as preparation method and application thereof
-
The invention discloses a nimodipine impurity IV reference substance and a preparation method thereof. The method includes the steps that diketene, ethyl alcohol and triethylamine are taken and addedinto a container to be heated and cooled, reaction liquid is washed with water, washing liquid is discarded, anhydrous sodium sulfate is added and placed overnight, filtrate is obtained after filtration, ammonia gas is introduced into the filtrate until the filtrate is saturated, and the nimodipine impurity IV reference substance is obtained; and after the reaction is finished, m-nitrobenzaldehyde, methoxyethyl acetoacetate and ethanol are added, heating refulx is performed, the mixture is cooled and filtered, the solvent is removed through volatilization in a water bath to obtain a yellow viscous liquid, and recrystallization is carried out to obtain a yellow acicular crystal, namely the nimodipine impurity IV reference substance. The invention also discloses an application of the nimodipine impurity IV reference substance in nimodipine tablet consistency evaluation. According to the preparation method, the impurity IV can be prepared in a general analysis laboratory, special preparation equipment is not needed, the operation is simple, the purity of the obtained impurity reference substance can reach 98.4%, the purity requirement of the reference substance is met, and the preparation method can be used for consistency evaluation of the variety.
- -
-
Paragraph 0064-0065
(2020/11/22)
-
- Transesterification of Methyl 2-Nitroacetate to Superior Esters
-
Methyl 2-nitroacetate and methyl acetoacetate have in common the presence of an electron-withdrawing substituent geminal to the methyl ester function but the well-known ease of thermal transesterification of methyl acetoacetate has not been found in methyl 2-nitroacetate. The latter gives uncatalysed thermal transesterification only in low yield and at a temperature higher than that of methyl acetoacetate. Comparative experiments provided further insight into the reactions; protic and Lewis acid catalysts promoted the smooth exchange of the alkanoyl groups, observing first the transesterification of methyl 2-nitroacetate with ethanol, already proved difficult to proceed. Dibutyltin(IV)oxide (DBTO) catalyst offered the spur to set up a convenient synthetic methodology from methyl 2-nitroacetate, encompassing higher molecular weight and functionalised alcohols: aliphatic, unsaturated and oxidation sensitive species were suited to react, delivering the corresponding 2-nitroacetate esters in good yields in most cases.
- Corsi, Massimo,Machetti, Fabrizio,Magnolfi, Stefano
-
-
- MnO2as a terminal oxidant in Wacker oxidation of homoallyl alcohols and terminal olefins
-
Efficient and mild reaction conditions for Wacker-type oxidation of terminal olefins of less explored homoallyl alcohols to β-hydroxy-methyl ketones have been developed by using a Pd(ii) catalyst and MnO2 as a co-oxidant. The method involves mild reaction conditions and shows good functional group compatibility along with high regio- and chemoselectivity. While our earlier system of PdCl2/CrO3/HCl produced α,β-unsaturated ketones from homoallyl alcohols, the present method provided orthogonally the β-hydroxy-methyl ketones. No overoxidation or elimination of benzylic and/or β-hydroxy groups was observed. The method could be extended to the oxidation of simple terminal olefins as well, to methyl ketones, displaying its versatility. An application to the regioselective synthesis of gingerol is demonstrated.
- Fernandes, Rodney A.,Ramakrishna, Gujjula V.,Bethi, Venkati
-
p. 6115 - 6125
(2020/10/27)
-
- Method for preparing ethyl acetoacetate
-
The invention belongs to the field of preparation of chemical intermediates, and concretely relates to a method for preparing ethyl acetoacetate. The ethyl acetoacetate is synthesized by using KF-Al2O3 as a catalyst and DMF as a solvent. The preparation method has the advantages of high yield reaching 88%, low prices of raw materials, simplicity, operation, suitableness for industrial production,and broad prospect.
- -
-
Paragraph 0010-0015
(2019/07/10)
-
- Rapid and Multigram Synthesis of Vinylogous Esters under Continuous Flow: An Access to Transetherification and Reverse Reaction of Vinylogous Esters
-
An environmentally benign approach for the synthesis of vinylogous esters from 1,3-diketone and its reverse reaction under continuous-flow has been developed with alcohols in the presence of inexpensive Amberlyst-15 as a catalyst. This methodology is highly selective and general for a range of cyclic 1,3-dicarbonyl compounds which gives a library of linear alkylated and arylated vinylogous esters in good to excellent yield under solvent and metal free condition. Furthermore, the long-time experiment in a continuous-flow up to 40 h afforded 8.0 g of the vinylogous ester with turnover number (TON) = 28.6 and turnover frequency (TOF) = 0.715 h-1 using Amberlyst-15 as a catalyst. Furthermore, a continuous-flow sequential transetherification of vinylogous esters with various alcohols has been achieved in high yield. Reversibly, this vinylogous ester was deprotected or hydrolyzed into ketone using environmentally benign water as a solvent and Amberlyst-15 as a catalyst under continuous-flow process.
- Mohanta, Nirmala,Chaudhari, Moreshwar B.,Digrawal, Naveen Kumar,Gnanaprakasam, Boopathy
-
p. 1034 - 1045
(2019/05/24)
-
- TRICYCLIC PI3K INHIBITOR COMPOUNDS AND METHODS OF USE
-
Described herein are tricyclic compounds with phosphoinositide-3 kinase (PI3K) modulation activity or function having the Formula I structure: or stereoisomers, tautomers, or pharmaceutically acceptable salts thereof, and with the substituents and structural features described herein. Also described are pharmaceutical compositions and medicaments that include the Formula I compounds, as well as methods of using such PI3K modulators, alone and in combination with other therapeutic agents, for treating diseases or conditions that are mediated or dependent upon PI3K dysregulation.
- -
-
-
- Regio- and chemoselective rearrangement of terminal epoxides into methyl alkyl and aryl ketones
-
The development of the highly active pincer-type rhodium catalyst 2 for the nucleophilic Meinwald rearrangement of functionalised terminal epoxides into methyl ketones under mild conditions is presented. An excellent regio- and chemoselectivity is obtained for the first time for aryl oxiranes.
- Tian, Yingying,Jürgens, Eva,Kunz, Doris
-
supporting information
p. 11340 - 11343
(2018/10/31)
-
- Screening, synthesis, crystal structure, and molecular basis of 6-amino-4-phenyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles as novel AKR1C3 inhibitors
-
AKR1C3 is a promising therapeutic target for castration-resistant prostate cancer. Herein, an evaluation of in-house library discovered substituted pyranopyrazole as a novel scaffold for AKR1C3 inhibitors. Preliminary SAR exploration identified its derivative 19d as the most promising compound with an IC50 of 0.160 μM among the 23 synthesized molecules. Crystal structure studies revealed that the binding mode of the pyranopyrazole scaffold is different from the current inhibitors. Hydroxyl, methoxy and nitro group at the C4-phenyl substituent together anchor the inhibitor to the oxyanion site, while the core of the scaffold dramatically enlarges but partially occupies the SP pockets with abundant hydrogen bond interactions. Strikingly, the inhibitor undergoes a conformational change to fit AKR1C3 and its homologous protein AKR1C1. Our results suggested that conformational changes of the receptor and the inhibitor should both be considered during the rational design of selective AKR1C3 inhibitors. Detailed binding features obtained from molecular dynamics simulations helped to finally elucidate the molecular basis of 6-amino-4-phenyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles as AKR1C3 inhibitors, which would facilitate the future rational inhibitor design and structural optimization.
- Zheng, Xuehua,Jiang, Zan,Li, Xiaolin,Zhang, Chen,Li, Zhe,Wu, Yinuo,Wang, Xinhua,Zhang, Chao,Luo, Hai-bin,Xu, Jun,Wu, Deyan
-
supporting information
p. 5934 - 5943
(2018/11/23)
-
- Rhodium-catalyzed asymmetric hydrogenation of tetrasubstituted β-acetoxy-α-enamido esters and efficient synthesis of droxidopa
-
A rhodium-catalyzed asymmetric hydrogenation of challenging tetrasubstituted β-acetoxy-α-enamido esters was developed, giving chiral β-acetoxy-α-amido esters in high yields with excellent enantioselectivities (up to >99% ee). The products could be easily transformed to β-hydroxy-α-amino acid derivatives which are valuable chiral building blocks and a novel route for the synthesis of droxidopa was also developed.
- Guan, Yu-Qing,Gao, Min,Deng, Xu,Lv, Hui,Zhang, Xumu
-
supporting information
p. 8136 - 8139
(2017/07/24)
-
- Nickel-catalyzed enantioselective hydrogenation of β-(acylamino)acrylates: Synthesis of chiral β-amino acid derivatives
-
The nickel-catalyzed asymmetric hydrogenation of β-(acylamino)acrylates has been developed, affording chiral β-amino acid derivatives with excellent yields (95-99% yield) and enantioselectivities (97-99% ee). With the Ni-Binapine system, high enantioselectivities (98-99% ee) have also been obtained in the hydrogenation of Z/E isomeric mixtures of β-alkyl and β-aryl β-(acylamino)acrylates. The synthesis of chiral β-amino acid derivatives on a gram scale has also been achieved with 0.2 mol % catalyst loading.
- Li, Xiuxiu,You, Cai,Li, Shuailong,Lv, Hui,Zhang, Xumu
-
supporting information
p. 5130 - 5133
(2017/11/06)
-
- O -Iodoxybenzoic Acid (IBX)-Iodine Mediated One-Pot Deacylative Sulfonylation of 1,3-Dicarbonyl Compounds: A Synthesis of β-Carbonyl Sulfones
-
A combination of o-iodoxybenzoic acid (IBX) and a catalytic amount of iodine is found to promote a facile one-pot deacylative sulfonylation reaction of 1,3-dicarbonyl compounds with sodium sulfinates to yield β-carbonyl sulfones. The present method provides the target products bearing a wide variety of functional groups in one step and in good yields.
- Katrun, Praewpan,Songsichan, Teerawat,Soorukram, Darunee,Pohmakotr, Manat,Reutrakul, Vichai,Kuhakarn, Chutima
-
supporting information
p. 1109 - 1121
(2017/02/24)
-
- Preparation technology of novel naphthol AS-IRG (2,5-Dimethoxy-4-chloroacetoacetanilide)
-
The invention relates to a preparation technology of novel naphthol AS-IRG (2,5-Dimethoxy-4-chloroacetoacetanilide). The preparation technology is characterized in that a novel separated reaction kettle is firstly designed, a three-blade sweepback axial flow stirrer is arranged in a reaction kettle body, a material inlet is formed in the upper part of the reaction kettle body, a material outlet is formed in the lower part of the reaction kettle body, and the bottom part of the reaction kettle body is provided with a water gathering pipe and a water separating valve; reactions of esterification, hydrolysis, amidation and the like are carried out in the reaction kettle. The preparation technology disclosed by the invention is novel, green and high-yield, water which is produced in a reaction process is effectively separated, amidation reaction equilibrium is promoted to continuously move rightwards, and the product yield of the naphthol AS-IRG is greatly increased through optimizing reaction conditions.
- -
-
Paragraph 0021; 0031
(2016/11/17)
-
- PROCESS FOR ACYL-TRANSFER ENZYME REACTIONS WITH ACYL- COENZYME A
-
The present invention relates to a method for acyltransferase reaction in which an acyl group of acyl coenzyme A is transferred to an acyl group receptor characterized in that the reaction is carried out by production and/or reproduction of acyl coenzyme A from coenzyme A in a reaction system by a chemical thioester exchange reaction with acylthioester. The present invention, wherein expensive acyl CoA is reproduced nonenzymatically in a reaction system, enables to continuously carry out acyltransferase reaction only by putting a small amount of acyl CoA with a donor and a receptor of an acyl group into a system. Accordingly, the method of the present invention can be applied to an industrial production method of various kinds of compounds including useful biological molecules and synthesis of polymers such as polyester.
- -
-
Paragraph 0089
(2016/07/27)
-
- Copper-catalyzed radical coupling of 1,3-dicarbonyl compounds with terminal alkenes for the synthesis of tetracarbonyl compounds
-
A novel and efficient copper-catalyzed radical cross-coupling of 1,3-dicarbonyl compounds with terminal alkenes for the synthesis of tetracarbonyl compounds with a quaternary carbon atom has been developed. Mechanistically, this transformation involves the construction of two C-C bonds and two CO bonds in a one-pot process. The reaction tolerates a wide range of functional groups and proceeds under mild conditions.
- Zhang, Mei-Na,Zhao, Mi-Na,Chen, Ming,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
-
supporting information
p. 6127 - 6130
(2016/05/19)
-
- Hypervalent Iodine as a Terminal Oxidant in Wacker-Type Oxidation of Terminal Olefins to Methyl Ketones
-
A mimic of the Wacker process for C=O bond formation in terminal olefins can be initiated by a combination of the Pd(II) and hypervalent iodine reagent, Dess-Martin periodinane to generate methyl ketones. This operationally simple and scalable method offers Markovnikov selectivity, has good functional group compatibility, and is mild and high yielding.
- Chaudhari, Dipali A.,Fernandes, Rodney A.
-
p. 2113 - 2121
(2016/03/15)
-
- 1,5-Diketones Synthesis via Three-Component Cascade Reaction
-
A mild and efficient cascade synthesis of 1,5-diketones from readily available N,N-dicyclohexylmethylamine, 1,3-dicarbonyl compounds, and trifluoromethyl β-diketones has been developed. This cascade reaction occurs via an oxidation/Mannich reaction/Cope elimination/Michael addition/retro-Claisen reaction sequence, and provides multiple C-C bond formations in one pot. In addition, exquisite chemoselectivity is achieved in the reaction between 1,3-dicarbonyl compounds and trifluoromethyl β-diketones.
- Xing, Li-Juan,Lu, Tao,Fu, Wei-Li,Lou, Mei-Mei,Chen, Bo,Wang, Zhi-Shen,Jin, Yang,Li, Dan,Wang, Bin
-
supporting information
p. 3076 - 3080
(2015/11/03)
-
- P2X3 AND/OR P2X2/3 COMPOUNDS AND METHODS
-
The present application provides novel compounds and methods for preparing and using these compounds. In one embodiment, the compounds are of the structure of formula (I), wherein R1-R4 are defined herein. In a further embodiment, these compounds are useful in method for regulating one or both of the P2X3 or P2X2/3 receptors. In another embodiment, these compounds are useful for treating pain in patients by administering one or more of the compounds to a patient.
- -
-
Paragraph 0226; 0227
(2015/07/07)
-
- Substrate profile of an ω-transaminase from Burkholderia vietnamiensis and its potential for the production of optically pure amines and unnatural amino acids
-
A new (S)-enantioselective ω-transaminase (ω-TA) gene from Burkholderia vietnamiensis G4 was functionally expressed in Escherichia coli BL21 (DE3), and the purified recombinant N-terminal His-tagged ω-TA (HBV-ω-TA) had a dimeric structure with optimum pH and temperature of 8.4 and 40 C, respectively. The enzyme showed higher activities toward aromatic amines than aliphatic amines and (S)-1-methylbenzylamine ((S)-α-MBA) was the most active amino donor. For amino acceptor, keto acids, keto esters and aldehydes were more reactive than ketones with pyruvate ethyl ester being most active. Several chiral amines and unnatural amino acids or esters were synthesized using HBV-ω-TA as the catalyst and isopropylamine or (S)-α-MBA as amino donor. Notably, HBV-ω-TA catalyzed the amino transfer to β-keto esters to give optically pure β-amino acid esters. In addition, glyoxylate was used as amino acceptor for the first time in the kinetic resolution of racemic amines and optically pure amines, such as (R)-1-methylbenzylamine, (R)-1-phenylpropylamine, (R)-2-amino-4-phenylbutane and (R)-1-aminotetraline, were obtained.
- Jiang, Jinju,Chen, Xi,Feng, Jinhui,Wu, Qiaqing,Zhu, Dunming
-
-
- Enantioselective Mannich reaction of β-keto esters with aromatic and aliphatic imines using a cooperatively assisted bifunctional catalyst
-
An efficient urea-enhanced thiourea catalyst enables the enantioselective Mannich reaction between β-keto esters and N-Boc-protected imines under mild conditions and minimal catalyst loading (1-3 mol %). Aliphatic and aromatic substituents are tolerated on both reaction partners, affording the products in good enantiomeric purity. The corresponding β-amino ketones can readily be accessed via decarboxylation without loss of enantiomeric purity.
- Neuvonen, Antti J.,Pihko, Petri M.
-
supporting information
p. 5152 - 5155
(2015/01/08)
-
- Iron(III) sulfate as terminal oxidant in the synthesis of methyl ketones via wacker oxidation
-
An efficient and environmentally benign method using Fe(III) sulfate as a terminal oxidant in the synthesis of methyl ketones from terminal olefins via the Wacker process is developed. The methodology offers high selectivity for a Markonikov product, shows good functional group compatibility, involves mild reaction conditions, and is operationally simple. Fe2(SO 4)3 is the sole terminal oxidant in this process. The method holds potential for future applications in organic synthesis.
- Fernandes, Rodney A.,Chaudhari, Dipali A.
-
p. 5787 - 5793
(2014/07/08)
-
- Synthesis of methyl ketones from terminal olefins using PdCl 2/CrO3 system mimicking the Wacker process
-
An efficient synthesis of methyl ketones from terminal olefins using PdCl2/CrO3 system mimicking the Wacker process is developed. The method shows good functional groups compatibility, no aldehyde by-products and is operationally simple. CrO3 is the sole oxidant and replaces both Cu-salts and molecular oxygen, traditionally used in this process. The method holds potential for future applications in organic synthesis.
- Fernandes, Rodney A.,Bethi, Venkati
-
p. 4760 - 4767
(2014/06/24)
-
- Platinum- and gold-catalyzed hydroalkoxylation and tetramerization of propiolate esters
-
PtCl2 was found to efficiently catalyze intermolecular additions of propiolate esters with alcohols. The reaction of propiolate esters and alcohols in the presence of PtCl2 gave (E)-vinyl ethers as the major products at 60 °C, whereas alkyl 3,3-dialkoxypropanoates were predominantly obtained when the reaction temperature was set to 80°C. On the other hand, a novel regioselective tetramerization of propiolate esters catalyzed by AuCl3 under mild conditions afforded 1,2,5,6-tetrasubstituted- cyclooctatetraene (1,2,5,6-COT) in moderate yields.
- Chen, Qian,Zhang, Changyuan,Wen, Chunxiao,Fang, Jin,Du, Zhiyun,Wu, Dongling
-
p. 101 - 105
(2014/08/18)
-
- First iodine-catalyzed deallylation of reactive allyl methylene esters
-
C-Allyl cleavage has been developed using the inexpensive and mild reagent iodine in dimethylsulfoxide. A variety of compounds with active methylene groups were C-deallylated using this reagent. This method is efficient and operationally simple in comparison to the methods using transition-metal complexes. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Nawghare, Beena R.,Lokhande, Pradeep D.
-
p. 1955 - 1963
(2013/06/05)
-
- Sequential deprotectionecyclisation reaction: Stereoselective synthesis of azabicyclic β-enamino ester derivatives and (-) indolizidine 209D
-
This paper describes a new strategy for the stereoselective synthesis of pyrrolizidine and indolizidine based enamino esters and their acyl derivatives from L-proline. The key reaction in this process involves deprotection followed by ring closure of cyclic N-Boc amino-β-ketoesters. Also, the synthesis of 5R,9R- (-)-indolizidine 209D has been accomplished using this protocol.
- Ponpandian, Thanasekaran,Muthusubramanian, Shanmugam
-
p. 527 - 536
(2013/07/27)
-
- Synthesis of β-ketonitriles, α,β-alkynones and biscabinols from esters using tert-butoxide-assisted C(=O)-C (i.e., acyl-C) coupling under ambient conditions
-
We demonstrated the synthesis of β-ketonitriles, α,β- alkynones, and biscarbinols using tert-butoxide-assisted C(CO)-C (i.e., acyl-C) coupling of esters under ambient conditions. tert-Butoxide-assisted C(CO)-C (i.e., acyl-C) coupling of esters with cyanomethylenes and acetylenes under transition metal-free ambient conditions gives β-ketonitriles, α,β-alkynones and/or aryl bis(phenylethynyl)carbinols in moderate-to-good yields. It is noteworthy that this is a rapid, facile, and efficient process under ambient conditions, and use of cheap and stable starting materials.
- Kim, Bo Ram,Lee, Hyung-Geun,Kang, Seung-Beom,Jung, Kwang-Ju,Sung, Gi Hyeon,Kim, Jeum-Jong,Lee, Sang-Gyeong,Yoon, Yong-Jin
-
p. 10331 - 10336
(2013/11/19)
-
- An efficient synthesis of β-ketoesters via transesterification and its application in Biginelli reaction under solvent-free, catalyst-free conditions
-
A simple and efficient transesterification process for the synthesis of β-ketoester derivatives has been achieved by the reaction of methyl β-ketoester with higher alcohols at 110 C under solvent-free, catalyst-free conditions and its application in synthesis of 3,4-dihydropyrimidin-2(1H)-ones C-5 ester derivatives via Biginelli reaction has been described.
- Dharma Rao,Acharya,Kaushik
-
supporting information
p. 6644 - 6647
(2013/11/19)
-
- Simple, fast and efficient synthesis of β-keto esters from the esters of heteroaryl compounds, its antimicrobial study and cytotoxicity towards various cancer cell lines
-
A series of β-keto esters were synthesized from heteroaryl esters and ethyl acetate using LiHMDS as base at -50 to -30 °C. The increase in yields of cross condensed product were observed and the percentage of self condensed product was reduced drastically by applying the suitable base (LiHMDS), solvent and the minimum amount of ethyl acetate. All these β-keto esters were characterized using 1H NMR, 13C NMR and mass spectral data. A plausible mechanism is also depicted to prove the formation of trans-esterified products. All the synthesized compounds were subjected to test for their cytotoxicity towards various cancer cell lines and also tested for their antimicrobial activity towards various bacterial and fungal strains and some of them were found to have promising activity.
- Venkat Ragavan,Vijayakumar,Rajesh,Palakshi Reddy,Karthikeyan,Suchetha Kumari
-
supporting information; experimental part
p. 4193 - 4197
(2012/07/14)
-
- Design and synthesis of new 1,4-dihydropyridines containing 4(5)-chloro-5(4)-imidazolyl substituent as a novel calcium channel blocker
-
New analogues of nifedipine, in which the ortho-nitro phenyl group at position 4 has been replaced by 4(5)-chloro-5(4)-imidazolyl substituent and which are able to interact with the receptor by hydrogen binding were designed, synthesized, and evaluated as calcium channel antagonists. The designed dihydropyridines were synthesized using the Hantzsch condensation and evaluated as calcium channel antagonists using the high K+ contraction of guineapig ileal longitudinal smooth muscle. A docking study was performed using the AutoDock4 program, and QSAR equations were obtained using multilinear regression. Our computational studies indicated that the oxygen of the ester (O10) and the N3′ of the imidazole ring form a hydrogen bonding interaction with the NH of HIS 363 and NH of LYS354, respectively, and that the sum of the BEHp5 and RDF075p are the most significant descriptors. The results of calcium channel antagonist evaluation demonstrated that increasing the chain length in C3 and C5 ester substituents increased activity. The most potent compound was the bis-phenylpropyl ester (5l) derivative, in that it was more active than the reference drug nifedipine and that the bis-phenylethyl ester (5k) derivative had comparable activity with nifedipine. The present research revealed that the 4(5)-chloro-5(4)-imidazolyl moiety is a bioisoster of o-nitrophenyl in nifedipine and provided novel dihydropyridines with more activity as calcium channel antagonists.
- Iman, Maryam,Davood, Asghar,Nematollahi, Ali Reza,Dehpoor, Ahmad Rerza,Shafiee, Abbas
-
scheme or table
p. 1417 - 1426
(2012/05/04)
-
- Efficient trans-acetoacylation mediated by ytterbium(III) triflate as a catalyst under solvent-free condition
-
A simple and efficient trans-acetoacylation method for the synthesis of β-keto ester derivatives has been described using ytterbium(III) triflate as a new catalyst under solvent-free condition. This method was found to be efficient and convenient for the synthesis of a wide variety of β-keto ester derivatives.
- Dharma Rao,Kaushik
-
experimental part
p. 5104 - 5106
(2011/10/08)
-
- PROCESS FOR PRODUCING ESTER COMPOUND
-
PROBLEM To provide an environmentally-friendly method for producing industrially an ester compound. SOLUTION The present invention is a method for producing an ester compound which comprises subjecting a carboxylic acid and an alcohol to dehydration-condensation reaction using an involatile acid catalyst and then removing the residual acid catalyst by bringing a weak basic substance into contact with the residual acid catalyst.
- -
-
Page/Page column 16-17
(2010/12/31)
-
- Thiadiazole carbamates: Potent inhibitors of lysosomal acid lipase and potential niemann-pick type C disease therapeutics
-
Niemann-Pick type C (NPC) disease is a lysosomal storage disorder characterized at the cellular level by abnormal accumulation of cholesterol and other lipids in lysosomal storage organelles. Lysosomal acid lipase (LAL) has been recently identified as a potential therapeutic target for NPC. LAL can be specifically inhibited by a variety of 3,4-disubstituted thiadiazole carbamates. An efficient synthesis of the C(3) oxygenated/C(4) aminated analogues has been developed that furnishes the products in high yields and high degrees of purity. Common intermediates can also be used for the synthesis of the C(3) carbon substituted derivatives. Herein we tested various thiadiazole carbamates, amides, esters, and ketones for inhibition of LAL. In addition, we tested a diverse selection of commercially available non-thiadiazole carbamates. Our studies show that, among the compounds examined herein, only thiadiazole carbamates are effective inhibitors of LAL. We present a mechanism for LAL inhibition by these compounds whereby LAL transiently carbamoylates the enzyme similarly to previously described inhibition of acetylcholinesterase by rivastigmine and other carbamates as well as acylation of various lipases by orlistat.
- Rosenbaum, Anton I.,Cosner, Casey C.,Mariani, Christopher J.,Maxfield, Frederick R.,Wiest, Olaf,Helquist, Paul
-
supporting information; experimental part
p. 5281 - 5289
(2010/10/19)
-
- Synthesis of Biginelli dihydropyrimidinone derivatives with various substituents on aluminium-planted mesoporous silica catalyst
-
Biginelli reactions were well catalyzed on mesoporous silica MCM-41 (M41) whose activity was much greater than that of amorphous silica. Octane was the most suitable among 6 kinds of solvents examined. The addition of metal ions on M41 enhanced the catalytic activity in the order Al > Ti > Fe = In. Al-planted M41s with Si/Al ratios of 45-35 showed the highest catalytic activity and could be used repeatedly though a small loss of the activity was observed. The catalysis could widely be applied to obtain various substituted dihydropyrimidinones (DHPMs) with high yields, some of which were very difficult to prepare until now. In addition, Biginelli reactions were combined with formyl C-H insertion reactions of diazoester on mesoporous silica; that is, a tandem one-pot four-component DHPM synthesis was attempted. Acetaldehyde, ethyl diazoacetate, p-tolualdehyde, and urea could be condensed and the corresponding DHPM derivative was obtained with 50% yield on Al-planted M41. The Royal Society of Chemistry.
- Murata, Hiroaki,Ishitani, Haruro,Iwamoto, Masakazu
-
experimental part
p. 1202 - 1211
(2010/06/13)
-
- A new regeneration system for oxidized nicotinamide cofactors
-
A novel regeneration system for oxidized nicotinamide cofactors (NAD + and NADP+) is presented. By combining 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS)-catalyzed oxidation of NAD(P)H with laccase-catalyzed utilization of molecular oxygen as terminal oxidant, a simple chemo-enzymatic NAD(P)+ regeneration method is achieved. Thus, the advantages of both worlds, chemical oxidation of reduced nicotinamide cofactors and laccase-catalyzed utilization of oxygen from air are combined in a simple and generally applicable new approach for biooxidation catalysis. This new application of the well-known laccase-mediator system (LMS) is successfully used to promote alcohol dehydrogenase-catalyzed oxidation reactions of primary and secondary alcohols. Already under non-optimized conditions, high turnover numbers of > 300 and > 16000 were obtained for the nicotinamide cofactor and ABTS, respectively. In this communication, we present the proofof-principle and initial characterization of the proposed new regeneration system.
- Aksu, Seda,Arends, Isabel W.C.E.,Hollmann, Frank
-
supporting information; experimental part
p. 1211 - 1216
(2010/03/01)
-
- HERBICIDAL COUMPOUNDS
-
The present invention relates to novel herbicidal [l,8]-naphthyridines of Formula (Ia) or (Ib), or an agronomically acceptable salt of said compound wherein R2, R3, R4, R5,R6,R7, R8, n, m, X and Q are as defined herein. The invention further relates to processes and intermediates for the preparation of the [l,8]-naphthyridines, to compositions which comprise the herbicidal compounds, and to their use for controlling weeds, in particular in crops of useful plants.
- -
-
Page/Page column 86
(2009/10/22)
-
- Structure-activity relationships of 1,4-dihydropyridines that act as enhancers of the vanilloid receptor 1 (TRPV1)
-
Vanilloid agonists such as capsaicin activate ion flux through the TRPV1 channel, a heat- and ligand-gated cation channel that transduces painful chemical or thermal stimuli applied to peripheral nerve endings in skin or deep tissues. We have probed the SAR of a variety of 1,4-dihydropyridine (DHP) derivatives as novel 'enhancers' of TRPV1 activity by examining changes in capsaicin-induced elevations in 45Ca2+-uptake in either cells ectopically expressing TRPV1 or in cultured dorsal root ganglion (DRG) neurons. The enhancers increased the maximal capsaicin effect on 45Ca2+-uptake by typically 2- to 3-fold without producing an action when used alone. The DHP enhancers contained 6-aryl substitution and small alkyl groups at the 1 and 4 positions, and a 3-phenylalkylthioester was tolerated. Levels of free intracellular Ca2+, as measured by calcium imaging, were also increased in DRG neurons when exposed to the combination of capsaicin and the most efficacious enhancer 23 compared to capsaicin alone. Thus, DHPs can modulate TRPV1 channels in a positive fashion.
- Roh, Eun Joo,Keller, Jason M.,Olah, Zoltan,Iadarola, Michael J.,Jacobson, Kenneth A.
-
scheme or table
p. 9349 - 9358
(2009/04/06)
-
- Selective synthesis of α-substituted β-keto esters from aldehydes and diazoesters on mesoporous silica catalysts
-
The titled reactions are effectively catalyzed on mesoporous silica MCM-41 but not on amorphous silica prepared from the same starting materials as those of MCM-41. The ordered porous structure was essential to generate the acid catalysis. Planting of Al or Ti ion improved not only the catalytic activity but also the tolerance to basic functional groups of substrates. The catalytic activity of Al- or Ti-MCM-41 was better than that of SnCl2 and NbCl5 in the homogeneous phase. In particular, Al (or Ti)-MCM-41 was characteristically active for the reaction of aldehydes with α-substituted diazoesters to give 2-substituted-3-oxo propionic acid esters.
- Murata, Hiroaki,Ishitani, Haruro,Iwamoto, Masakazu
-
p. 4788 - 4791
(2008/12/22)
-
- METHOD FOR SYNTHESIS OF KETO ACID OR AMINO ACID BY HYDRATION OF ACETHYLENE COMPOUND
-
An object of the present invention is to provide a method for synthesis of keto acids by hydration of an acetylene compound (acetylene-carboxylic acids) under mild conditions free from harmful mercury catalysts and a method for synthesis of amino acids from acetylene-carboxylic acids in a single container (one-pot or tandem synthesis). In one embodiment of the method according to the present invention for synthesis of keto acids, acetylene-carboxylic acids is hydrated in the presence of a metal salt represented by General Formula (1), where M1 represents an element in Group VIII, IX, or X of the periodic table, and X1, X2, or X3 ligand represents halogen, H2O, or a solvent molecule, and k represents a valence of a cation species, and Y represents an anion species, and L represents a valence of the anion species, and each of K and L independently represents 1 or 2, and k × m = L × n.
- -
-
Page/Page column 22; 23; 27
(2008/12/06)
-
- Isolation and crystal structures of both enol and keto tautomer intermediates in a hydration of an alkyne-carboxylic acid ester catalyzed by iridium complexes in water
-
Hydration of tetrolic acid ethyl ester as an alkyne-carboxylic acid ester catalyzed by an Ir-aqua complex [IrIIICp*(bpy)(OH 2)]2+ (1, Cp* = η5-C 5Me5, bpy = 2,2′-bipyridine) in water provides ethyl acetoacetate as a β-keto acid ester. We report the successful isolation of both an Ir-enol tautomer intermediate [IrIIICp*(bpy){CH 3C(OH)=CC(O)OC2H5}]+ (2) and an Ir-keto tautomer intermediate [IrIIICp*(bpy){CH 3C(O)-CHC(O)OC2H5}]+ (3) in the catalytic hydration by optimizing the conditions of the isolation, such as pH of the solution, reaction time, and selection of counteranions. The structures of the enol and keto complexes with characteristic Ir-(sp2carbon) bond and Ir-(sp3 carbon) bond, respectively, were unequivocally determined by X-ray analysis, IR, electrospray ionization mass spectrometry (ESI-MS), and NMR studies including 1H, 13C, distortionless enhancement by polarization transfer (DEPT) and correlation spectroscopy (COSY) experiments. It was confirmed that the hydration of tetrolic acid ethyl ester catalyzed by 2 or 3 as initial catalysts provides ethyl acetoacetate. Mechanism of the catalytic hydration of tetrolic acid ethyl ester as an alkyne-carboxylic acid ester is discussed based on isotopic labeling experiments with the Ir-enol and Ir-keto tautomers.
- Kanemitsu, Hironobu,Uehara, Keiji,Fukuzumi, Shunichi,Ogo, Seiji
-
supporting information; scheme or table
p. 17141 - 17147
(2009/04/13)
-
- Ionic liquid promoted selective debromination of α-bromoketones under microwave irradiation
-
The debromination of α-bromoketones with an easily accessible ionic liquid, 1-methyl-3-pentylimidazolium tetrafluoroborate, [pmIm]BF4 under microwave irradiation has been investigated. By controlling the reaction time gem-α-dibromoketones are selectively debrominated to either monobromo or debromoketones. The α-monobromo- and α-monoiodoketones are dehalogenated while the corresponding chloroketones remain inert. The activated vic-bromoacetates are converted to the corresponding (E)-alkenes by the same procedure. These reactions do not require any organic solvent, any metal or any conventional reducing agent. The ionic liquid works here as catalyst as well as reaction medium and is recycled without any appreciable loss of its catalytic efficiency.
- Ranu, Brindaban C.,Chattopadhyay, Kalicharan,Jana, Ranjan
-
p. 155 - 159
(2007/10/03)
-
- 2-Acetyl-2,3,4,9-tetrahydro-1H-carbazol-1-one in the synthesis of heteroannulated carbazoles
-
The reaction of 2,3,4,9-tetrahydro-1H-carbazol-1-ones with ethyl acetate yielded 2-acetyl-1-hydroxycarbazole and 2-acetyl-2,3,4,9-tetrahydro-1H-carbazol- 1-one. These were used to prepare isoxazolo- and pyrazolo-fused carbazoles. Mechanisms for the format
- Martin, Arputharaj Ebenezer,Prasad, Karnam Jayarampillai Rajendra
-
p. 699 - 704
(2008/09/20)
-
- Phenyl derivatives, their manufacture and use as pharmaceutical agents
-
This invention relates to compounds of the formula wherein one of R5, R6 and R7 is and X1, X2, Y1 to Y4, R1 to R13 and m and n are defined in the description, and to all enantiomers and pharmaceutically acceptable salts and/or esters thereof. The invention further relates to pharmaceutical compositions containing such compounds, to a process for their preparation and to their use for the treatment and/or prevention of diseases which are modulated by PPARδ and/or PPARα agonists.
- -
-
Page/Page column 45-46
(2010/02/11)
-
- Reactions of diethyl dibromomalonate and ethyl 2,2-dichloroacetoacetate with water and carbonyl compounds (aldehydes and ketones) in the presence of pentacarbonyliron
-
Diethyl dibromomalonate and ethyl 2,2-dichloroacetoacetate are effectively reduced with the system pentacarbonyliron-proton-donor compound (water or butyl methyl ketone) to give the corresponding hydrodehalogenation products. These results provide a support for the previous assumption that the key reaction stage is reduction with pentacarbonyliron of initially formed radical to anion which is then involved in proton transfer.
- Terent'ev,Vasil'eva,Mysova,Chakhovskaya
-
p. 924 - 927
(2007/10/03)
-
- Novel isoxazole carboxamides as growth hormone secretagogue receptor (GHS-R) antagonists
-
Novel isoxazole carboxamides have been identified as growth hormone secretagogue receptor (GHS-R) antagonists. Substituent modification off the 5-position of the isoxazole ring led to analogues with potent binding affinity and functional antagonism of GHS-R. A potent analogue (32) with high aqueous solubility and good GPCR selectivity was also identified as a potential pharmacological tool for in vivo studies.
- Liu, Bo,Liu, Gang,Xin, Zhili,Serby, Micheal D.,Zhao, Hongyu,Schaefer, Verlyn G.,Falls, H. Douglas,Kaszubska, Wiweka,Collins, Christine A.,Sham, Hing L.
-
p. 5223 - 5226
(2007/10/03)
-
