- Green Esterification of Carboxylic Acids Promoted by tert-Butyl Nitrite
-
In this work, the green esterification of carboxylic acids promoted by tert-butyl nitrite has been well developed. This transformation is compatible with a broad range of substrates and exhibits excellent functional group tolerance. Various drugs and substituted amino acids are applicable to this reaction under near neutral conditions, with good to excellent yields.
- Cheng, Xionglve,Jiang, Gangzhong,Li, Xingxing,Tao, Suyan,Wan, Xiaobing,Zhao, Yanwei,Zheng, Yonggao
-
supporting information
p. 2713 - 2718
(2021/06/25)
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- Preparation method of carboxylic ester compound
-
The invention relates to a preparation method of a carboxylic ester compound, which comprises the following steps: reacting carboxylic acid with methanol in air under the catalysis of nitrite to obtain an ester compound, the preparation method disclosed by the invention has the advantages of rich raw material sources, cheap and easily available catalyst, mild reaction conditions, simplicity and convenience in operation and the like, a series of fatty carboxylic acids can be modified with high yield, and particularly, the traditional esterification method is generally not suitable for esterification of drug molecules. By utilizing the method, a series of known drug molecules can be modified, so that a shortcut is provided for discovering new drug molecules.
- -
-
Paragraph 0049-0050
(2021/03/30)
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- Preparation method of 4-bromomethyl methyl benzoate and derivative thereof
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The invention provides a preparation method of methyl 4-bromomethyl benzoate and a derivative thereof, and the method comprises an esterification reaction for converting methyl benzoic acid into methyl benzoate and a bromination reaction for converting the methyl benzoate into the methyl 4-bromomethyl benzoate and the derivative thereof, the brominating agent for the bromination reaction is dibromohydantoin, and the structural formulas of the 4-bromomethyl methyl benzoate and the derivatives thereof are shown in the specification, wherein n1 is equal to 0, 1 or 2; n2 is equal to 1 or 2; according to the preparation method disclosed by the invention, the reaction time can be greatly shortened, the reaction yield is high, and the production efficiency is improved.
- -
-
Paragraph 0039; 0041
(2021/05/05)
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- B(C6F5)3-catalyzed O-H insertion reactions of diazoalkanes with phosphinic acids
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A highly efficient base-, metal-, and oxidant-free catalytic O-H insertion reaction of diazoalkanes and phosphinic acids in the presence of B(C6F5)3has been developed. This powerful methodology provides a green approach towards the synthesis of a broad spectrum of α-phosphoryloxy carbonyl compounds with good to excellent yields (up to 99% yield). The protocol features the advantages of operational simplicity, high atom economy, practicality, easy scalability and environmental friendliness.
- Jiang, Jun,Zhang, Xinzhi,Zhang, Yangyang,Zhao, Jincheng
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supporting information
p. 5772 - 5776
(2021/07/12)
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- B(C6F5)3-Catalyzed site-selective N1-alkylation of benzotriazoles with diazoalkanes
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Alkylation of benzotriazoles is synthetically challenging, often leading to mixtures of N1 and N2 alkylation. Herein, metal-free catalytic site-selective N1-alkylation of benzotriazoles with diazoalkanes is described in the presence of 10 mol% of B(C6F5)3. These reactions provide N1-alkylated benzotriazoles in good to excellent yields and this protocol is successfully adapted to gram-scale syntheses as well as a derivative with antimicrobial activity.
- Guo, Jing,Mandal, Dipendu,Stephan, Douglas W.,Wu, Yile,Zhao, Yunbo
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supporting information
p. 7758 - 7761
(2021/08/13)
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- Insertion of Diazo Esters into C-F Bonds toward Diastereoselective One-Carbon Elongation of Benzylic Fluorides: Unprecedented BF3Catalysis with C-F Bond Cleavage and Re-formation
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Selective transformation of C-F bonds remains a significant goal in organic chemistry, but C-F insertion of a one-carbon-atom unit has never been established. Herein we report the BF3-catalyzed formal insertion of diazo esters as one-carbon-atom sources into C-F bonds to accomplish one-carbon elongation of benzylic fluorides. A DFT calculation study revealed that the BF3 catalyst could contribute to both C-F bond cleavage and re-formation. This elongation provided α-fluoro-α,β-diaryl esters with a high level of diastereoselectivity. Various benzylic fluorides and diazo esters were applicable. The synthetic utility of this method was demonstrated by the synthesis of a fluoro analogue of a compound that is used as a transient receptor and potential canonical channel inhibitor.
- Wang, Fei,Nishimoto, Yoshihiro,Yasuda, Makoto
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supporting information
p. 20616 - 20621
(2021/11/23)
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- PCl3-mediated transesterification and aminolysis of tert-butyl esters via acid chloride formation
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A PCl3-mediated conversion of tert-butyl esters into esters and amides in one-pot under air is developed. This novel protocol is highlighted by the synthesis of skeletons of bioactive molecules and gram-scale reactions. Mechanistic studies revealed that this transformation involves the formation of an acid chloride in situ, which is followed by reactions with alcohols or amines to afford the desired products.
- Wu, Xiaofang,Zhou, Lei,Li, Fangshao,Xiao, Jing
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p. 491 - 497
(2021/01/20)
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- Synthesis, in-vitro, in-vivo anti-inflammatory activities and molecular docking studies of acyl and salicylic acid hydrazide derivatives
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Over the course of time several drugs have been synthesized and are available in market for the treatment of inflammation. However, they were unable to cure effectively and associated with side effects. To effectively deal with such diseases, heterocycles and their derivatives have gained their special position. For this reason 1,3,4-oxadiazole (15–16), 1,2,4-triazole (17–18), Schiff base (19–24) and 3,5-disubstituted pyrazole (25) derivatives were synthesized starting from salicylic acid and acyl acid hydrazides (12–14) as COX-1 and COX-2 inhibitors. In vivo anti-inflammatory activities were also tested by carrageenan-induced mice paw edema against albino mice of any sex. Structures of all the synthesized compounds were confirmed by FT-IR and 1H NMR analysis. Schiff base derivative of 4-amiontirazole (24) with IC50 value of 1.76 ± 0.05 (COX-2) and 117.8 ± 2.59 emerged as potent COX-2 inhibitor. Furthermore, we also performed in-vivo anti-inflammatory investigations by using carrageenan induced paw edema test. From in-vivo anti-inflammatory activities, it was found that after 1 h the maximum percentage inhibition 15.8% was observed by compound 14 which is comparable with that of the standard drug followed by the compound 18 with percentage inhibition of 10.5%. After 3 h, the maximum percentage inhibition was observed by compound 18 with 22.2% and compound 14 with 16.7%. After 5 h the maximum percentage inhibition was observed by compound 18 with 29.4% followed by compound 16 with 23.5%. We further explore the mechanism of the inhibition by using docking simulations. Docking studies revealed that the selective COX-2 inhibitors established interactions with additional COX-2 enzyme pocket residues.
- Ali, Gowhar,Ashraf, Zaman,Hussain, Izhar,Khushal, Adil,Mumtaz, Amara,Munir, Abida,Rashid, Umer,Sadiq, Abdul,Saeed Jan, Muhammad,Saeed, Kiran,Ullah Mughal, Ehsan,Ullah, Rahim
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-
- 3,3′-Disubstituted Oxindoles Formation via Copper-Catalyzed Arylboration and Arylsilylation of Alkenes
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Arylboration and arylsilylation reactions of N-(2-iodoaryl)acrylamides with bis(pinacolato)-diboron (B2pin2) or PhMe2Si-Bpin are developed by using simple CuOAc as the sole catalyst. A range of boron-or silane-bearing 3,3′-disubstituted oxindoles are obtained in moderate to excellent yields. The reaction is proposed to proceed via a domino sequence involving intermolecular olefin borylcupration or silylcupration followed by intramolecular coupling of an alkyl-Cu intermediate with aryl iodide.
- Liang, Ren-Xiao,Chen, Ru-Yi,Zhong, Chao,Zhu, Jia-Wen,Cao, Zhong-Yan,Jia, Yi-Xia
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supporting information
p. 3215 - 3218
(2020/04/10)
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- Pd-Catalyzed Decarboxylative Olefination: Stereoselective Synthesis of Polysubstituted Butadienes and Macrocyclic P-glycoprotein Inhibitors
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The efficient and stereoselective synthesis of polysubstituted butadienes, especially the multifunctional butadienes, represents a great challenge in organic synthesis. Herein, we wish to report a distinctive Pd(0) carbene-initiated decarboxylative olefination approach that enables the direct coupling of diazo esters with vinylethylene carbonates (VECs), vinyl oxazolidinones, or vinyl benzoxazinones to afford alcohol-, amine-, or aniline-containing 1,3-dienes in moderate to high yields and with excellent stereoselectivity. This protocol features operational simplicity, mild reaction conditions, a broad substrate scope, and gram-scalability. Notably, a structurally unique allylic Pd(II) intermediate was isolated and characterized. DFT calculation and control experiments demonstrated that a rare Pd(0) carbene intermediate could be involved in this reaction. Moreover, the polysubstituted butadienes as novel building blocks were unprecedentedly assembled into macrocycles, which efficiently inhibited the P-glycoprotein and dramatically reversed multidrug resistance in cancer cells by 190-fold.
- Chen, Xiangyang,Hao, Jiping,Houk, K. N.,Li, Yingzi,Lou, Liguang,Quan, Haitian,Song, Bichao,Wang, Lu,Xia, Yuanzhi,Xie, Peipei,Xu, Zhongliang,Yang, Weibo
-
supporting information
p. 9982 - 9992
(2020/06/27)
-
- Palladium-catalyzed intermolecular C-H silylation initiated by aminopalladation
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A Pd(ii)-catalyzed intermolecular C-H silylation reaction initiated by aminopalladation has been developed. The C-H bonds were activated by an alkyl Pd(ii) species generated through aminopalladation and then disilylated with hexamethyldisilane to form disilylated indolines as the final products. The reaction provides a new method for the introduction of silyl groups into complex organic molecules.
- Ji, Xiaoming,Wei, Feng,Wan, Bin,Cheng, Cang,Zhang, Yanghui
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supporting information
p. 7801 - 7804
(2020/07/27)
-
- Iron-catalysed 1,2-aryl migration of tertiary azides
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1,2-Aryl migration of α,α-diaryl tertiary azides was achieved by using the catalytic system of FeCl2/N-heterocyclic carbene (NHC) SIPr·HCl. The reaction generated aniline products in good yields after one-pot reduction of the migration-resultant imines.
- Wei, Kaijie,Yang, Tonghao,Chen, Qing,Liang, Siyu,Yu, Wei
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supporting information
p. 11685 - 11688
(2020/10/19)
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- CuII-Catalyzed Oxidative Formation of 5-Alkynyltriazoles
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In an alcoholic solvent under the catalysis of Cu(OAc)2?H2O, organic azide and terminal alkyne could oxidatively couple to afford 5-alkynyl-1,2,3-triazole (alkynyltriazole) at room temperature under an atmosphere of O2 in a few hours. The involvement of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) is essential, without which the redox neutral coupling instead proceeds to produce 5-H-1,2,3-triazole (protiotriazole) as the major product. Therefore, DBN switches the redox neutral coupling between terminal alkyne and organic azide, the copper-catalyzed “click” reaction to afford protiotriazole, to an oxidation reaction that results in alkynyltriazole. The organic base DBN is effective in accelerating the copper(II)-catalyzed oxidation of terminal alkyne or copper(I) acetylide, which is intercepted by an organic azide to produce alkynyltriazole. The proposed mechanistic model suggests that the selectivity between alkynyl- and protiotriazole, and other acetylide or triazolide oxidation products is determined by the competition between copper(I)-catalyzed redox neutral cycloaddition and copper(II)/O2-mediated acetylide oxidation after the formation of copper(I) acetylide.
- Liu, Peiye,Brassard, Christopher J.,Lee, Justin P.,Zhu, Lei
-
supporting information
p. 380 - 390
(2020/01/24)
-
- Synthesis and bio-evaluation of natural butenolides-acrylate conjugates
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A series of novel 3-aryl-4-hydroxy-2(5H) furanone-acrylate hybrids were designed and synthesized based on the natural butenolides and acrylates scaffolds. The structures of the prepared compounds were characterized by 1H-NMR, 13C-NMR and electrospray ionization mass spectrometry (ESI-MS), and the bioactivity of the target compounds against twelve phytopathogenic fungi was investigated. The preliminary in vitro antifungal activity screening showed that most of the target compounds had moderate inhibition on various pathogenic fungi at the concentration of 100 mg·L?1, and presented broad-spectrum antifungal activities. Further studies also indicated that compounds 7e and 7k still showed some inhibitory activity against Pestallozzia theae, Sclerotinia sclerotiorum and Gibberella zeae on rape plants at lower concentrations, which could be optimized as a secondary lead for further research.
- Bao, Longzhu,Wang, Shuangshuang,Song, Di,Wang, Jingjing,Cao, Xiufang,Ke, Shaoyong
-
-
- Efficient Synthesis of Spirooxindole Pyrrolones by a Rhodium(III)-Catalyzed C?H Activation/Carbene Insertion/Lossen Rearrangement Sequence
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A rhodium(III)-catalyzed domino annulation of simple olefins with diazo oxindoles to give spirooxindole pyrrolone products is described. This reaction can be formally viewed as the result of an anomalous tandem C?H activation, carbene insertion, Lossen rearrangement, and a nucleophilic addition process. The potential utility of this reaction was further demonstrated by the late-stage diversification of drug molecules.
- Ma, Biao,Wu, Peng,Wang, Xing,Wang, Zhengyu,Lin, Hai-Xia,Dai, Hui-Xiong
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supporting information
p. 13335 - 13339
(2019/08/20)
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- Macrolide Synthesis through Intramolecular Oxidative Cross-Coupling of Alkenes
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A RhIII-catalyzed intramolecular oxidative cross-coupling between double bonds for the synthesis of macrolides is described. Under the optimized reaction conditions, macrocycles containing a diene moiety can be formed in reasonable yields and with excellent chemo- and stereoselectivity. This method provides an efficient approach to synthesize macrocyclic compounds containing a 1,3-conjugated diene structure.
- Jiang, Bing,Zhao, Meng,Li, Shu-Sen,Xu, Yun-He,Loh, Teck-Peng
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supporting information
p. 555 - 559
(2018/02/21)
-
- Comparison of Phenylacetates with Benzoates and Phenylpropanoates as Antifeedants for the Pine Weevil, Hylobius abietis
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This study concludes an extensive investigation of antifeedants for the pine weevil, Hylobius abietis (Coleoptera: Curculionidae), an economically important pest of planted conifer seedlings. Building on the previously reported antifeedant effects of benzoates and phenylpropanoids (aromatic compounds with one- or three-carbon-atom substituents on the benzene ring), we here report the antifeedant effects of compounds with two-carbon-atom side chains (i.e., phenylacetates). We also present new results; the best antifeedants from the benzoate class were tested at 10-fold lower concentrations in order to find the optimal antifeedants. Generally, for all three compound classes, efficient antifeedants were found to have one or two methyl, chloro, or methoxy substituents on the aromatic ring. For monosubstituted phenylpropanoids, the substituent preferably should be in the para-position. In the search for synergistic antifeedant effects among the three compound classes, combinations of compounds from the three classes were tested in binary and ternary mixtures.
- Unelius, C. Rikard,Bohman, Bj?rn,Nordlander, G?ran
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p. 11797 - 11805
(2018/11/21)
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- Pd-Catalyzed Three-Component Domino Reaction of Vinyl Benzoxazinanones for Regioselective and Stereoselective Synthesis of Allylic Sulfone-Containing Amino Acid Derivatives
-
A Pd-catalyzed, highly regioselective and stereoselective three-component domino allylic substitution/N-H carbene insertion reaction under mild conditions is described. This reaction demonstrates a wide substrate scope and satisfactory functional group tolerance, providing a broad range of allylic sulfone-containing amino acid derivatives. Moreover, DBU mediates highly diastereoselective cross-dehydrogenative coupling annulation of allylic sulfones without using peroxides or any metal oxidants. This developed protocol affords 7-membered ring heterocyclic compounds incorporating both sulfone-containing amino acid esters and one quaternary carbon center. Mechanistic studies indicate that an unusual umpolung of glycine occurred in this annulation.
- Hao, Jiping,Xu, Yi,Xu, Zhongliang,Zhang, Zhiqiang,Yang, Weibo
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supporting information
p. 7888 - 7892
(2019/01/04)
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- Palladium-Catalyzed C?H Silylation through Palladacycles Generated from Aryl Halides
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A highly efficient palladium-catalyzed disilylation reaction of aryl halides through C?H activation has been developed for the first time. The reaction has broad substrate scope. A variety of aryl halides can be disilylated by three types of C?H activation, including C(sp2)?H, C(sp3)?H, and remote C?H activation. In particular, the reactions are also unusually efficient. The yields are essentially quantitative in many cases, even in the presence of less than 1 mol % catalyst and 1 equivalent of the silylating reagent under relatively mild conditions. The disilylated biphenyls can be converted into disiloxane-bridged biphenyls.
- Lu, Ailan,Ji, Xiaoming,Zhou, Bo,Wu, Zhuo,Zhang, Yanghui
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supporting information
p. 3233 - 3237
(2018/02/23)
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- The computer-aided discovery of novel family of the 5-HT6 serotonin receptor ligands among derivatives of 4-benzyl-1,3,5-triazine
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The work describes a discovery of new chemical family of potent ligands for the 5-HT6 serotonin receptors. During the search for new histamine H4 receptor antagonists among 1,3,5-triazine derivatives, compound 2 (4-benzyl-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine) was found. Compound 2, weakly active for the H4 receptor but fitted in 3/4 of pharmacophore features of the 5-HT6R ligand, occurred to be a moderate 5-HT6R agent, useful as a lead structure for further modifications. A series of new derivatives (3–19) of the lead 2 was synthesized, evaluated in the radioligand binding assay (RBA) and explored in comprehensive molecular modelling, including both pharmacophore- and structure-based approaches with docking to the homology model of 5-HT6R. The most active compounds displayed a potent affinity for the 5-HT6R in the nanomolar range (Ki?=?20–30?nM), some of them (4, 11 and 19) were tested in the rat forced swim test that revealed their antidepressant-like effect. SAR-analysis on the basis of both, RBA and docking results, indicated that action on the receptor is related to the hydrophobicity and the size of aromatic moiety substituted by a methylene linker at the position 4 of 1,3,5-triazine.
- ?a?ewska, Dorota,Kurczab, Rafa?,Wi?cek, Ma?gorzata,Kamińska, Katarzyna,Sata?a, Grzegorz,Jastrz?bska-Wi?sek, Magdalena,Partyka, Anna,Bojarski, Andrzej J.,Weso?owska, Anna,Kie?-Kononowicz, Katarzyna,Handzlik, Jadwiga
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supporting information
p. 117 - 124
(2017/04/26)
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- An approach to spirooxindoles: Via palladium-catalyzed remote C-H activation and dual alkylation with CH2Br2
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A facile and efficient approach for the synthesis of spirooxindoles has been developed via the coupling of spirocyclic C,C-palladacycles with CH2Br2. The key spirocyclic palladacycles are generated catalytically via remote C-H activation. A range of spirooxindoles can be synthesized in good to excellent yields from readily available starting material.
- Shao, Changdong,Wu, Zhuo,Ji, Xiaoming,Zhou, Bo,Zhang, Yanghui
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supporting information
p. 10429 - 10432
(2017/09/25)
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- Development of a simple system for the oxidation of electron-rich diazo compounds to ketones
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Mild heating of diazo compounds in DMSO furnishes ketone products in moderate to excellent yields. The reaction is particularly effective on electron-rich substrates and exhibits high chemoselectivity, allowing for the use of diazo compounds containing additional oxidation-prone functional groups. This straightforward protocol offers an alternate route to synthetically useful α-ketoesters from readily available aryl diazoacetates.
- O'Connor, Nicholas R.,Bolgar, Peter,Stoltz, Brian M.
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supporting information
p. 849 - 851
(2016/02/05)
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- Highly efficient and chemoselective zinc-catalyzed hydrosilylation of esters under mild conditions
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A mild and highly efficient catalytic hydrosilylation protocol for room-temperature ester reductions has been developed using diethylzinc as the catalyst. The methodology is operationally simple, displays high functional group tolerance and provides for a facile access to a broad range of different alcohols in excellent yields.
- Kovalenko, Oleksandr O.,Adolfsson, Hans
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supporting information
p. 2785 - 2788
(2015/02/05)
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- Copper-Catalyzed Regiospecific and 1,2-Regioselective Cyclopropanation of (1 Z)-1-Amino- and (1 Z)-1-Oxy-1,3-butadienyl Derivatives
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The copper-catalyzed regiospecific and 1,2-regioselective cyclopropanation of (1Z)-1-amino- and (1Z)-1-oxy-1,3-butadienyl derivatives, which could be prepared by Z-stereoselective 1,4-elimination with α-aryl diazoesters was successfully demonstrated. This successful regiospecific protocol enabled the preparation of the corresponding 1-amino- and 1-oxy-2-vinylcyclopropane derivatives as almost single stereoisomers.
- Tayama, Eiji,Saito, Shun
-
supporting information
p. 1880 - 1884
(2015/08/06)
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- HETEROARYL INHIBITORS OF PDE4
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The present invention relates to compounds and methods useful as inhibitors of phosphodiesterase 4 (PDE4) for the treatment or prevention of disease.
- -
-
Paragraph 0841
(2014/05/24)
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- Rhodium-catalyzed oxygenative addition to terminal alkynes for the synthesis of esters, amides, and carboxylic acids
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A gem of a couple: The title reaction of terminal alkynes with O and Nnucleophiles proceeds in the presence of [Rh(cod)Cl}2], P(4-FC 6H4)3, and 4-picoline N-oxide. Alcohols, amines, and water add to the terminal alkynes to give esters, amides, and carboxylic acids, respectively. The reaction involves formation of a rhodium vinylidene, oxidation to a ketene by oxygen transfer, and nucleophilic addition.
- Kim, Insu,Lee, Chulbom
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supporting information
p. 10023 - 10026
(2013/10/01)
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- Ene reductase-catalysed synthesis of (R)-profen derivatives
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Enantiomerically pure (R)-profen derivatives and intermediates are synthesised utilising the enzyme YqjM, an ene reductase from Bacillus subtilis. After optimisation of the reaction conditions, the chemoenzymatic approach was applied for the first time in the synthesis of (R)-flurbiprofen methyl ester. Copyright
- Pietruszka, Joerg,Schoelzel, Melanie
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scheme or table
p. 751 - 756
(2012/04/23)
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- Tripeptidic BACE1 inhibitors devised by in-silico conformational structure-based design
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Previously reported pentapeptidic BACE1 inhibitors, designed using a substrate-based approach, were used as lead compounds for the further design of non-peptidic BACE1 inhibitors. Although these peptidic and non-peptidic inhibitors, with a hydroxymethylcarbonyl isostere as a substrate transition-state mimic, exhibited potent BACE1 inhibitory activities, their molecular-sizes appeared a little too big (molecular weight of >600 daltons) for developing practical anti-Alzheimer's disease drugs. To develop lower weight BACE1 inhibitors, a series of tripeptidic BACE1 inhibitors were devised using a design approach based on the conformation of a virtual inhibitor bound to the BACE1 active site, also called 'in-silico conformational structure-based design'. Although these tripeptidic BACE1 inhibitors contained some natural amino acid residues, they are expected to be useful as lead compounds for developing the next generation BACE1 inhibitors, due to their low molecular size and unique structural features compared with previously reported inhibitors.
- Hamada, Yoshio,Tagad, Harichandra D.,Nishimura, Yoshinori,Ishiura, Shoichi,Kiso, Yoshiaki
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scheme or table
p. 1130 - 1135
(2012/03/26)
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- Studies on benzofuran-7-carboxamides as poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors
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Benzofuran-7-carboxamide was identified as a novel scaffold of poly(ADP-ribose) polymerase-1 (PARP-1) inhibitor. A series of compounds with various 2-substituents including (tertiary amino)methyl moieties substituted with aryl ring and aryl groups containing tertiary amines, were synthesized and biologically evaluated to elucidate the structure-activity relationships and optimize the potency. 2-[4-(Pyrrolidin-1-ylmethyl)phenyl]-benzofuran-7- carboxamide (42) was the most potent as an IC50 value of 40 nM among those.
- Lee, Sunkyung,Yi, Kyu Yang,Lee, Byung Ho,Oh, Kwang Seok
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experimental part
p. 1147 - 1153
(2012/07/14)
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- Formal asymmetric hydration of non-activated alkenes in aqueous medium through a "chemoenzymatic catalytic system"
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A direct one-pot conversion of (substituted) styrene(s) into the corresponding (substituted) (R)-phenylethan-1-ol(s) in a highly enantioselective manner has been achieved by using a "chemoenzymatic catalytic system", comprising a palladium-catalyzed Wacker-Tsuji oxidation and subsequent enantioselective enzymatic reduction of the in situ formed (substituted) acetophenone(s) (see scheme). Copyright
- Schnapperelle, Ingo,Hummel, Werner,Groeger, Harald
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supporting information; experimental part
p. 1073 - 1076
(2012/03/26)
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- Microwave-assisted synthesis of 5-substituted 2-aminothiophenes starting from arylacetaldehydes
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An easy three-step pathway for the synthesis of arylacet-aldehydes from the corresponding carboxylic acids in very high yields is described. Their use as precursors of 5-substituted-2-aminothiophenes is illustrated via a microwave-assisted Gewald reaction. This method allows obtaining the expected compounds in a shorter time and with better yields and purities than the classical procedures. Georg Thieme Verlag Stuttgart - New York.
- Revelant, Germain,Dunand, Sandrine,Hesse, Stephanie,Kirsch, Gilbert
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experimental part
p. 2935 - 2940
(2011/11/01)
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- Synthesis of α-Aryl nitriles through palladium-catalyzed decarboxylative coupling of cyanoacetate salts with aryl halides and triflates
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Worth its salt: The palladium-catalyzed decarboxylative coupling of the cyanoacetate salt as well as its mono- and disubstituted derivatives with aryl chlorides, bromides, and triflates is described (see scheme). This reaction is potentially useful for the preparation of a diverse array of α-aryl nitriles and has good functional group tolerance. S-Phos=2-(2,6- dimethoxybiphenyl)dicyclohexylphosphine), Xant-Phos=4,5-bis(diphenylphosphino)- 9,9-dimethylxanthene. Copyright
- Shang, Rui,Ji, Dong-Sheng,Chu, Ling,Fu, Yao,Liu, Lei
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supporting information; experimental part
p. 4470 - 4474
(2011/06/24)
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- Oxidative rearrangement of alkyl aryl/heteroaryl ketones by 1,2-aryl/heteroaryl shift using iodic acid
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A method for synthesis of α-aryl/heteroaryl alkanoic acids involving oxidative rearrangement of alkyl aryl/heteroaryl ketones by 1,2-aryl/heteroaryl shift using iodic acid is described. ARKAT-USA, Inc.
- Huddar, Sameerana N.,Deshmukh, Swapnil S.,Akamanchi, Krishnacharya G.
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experimental part
p. 67 - 75
(2011/06/19)
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- Oxidative rearrangements of arylalkanones with 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide, a 'green' analog of Koser's reagent
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Previous methods for the conversion of arylalkanones to alkyl 2-arylesters by oxidative rearrangement utilized reagents which either produced toxic metal salts or halogenated organics as by-products. In this report, 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide (HMBI) is used to effect this useful transformation, where the reduced iodine reagent is water-soluble and readily recycled.
- Justik, Michael W.
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p. 3003 - 3007
(2008/02/06)
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- PALLADACYLES, THEIR PREPARATION AND CATALYTIC PROCESSES INVOLVING THEIR USE AS CATALYST, ESPECIALLY CATALYTIC CARBONYLATION PROCESSES
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The present invention relates to palladium compounds and their use as catalysts for improved catalytic processes. Specifically there is disclosed an improved catalytic carbonylation process and improved carbonylation catalysts. Catalysts in dimer form are also disclosed, as is their catalytic activity and methods of making the compounds.
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Page/Page column 30-31
(2008/06/13)
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- Palladium-catalyzed carbonylation of arylmethyl halides: Efficient synthesis of arylacetic acid and esters
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Organopalladium complexes derived from 2-(bromomethyl)benzenemethanol, 2- bromo- and iodobenzenemethanols and 2-iodobenzeneethanol are efficient catalysts for the reaction of carbon monoxide and arylmethyl halides leading to arylacetic acids and esters.
- Jones, Ray V.H.,Lindsell, W. Edward,Palmer, Daniel D.,Preston, Peter N.,Whitton, Alan J.
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p. 8695 - 8697
(2007/10/03)
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- NOVEL ADENINE COMPOUND AND USE THEREOF
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A drug for topically administration which is effective as an antiallergic agent. The drug for topically administration contains as an active ingredient an adenine compound represented by the general formula (1): [wherein ring A represents a 6 to 10 membered, mono or bicyclic, aromatic hydrocarbon or a 5 to 10 membered, mono or bicyclic, aromatic heterocycle containing one to three heteroatoms selected among 0 to 2 nitrogen atoms, 0 or 1 oxygen atom, and 0 or 1 sulfur atom; n is an integer of 0 to 2; m is an integer of 0 to 2; R represents halogeno, (un)substituted alkyl, etc.; X1 represents oxygen, sulfur, NR1 (R1 represents hydrogen or alkyl), or a single bond; Y1 represents a single bond, alkylene; etc.; Y2 represents a single bond, alkylene, etc.; Z represents alkylene; and at least one of Q1 and Q2 represents -COOR10 (wherein R10 represents (un)substituted alkyl, etc.), etc.] or a pharmaceutically acceptable salt of the compound.
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Page/Page column 28
(2010/02/12)
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- A facile conversion of aryl alkyl ketones into methyl 2-arylalkanoates using poly[4-(diacetoxyiodo)styrene]
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Treatment of aryl alkyl ketones with poly[4-(diacetoxyiodo)styrene] and trimethyl orthoformate in the presence of sulfuric acid followed by hydrolysis afforded methyl 2-arylalkanoates in good yields. The polymeric reagent can be regenerated and reused as an environmentally benign reagent.
- Sheng, Shou-Ri,Zhong, Ming-Hua,Liu, Xiao-Ling,Luo, Qiu-Yan,Chen, Hui-Zong
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p. 392 - 393
(2007/10/03)
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- Synthesis and structure-antifungal activity relationships of 3-aryl-5-alkyl-2,5-dihydrofuran-2-ones and their carbanalogues: Further refinement of tentative pharmacophore group
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Two series of 3-(substituted phenyl)-5-alkyl-2,5-dihydrofuran-2-ones related to a natural product, (-)incrustoporine, were synthesized and their in vitro antifungal activity evaluated. The compounds with halogen substituents on the phenyl ring exhibited selective antifungal activity against the filamentous strains of Absidia corymbifera and Aspergillus fumigatus. On the other hand, the influence of the lenghth of the alkyl chain at C(5) was marginal. The antifungal effect of the most active compound against the above strains was higher than that of ketoconazole, and close to that of amphotericin B. In order to verify the hypothesis about a possible relationship between the Michael-accepting ability of the compounds and their antifungal activity, a series of simple carbanalogues, 2-(substituted phenyl)cyclopent-2-enones, was prepared and subjected to antifungal activity assay as well.
- Pour, Milan,Spulak, Marcel,Balsanek, Vojtech,Kunes, Jiri,Kubanova, Petra,Buchta, Vladimir
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p. 2843 - 2866
(2007/10/03)
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- Arylacetamides and their use as medicaments
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The new arylacetamides are obtained by first converting appropriately substituted arylacetic acids into the acetyl chlorides and then converting these into the amides using the appropriate amines. The new arylacetamides can be used as active compounds in medicaments, in particular in antiatherosclerotic medicaments.
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- 3-Phenyl-5-methyl-2H,5H-furan-2-ones: Tuning antifungal activity by varying substituents on the phenyl ring
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A series of racemic 3-phenyl-5-methyl-2H,5H-furan-2-ones related to a natural product, (-)incrustoporine, was synthesized, and their antifungal activity evaluated. The key structural feature, furanone ring, was closed via H2SO4-mediated cyclization of 2-phenylpent-4-enoic acids. The compounds displayed antifungal activity, especially against filamentous fungi. Expressed as the minimum inhibition concentration (MIC) in μmol/L, the activity of the most promising derivative against Absidia corymbifera matched that of ketoconazole (31.25 μmol/L). In terms of μg/mL, the substance was more active (7.6 μg/mL) than this standard antifungal drug (16.6 μg/mL). (C) 2000 Elsevier Science Ltd. All rights reserved.
- Pour, Milan,Spulak, Marcel,Balsanek, Vojtech,Kunes, Jiri,Buchta, Vladimir,Waisser, Karel
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p. 1893 - 1895
(2007/10/03)
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- Radicals from fragmentation of benzyloxymethoxycarbenes in solution
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2-Benzyloxy-2-methoxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines, including the parent as well as p-substituted analogues, undergo thermolysis at 100°C in benzene to afford a mixture of products. Two primary fragmentations of the oxadiazolines were identified. The major pathway involves 1,3-dipolar cycloreversion to N2 and the corresponding carbonyl ylides. The latter dissociate to acetone and the corresponding benzyloxy(methoxy)carbenes, which undergo fragmentation to ArCH2 and MeOCO radical pairs that recombine to afford methyl arylacetates. Carbene dimers were not observed, showing that the fragmentation process is faster than carbene dimerization. A second fragmentation pathway observed for the oxadiazolines is an alternative cycloreversion to the corresponding benzyl methyl carbonate and 2- diazopropane. Products from diazopropane included acetone azine and, in some instances, traces of propene.
- Merkley, Nadine,El-Saidi, Manal,Warkentin, John
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p. 356 - 361
(2007/10/03)
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- Synthetic use of poly[4-(diacetoxyiodo)styrene] for organic reactions
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Poly[4-(diacetoxyiodo)styrene] is sufficiently reactive for the iodination of aromatics, the oxidative 1,2-aryl migration of alkyl aryl ketones, the α-hydroxylation of ketones, and the oxidation of hydroquinones and sulfides similarly to (diacetoxyiodo)benzene. Here, those reactions with poly[4-(diacetoxyiodo)styrene] are very useful because of the simple operation; thus, filtration gives the crude products and recovered poly(4- iodostyrene), and then poly[4-(diacetoxyiodo)-styrene] can be regenerated by oxidation of the recovered poly(4-iodostyrene), which are reused for the same reactions.
- Togo, Hideo,Abe, Seiichiro,Nogami, Genki,Yokohama, Masataka
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p. 2351 - 2356
(2007/10/03)
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- Regioselectivity of the Base-Induced Ring Cleavage of 1-Oxygenated Derivatives of Cyclobutabenzene
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Oxy anions 3 generated from 1,2-dihydrocyclobutabenzen-1-ones 1 through addition of a charged nucleophile or from 1-hydroxy-1,2-dihydrocyclobutabenzenes 2 by deprotonation with base lead to stable products through distal and/or proximal cleavage of the strained four-membered ring via benzyl carbanion 4 and/or aryl carbanion 5. A systematic study of this process reveals the relative stability of the two isomeric carbanions 4 and 5 as a key factor in determining the course of the ring-cleavage reaction. While benzyl carbanions 4 can be trapped with carbon electrophiles, attempts at trapping aryl carbanions 5 with electrophiles other than H+ failed. In protic solvents, the magnesium salt of the tertiary alcohol 2 shows an increased rate of proximal cleavage as compared to its alkali salts. From this, we conclude that, in contrast to benzyl carbanions 4, free aryl carbanions 5 are of transient existence only. Proximal C,C-bond cleavage seems to occur either through protonation of 5 from a fast, reversible equilibrium 3?5 in which 3 strongly predominates, or in protic solvents possibly even through a rate-limiting protonation of 3 at the aromatic C-atom, bypassing free anion 5 altogether. Thus, additional factors other than just the relative stability of isomeric carbanions 4 and 5 are of importance in determining the regiochemistry of the base-induced C,C-bond cleavage in ketones 1 and in alcohols 2.
- Gokhale, Abha,Schiess, Peter
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p. 251 - 267
(2007/10/03)
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- Synthetic application of poly[styrene(iodoso diacetate)]
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Poly[styrene(iodoso diacetate)] is sufficiently reactive to effect the iodination of aromatics and oxidative 1,2-aryl migration of alkyl aryl ketones as (diacetoxyiodo)benzene, and can be regenerated and reused for the same reactions.
- Togo, Hideo,Nogami, Genki,Yokoyama, Masataka
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p. 534 - 536
(2007/10/03)
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- Media controlled photo - Favorskii type rearrangement of α-chloro acetophenones: Synthesis of phenylacetic acids
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Photolysis of substituted α-chloro acetophenones has been studied in different solvent systems wherein 1,2-aryl migration is found to be media controlled. Effect of substituents on the migratory aptitude and a direct access to phenylacetic acids, in practical yields, has been described.
- Dhavale, Dilip D.,Mali, Vasant P.,Sudrik, Surendra G.,Sonawane, Harikisan R.
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p. 16789 - 16794
(2007/10/03)
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- Conformational Control of the Photochemistry and Photophysics of Diphenylacetone
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We report the direct observation of the lowest triplet states of 1,3-diphenylacetone (DBK) and two methylated derivatives by direct detection time-resolved electron spin resonance (TRESR) at 15 K in methylcyclohexane glass.The spectral features are broad with multiple peaks in the ΔM2 = 2 region, which we assign to a multitude of conformations frozen into the glass.Successive experiments on a single sample provide evidence that cartain of these conformations can be photochemically removed.DBK and 1-p-tolyl-3-phenylacetone (p-MeDBK) give single-exponential fluorescence lifetimes of 2.7 ns. 1,3-di-p-tolylacetone (p,p'-diMeDBK) gives a multiexponential fluorescence decay.ZFS parameters, triplet sublevel populating rates, and rates of triplet-state α-cleavage appear to be more sensitive functions of conformation than would be expected for nominally aliphatic ketones.We conclude that a significant portion of the unpaired electron density of the triplet state of DBK (and its derivatives) is delocalized into the phenyl rings and propose that this delocalization is responsible for the previously observed change in rate of triplet-state α-cleavage with substitution in the phenyl rings.
- Lipson, Matthew,Noh, TaeHee,Doubleday, Charles E.,Zaleski, Jeffrey M.,Turro, Nicholas J.
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p. 8844 - 8850
(2007/10/02)
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- N-(3-pyridylalkyl)sulfonamide compounds which have useful pharmaceutical activity
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Illustrative examples of the N-(3-pyridylalkyl)sulfonamide derivative are represented by the following formulae [II] and [III]: STR1 The derivatives are available for a thromboxane A2 production inhibitor, a thromboxane A2 antagonist, a prostaglandin H2 antagonist, an anti-thrombus agent, a thrombus-preventing agent and an anti-allergy agent.
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- Anodic Oxidation of α-Substituted p-Xylenes. Electronic and Stereoelectronic Effects of α-Substituents in the Deprotonation of Alkylaromatic Radical Cations
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The effect of α-substituents on the deprotonation rate from the benzylic position of alkylaromatic radical cations, k(CH2Z)/k(CH3), has been investigated by determining the intramolecular selectivity in the anodic oxidation in acetic acid of a α-Z-substituted p-xylenes 1 (Z = H, OMe, OH, Me, tert-butyl, OAc, COOMe, CN), 5,6-dimethylindan 4 (R = H), and 2,2,5,6-tetramethylindan 4 (R = Me).Some oxidations induced by CAN have also been carried out.It has been found that, with the exception of when Z = tert-butyl, the deprotonation rate of 1.+ is always faster from the CH2Z group than from the CH3 group, independently of the electron-donating or electron-withdrawing nature of Z.The electron-donating groups (OH, OMe, Me), however, exert a larger effect than the electron-withdrawing ones (COOMe, CN).The negligible deprotonation rate from CH2-t-Bu has been ascribed to stereoelectronic effects (the bulky tert-butyl group does not allow the C-H bonds to be collinear with the ?-system), the suggestion being nicely confirmed by the observation that the deprotonation rate from the position 1(3), relative to that from the 5(6)-methyl group, is almost identical in the radical cations of 4 (R = H and Me).The effect of the other α-substituents is mainly of electronic nature and has been rationalized on the basis of a variable transition-state structure for the deprotonation process.It is suggested that with +R groups most of the charge, in the transition state, has been transferred to the Cα-H bond where it can be stabilized by the α-substituent.With electron-withdrawing groups less charge transfer has taken place and the rate-enhancing effects of these groups is ascribed to their capability to significantly decrease the strength of the Cα-H bond.
- Baciocchi, Enrico,Mattioli, Mario,Romano, Roberta,Ruzziconi, Renzo
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p. 7154 - 7160
(2007/10/02)
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