- Para-Selective C-H Borylation of Common Arene Building Blocks Enabled by Ion-Pairing with a Bulky Countercation
-
The selective functionalization of C-H bonds at the arene para position is highly challenging using transition metal catalysis. Iridium-catalyzed borylation has emerged as a leading technique for arene functionalization, but there are only a handful of strategies for para-selective borylation, which operate on specific substrate classes and use bespoke ligands or catalysts. We describe a remarkably general protocol which results in para-selectivity on some of the most common arene building blocks (anilines, benzylamines, phenols, benzyl alcohols) and uses standard borylation ligands. Our strategy hinges upon the facile conversion of the substrates into sulfate or sulfamate salts, wherein the anionic arene component is paired with a tetrabutylammonium cation. We hypothesize that the bulk of this cation disfavors meta-C-H borylation, thereby promoting the challenging para-selective reaction.
- Mihai, Madalina T.,Williams, Benjamin D.,Phipps, Robert J.
-
supporting information
p. 15477 - 15482
(2019/10/11)
-
- Dihydroxy pyrimidine compound and use thereof
-
The invention provides a dihydroxy pyrimidine compound, its structural general formula is: Wherein R1 In order to contain the substituent of the aryl, heterocyclic or containing substituent is C1 - C6 alkyl; R2 Is C1 - C6 alkyl, C1 - C6 alkyl aryl, C1 - C6 alkyl heterocyclic group or a hydrogen atom; x, y each is between 0 - 6 is any natural number. The invention also provides a two-hydroxy pyrimidine compounds in the preparation of anti-influenza virus in the application. The present invention provides a dihydroxy pyrimidine compounds to the influenza virus activity has better inhibition, can remarkably reduce the toxicity of the influenza virus, and cytotoxicity is relatively low, thus can such compounds for the preparation of anti-influenza virus drugs.
- -
-
Paragraph 0026-0028
(2019/07/04)
-
- Antiproliferative activity and SARs of caffeic acid esters with mono-substituted phenylethanols moiety
-
A series of CAPE derivatives with mono-substituted phenylethanols moiety were synthesized and evaluated by MTT assay on growth of 4 human cancer cell lines (Hela, DU-145, MCF-7 and ECA-109). The substituent effects on the antiproliferative activity were systematically investigated for the first time. It was found that electron-donating and hydrophobic substituents at 2′-position of phenylethanol moiety could significantly enhance CAPE's antiproliferative activity. 2′-Propoxyl derivative, as a novel caffeic acid ester, exhibited exquisite potency (IC50?=?0.4?±?0.02 & 0.6?±?0.03?μM against Hela and DU-145 respectively).
- Xie, Jin,Yang, Fengzhi,Zhang, Man,Lam, Celine,Qiao, Yixue,Xiao, Jia,Zhang, Dongdong,Ge, Yuxuan,Fu, Lei,Xie, Dongsheng
-
p. 131 - 134
(2016/12/27)
-
- Discovery, synthesis, and structure-activity relations of 3,4-dihydro-1H-spiro(naphthalene-2,2′-piperidin)-1-ones as potassium-competitive acid blockers
-
With the aim to discover a gastric antisecretory agent more potent than the existing proton pump inhibitors, novel 3,4-dihydro-1H-spiro(naphthalene-2,2′-piperidin)-1-one derivatives, which could occupy two important lipophilic pockets (described as LP-1 and LP-2) of H+,K+-ATPase and can strongly bind to the K+-binding site, were designed based on a docking model. Among the compounds synthesized, compound 4d showed a strong H+,K+-ATPase-inhibitory activity and a high stomach concentration in rats, resulting in potent inhibitory action on histamine-stimulated gastric acid secretion in rats. Furthermore, 4d exerted significant inhibitory action on histamine-stimulated gastric-acid secretion in rats with a rapid onset and moderate duration of action after the administration. These findings may lead to a new insight into the drug design of potassium-competitive acid blockers.
- Imaeda, Toshihiro,Ono, Koji,Nakai, Kazuo,Hori, Yasunobu,Matsukawa, Jun,Takagi, Terufumi,Fujioka, Yasushi,Tarui, Naoki,Kondo, Mitsuyo,Imanishi, Akio,Inatomi, Nobuhiro,Kajino, Masahiro,Itoh, Fumio,Nishida, Haruyuki
-
p. 3719 - 3735
(2017/06/13)
-
- Preparation method for hemihydrate lorcaserin hydrochloride
-
The invention discloses a preparation method for hemihydrate lorcaserin hydrochloride. The preparation method comprises the following steps: (1) making a compound shown as a formula III react with ammonia to obtain a compound shown as a formula II; (2) under the protection of nitrogen gas, dissolving the compound shown as the formula II in an organic solvent, adding a hydrogen chloride solution of which the solvent is the organic solvent to salify, and adding water and cyclohexane to form a hemihydrate in order to obtain the compound shown as a formula I, wherein the organic solvent is isopropanol or 1,4-dioxane. In the preparation method disclosed by the invention, ammonium hydroxide substitutes for potassium carbonate in the prior art, so that unqualified ignition residues of a finial product caused by potassium chloride generated after salt removal can be avoided; an isopropoxide hydrochloride solution substitutes for the conventional hydrogen chloride gas, so that other impurities can be prevented from being introduced in a preparation process under the improper control of dosage and rate of the gas.
- -
-
Paragraph 0106; 0107
(2017/08/28)
-
- Direct Ruthenium-Catalyzed Hydrogenation of Carboxylic Acids to Alcohols
-
The "green" reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids. The novel method showed broad substrate tolerance and a variety of aliphatic carboxylic acids including biomass-derived compounds can be smoothly reduced.
- Cui, Xinjiang,Li, Yuehui,Topf, Christoph,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 10596 - 10599
(2015/09/02)
-
- A General, Practical Triethylborane-Catalyzed Reduction of Carbonyl Functions to Alcohols
-
A combination of the abundant and low-cost triethylborane and sodium alkoxide generates a highly efficient catalyst for reduction of esters, as well as ketones and aldehydes, to alcohols using an inexpensive hydrosilane under mild conditions. The catalyst system exhibits excellent chemoselectivity and a high level of functional group tolerance. Mechanistic studies revealed a resting state of sodium triethylalkoxylborate that is the product of the reaction of BEt3 with sodium alkoxide. This borate species reacts with hydrosilane to form NaBEt3H, which rapidly reduces esters.
- Peng, Dongjie,Zhang, Mintao,Huang, Zheng
-
supporting information
p. 14737 - 14741
(2015/10/19)
-
- Enantioselective hydrosilylation of aromatic alkenes catalyzed by chiral bis(oxazolinyl)phenyl-rhodium acetate complexes
-
Highly efficient and enantioselective hydrosilylation of aromatic alkenes catalyzed by the chiral rhodium acetate complexes with the bis(oxazolinyl)phenyl ligands has been reported that afforded chiral silane derivatives with up to 99% ee. Georg Thieme Ve
- Naito, Tatsuo,Yoneda, Takuma,Ito, Jun-Ichi,Nishiyama, Hisao
-
p. 2957 - 2960
(2013/02/22)
-
- Exploiting self-assembly for ligand-scaffold optimization: Substrate-tailored ligands for efficient catalytic asymmetric hydroboration
-
(Chemical Equation Presented) Mix and match: A self-assembled ligand library (SAL XY) affords a wide range of R/S ratios in Rh-catalyzed asymmetric hydroboration (see scheme; nbd = 2,5-norbornadiene, R* is a chiral substituent). Ligand-scaffold optimization reveals "substrate- tailored" ligands that afford high regio- and enantioselectivity for a variety of ortho-substituted styrene derivatives.
- Moteki, Shin A.,Takacs, James M.
-
p. 894 - 897
(2008/09/20)
-
- Effect of chain length on radical to carbanion cyclo-coupling of bromoaryl alkyl-linked oxazolines: 1,3-Areneotropic migration of oxazolines
-
(Chemical Equation Presented) 2-Halophenylalkyl-2-oxazolines with alkyl chain spacers of two to six C atoms (n = 0-4) were prepared and their S RN1-type reactions with several base systems examined. The best conditions to promote cyclocoupling to the corresponding benzocycloalkane derivatives involved use of LDA in THF. The precursors with 3-C-atom and 4-C-atom spacers gave good yields of 2-(1′-phenylindan-1′-yl)-2- oxazolines and 2-(1-phenyl-1,2,3,4-tetrahydronaphthalen-1-yl)-2-oxazoline, respectively. The major products from the precursor with a 5-C-atom spacer were derivatives of benzocycloheptane in which the oxazoline group had undergone a novel areneotropic migration from the end of the spacer to the benzo ring. The product from reaction of the corresponding 2-C-atom precursor was a 9-oxazolinophenanthrene derivative. EPR spectroscopy showed the intermediates of the LDA-promoted reactions to be radical anions of the product benzocycloalkanes. This supported an SRN1-type chain mechanism involving initial production of aryl radicals connected to azaenolate ions via the spacer groups. Intramolecular radical to carbanion coupling then generated ring-closed benzocycloalkane radical anions that transferred an electron to more precursor. Diastereoselective radical to carbanion cyclo-coupling reactions were carried out with 2-bromophenylpropyl precursors containing chiral 2-oxazolines. The diastereoselectivity achievable was modest, but the product diastereoisomeric Indane derivatives were easily separable by chromatography.
- Marshall, Laura J.,Roydhouse, Mark D.,Slawin, Alexandra M. Z.,Walton, John C.
-
p. 898 - 911
(2007/10/03)
-
- Radical-carbanion cyclo-coupling in armed aromatics: Overriding steric hindrance to ring closure
-
ω-(2-Halophenyl)alkyl-2-oxazolines were prepared and reacted via base promoted intramolecular coupling of radical with carbanionic centres to yield 1-phenyl-1-oxazolino-indan and -tetralin derivatives containing quaternary C-atoms. The Royal Society of Chemistry 2005.
- Roydhouse, Mark D.,Walton, John C.
-
p. 4453 - 4455
(2007/10/03)
-
- Pyrrolo[2,3-d] pyrimidines as antiviral agents
-
This invention relates to a novel class of 4,5,6,7-substituted non-nucleoside, non-phosphorylatable pyrrolo[2,3-d]pyrimidines which exhibit both significantly lower levels of cytotoxicity and superior antiviral activity than known nucleoside, non-nucleoside, and non-nucleoside, non-phosphorylatable pyrrolo[2,3-d]pyrimidine derivatives, particularly against human DNA viruses such as cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1). These compounds are represented by the following formula: wherein: R4is —NR1R2or oxo; R5is —CN, or —CSNR1R2, or —CONR1R2; R6is —H, or halo, or —NR1R2; wherein R1and R2are independently —H or an aliphatic group; and R7is of the formula R3—Ar, wherein R3is an aliphatic group and Ar is an unsubstituted aryl or an aryl independently substituted with halo, nitro, amino, or aliphatic groups; provided that when R5is a —CN or —CSNH2, and R6is a —H or —NH2, and Ar is a —C6H5or a phenyl substituted with only one aliphatic group, R3is an aliphatic group other than methyl such that —R3— is not a —CH2—; and pharmaceutically acceptable salts, prodrugs and derivatives thereof.
- -
-
-
- New C2-symmetrical 1,2-diphosphanes for the efficient rhodium-catalyzed asymmetric hydroboration of styrene derivatives
-
A double [2,3] sigmatropic rearrangement enables the fast synthesis of novel C2-symmetrical 1,2-diphosphanes in good yields. These phosphanes (for example, 1; c-Hex = cyclohexyl) are highly efficient ligands for the rhodium-catalyzed asymmetric hydroboration of a wide variety of styrenes (see scheme). cod = 1,5-cyclooctadiene; DME = 1,2-dimethoxyethane.
- Demay, Steandphane,Volant, Florence,Knochel, Paul
-
p. 1235 - 1238
(2007/10/03)
-
- The scope of catalytic asymmetric hydroboration/oxidation with rhodium complexes of 1,1'-(2-diarylphosphino-1-naphthyl)isoquinolines
-
Preformed cationic Rh complexes of the title ligands are effective for the asymmetric hydroboration/oxidation of vinylarenes at ambient temperature. These vinylarenes may carry E- or Z-β substituents but not a substituents. Enantiomer excesses of up to 97% can be obtained in the most favourable cases. The enantioselectivity is moderately sensitive to the structure of the ligand: the difurylphosphino ligand gave superior results for electron-poor styrenes and the diphenylphosphino ligand the best results for electron-rich reactants. Mechanistic aspects are discussed.
- Doucet, Henri,Fernandez, Elena,Layzell, Timothy P.,Brown, John M.
-
p. 1320 - 1330
(2007/10/03)
-
- Stereochemical control in microbial reduction. Part 31: Reduction of alkyl 2-oxo-4-arylbutyrates by baker's yeast under selected reaction conditions
-
Treatment of baker's yeast with phenacyl chloride in an aqueous-organic solvent has been proven to be an effective method of inhibiting the enzymes that afford (S)-enantiomers of α-hydroxy esters in the reduction of α-keto esters. The procedure is effective for the whole-cell system to produce the (R)-product with high chemical yield and high enantiomeric excess.
- Dao, Duc Hai,Okamura, Mutsuo,Akasaka, Takeshi,Kawai, Yasushi,Hida, Kouichi,Ohno, Atsuyoshi
-
p. 2725 - 2737
(2007/10/03)
-
- Synthesis and evaluation of novel alkylpiperazines as potential dopamine antagonists
-
Several alkylpiperazines, monocyclic subfragments of known tricyclic neuroleptic agents, were evaluated as dopamine antagonists in the isolated rabbit ear artery preparation. Compounds prepared and evaluated are of the general structure Ar-X-(CH2)(n)-Y, where X = C, O, and N, n = 1-3, and Y, for the most part, was 4-methylpiperazine. Those compounds where X = NH, n = 3, and X = (Z)-CH=CH, n = 2, with an electron-witdrawing group meta to the side chain, possess dopamine antagonist activity comparable to that of clozapine. It is concluded that the entire tricyclic structure of phenothiazine-like agents (or at least more than a monocyclic ring system) is necessary for optimal activity as a dopamine antagonist in the receptor preparation used in this study.
- Glennon,Salley Jr.,Steinsland,Nelson
-
p. 678 - 683
(2007/10/02)
-