- Metal-free protocol for the synthesis of α-bromo ketones from olefins using TsNBr2
-
TsNBr2 reacts readily with olefins to produce α-bromo ketones at room temperature. The synthesis was carried out by treating an olefin with TsNBr2 in acetone-water mixture in 30:1 ratio. Excellent yield of corresponding α-bromo ketone could be achieved within a short time.
- Rajbongshi, Kamal Krishna,Hazarika, Debojit,Phukan, Prodeep
-
-
Read Online
- Water-soluble poly(ε-caprolactone)-Paclitaxel prodrugs toward an efficient drug delivery system
-
In this paper, poly(ε-caprolactone)-graft-carboxylic acid (P(α-C2CL)) was prepared via a thio-bromo click reaction between mercaptosuccinic acid and poly(α-bromo-ε-caprolactone). It is readily soluble in aqueous solutions (pH 5.5-9.8) due to the presence
- Wang, Ji,Sun, Huanjiao,Li, Deshan,Yuan, Jie,Zhang, Xuefei,Tang, Haoyu
-
-
Read Online
- Synthesis of Antibacterial Glycosylated Polycaprolactones Bearing Imidazoliums with Reduced Hemolytic Activity
-
Most synthetic antimicrobial polymers are not biodegradable, thus limiting their potential for large-scale applications in personal care disinfection and environmental contaminations. Poly(?-caprolactone) (PCL) is known to be both biodegradable and biocom
- Xu, Yuan,Zhang, Kaixi,Reghu, Sheethal,Lin, Yichao,Chan-Park, Mary B.,Liu, Xue-Wei
-
-
Read Online
- Molecular modeling and biological evaluation of 2-N,N- dimethylaminecyclohexyl 1-N′,N′-dimethylcarbamate isomers and their methylsulfate salts as cholinesterases inhibitors
-
This work presents a detailed theoretical and experimental study on the inhibitory properties of 2-N,N-dimethylaminecyclohexyl 1-N′,N′- dimethylcarbamate isomers and their methylsulfate salts against the cholinesterases enzymes. The in vitro inhibition test performed by the Ellman's method showed that the salt form compounds were more active than the neutral ones in cholinesterases inhibition. The trans salt showed good selectivity towards the inhibition of erythrocyte cholinesterase with a maximum limit around 90% and 55% for the plasma cholinesterase inhibition. Molecular modeling, docking and experimental results performed in this study showed to be important initial steps toward the development of a novel pharmaceuticals in the fight against Alzheimer's disease.
- Bocca, Cleverson C.,Rittner, Roberto,H?ehr, Nelci F.,Pinheiro, Glaucia M.S.,Abiko, Layara A.,Basso, Ernani A.
-
-
Read Online
- Application of poly(vinylphenyltrimethylammonium tribromide) resin as an efficient polymeric brominating agent in the α-bromination and α-bromoacetalization of acetophenones
-
The applications of a new supported tribromide reagent based on poly(vinylbenzyltrimethylammonium hydroxide) resin (Amberlite 717) were reported. This supported tribromide resin was used directly in α-bromination and α-bromoacetalization of acetophenones without any other catalyst under mild conditions. The effects of solvents and the amount of the supported tribromide resin on the reactions were investigated. Under the optimal conditions, most of α-bromo and α-bromoacetal of acetophenones were selectively obtained in excellent yields.
- Han, Bingbing,Zheng, Zubiao,Zheng, Dongcheng,Zhang, Lei,Cui, Peng,Shi, Jianjun,Li, Changjiang
-
-
Read Online
- Protonation of silylenol ether via excited state proton transfer catalysis
-
We demonstrate the photocatalytic protonation of a silylenol ether using 7-bromo-2-naphthol as an ESPT catalyst with phenol as the sacrificial proton source. Greater than 95% conversion is achieved with 1 mol% catalyst. The reaction cycle is dependent on the significantly increased acidity of the catalyst in the excited state as well as the long lifetime for the triplet excited state of 7-bromo-2-naphthol. The reaction does not occur in the absence of light (367 nm) and can readily be controlled by light intensity modulation. We also demonstrate that a 72% reaction yield can be obtained with unsubstituted naphthol as the catalyst by coupling triplet energy transfer, via a visible light absorbing (445 nm) sensitizer, into the catalytic cycle. These results open the door to an entirely new class of sensitized photocatalytic reactions that harness the excited state acidity of ESPT dyes.
- Das, Anjan,Banerjee, Tanmay,Hanson, Kenneth
-
-
Read Online
- 1,3-Dibromo-5,5-dimethylhydantoin (DBH) mediated one-pot syntheses of α-bromo/amino ketones from alkenes in water
-
α-Bromo ketones are versatile intermediates of high practical utility. Traditional approaches to these compounds are restricted to a relatively hazardous/complex reagent combination, a long reaction time, the use of non-environmentally friendly solvents, or a limited substrate scope. Herein, we describe the development of a new methodology for the preparation of α-bromo ketones from alkenes using 1,3-dibromo-5,5-dimethylhydantoin (DBH) as a bromine source and an oxidant simultaneously. This easy to carry out two-step one-pot protocol proceeds in water and provides high yield of a great variety of α-bromo ketones. Addition of an amine to the intermediate α-bromo ketone further enables the preparation of α-amino ketones in a one-pot sequence.
- Xu, Senhan,Wu, Ping,Zhang, Wei
-
-
Read Online
- On the4 JHH long-range coupling in 2-bromocyclohexanone: Conformational insights
-
2-Bromocyclohexanone is a model compound in which a 4J H2,H6 coupling constant is observed, whereas the corresponding 4-4H2,H4 is absent. The observed long-range coupling is not only a result of the known W-type
- Coelho, Jakelyne V.,Freitas, Matheus P.,Tormena, Claudio F.,Rittner, Roberto
-
-
Read Online
- SYNTHESIS OF 4-IMIDAZOLIN-2-ONES
-
The reaction of α-bromoketones with CO(NH2)2 and AcONH4 in aqueous acetic acid gave substituted 4-imidazolin-2-ones.
- Zav'yalov, S. I.,Sitkareva, I. V.,Ezhova, G. I.,Dorofeeva, O. V.,Zavozin, A. G.,Rumyantseva, E. E.
-
-
Read Online
- Tuned Cationic Dendronized Polymer: Molecular Scavenger for Rheumatoid Arthritis Treatment
-
Cell-free deoxyribonucleic acid (cfDNA) released from either dead or damaged cells serves as a key autoantigen in rheumatoid arthritis (RA). They can be recognized by nucleic acid (NA) sensors such as the toll-like receptor (TLR), leading to activation of
- Peng, Bo,Liang, Huiyi,Li, Yuyan,Dong, Cong,Shen, Jun,Mao, Hai-Quan,Leong, Kam W.,Chen, Yongming,Liu, Lixin
-
-
Read Online
- Conformational analysis of cis-2-halocyclohexanols; Solvent effects by NMR and theoretical calculations
-
Conformational problems often involve very small energy differences, even low as 0.5 kcal mol-1. This accuracy can be achieved by theoretical methods in the gas phase with the appropriate accounting of electron correlation. The solution behavio
- Basso, Ernani A.,Abiko, Layara A.,Gauze, Gisele F.,Pontes, Rodrigo M.
-
-
Read Online
- Structural characterization of two novel potential anticholinesterasic agents
-
Two novel compounds with possible anticholinesterase activity have been synthesized containing a carbamate and a dimethylamine group in 1,2-positions of a cyclohexane ring (cis and trans isomers). Conformer populations were established by a combination of NMR 1H coupling constant analysis and DFT (B3LYP/6-311 + G(d,p)) calculations. 13C chemical shifts were calculated in order to confirm signal attributions. The cis isomer adopts a conformation in which the carbamate group lies at the axial position (>99%), whereas the trans isomer adopts a diequatorial arrangement (98%). These preferences have been explained in terms of syn-1,3-diaxial interactions of the individual groups.
- Oliveira, Paulo R.,Wiectzycosky, Franciele,Basso, Ernani A.,Gon?alves, Regina A.C.,Pontes, Rodrigo M.
-
-
Read Online
- Molecular modeling and anticholinesterasic activity of novel 2-arylaminocyclohexyl N,N-dimethylcarbamates
-
This work reports a detailed theoretical and experimental study of the novel isomer series cis- and trans-2-arylaminocyclohexyl N,N-dimethylcarbamates as potential inhibitors of cholinesterases. In vitro inhibition assay by Ellman's method with human bloo
- Bagatin, Mariane C.,Ca?ndido, Augusto A.,Pinheiro, Glaucia M.S.,Ho?ehr, Nelci F.,Machinski Jr., Miguel,Mossini, Simone A.G.,Basso, Ernani A.,Gauze, Gisele F.
-
-
Read Online
- A new NBS/oxone promoted one pot cascade synthesis of 2-aminobenzimidazoles/2-aminobenzoxazoles: A facile approach
-
A new strategy for the synthesis of 2-aminobenzimidazoles via a reaction of α-halogenated cyclohexanone with guanidine is reported. It provides a facile N-bromosuccinimide (NBS) mediated transition metal free, sustainable path for the synthesis of 2-substituted azoles. NBS along with the oxone promotes in situ halogenation of cyclohexanone, which in turn, when allowed to react with guanidine, afforded 2-aminobenzimidazoles (2-ABI). This eco-friendly protocol provides a competent laboratory synthesis method associated with significant advantages such as greater selectivity, cost-efficiency, mild reaction conditions, absence of chromatographic purification, clean reaction profile, and a simple work-up procedure to furnish high yields. The structures of all the synthesized compounds were confirmed on the basis of IR, 1H and 13C NMR, mass spectrometry, and elemental analyses data. In addition, we have also extended the scope of this strategy for obtaining 2-amino substituted benzoxazoles.
- Daswani, Ujla,Dubey, Nitin,Sharma, Pratibha,Kumar, Ashok
-
-
Read Online
- Synthesis of several isotopically labeled pyrrolo[1,3-d]pyrimidine analogs
-
Four members of a novel class of pyrrolo[2,3-d]pyrimidines that show potential for the treatment of asthma and neurodegenerative disorders, have been prepared with radioisotope labels and in one case with multiple stable isotope labels for ADME studies as
- Easter, John A.,Stolle, Wayne T.
-
-
Read Online
- Room-Temperature oxidation of secondary alcohols by bromate-bromide coupling in acidic water
-
The use of environmentally benign reactions is currently an important topic in the field of synthetic chemistry. Here we report a high-yielding method to oxidize aliphatic or aromatic secondary alcohols into corresponding ketones using nonhazardous and inexpensive BrOH reagent at room temperature in water. BrOH reagent was derived from NaBr and NaBrO3 in aqueous acid. Based on the presented results, a mechanism was proposed for this oxidation. The reported method offers a facile, efficient procedure to produce various ketones with a low amount of side products. Taylor & Francis Group, LLC.
- Paeaekkoenen, Sanna,Pursiainen, Jouni,Lajunen, Marja
-
-
Read Online
- Stereochemically defined cyclohexanediols through the regioselective ring-opening of silylated epoxy alcohols
-
The nucleophilic ring-opening of the silylated epoxy alcohol 2 leads to highly functionalized building blocks of defined stereochemistry, whereby the regioselectivity may be controlled through the proper choice of the nucleophilic and the reaction conditi
- Adam, Waldemar,Prein, Michael,Richter, Markus J.
-
-
Read Online
- Quinoxaline compound, preparation method and application of quinoxaline compound in medicine
-
The invention provides a quinoxaline compound, a preparation method and application of the quinoxaline compound in medicine, and particularly relates to a quinoxaline compound with PAR4 antagonistic activity, a preparation method of the quinoxaline compound, a pharmaceutical composition containing the quinoxaline compound and application of the quinoxaline compound. Specifically, the invention provides a compound shown as a general formula I and/or II or a tautomer or pharmaceutically acceptable salt thereof, a preparation method of the compound, and application of the compound or the tautomer or the pharmaceutically acceptable salt in medicines for preventing and/or treating thromboembolic diseases.
- -
-
Paragraph 0203-0206
(2021/07/24)
-
- Diastereoselective Additions of Allylmagnesium Reagents to α-Substituted Ketones When Stereochemical Models Cannot Be Used
-
The stereoselectivities of reactions of allylmagnesium reagents with chiral ketones cannot be easily explained by stereochemical models. Competition experiments indicate that the complexation step is not reversible, so nucleophiles cannot access the widest range of possible encounter complexes and therefore cannot be analyzed easily using available models. Nevertheless, additions of allylmagnesium reagents to a ketone can still be stereoselective provided that the carbonyl group adopts a conformation that leads to one face being completely blocked from the approach of the allylmagnesium reagent.
- Bartolo, Nicole D.,Demkiw, Krystyna M.,Valentín, Elizabeth M.,Hu, Chunhua T.,Arabi, Alya A.,Woerpel
-
p. 7203 - 7217
(2021/05/29)
-
- Copper-Mediated Dichotomic Borylation of Alkyne Carbonates: Stereoselective Access to (E)-1,2-Diborylated 1,3-Dienes versus Traceless Monoborylation Affording α-Hydroxyallenes
-
A mild copper-mediated protocol has been developed for borylation of alkynyl cyclic carbonates. Depending on the nature of the borylating reaction partner, either stereoselective diborylation of the propargylic surrogate takes place, providing convenient access to (E)-1,2-borylated 1,3-dienes, or traceless monoborylation occurs, which leads to α-hydroxyallenes as the principal product. The dichotomy in this borylation protocol has been scrutinized by several control experiments, illustrating that a relatively small change in the diboron(4) reagent allows for competitive alcohol-assisted protodemetalation to forge an α-hydroxyallene product under ambient conditions.
- Guo, Kun,Kleij, Arjan W.
-
supporting information
p. 4901 - 4906
(2021/01/21)
-
- Flexible on-site halogenation paired with hydrogenation using halide electrolysis
-
Direct electrochemical halogenation has appeared as an appealing approach in synthesizing organic halides in which inexpensive inorganic halide sources are employed and electrical power is the sole driving force. However, the intrinsic characteristics of direct electrochemical halogenation limit its reaction scope. Herein, we report an on-site halogenation strategy utilizing halogen gas produced from halide electrolysis while the halogenation reaction takes place in a reactor spatially isolated from the electrochemical cell. Such a flexible approach is able to successfully halogenate substrates bearing oxidatively labile functionalities, which are challenging for direct electrochemical halogenation. In addition, low-polar organic solvents, redox-active metal catalysts, and variable temperature conditions, inconvenient for direct electrochemical reactions, could be readily employed for our on-site halogenation. Hence, a wide range of substrates including arenes, heteroarenes, alkenes, alkynes, and ketones all exhibit excellent halogenation yields. Moreover, the simultaneously generated H2at the cathode during halide electrolysis can also be utilized for on-site hydrogenation. Such a strategy of paired halogenation/hydrogenation maximizes the atom economy and energy efficiency of halide electrolysis. Taking advantage of the on-site production of halogen and H2gases using portable halide electrolysis but not being suffered from electrolyte separation and restricted reaction conditions, our approach of flexible halogenation coupled with hydrogenation enables green and scalable synthesis of organic halides and value-added products.
- Shang, Xiao,Liu, Xuan,Sun, Yujie
-
supporting information
p. 2037 - 2043
(2021/03/26)
-
- Synthesis and evaluation of novel and potent protease activated receptor 4 (PAR4) antagonists based on a quinazolin-4(3H)-one scaffold
-
Protease activated receptor 4 (PAR4) is an important target in antiplatelet therapy to reduce the risk of heart attack and thrombotic complications in stroke. PAR4 antagonists can prevent harmful and stable thrombus growth, while retaining initial thrombus formation, by acting on the late diffusion stage of platelet aggregation, and may provide a safer alternative to other antiplatelet agents. To date, only two PAR4 antagonists, BMS-986120 and BMS-986141 have entered clinical trials for thrombosis. Thus, the development of a potent and selective PAR4 antagonist with a novel chemotype is highly desirable. In this study, we explored the activity of quinazolin-4(3H)-one-based PAR4 antagonists, beginning with their IDT analogues. By repeated structural optimisation, we developed a series of highly selective PAR4 antagonists with nanomolar potency on human platelets. Of these, 13 and 30g, with an 8-benzo[d]thiazol-2-yl-substituted quinazolin-4(3H)-one structure, showed optimal activity (h. PAR4-AP PRP IC50 = 19.6 nM and 6.59 nM, respectively) on human platelets. Furthermore, 13 and 30g showed excellent selectivity for PAR4 versus PAR1 and other receptors (IC50s > 10 μM) on human platelets. And 13 and 30g were lack of cross-reactivity for PAR1 or PAR2 (PAR1 AP FLIPR IC50 > 3162 nM, PAR2 AP FLIPR IC50 > 1000 nM) in the calcium mobilization assays. Metabolic stability assays and cytotoxicity tests of 13 and 30g indicated that these compounds could sever as promising drug candidates for the development of novel PAR4 antagonists. In summary, the quinazolin-4(3H)-one-based analogues are the first reported chemotypes with excellent activity and selectivity against PAR4, and, in the current study, we expanded the structural diversity of PAR4 antagonists. The two compounds, 13 and 30g, found in our study could be promising starting points with great potential for further research in antiplatelet therapy.
- Kong, Yi,Li, Shanshan,Liu, Shangde,Xie, Roujie,Yuan, Duo,Zhu, Xiong
-
supporting information
(2021/08/16)
-
- New Mercaptoacetamide Derivatives: Synthesis and Assessment as Antimicrobial and Antimycobacterial Agents
-
During last few years, the frightening elevation of bacterial resistance was accompanied by dramatic decline in recent treatments of infectious diseases, which became a point of anxiety for healthcare industries. MDR and XDR strains of Mycobacterium tuberculosis (Mtb) result in the tuberculosis. In this regard, herein, a series of new mercaptoacetamide derivatives were synthesized via multipot synthetic pathway and the rationale was the appraisal of bioactivity in compact heteronuclei and their assessment as potential antimicrobial and antimycobacterial agents against virulent strain of Mtb, H37Ra for structure–activity relationship (SAR) studies. The inhibition zones of compounds 4c and 4e were found to be nearest to that of standard drug Ciprofloxacin, while compounds 4h and 4j were mild to moderately active against Gram positive bacteria (Staphylococcus aureus, Streptococus pneumonia) and Gram negative bacteria (Pseudomonas aeruginosa, Salmonella typhimurium and Escherichia coli). MIC90 assays indicated that new mercaptoacetamides did not exhibit in vitro activity against Mtb in contrast to Rifampicin and Streptomycin, first-line antimycobacterial chemotherapeutic agents. According to the present study, it was concluded that mercaptoacetamides of the new series succeeded as antimicrobial agents but could not develop as potential lead compounds against Mtb when tested in concentrations of 50, 25, 12.5 and 6.25 μg/mL.
- Hashim, Syed Riaz,Hegde, Rahul Rama,Pal, Dilipkumar,Rani, Priyanka
-
p. 715 - 723
(2021/10/27)
-
- Bicyclic heteroaryl compound with PAR4 antagonistic activity and application thereof
-
The invention discloses a bicyclic heteroaryl compound with PAR4 antagonistic activity and application thereof. The invention provides the bicyclic heteroaryl compound with PAR4 antagonistic activity,and the bicyclic heteroaryl compound has remarkable antagonistic activity on PAR4 in an in-vitro anti-platelet aggregation experiment, so that platelet aggregation is effectively inhibited, and the bicyclic heteroaryl compound can be used for preparing medicines for preventing or treating various thromboembolic diseases.
- -
-
Paragraph 0134-0137
(2020/08/02)
-
- Enantioselective Construction of Sulfur-Containing Tetrasubstituted Stereocenters via Asymmetric Functionalizations of α-Sulfanyl Cyclic Ketones
-
Asymmetric functionalizations of α-sulfanyl cyclic ketones were realized via chiral phosphoric acid catalyzed enantioselective addition reactions with aldimines, azodicarboxylates and allenamides. A series of chiral organosulfur compounds possessing sulfur-containing tetrasubstituted stereocenters were accessed via these methods, with excellent regioselectivities and high stereoselectivities. (Figure presented.).
- Ye, Xueqian,Pan, Yongkai,Chen, Yunrong,Yang, Xiaoyu
-
supporting information
p. 3374 - 3379
(2020/07/16)
-
- Cobalt-Catalyzed α-Arylation of Substituted α-Bromo α-Fluoro β-Lactams with Diaryl Zinc Reagents: Generalization to Functionalized Bromo Derivatives
-
A cobalt-catalyzed cross-coupling of α-bromo α-fluoro β-lactams with diarylzinc or diallylzinc reagents is herein disclosed. The protocol proved to be general, chemoselective and operationally simple allowing the C4 functionalization of β-lactams. The substrate scope was expanded to α-bromo lactams and amides, α-bromo lactones and esters as well as N- and O-containing heterocycles.
- Br?se, Stefan,Chen, Hi-Yung,Cossy, Janine,Koch, Vanessa,Lei, Aiwen,Lorion, Mélanie M.,Nieger, Martin
-
supporting information
p. 13163 - 13169
(2020/09/23)
-
- SUBSTITUTED AMINOTHIAZOLES AS INHIBITORS OF NUCLEASES
-
The invention provides compounds represented by the structural formula (1): wherein R1, R2, R3, R4, R5, R6 are as defined in the claims. The compounds are inhibitors of nucleases, and are useful in particular in a method of treatment and/or prevention of proliferative diseases, neurodegenerative diseases, and other genomic instability associated diseases.
- -
-
Page/Page column 14; 56-57
(2019/11/12)
-
- Chemoselective Oxidation of Equatorial Alcohols with N-Ligated λ3-Iodanes
-
The site-selective and chemoselective functionalization of alcohols in complex polyols remains a formidable synthetic challenge. Whereas significant advancements have been made in selective derivatization at the oxygen center, chemoselective oxidation to the corresponding carbonyls is less developed. In cyclic systems, whereas the selective oxidation of axial alcohols is well known, a complementary equatorial selective process has not yet been reported. Herein we report the utility of nitrogen-ligated (bis)cationic λ3-iodanes (N-HVIs) for alcohol oxidation and their unprecedented levels of selectivity for the oxidation of equatorial over axial alcohols. The conditions are mild, and the simple pyridine-ligated reagent (Py-HVI) is readily synthesized from commercial PhI(OAc)2 and can be either isolated or generated in situ. Conformational selectivity is demonstrated in both flexible 1,2-substituted cyclohexanols and rigid polyol scaffolds, providing chemists with a novel tool for chemoselective oxidation.
- Mikhael, Myriam,Adler, Sophia A.,Wengryniuk, Sarah E.
-
supporting information
p. 5889 - 5893
(2019/08/26)
-
- The invention relates to a polyethylene glycol - b - poly-ε - caprolactone as carrier of the pH response type anti-tumor prodrug and its preparation method
-
The invention discloses a pH response type anti-tumor prodrug by using polyethylene glycol-b-poly-epsilon-caprolactone as a vector and a preparation method thereof. The preparation method of the pH response type anti-tumor prodrug comprises the following
- -
-
Paragraph 0072; 0073
(2018/03/24)
-
- A new and versatile one-pot strategy to synthesize alpha-bromoketones from secondary alcohols using ammonium bromide and oxone
-
A new, efficient and green protocol for the one-pot synthesis of α-bromoketones from secondary alcohols using cheap, air stable and non-toxic reagents such as NH4Br and oxone has been developed. This reaction proceeds via two consecutive steps such as oxidation of secondary alcohols and oxidative bromination of in situ generated ketones.
- Rammurthy, Banothu,Swamy, Peraka,Naresh, Mameda,Srujana, Kodumuri,Durgaiah, Chevella,Krishna Sai, Gajula,Narender, Nama
-
p. 3710 - 3714
(2017/07/12)
-
- Ligustrazine-fused cyclic compound and medicine composition thereof, as well as application in medicine thereof
-
The invention discloses a ligustrazine-fused cyclic compound and a medicine composition thereof and application in a medicine. The ligustrazine-fused cyclic compound has the following structural general formula I: as shown in the specification. The medicine composition is a medicinal active component for the ligustrazine-fused cyclic compound and a pharmaceutically acceptable carrier, an excipient, a diluent, an adjuvant, a medium or a combination thereof; the ligustrazine-fused cyclic compound and the medicine composition can be used for preventing or treating cardiovascular and cerebrovascular diseases, digestive system diseases, respiratory diseases, the alzheimer's disease, kidney diseases and complications of the above-mentioned diseases due to thrombus and excessive free radicals. The ligustrazine-fused cyclic compound disclosed by the invention has an extremely good inhibition effect on in vitro ADP (adenosine diphosphate)-induced platelet aggregation; meanwhile, compared with the pharmacokinetic property of ligustrazine serving as a female parent, the pharmacokinetic property of the ligustrazine-fused cyclic compound in the body of a rat is obviously improved.
- -
-
Paragraph 0038; 0039; 0040; 0041
(2017/07/21)
-
- Sc(OTf)3-Catalyzed Addition of Bromomagnesium 2-Vinyloxy Ethoxide to Various Aldehydes Leading to Protected Aldol Products
-
The addition of bromomagnesium 2-vinyloxy ethoxide to various aldehydes in the presence of 10 mol% Sc(OTf)3 provides a broad range of functionalized protected aldol compounds. The enantioselective preparation of these aldols can be achieved via a Swern oxidation-CBS reduction sequence. Use of the dioxolane derived from 2-bromocyclohexanone provides the expected aldol product as the anti diastereoisomer (dr >99:1).
- Quinio, Pauline,Kohout, Laura,Roman, Daniela Sustac,Gaar, Jakob,Karaghiosoff, Konstantin,Knochel, Paul
-
p. 1715 - 1719
(2016/07/06)
-
- Imidazole [2, 1-b] thiazole derivative as well as preparation method and application thereof
-
The invention belongs to the field of chemical pharmaceuticals, and particularly relates to an imidazole [2, 1-b] thiazole derivative as well as a preparation method and an application thereof. The structure of the imidazole [2, 1-b] thiazole derivative i
- -
-
Paragraph 0213; 0214; 0215
(2017/01/02)
-
- Kinetic Resolution Driven Diastereo- and Enantioselective Synthesis of cis-β-Heteroaryl Amino Cycloalkanols by Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation
-
The utility of tethered Ru-TsDPEN catalyst has been demonstrated for the asymmetric transfer hydrogenation of rac-α-heteroaryl amino cycloalkanones to construct biologically important cis-β-heteroaryl amino cycloalkanols with two contiguous chiral centers
- Vyas, Vijyesh K.,Bhanage, Bhalchandra M.
-
supporting information
p. 6436 - 6439
(2016/12/23)
-
- On the bromination of aromatics, alkenes and alkynes using alkylammonium bromide: Towards the mimic of bromoperoxidases reactivity
-
This article describes an efficient method of bromination of organic substrates including aromatics, alkenes and alkynes with NH4VO3as a catalyst and H2O2as an oxidant agent using a non-toxic and easy-to-handle source of bromine, tetrabutylammonium bromide. The process was developed under mild reaction conditions and is an innovation from reported methods in aspects such as: i) short reaction times, ii) the ability to work at room temperature, iii) regioselectivity and good yields.
- Mendoza, Fabian,Ruíz-Guerrero, Rosario,Hernández-Fuentes, Carlos,Molina, Paulina,Norzagaray-Campos, Mariano,Reguera, Edilso
-
supporting information
p. 5644 - 5648
(2016/11/28)
-
- Hexamethonium bis(tribromide) (HMBTB) a recyclable and high bromine containing reagent
-
A recyclable and high bromine containing di-(tribromide) reagent, hexamethonium bis(tribromide) (HMBTB) has been synthesized and utilized for the bromination of various organic substrates. The spent reagent hexamethonium bromide (HMB) can be effectively recycled by regenerating and reusing it without significant loss of activity. The crystalline and stable bis(tribromide) is an effective storehouse of very high percentage of active bromine requiring just half an equivalent of it for complete bromination. Both the Br3- moieties in HMBTB are nearly linear with Br-Br-Br angle of 179.55°.
- Paul, Bappi,Bhuyan, Bishal,Purkayastha, Debraj D.,Dhar, Siddhartha S.,Patel, Bhisma K.
-
p. 5646 - 5650
(2015/09/21)
-
- Discovery of imidazo[2,1- b ]thiazole HCV NS4B inhibitors exhibiting synergistic effect with other direct-acting antiviral agents
-
The design, synthesis, and SAR studies of novel inhibitors of HCV NS4B based on the imidazo[2,1-b]thiazole scaffold were described. Optimization of potency with respect to genotype 1b resulted in the discovery of two potent leads 26f (EC50 = 16
- Wang, Ning-Yu,Xu, Ying,Zuo, Wei-Qiong,Xiao, Kun-Jie,Liu, Li,Zeng, Xiu-Xiu,You, Xin-Yu,Zhang, Li-Dan,Gao, Chao,Liu, Zhi-Hao,Ye, Ting-Hong,Xia, Yong,Xiong, Ying,Song, Xue-Jiao,Lei, Qian,Peng, Cui-Ting,Tang, Hong,Yang, Sheng-Yong,Wei, Yu-Quan,Yu, Luo-Ting
-
p. 2764 - 2778
(2015/04/14)
-
- Synthesis of Multiple-Substituted Pyrroles via Gold(I)-Catalyzed Hydroamination/Cyclization Cascade
-
A gold-catalyzed cascade hydroamination/cyclization reaction of α-amino ketones with alkynes to form substituted pyrroles has been developed. The method offers several advantages such as high regioselectivity with the tested cases, wide functional group tolerance, and easily accessible starting materials. The synthetic utility of the obtained pyrrole products was demonstrated by their efficient transformations to 2-vinylated pyrroles via gold-catalyzed intermolecular hydroarylation.
- Li, Xiangdong,Chen, Ming,Xie, Xin,Sun, Ning,Li, Shi,Liu, Yuanhong
-
supporting information
p. 2984 - 2987
(2015/06/30)
-
- Silica gel catalyzed α-bromination of ketones using N-bromosuccinimide: An easy and rapid method
-
An easy and rapid method for the α-bromination of ketones using N-bromosuccinimide (NBS) catalyzed by silica gel in methanol under reflux conditions was developed. The expected products were formed in excellent isolated yields within a short period of time (5-20 min). Major advantages of the present procedure include use of inexpensive and readily available catalyst, exclusion of pre- and post-chemical treatment of catalyst and use of methanol as solvent instead of ethers and chlorinated solvents.
- Mohan Reddy, Bodireddy,Venkata Ramana Kumar, Velpula,Chinna Gangi Reddy, Nallagondu,Mahender Rao, Siripragada
-
p. 179 - 182
(2014/02/14)
-
- IBX works efficiently under solvent free conditions in ball milling
-
IBX (2-iodoxybenzoic acid), discovered in 1893, is an oxidant in synthetic chemistry whose extensive use is impeded by its explosiveness at high temperature and poor solubility in common organic solvents except DMSO. Since the discovery of Dess-Martin Periodinane in 1983, several modified IBX systems have been reported. However, under ball milling conditions, IBX works efficiently with various organic functionalities at ambient temperature under solvent free conditions. Also, the waste IBA (2-iodosobenzoic acid) produced from the reactions was in situ oxidized to IBX in the following step using oxone and thus reused for multiple cycles by conserving its efficiency (only ~6% loss after 15 cycles). This work describes an overview of a highly economical synthetic methodology which overcomes the problems of using IBX, efficiently in gram scale and in a non-explosive way. This journal is the Partner Organisations 2014.
- Achar, Tapas Kumar,Maiti, Saikat,Mal, Prasenjit
-
p. 12834 - 12839
(2014/04/03)
-
- Methoxy-poly(ethylene glycol)-block-poly(ε-caprolactone) bearing pendant aldehyde groups as pH-responsive drug delivery carrier
-
A biodegradable amphiphilic block copolymer of methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) bearing pendant aldehyde groups was synthesised by a combination of ring-opening polymerisation and thio-bromo 'click' chemistry. The free aldehyde gro
- Ma, Gejun,Li, Deshan,Wang, Ji,Zhang, Xuefei,Tang, Haoyu
-
p. 1576 - 1583
(2014/01/23)
-
- Structure-activity relationships of tetrahydrocarbazole derivatives as antifungal lead compounds
-
A Saccharomyces cerevisiae N-myristoyltransferase (NMT) inhibitor bearing a tetrahydrocarbazole scaffold was found to possess broad-spectrum antifungal activity. A series of C6- and N9-modified tetrahydrocarbazole derivatives were designed and synthesized
- Wang, Wenya,Dong, Guoqiang,Gu, Julin,Zhang, Yongqiang,Wang, Shengzheng,Zhu, Shiping,Liu, Yang,Miao, Zhenyuan,Yao, Jianzhong,Zhang, Wannian,Sheng, Chunquan
-
p. 353 - 362
(2013/06/04)
-
- Metal-free desulfonylation reaction through visible-light photoredox catalysis
-
The desulfonylation of β-arylketosulfones has been achieved in good to excellent yields by using 3-W blue LEDs light, 1 mol-% organic dye eosin Y bis(tetrabutylammonium salt) as photocatalyst, and diisopropylethylamine as reducing agent. Mechanistic studies demonstrate that oxidative quenching of the excited eosin Y by β-arylketosulfones plays a crucial role in the present photoredox catalytic cycle. Reductive desulfonylation is essential to enable to use of a sulfone as an auxiliary group. For reductive removal of sulfones, highly aggressive metal-containing reducing agents and harsh reaction conditions are often employed. In this paper, metal-free desulfonylation of β-arylketosulfones can be achieved efficiently at room temperature under visible-light irradiation.
- Yang, Deng-Tao,Meng, Qing-Yuan,Zhong, Jian-Ji,Xiang, Ming,Liu, Qiang,Wu, Li-Zhu
-
p. 7528 - 7532
(2013/12/04)
-
- Toward the total synthesis of palhinine A: Expedient assembly of multifunctionalized isotwistane ring system with contiguous quaternary stereocenters
-
The stereoselective, expedient assembly of the key functionalized isotwistane (bridged tricyclo[4.3.1.03,7]decane) system, 5/6/6 ring, with contiguous quaternary stereocenters in Lycopodium alkaloid palhinine A and its analogues via an intramol
- Zhang, Guo-Biao,Wang, Fang-Xin,Du, Ji-Yuan,Qu, Hu,Ma, Xiao-Yan,Wei, Meng-Xue,Wang, Cheng-Tao,Li, Qiong,Fan, Chun-An
-
supporting information; experimental part
p. 3696 - 3699
(2012/09/21)
-
- Stereocontrolled 1,3-phosphatyloxy and 1,3-halogen migration relay toward highly functionalized 1,3-dienes
-
A double migratory cascade reaction of α-halogen-substituted propargylic phosphates to produce highly functionalized 1,3-dienes has been developed. This transformation features 1,3-phosphatyloxy group migration followed by 1,3-shifts of bromine and chlorine as well as the unprecedented 1,3-migration of iodine. The reaction is stereodivergent: (Z)-1,3-dienes are formed in the presence of a copper catalyst, whereas gold-catalyzed reactions exhibit inverted stereoselectivity, producing the corresponding E products.
- Kazem Shiroodi, Roohollah,Dudnik, Alexander S.,Gevorgyan, Vladimir
-
supporting information; experimental part
p. 6928 - 6931
(2012/06/15)
-
- Simple and efficient system for the α-bromination of a β-ketoester by using N-bromosuccinimide in the presence of silicasupported NaHCo3 as the heterogeneous catalyst: An environmentally benevolent approach
-
Selective and efficient α-bromination of β-ketoesters and cyclic and acyclic ketones is achieved by reaction with N-bromosuccinimide (NBS) catalyzed by silica-supported sodium bicarbonate (NaHCO3 · SiO2) under mild reaction conditions and with short reaction times. With 100% selectivity with all substrates, after 45 min at room temperature (20±2 °C), conversions for ethylacetoacetate were 67% and for acetophenone, cyclohexanone, and cycloheptanone were 58, 50, and 55%, respectively. Acetyl acetone recorded 65% conversion with 100% selectivity. Although cyclopentanone and toluene had only 20% conversion, both reactions showed 100% selectivity toward α-bromination. The catalysts exhibit activity and reusability. Copyright Taylor & Francis Group, LLC.
- Rahman, Ateeq,Jonnalagadda
-
experimental part
p. 1091 - 1100
(2012/05/05)
-
- A novel and efficient one pot synthesis of 2,4-disubstituted thiazoles and oxazoles using phenyltrimethylammoniumtribromide in ionic liquid
-
A novel and efficient one-pot procedure has been described for synthesis of 2,4-disubstituted thiazoles and oxazoles from substituted ketones using phenyltrimethylammoniumtribromide as in situ brominating agent followed by reaction with thioamide/thiourea and amides/ureas, respectively in [bmim][BF4] ionicliquid. The advantages of the procedure include avoiding the handling of lacrymetric compounds, hazardous and toxic organic solvents along with good to excellent yield of the products.
- Muthyala, Manoj Kumar,Kumar, Anil
-
p. 959 - 964
(2012/10/29)
-
- Visible-light photoredox catalysis: Dehalogenation of vicinal dibromo-, α-halo-, and α,α-dibromocarbonyl compounds
-
vic-Dibromo-, α-halo-, or α,α-dibromocarbonyl compounds can be efficiently dehalogenated using catalytic tris(2,2′-bipyridyl) ruthenium dichloride (Ru(bpy)3Cl2) in combination with 1,5-dimethoxynaphthalene (DMN) and ascorbate as sacrificial electron donor. For this process, a visible light promoted photocatalytic cycle is proposed that involves the reduction of carbon halogen bonds via free radical intermediates.
- Maji, Tapan,Karmakar, Ananta,Reiser, Oliver
-
supporting information; experimental part
p. 736 - 739
(2011/03/20)
-
- Discovery and hit-to-lead optimization of novel allosteric glucokinase activators
-
We report on a hit generation and hit-to-lead program of a novel class of glucokinase activators (GKAs). Hit compounds, activators at low glucose concentration only were identified by vHTS. Scaffold modification reliably afforded activators also at high s
- Lang, Martin,Seifert, Markus H.-J.,Wolf, Kristina K.,Aschenbrenner, Andrea,Baumgartner, Roland,Wieber, Tanja,Trentinaglia, Viola,Blisse, Marcus,Tajima, Nobumitsu,Yamashita, Tokuyuki,Vitt, Daniel,Noda, Hitoshi
-
supporting information; scheme or table
p. 5417 - 5422
(2011/10/12)
-
- Synthesis of quinoxaline analogues
-
Substituted tricyclic or tetracyclic quinoxalines, tricyclic pyridoquinoxalines and bis-quinoxalines were synthesized in high yields starting from cyclic ketones by the -bromination of cyclic ketones with N-bromosuccinimide (NBS) followed by condensation of the resulting -bromo ketones with 1,2-diaminobenzene, 3,4-diaminopyridine, or 3,3-diaminobenzidine. Georg Thieme Verlag Stuttgart New York.
- Chang, Meng-Yang,Lee, Tein-Wei,Hsu, Ru-Ting,Yen, Tzu-Lin
-
experimental part
p. 3143 - 3151
(2011/10/30)
-
- A family of thiazolium salt derived N-heterocyclic carbenes (NHCs) for organocatalysis: Synthesis, investigation and application in cross-benzoin condensation
-
A family of thiazolium salt derived N-heterocyclic carbenes (NHCs) bearing sterically demanding aryl substituents on the nitrogen and with varying backbone substitution patterns have been synthesized. Investigation of the catalytic activity of these NHCs in a number of benzoin-type coupling reactions revealed markedly different levels of reactivity and selectivity. To elucidate the underlying factors leading to differences in reactivity, a study of the electronic and steric properties of these NHC catalysts was conducted. By using the best catalyst in this study, the intermolecular cross-benzoin condensation reaction was explored in more detail.
- Piel, Isabel,Pawelczyk, Marius D.,Hirano, Keiichi,Froehlich, Roland,Glorius, Frank
-
supporting information; experimental part
p. 5475 - 5484
(2011/11/29)
-
- Direct conversion of olefins into α-bromo ketones using O-iodoxybenzoic acid and tetraethylammonium bromide
-
Utilizing full potential of IBX, a mild, selective, and facile method has been developed for the direct conversion of olefins into the corresponding α-bromo ketones by using 1.1 equivalents each of o-iodoxybenzoic acid and tetraethylammonium bromide. Georg Thieme Verlag Stuttgart - New York.
- Deshmukh, Swapnil S.,Chaudhari, Kiran H.,Akamanchi, Krishnacharya G.
-
experimental part
p. 81 - 83
(2011/03/20)
-
- The case of infrared carbonyl stretching intensities of 2-bromocyclohexanone: Conformational and intermolecular interaction insights
-
The infrared spectrum of 2-bromocyclohexanone in the vapor phase was obtained for the first time, and the νCO intensity for the more polar equatorial conformer was surprisingly found to be higher than for the axial form, suggesting its larger p
- Coelho, Jakelyne V.,Freitas, Matheus P.,Ramalho, Teodorico C.,Martins, Carina R.,Bitencourt, Michelle,Cormanich, Rodrigo A.,Tormena, Cláudio F.,Rittner, Roberto
-
experimental part
p. 26 - 30
(2010/10/05)
-
- Mild and efficient method for-thiocyanation of ketones and-dicarbonyl compounds using bromodimethylsulfonium bromide-ammonium thiocyanate
-
An efficient and convenient method for-thiocyanation of ketones and-dicarbonyl compounds has been developed using a reagent combination of bromodimethylsulfonium bromide (BDMS) and ammonium thiocyanate in acetonitrile. The developed method is mild and gave good yield of the products at room temperature.
- Bhalerao, Dinesh S.,Akamanchi, Krishnacharya G.
-
experimental part
p. 799 - 807
(2010/05/17)
-
- Azole derivatives as histamine H3 receptor antagonists, Part I: Thiazol-2-yl ethers
-
Most human histamine H3 receptor (hH3R) antagonists follow a general structural blueprint, containing a basic moiety linked by a spacer to a substituted core element. In this investigation the acceptance of thiazol-2-yl ether moieties in the core region is proved with some ether derivatives showing hH3R binding affinities in the nanomolar concentration range. A diversity of structural motifs is used as substituents to enhance the in vitro hH3R binding affinity.
- Walter,Von Coburg,Isensee,Sander,Ligneau,Camelin,Schwartz,Stark
-
supporting information; experimental part
p. 5879 - 5882
(2010/11/18)
-