cas 728-87-0, 4,4'-DIMETHOXYBENZHYDROL | Articles data

Articles about 728-87-0Total 95 be found

Article title
Article abstract
Author
Journal number and time
Download

Solid-phase synthesis of NH-1,2,3-triazoles using 4,4′- bismethoxybenzhydryl azide
Readily available 4,4′-bismethoxybenzhydryl azide was found to be a useful building block for the synthesis of NH-1,2,3-triazoles through copper(I)-catalyzed cycloaddition reactions with solid-supported terminal alkynes, followed by acid-mediated deprotection. Peptide-containing NH-1,2,3-triazoles were obtained in good yield and excellent purity (typically >95%). Georg Thieme Verlag Stuttgart. New York.
Cohrt, A. Emil,Le Quement, Sebastian T.,Nielsen, Thomas E.
p. 1891 - 1895
(2014)
Read Online

Light-driven MPV-type reduction of aryl ketones/aldehydes to alcohols with isopropanol under mild conditions
Alcohols are versatile structural motifs of pharmaceuticals, agrochemicals and fine chemicals. With respect to green chemistry, the development of more sustainable and cost-efficient processes for converting ketones/aldehydes to alcohols is highly desired. Herein, a direct light-driven strategy for reducing ketones/aldehydes to alcohols using isopropanol as the reducing agent and solvent, in the presence of t-BuOLi, under an air atmosphere at room temperature is developed. This operationally simple light-promoted Meerwein-Ponndorf-Verley (MPV) type reduction can be used to produce various benzylic alcohol derivatives as well as applied to bioactive molecules and PEEK model compounds, demonstrating its application potential.
Cao, Dawei,Xia, Shumei,Pan, Pan,Zeng, Huiying,Li, Chao-Jun,Peng, Yong
supporting information
p. 7539 - 7543
(2021/10/12)

Ruthenium complexes of phosphine-amide based ligands as efficient catalysts for transfer hydrogenation reactions
This work presents three mononuclear Ru(ii) complexes of tridentate phosphine-carboxamide based ligands providing a NNP coordination environment. The octahedral Ru(ii) ion shows additional coordination with co-ligands; CO, Cl and CH3OH. All three Ru(ii) complexes were thoroughly characterized including their crystal structures. These Ru(ii) complexes were utilized as catalysts for the transfer hydrogenation of assorted carbonyl compounds, including some challenging biologically relevant substrates, using isopropanol as the hydrogen source. The binding studies illustrated the coordination of the isopropoxide ion by replacing a Ru-ligated chloride ion followed by the generation of the Ru-H intermediate that was isolated and characterized and was found to be involved in the catalysis.
Yadav, Samanta,Vijayan, Paranthaman,Yadav, Sunil,Gupta, Rajeev
p. 3269 - 3279
(2021/03/16)

Simple synthesis of [Ru(CO3)(NHC)(p-cymene)] complexes and their use in transfer hydrogenation catalysis
A novel, efficient and facile protocol for the synthesis of a series of [Ru(NHC)(CO3)(p-cymene)] complexes is reported. This family of Ru-NHC complexes was obtained from imidazol(in)ium tetrafluoroborate or imidazolium hydrogen carbonate salts in moderate to excellent yields, employing sustainable weak base. The ruthenium complexes were successfully utilized in the transfer hydrogenation of ketones as highly active multifunctional catalysts.
Cazin, Catherine S. J.,Guillet, Sébastien G.,Liu, Yaxu,Ma, Xinyuan,Nolan, Steven P.
p. 13012 - 13019
(2021/10/12)

Trivalent Rare-Earth Metal Amide Complexes as Catalysts for the Hydrosilylation of Benzophenone Derivatives with HN(SiHMe2)2 by Amine-Exchange Reaction
The rare-earth metal complexes Ln(L1)[N(SiHMe2)2](thf) (Ln=La, Ce, Y; L1=N,N′′-bis(pentafluorophenyl)diethylenetriamine dianion) were synthesized by treating Ln[N(SiHMe2)2]3(thf)2 with L1H2. The lanthanum and cerium derivatives are active catalysts for the hydrosilylation of benzophenone derivatives with HN(SiHMe2)2. An amine-exchange reaction was revealed as a key step of the catalytic cycle, in which Ln?Si?H β-agostic interactions are proposed to promote insertion of the carbonyl moiety into the Si?H bond.
Shinohara, Koichi,Tsurugi, Hayato,Anwander, Reiner,Mashima, Kazushi
supporting information
p. 14130 - 14136
(2020/10/06)

Metal-Free Direct Deoxygenative Borylation of Aldehydes and Ketones
Direct conversion of aldehydes and ketones into alkylboronic esters via deoxygenative borylation represents an unknown yet highly desirable transformation. Herein, we present a one-step and metal-free method for carbonyl deoxy-borylation under mild conditions. A wide range of aromatic aldehydes and ketones are tolerated and successfully converted into the corresponding benzylboronates. By the same deoxygenation manifold with aliphatic aldehydes and ketones, we also enable a concise synthesis of 1,1,2-tris(boronates), a family of compounds that currently lack efficient synthetic methods. Given its simplicity and versatility, we expect that this novel borylation approach could show great promise in organoboron synthesis and inspire more carbonyl deoxygenative transformations in both academic and industrial settings.
Huang, Chia-Yu,Li, Chao-Jun,Li, Jianbin,Qiu, Zihang,Wang, Haining
p. 13011 - 13020
(2020/09/01)

Synthesis of non-nucleoside anti-viral cyclopropylcarboxacyl hydrazones and initial anti-HSV-1 structure-activity relationship studies
The synthesis of a lead anti-viral cyclopropyl carboxy acyl hydrazone 4F17 (5) and three sequential arrays of structural analogues along with the initial assessment and optimization of the antiviral pharmacophore against the herpes simplex virus type 1 (HSV-1) are reported.
Babu Dokuburra, Chanti,D'Aiuto, Leonardo,Demers, Matthew,McClain, Lora,McNulty, James,Nimgaonkar, Vishwajit L.,Piazza, Paolo,Williamson, Kelly,Zheng, Wenxiao
supporting information

(2020/10/02)

Site-Selective Alkoxylation of Benzylic C?H Bonds by Photoredox Catalysis
Methods that enable the direct C?H alkoxylation of complex organic molecules are significantly underdeveloped, particularly in comparison to analogous strategies for C?N and C?C bond formation. In particular, almost all methods for the incorporation of alcohols by C?H oxidation require the use of the alcohol component as a solvent or co-solvent. This condition limits the practical scope of these reactions to simple, inexpensive alcohols. Reported here is a photocatalytic protocol for the functionalization of benzylic C?H bonds with a wide range of oxygen nucleophiles. This strategy merges the photoredox activation of arenes with copper(II)-mediated oxidation of the resulting benzylic radicals, which enables the introduction of benzylic C?O bonds with high site selectivity, chemoselectivity, and functional-group tolerance using only two equivalents of the alcohol coupling partner. This method enables the late-stage introduction of complex alkoxy groups into bioactive molecules, providing a practical new tool with potential applications in synthesis and medicinal chemistry.
Lee, Byung Joo,DeGlopper, Kimberly S.,Yoon, Tehshik P.
supporting information
p. 197 - 202
(2019/11/26)

Structure-based virtual screening, synthesis and biological evaluation of potential FAK-FAT domain inhibitors for treatment of metastatic cancer
Focal adhesion kinase (FAK) is a tyrosine kinase that is overexpressed and activated in several advanced-stage solid cancers. In cancer cells, FAK promotes the progression and metastasis of tumours. In this study, we used structure-based virtual screening to filter a library of more than 210K compounds against the focal adhesion targeting FAK-focal adhesion targeting (FAT) domain to identify 25 virtual hit compounds which were screened in the invasive breast cancer line (MDA-MB-231). Most notably, compound I showed low micromolar antiproliferative activity, as well as antimigratory activity. Moreover, examination in a model of triple negative breast cancer (TNBC), revealed that, despite not effecting FAK phosphorylation, compound I significantly impairs proliferation whilst impairing focal adhesion growth and turnover leading to reduced migration. Further optimisation and synthesis of analogues of the lead compound I using a four-step synthetic procedure was performed, and analogues were assessed for their antiproliferative activity against three breast cancer (MDA-MB-231, T47D, BT474) cell lines and one pancreatic cancer (MIAPaCa2) cell line. Compound 5f was identified as a promising lead compound with IC50 values in the range of 4.59–5.28 μM in MDA-MB-231, T47D, BT474, and MIAPaCa2. Molecular modelling and pharmacokinetic studies provided more insight into the therapeutic features of this new series.
Hiscox, Stephen E.,Jones, Samuel R.,Kandil, Sahar B.,Smith, Sonia,Westwell, Andrew D.
(2020/08/28)

Photo-induced phosphorus radical involved semipinacol rearrangement reaction: Highly synthesis of γ-oxo-phosphonates
Hydroxyphosphoric acids display the unique biological activities, and they have some attractive prospects as clinical drug moleculars. Herein, a new approach for the synthesis of γ-oxo-phosphonates (the precursor of hydroxyphosphoric acid) has been established through the semipinacol rearrangement tactic involved the photo-induced phosphorus radical process. Most important, this transformation is avoid of the external oxidants, and occurs very well under the sunlight irradiation, meanwhile the γ-oxo-phosphonate was easily derivatized to obtain γ-hydroxyphosphoric acid, thus highlights the synthesis value of this method.
Wang, Chunhai,Huang, Xiaoling,Liu, Xueting,Gao, Suqian,Zhao, Bin,Yang, Shangdong
supporting information
p. 677 - 680
(2019/08/27)

New ferrocenyl-containing organic hole-transporting materials for perovskite solar cells in regular (n-i-p) and inverted (p-i-n) architectures
Three triphenylamine derivatives containing ferrocenyl groups (JW6, JW7 and JW8) were synthesized by facile syntheses. Their HOMO levels match the valence band energy of CH3NH3PbI3. The introduction of ferrocenyl was aimed to obtain hole transporting materials with high mobility for perovskite solar cells. JW7 shows higher hole mobility (4.2 × 10?4 cm2 V?1 s?1) than JW6 (1.3 × 10?4 cm2 V?1 s?1) and JW8 (1.5 × 10?4 cm2 V?1 s?1). Their film-forming properties are affected by their molecule structures. The methoxyl and N,N-dimethyl terminal substituents of JW7 and JW8 are beneficial for having better solubility than JW6. The regular mesoporous TiO2-based perovskite solar cells (n-i-p) and the inverted planar heterojunction perovskite solar cells (p-i-n) fabricated using JW7 show the highest power conversion efficiency of 9.36% and 11.43% under 100 mW cm?2 AM1.5G solar illumination. For p-i-n cells, the standard HTM PEDOT-based cell reaches an efficiency of 12.86% under the same conditions.
Jia, Jingwen,Duan, Liangsheng,Chen, Yu,Zong, Xueping,Sun, Zhe,Wu, Quanping,Xue, Song
p. 216 - 223
(2019/01/16)

Base-Promoted Aerobic Oxidation/Homolytic Aromatic Substitution Cascade toward the Synthesis of Phenanthridines
The current protocol represents a transition metal-free synthesis of polysubstituted phenanthridines from abundant starting materials like benzhydrol and 2-iodoaniline derivatives. The reaction involves sequential oxidation of alcohol and direct condensation reaction with the amine resulting in a C?N bond formation followed by a radical C?C coupling in a cascade sequence. The used base potassium tert-butoxide plays a dual role in dehydrogenation and homolytic aromatic substitution reaction. Using this methodology, twenty substituted phenanthridine derivatives were synthesized with up to 85% isolated yield. (Figure presented.).
Maiti, Debabrata,Halder, Atreyee,De Sarkar, Suman
supporting information
p. 4941 - 4948
(2019/11/03)

Kinetic studies on tetrabutylammonium bromochromate oxidation of some mono-and di-substituted benzhydrols
The oxidation of 12 mono- and di-substituted benzhydrols (BH) by tetrabutylammonium bromochromate (TBABC) have been studied in aqueous acetic acid medium. Absence of any effect of added acrylonitrile on the reaction discounts the possibility of a one-electron oxidation, leading to the formation of free radicals. The tetrabutylammonium bromochromate oxidation of 12 mono- and di-substituted benzhydrols complies with the isokinetic relationship and Hammett relationship. The overall mechanism is proposed to involve a cyclic concerted symmetrical transition state leading to the product.
Hemalatha,Asghar, Basim H.,Mansoor, S Sheik
p. 821 - 826
(2018/03/13)

Large-scale synthesis of novel sterically hindered acenaphthene-based α-diimine ligands and their application in coordination chemistry
An efficient method to synthesize novel highly sterically hindered acenaphthene-based α-diimine ligands bearing bulky diarylmethyl moiety was achieved by two-step reactions. These reactions could be carried out on a scale of 100 g with no chromatography involved. On the basis of this method, a series of novel highly sterically hindered acenaphthene-based α-diimine Pd(II) and Ni(II) complexes, imidazolium precursors and the corresponding NHCs-metal complexes were also successfully synthesized. These novel complexes can offer great potential for metal-catalyzed polymerizations and organic reactions.
Guo, Lihua,Kong, Wenyu,Xu, Yanjian,Yang, Yuliang,Ma, Rui,Cong, Li,Dai, Shengyu,Liu, Zhe
supporting information
p. 58 - 67
(2018/02/14)

Different Selectivities in the Insertions into C(sp2)?H Bonds: Benzofulvenes by Dual Gold Catalysis Competition Experiments
An unprecedented, often almost quantitative access to tricyclic aromatic compounds by dual gold catalysis was developed. This synthetic route expands the scope of benzofulvene derivatives through a C(sp2)?H bond insertion in easily available starting materials. The insertion takes place with an exclusive chemoselectivity with respect to the competing aromatic C?H positions. A bidirectional synthesis with two competing ortho-aryl C?H bonds in the selectivity-determining step also shows perfect selectivity; this result is explained by a computational investigation of the two conceivable intermediates. The intramolecular competition of two non-equivalent aryl C?H bonds with a benzylic methyl group also showed perfect selectivity.
Plajer, Alex J.,Ahrens, Lukas,Wieteck, Marcel,Lustosa, Danilo M.,Babaahmadi, Rasool,Yates, Brian,Ariafard, Alireza,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information
p. 10766 - 10772
(2018/08/03)

Direct allylation of benzyl alcohols, diarylmethanols, and triarylmethanols mediated by XtalFluor-E
We report the direct allylation of benzyl alcohols, diarylmethanols and triarylmethanols mediated by XtalFluor-E using allyltrimethylsilane. The resulting allylated products are obtained in moderate to high yield.
Lebleu, Thomas,Paquin, Jean-Fran?ois
supporting information
p. 442 - 444
(2017/01/10)

Neutral Dinuclear Copper(I)-NHC Complexes: Synthesis and Application in the Hydrosilylation of Ketones
The synthesis of a class of highly stable neutral dinuclear Cu(I)-NHC complexes using 1,2,4-triazole as a bridging ligand is described. Various NHCs were used to generate a library of [Cu(μ-trz)(NHC)]2 complexes. Interestingly, [Cu(μ-trz)(IPr)]2 was found to be highly active in the hydrosilylation of ketones, without the need for an external base or any other additive. A wide range of aryl and alkyl ketones, as well as sterically hindered ketones, was successfully reduced to alcohols using the lowest catalyst loading reported to date.
Trose, Michael,Lazreg, Fa?ma,Chang, Tao,Nahra, Fady,Cordes, David B.,Slawin, Alexandra M. Z.,Cazin, Catherine S. J.
p. 238 - 242
(2017/06/07)

High triplet energy exciton blocking materials based on triphenylamine core for organic light-emitting diodes
A series of novel high triplet energy materials have been designed and synthesized from the simple starting compounds through a simple one-step Friedel–Crafts reaction by using triphenylamine and methoxy, fluoro substituted diphenylmethanoles and triphenylmethanol as the starting materials. The synthesized compounds exhibit the ionization potentials in an interval of 5.4–5.7?eV in the solid state, the wide bang-gaps of 3.6?eV and the high triplet energies of about 3.0?eV. The photophysical properties have been confirmed by DFT. The introduction of a material with the lowest ionization potential as the high triplet energy exciton blocking thin layer of the green organic light-emitting diode doubled the quantum efficiency of the device. The best fabricated green device exhibited the maximum current, power, and external quantum efficiencies of 80.1?Cd?A?1 and 31.4?Lm?W?1, 23.2%, respectively. The triplet-triplet annihilation and triplet-polaron quenching effects for the devices without and with exciton blocking layer have been analyzed.
Bagdziunas, Gintautas,Surka, Mindaugas,Ivaniuk, Khrystyna
p. 122 - 129
(2016/12/16)

Solvolytic Behavior of Aryl and Alkyl Carbonates. Impact of the Intrinsic Barrier on Relative Reactivities of Leaving Groups
The effect of negative hyperconjugation on the solvolytic behavior of carbonate diesters has been investigated kinetically by applying the LFER equation log k = sf(Ef + Nf). The observation that carbonate diesters solvolyze faster than the corresponding carboxylates and that the enhancement of aromatic carbonates is more pronounced indicates that the negative hyperconjugation and π-resonance within the carboxylate moiety is operative in TS. The plots of ΔG? vs approximated ΔrG° for solvolysis of benzhydryl aryl/alkyl carbonates and benzhydryl carboxylates reveal that a given carbonate solvolyzes over the higher Marcus intrinsic barrier and over the earlier transition state than carboxylate that produces an anion of similar stability. Due to the lag in development of the electronic effects along the reaction coordinate, the impact of the intrinsic barrier on solvolytic behavior of carbonates is more important than in the case of carboxylates and phenolates. Consequently, the solvolytic reaction constants (sf) are generally lower for carbonates than for carboxylates. Because of considerable lower reaction constants of carbonates, an inversion of relative reactivities between aryl/alkyl carbonate and another leaving group of similar nucleofugality (Nf) may occur if the electrofuge moiety of a substrate is switched.
Mati?, Mirela,Kati?, Matija,Denegri, Bernard,Kronja, Olga
p. 7820 - 7831
(2017/08/14)

Synthesis and biological evaluation of aryloxyacetamide derivatives as neuroprotective agents
A series of new aryloxyacetamide derivatives 10a-s and 14a-m are designed and synthesized. Their protective activities against the glutamate-induced cell death were investigated in differentiated rat pheochromocytoma cells (PC12 cells). Most compounds exhibited neuroprotective effects, especially for 10m, 10r, 14b and 14c, which showed potential protection of PC12 cells at three doses (0.1, 1.0, 10 μM). MTT assay, Hoechst 33342/PI double staining, and high content screening (HCS) revealed that pretreatment of the cells with 10m, 10r, 14b and 14c has significantly decreased the extent of cell apoptosis in a dose-dependent manner. The results of western blot analysis demonstrated these compounds suppressed apoptosis of glutamate-induced PC12 cells via caspase-3 pathway. These compounds can be lead compounds for further discovery of neuroprotective agents for treating cerebral ischemic stroke. Basic structure-activity relationships are also presented.
Zhong, Yan,Xu, Yi,Zhang, Ai-Xia,Li, Xiao-Feng,Xu, Zhao-Ying,Li, Ping,Wu, Bin
supporting information
p. 2526 - 2530
(2016/07/07)

Highly selective direct azidation of alcohols over a heterogeneous povidone-phosphotungstic solid acid catalyst
A simple protocol for the selective azidation of alcohols is developed using a solid acid hybrid of a povidone and phosphotungstic acid (PVP-PWA) using azidotrimethylsilane as an azide source at room temperature. In a broad substrate scope, various activated as well as unactivated benzylic and diphenyl alcohols were treated smoothly with TMS-N3 to selectively produce only azide products with excellent yields in a very short reaction time of 2 h. FT-IR confirmed the stability of the catalyst with retention of the Keggins structure after the reaction. Recycling experiments demonstrated the reusability of the PVP-PWA (3?:?1) several times without losing its original activity.
Kamble, Sumit,More, Sagar,Rode, Chandrashekhar
supporting information
p. 10240 - 10245
(2016/12/06)

REAGENT FOR ENHANCING GENERATION OF CHEMICAL SPECIES
A reagent that enhances acid generation of a photoacid generator and composition containing such reagent is disclosed.
-
Paragraph 0064

(2016/08/07)

A general Br?nsted acid-catalyzed allylation of benzhydryl alcohols
Efficient Br?nsted acid-catalyzed allylation of benzhydryl alcohols has been developed. The reaction occurs within 5?min in the presence of sub-stoichiometric amounts of HBF4·OEt2to afford the desired products in good to excellent yields. A variety of functional groups were tolerated under the developed conditions including amides, aldehydes, hydroxyl and carboxylic acid.
Orizu, Ifedi,Bolshan, Yuri
supporting information
p. 5798 - 5800
(2016/12/03)

Co(III)-Catalyzed Synthesis of Quinazolines via C-H Activation of N-Sulfinylimines and Benzimidates
C-H activation of arenes has been established as an important strategy for heterocycle synthesis via annulations between arenes and unsaturated coupling partners. However, nitriles failed to act as such a coupling partner. Dioxazolones have been employed as a synthon of nitriles, and subsequent coupling with arenes such as N-sulfinylimines and benzimidates bearing a functionalizable directing group provided facile access to two classes of quinazolines under Co(III)-catalysis.
Wang, Fen,Wang, He,Wang, Qiang,Yu, Songjie,Li, Xingwei
supporting information
p. 1306 - 1309
(2016/04/01)

The Stereoselective Reductions of Ketones to the Most Thermodynamically Stable Alcohols Using Lithium and Hydrated Salts of Common Transition Metals
A simple method is presented for the highly stereoselective reductions of ketones to the most thermodynamically stable alcohols. In this procedure, the ketone is treated with lithium dispersion and either FeCl2·4H2O or CuCl2·2H2O in THF at room temperature. This protocol is applied to a large number and variety of ketones and is both more convenient and efficient than those commonly reported for the diastereoselective reduction of five- and six-membered cyclic ketones.
Kennedy, Nicole,Cohen, Theodore
p. 8134 - 8141
(2015/09/02)

A conjugated ketone as a catalyst in alcohol amination reactions under transition-metal and hetero-atom free conditions
Here, we show the results of a molecular-defined conjugated ketone catalyzed alcohol amination reaction. Under the optimized reaction conditions, the yields to the desired products reached 98%. The reaction mechanism and kinetic study supposed that carbonyl-hydroxyl groups are the catalytically active sites, and the transfer-hydrogenation reactions progress via the recycling of carbonyl and hydroxyl groups. The catalytic process shows promise as an efficient and economic route for alcohol amination reactions.
Dai, Xingchao,Cui, Xinjiang,Deng, Youquan,Shi, Feng
p. 43589 - 43593
(2015/05/27)

Solvolytic reactivity of pyridinium ions
The leaving group abilities of pyridine, 4-methylpyridine, and 4-chloropyridine in SN1 solvolytic reactions have been determined by analyzing the rate constants of X,Y-substituted benzhydrylpyridinium salts obtained in various solvents. By applying the linear free energy relationship equation, log k = sf (Ef + Nf), the nucleofuge specific parameters of 4-substituted pyridine have been extracted. Because of solvation in the reactant ground state, the reactivity (nucleofugality, Nf) of a given pyridine decreases as the polarity of the solvent increases. High slope parameters (sf > 1) may be due to the spread of the energy levels of the benzhydrylium ion/pyridine pair intermediates in comparison to benzhydrylium ion/chloride pairs (sf ≈ 1). Because of slow heterolysis step of pyridinium salts in various solvents, some are stable under normal conditions.
Juric, Sandra,Kronja, Olga
p. 314 - 319
(2015/05/05)

Br?nsted Acid-Catalyzed Reactions of Trifluoroborate Salts with Benzhydryl Alcohols
Br?nsted acid-catalyzed carbon-carbon bond forming methodology using potassium alkynyl- and alkenyltrifluoroborate salts has been developed. Organotrifluoroborates react with benzhydryl alcohols to afford a broad range of alkynes and alkenes in good to excellent yields. This protocol features good atom economy because organotrifluoroborate salts and alcohols react in a 1:1 ratio. Furthermore, a variety of unprotected functional groups were tolerated under the developed conditions, including amide, aldehyde, free hydroxyl, and carboxylic acid.
Fisher, Kayla M.,Bolshan, Yuri
p. 12676 - 12685
(2016/01/09)

UV light-mediated difunctionalization of alkenes through aroyl radical addition/1,4-/1,2-Aryl shift cascade reactions
UV light-mediated difunctionalization of alkenes through an aroyl radical addition/1,4-/1,2-aryl shift has been described. The resulted aroyl radical from a photocleavage reaction added to acrylamide compounds followed by cyclization led to the formation of oxindoles, whereas the addition to cinnamic amides aroused a unique 1,4-aryl shift reaction. Furthermore, the difunctionalization of alkenes of prop-2-en-1-ols was also achieved through aroyl radical addition and a sequential 1,2-aryl shift cascade reaction.
Zheng, Lewei,Huang, Hongli,Yang, Chao,Xia, Wujiong
supporting information
p. 1034 - 1037
(2015/03/30)

Visible light-mediated arylalkylation of allylic alcohols through concomitant 1,2-aryl migration
A photocatalytic process for selective arylalkylation of allylic alcohols with α-bromo diethyl malonate has been developed. The reaction provided a straightforward approach to synthesize α-aryl-β-alkylated ketones via unique 1,2-aryl migration. The procedure is highlighted by its operational simplicity and mild reaction conditions.
Huang, Hong-Li,Yan, Hang,Yang, Chao,Xia, Wujiong
supporting information
p. 4910 - 4913
(2015/03/18)

MELANIN PRODUCTION INHIBITOR
Disclosed is a melanin production inhibitor which has an excellent inhibitory activity on the production of melanin and is highly safe. The melanin production inhibitor is represented by general formula (1) (excluding clotrimazole) and/or a pharmacologically acceptable salt thereof. In the formula, A1, A2 and A3 are independently selected from a hydrogen atom, an aryl group which may have a substituent, and an aromatic heterocyclic group which may have a substituent. At least one of A1, A2 and A3 is selected from the aryl group and the aromatic heterocyclic group, the total number of carbon atoms contained in A1, A2 and A3 is 6 to 50 and, when at least two of A1, A2 and A3 represent the aryl groups or the aromatic heterocyclic groups, the adjacent two aryl or aromatic heterocyclic groups may be bound to each other via an alkyl chain or an alkenyl chain to form a ring; m represents an integer of 0 to 2; X represents a hetero atom, a hydrogen atom, or a carbon atom; R1 and R2 are independently selected from a hydrogen atom and an oxo group. When one of R1 and R2 is an oxo group, the other is not present. R3 is selected from a hydrogen atom, and a C1-8 hydrocarbon group in which one or some of hydrogen atoms or carbon atoms may be substituted by a hetero atom or hetero atoms. The number of R3's present in the compound corresponds to X and, when two or more R3's are present, the R3's are independently present and the adjacent two R3's may be bound to each other to form, together with X, a ring, and the terminal of R3 may be bound to a carbon atom to which A1, A2 and A3 are bound, thereby forming a ring.
-
Paragraph 0220 - 0223; 0227 - 0229

(2015/12/17)

Direct trifluoromethylthiolation of alcohols under mild reaction conditions: Conversion of R-OH into R-SCF3
A direct process for the trifluoromethylthiolation of allylic and benzylic alcohols under mild conditions has been developed. A wide range of free alcohols underwent nucleophilic substitution in the presence of stable CuSCF3 and BF3·Et2O to give the corresponding products in good to excellent yields.
Nikolaienko, Pavlo,Pluta, Roman,Rueping, Magnus
supporting information
p. 9867 - 9870
(2014/08/18)

Solvolytic Behavior of Aliphatic Carboxylates
The leaving group abilities (nucleofugalities) of a series of aliphatic carboxylates have been obtained by determining the nucleofuge-specific parameters (Nf and sf) from solvolysis rate constants of X,Y-substituted benzhydryl carboxylates in a series of aqueous ethanol mixtures by applyication of the linear free energy relationship (LFER) equation: log k = sf (Ef + Nf). These values can be employed to compare reactivities of carboxylates with those of other leaving groups previously included in the nucleofugality scale, and also to estimate the solvolysis rates of various carboxylates. It is confirmed that the inductive effect is the most important variable governing the reactivities of halogenated carboxylates in solution. Moreover, both the Hammett correlation and the solvolytic activation parameters have revealed a strong influence of the inductive effect on the nucleofugality of alkyl-substituted carboxylates. The reaction constants (sf) indicate that carboxylate substrates with weaker leaving groups solvolyze via later, more carbocation-like, transition states, which is in accord with the Hammond postulate. In addition, due to the weaker demand for solvation of transition states that produce more strongly stabilized benzhydrylium ions, in which more efficient charge delocalization occurs, the reaction constants (sf) obtained with most of the leaving groups investigated here increase as the polarity of the solvent decreases.
Matic, Mirela,Denegri, Bernard,Kronja, Olga
p. 1477 - 1486
(2015/10/05)

Nucleofugality of aliphatic carboxylates in mixtures of aprotic solvents and water
The leaving group ability (nucleofugality) of fluoroacetate, chloroacetate, bromoacetate, dichloroacetate, trifluoroacetate, trichloroacetate, heptafluorobutyrate, formate, isobutyrate, and pivalate have been derived from the solvolysis rate constants of the corresponding X,Y-substituted benzhydryl carboxylates in 60 % and 80 % aqueous acetonitrile and 60 % aqueous acetone, applying the LFER equation: log k = sf(Ef + Nf). The experimental barriers (ΔG?,exp) for solvolyses of 11 reference dianisylmethyl carboxylates in these solvents correlate very well (r = 0.994 in all solvents) with ΔG?,model of the model σ-assisted heterolytic displacement reaction of cis-2,3-dihydroxycyclopropyl trans-carboxylates calculated earlier. Linear correlation observed between the log k for the reference dianisylmethyl carboxylates and the sf values enables estimation of the reaction constant (sfestim). Using the ΔG?,exp vs. ΔG?,model correlation, and taking the estimated sfestim, the nucleofugality parameters for other 34 aliphatic carboxylates have been determined in 60 % and 80 % aqueous acetonitrile and 60 % aqueous acetone. The most important variable that determines the reactivity of aliphatic carboxylates in aprotic solvent/water mixtures is the inductive effect of the group(s) attached onto the carboxylate moiety.
Mati, Mirela,Denegri, Bernard,Kronja, Olga
p. 375 - 384
(2015/10/12)

Dual gold catalysis: Synthesis of polycyclic compounds via C-H insertion of gold vinylidenes
New and interesting polycyclic compounds have been synthesized from non-conjugated diyne systems by dual gold catalysis. A quaternary carbon center in the backbone and the accompanying Thorpe-Ingold effect enabled the unprecedented insertion of sp3 and sp2 C-H bonds that for the first time were incorporated within the backbone of the diyne system and allowed the construction of complex polycyclic carbon scaffolds inaccessible by previous approaches in which the C-H bonds for the insertion were situated at the other end of the alkyne.
Wieteck, Marcel,Tokimizu, Yusuke,Rudolph, Matthias,Rominger, Frank,Ohno, Hiroaki,Fujii, Nobutaka,Hashmi, A. Stephen K.
supporting information
p. 16331 - 16336
(2015/01/09)

Highly selective fluoride sensing via chromogenic aggregation of a silyloxy-functionalized tetraphenylethylene (TPE) derivative
A silyloxy-functionalized tetraphenylethylene (TPE) derivative shows a remarkable change in the absorption spectrum on deprotection with fluoride ions. The reaction process is highly selective for fluoride and the resulting charge transfer band results in a bright green solution. A simple selective visual assay of aqueous fluoride ions was also obtained by the impregnation of cellulose strips with the TPE derivative.
Simsek Turan, Ilke,Pir Cakmak, Fatma,Sozmen, Fazli
supporting information
p. 456 - 459
(2014/01/06)

Fe(OTf)3-catalyzed α-benzylation of aryl methyl ketones with electrophilic secondary and aryl alcohols
Acid-catalyzed Friedel-Crafts alkylation of 1,3-dicarbonyl compounds with electrophilic alcohols, is known to be an effective C-C bond forming reaction. However, until now, this reaction has not been amenable for α-alkylation of aryl methyl ketones because of the notoriously low nucleophilicities of these compounds. Therefore, α-alkylation of aryl methyl ketone relies on precious metal catalysts and also, the use of primary alcohols is mandatory. In this study, we found that a system composed of a Fe(OTf)3 catalyst and chlorobenzene solvent is sufficient to promote the title Friedel-Crafts reaction by using benzhydrols as electrophiles. 3,4-Dihydro-9-(2-hydroxy-4,4- dimethyl-6-oxo-1-cyclohexen-1-yl)-3,3-dimethyl-xanthen-1(2 H)-one was also applicable as an electrophile in this type of benzylation reaction. On the basis of this result, a three-component reaction of salicylaldehyde, dimedone, and aryl methyl ketone was also developed, and this provided an efficient way for the synthesis of densely substituted 4H-chromene derivatives. Copyright
Pan, Xiaojuan,Li, Minghao,Gu, Yanlong
supporting information
p. 268 - 274
(2014/01/06)

Sequential retro-ene arylation reaction of N-alkoxyenamides for the synthesis of tert -alkylamines
A sequential retro-ene arylation reaction has been developed for the conversion of N-alkoxyenamides to the corresponding tert-alkylamines in good yields via the nucleophilic addition of a triarylaluminum reagent to an in situ generated N-acylketimine. The reaction is tolerant of a range of functional groups and provides facile access to a series of tert-alkylamines that would be otherwise difficult to access using conventional procedures.
Miyoshi, Tetsuya,Matsuya, Syota,Tsugawa, Mikako,Sato, Shohei,Ueda, Masafumi,Miyata, Okiko
supporting information
p. 3374 - 3377
(2013/07/26)

Competition of C-H and C-O fragmentation in substituted p-methoxybenzyl ether radical cations generated by photosensitized oxidation
Laser and steady-state photolysis, sensitized by 2,4,6-triphenylpyrylium tetrafluoroborate (TPP+BF4-), of 4-methoxybenzyl ethers [4-CH3O-C6H4CH(OR 1)R, 1a: R = H, R1 = CH3; 1b: R = H, R 1 = C(CH3)3; 1c: R = CH3, R 1 = C(CH3)3; 1d: R = 4-CH3O-C 6H4, R1 = CH3] was carried out in CH3CN in the presence of oxygen. In particular, steady-state irradiation of 1a, b and d produced benzylic alcohols (together with a small amount of acetamide for 1a and 1b) and the oxidation carbonyl compounds (esters and ketones); 4-methoxy-α-methylbenzyl alcohol was the only product observed with 1c. Time-resolved investigations of 1c and 1d gave evidence of the intermediate benzylic carbocation, coming from the ether radical cation formed within the laser pulse by an electron transfer process from the ether to the TPP+ excited state. These results suggested that, besides the deprotonation of the benzyl carbon, the cleavage of the C-OR1 bond is also operative in the reaction pathways of the ether radical cation. The comparison of these results with those obtained in the photolysis of 1c with the uncharged 9,10-dicyanoanthracene (DCA) upholds a particular behavior of TPP+BF4-, probably due to the specific electrostatic interactions of BF4- with the radical cation. This is also supported by quantum mechanical calculation results performed at the B3LYP/6-31G(d) level to obtain the charge and spin density distributions of radical cations, free and complexed with BF4 -.
Carlotti, Benedetta,Del Giacco, Tiziana,Elisei, Fausto
p. 489 - 499
(2013/07/11)

Synthesis and antiproliferative activities of quebecol and its analogs
Simple and efficient synthesis of quebecol and a number of its analogs was accomplished in five steps. The synthesized compounds were evaluated for antiproliferative activities against human cervix adenocarcinoma (HeLa), human ovarian carcinoma (SK-OV-3), human colon carcinoma (HT-29), and human breast adenocarcinoma (MCF-7) cancer cell lines. Among all the compounds, 7c, 7d, 7f, and 8f exhibited antiproliferative activities against four tested cell lines with inhibition over 80% at 75 μM after 72 h, whereas, compound 7b and 7g were more selective towards MCF-7 cell line. The IC50 values for compounds 7c, 7d, and 7f were 85.1 μM, 78.7 μM, and 80.6 μM against MCF-7 cell line, respectively, showing slightly higher antiproliferative activtiy than the synthesized and isolated quebecol with an IC50 value of 104.2 μM against MCF-7.
Pericherla, Kasiviswanadharaju,Shirazi, Amir Nasrolahi,Kameshwara Rao,Tiwari, Rakesh K.,Dasilva, Nicholas,McCaffrey, Kellen T.,Beni, Yousef A.,Gonzalez-Sarrias, Antonio,Seeram, Navindra P.,Parang, Keykavous,Kumar, Anil
supporting information
p. 5329 - 5331
(2013/09/23)

Development of small-molecule probes that selectively kill cells induced to express mutant RAS
Synthetic lethal screening is a chemical biology approach to identify small molecules that selectively kill oncogene-expressing cell lines with the goal of identifying pathways that provide specific targets against cancer cells. We performed a high-throughput screen of 303,282 compounds from the National Institutes of Health-Molecular Libraries Small Molecule Repository (NIH-MLSMR) against immortalized BJ fibroblasts expressing HRASG12V followed by a counterscreen of lethal compounds in a series of isogenic cells lacking the HRASG12V oncogene. This effort led to the identification of two novel molecular probes (PubChem CID 3689413, ML162 and CID 49766530, ML210) with nanomolar potencies and 4-23-fold selectivities, which can potentially be used for identifying oncogene-specific pathways and targets in cancer cells.
We?wer, Michel,Bittker, Joshua A.,Lewis, Timothy A.,Shimada, Kenichi,Yang, Wan Seok,MacPherson, Lawrence,Dandapani, Sivaraman,Palmer, Michelle,Stockwell, Brent R.,Schreiber, Stuart L.,Munoz, Benito
supporting information; experimental part
p. 1822 - 1826
(2012/04/04)

Method for estimating SN1 rate constants: Solvolytic reactivity of benzoates
Nucleofugalities of pentafluorobenzoate (PFB) and 2,4,6-trifluorobenzoate (TFB) leaving groups have been derived from the solvolysis rate constants of X,Y-substituted benzhydryl PFBs and TFBs measured in a series of aqueous solvents, by applying the LFER equation: log k = sf(Ef + Nf). The heterolysis rate constants of dianisylmethyl PFB and TFB, and those determined for 10 more dianisylmethyl benzoates in aqueous ethanol, constitute a set of reference benzoates whose experimental ΔG ? have been correlated with the ΔH? (calculated by PCM quantum-chemical method) of the model epoxy ring formation. Because of the excellent correlation (r = 0.997), the method for calculating the nucleofugalities of substituted benzoate LGs have been established, ultimately providing a method for determination of the SN1 reactivity for any benzoate in a given solvent. Using the ΔG? vs ΔH? correlation, and taking sf based on similarity, the nucleofugality parameters for about 70 benzoates have been determined in 90%, 80%, and 70% aqueous ethanol. The calculated intrinsic barriers for substituted benzoate leaving groups show that substrates producing more stabilized LGs proceed over lower intrinsic barriers. Substituents on the phenyl ring affect the solvolysis rate of benzhydryl benzoates by both field and inductive effects.
Matic, Mirela,Denegri, Bernard,Kronja, Olga
p. 8986 - 8998,13
(2012/12/12)

Facile preparation of aromatic esters from aromatic bromides with ethyl formate or DMF and molecular iodine via aryllithium
Various aromatic bromides were treated with n-BuLi and subsequently with ethyl formate, followed by the reaction with ethanol and molecular iodine in the presence of K2CO3 to provide the corresponding aromatic ethyl esters in good yields. Moreover, aromatic bromides could be transformed into the corresponding aromatic methyl esters in good yields by the treatment with n-BuLi and subsequently with DMF, followed by the reaction with methanol, molecular iodine, and K2CO3. Some aromatics could be also converted into the corresponding aromatic esters in good yields by the treatment with n-BuLi, and subsequently with ethyl formate or DMF, followed by the reaction with molecular iodine and K2CO3. The present reactions offer a novel route for the transition-metal-free, carbon-monoxide-free, and therefore environmentally benign one-pot conversion of aromatic bromides and aromatics into aromatic esters.
Ushijima, Sousuke,Moriyama, Katsuhiko,Togo, Hideo
experimental part
p. 4701 - 4709
(2012/07/28)

Aryl aryl methyl thio arenes prevent multidrug-resistant malaria in mouse by promoting oxidative stress in parasites
We have synthesized a new series of aryl aryl methyl thio arenes (AAMTAs) and evaluated antimalarial activity in vitro and in vivo against drug-resistant malaria. These compounds interact with free heme, inhibit hemozoin formation, and prevent Plasmodium falciparum growth in vitro in a concentration-dependent manner. These compounds concentration dependently promote oxidative stress in Plasmodium falciparum as evident from the generation of intraparasitic oxidants, protein carbonyls, and lipid peroxidation products. Furthermore, AAMTAs deplete intraparasite GSH levels, which is essential for antioxidant defense and survival during intraerythrocytic stages. These compounds displayed potent antimalarial activity not only in vitro but also in vivo against multidrug-resistant Plasmodium yoelii dose dependently in a mouse model. The mixtures of enantiomers of AAMTAs containing 3-pyridyl rings were found to be more efficient in providing antimalarial activity. Efforts have been made to synthesize achiral AAMTAs 17-23 and among them, compound 18 showed significant antimalarial activity in vivo
Goyal, Manish,Singh, Priyanka,Alam, Athar,Kumar Das, Sajal,Shameel Iqbal, Mohd,Dey, Sumanta,Bindu, Samik,Pal, Chinmay,Kumar Das, Sanjit,Panda, Gautam,Bandyopadhyay, Uday
scheme or table
p. 129 - 142
(2012/09/07)

The reactivity of benzoates in mixtures of water and aprotic solvents
Nucleofugalities of pentafluorobenzoate (PFB), 2,4,6-trifluorobenzoate (TFB), 2-nitrobenzoate, and 3,5-dinitrobenzoate (DNB) leaving groups have been derived from the solvolysis rate constants of the corresponding X,Y-substituted Z-benzhydryl benzoates in
Matic, Mirela,Denegri, Bernard,Kronja, Olga
p. 585 - 594
(2013/06/26)

Nucleofugality and nucleophilicity of fluoride in protic solvents
A series of p-substituted benzhydryl fluorides (diarylfluoromethanes) were prepared and subjected to solvolysis reactions, which were followed conductometrically. The observed first-order rate constants k1(25 °C) were found to follow the correlation equation log k1(25 °C) = sf(Nf + Ef), which allowed us to determine the nucleofuge-specific parameters Nf and sf for fluoride in different aqueous and alcoholic solvents. The rates of the reverse reactions were measured by generating benzhydrylium ions (diarylcarbenium ions) laser flash photolytically in various alcoholic and aqueous solvents in the presence of fluoride ions and monitoring the rate of consumption of the benzhydrylium ions by UV-vis spectroscopy. The resulting second-order rate constants k-1(20 °C) were substituted into the correlation equation log k-1 = sN(N + E) to derive the nucleophilicity parameters N and sN for fluoride in various protic solvents. Complete Gibbs energy profiles for the solvolysis reactions of benzhydryl fluorides are constructed.
Nolte, Christoph,Ammer, Johannes,Mayr, Herbert
supporting information; scheme or table
p. 3325 - 3335
(2012/06/17)

Synthesis of fluorenone derivatives through Pd-catalyzed dehydrogenative cyclization
Palladium-catalyzed dual C-H functionalization of benzophenones to form fluorenones by oxidative dehydrogenative cyclization is reported. This method provides a concise and effective route toward the synthesis of fluorenone derivatives, which shows outstanding functional group compatibility.
Li, Hu,Zhu, Ru-Yi,Shi, Wen-Juan,He, Ke-Han,Shi, Zhang-Jie
supporting information
p. 4850 - 4853,4
(2012/12/12)

Ru(II) xantphos complex as an efficient catalyst in transfer hydrogenation of carbonyl compounds
In the transfer hydrogenation of aromatic/aliphatic carbonyl compounds using iso-propanol-potassium hydroxide mixture as hydrogen donor, a mixed ligand Ru(II) complex, prepared from xantphos ligand and RuCl2(dmso) 4, was examined. Besides, the solid state structure of the Ru (II) complex was determined using X-ray single crystallography. The catalytic reactivity of the complex was remarkable (up to 99%) and the catalyst showed more efficiency in the reduction of ketones than aldehydes.
Kharat, Ali Nemati,Bakhoda, Abolghasem,Jahromi, Bahareh Tamaddoni
scheme or table
p. 1161 - 1164
(2011/06/28)

MELANIN PRODUCTION INHIBITOR
Disclosed is a melanin production inhibitor which has an excellent inhibitory activity on the production of melanin and is highly safe. The melanin production inhibitor comprises a compound represented by general formula (1) (excluding clotrimazole), and/or a pharmacologically acceptable salt thereof. In the formula, A1, A2 and A3 are independently selected from a hydrogen atom, an aryl group which may have a substituent, and an aromatic heterocyclic group which may have a substituent, wherein at least one of A1, A2 and A3 is selected from the aryl group and the aromatic heterocyclic group, the total number of carbon atoms contained in A1, A2 and A3 is 6 to 50 and, when at least two of A1, A2 and A3 represent the aryl groups or the aromatic heterocyclic groups, the adjacent two aryl or aromatic heterocyclic groups may be bound to each other via an alkyl chain or an alkenyl chain to form a ring; m represents an integer of 0 to 2; X represents a hetero atom, a hydrogen atom, or a carbon atom; R1 and R2 are independently selected from a hydrogen atom and an oxo group, wherein when one of R1 and R2 is an oxo group, the other is not present; and R3 is selected from a hydrogen atom, and a C1-8 hydrocarbon group in which one or some of hydrogen atoms or carbon atoms may be substituted by a hetero atom or hetero atoms, wherein the number of R3's present in the compound corresponds to the number of X's and, when two or more R3's are present, the R3's are independently present and the adjacent two R3's may be bound to each other to form, together with X, a ring, and the terminal of R3 may be bound to a carbon atom to which A1, A2 and A3 are bound, thereby forming a ring.
-
(2011/10/13)

On the photodegradation of some 2H-chromene derivatives in fluid solution or in polyurethane matrix
The time profile of the optical density was monitored during the photodegradation of three derivatives of 2,2-diphenyl-2H-naphtho[1,2-b]pyran (1), namely 2,2-bis(4-methoxyphenyl)-5,6-dimethyl-2H-naphtho[1,2-b]pyran (2), 2,2-diphenyl-5-[(ethoxycarbonyl)methoxycarbonyl]-8-methyl-2H-naphtho[1,2-b] pyran (3), and 3,3-bis(4-methoxyphenyl)-6,11-dimethyl-13-hydroxy-13-isopropyl- 3H-indeno[2,1-f ]naphtho[1,2-b]pyran (4) either in toluene solution or in a polyurethane matrix. The photoproducts were identified using HPLC, GC/MS, and direct insertion MS techniques. High molecular weight oxygenated derivatives and new photoproducts deriving from a secondary oxidative pathway were characterized along with expected degradation derivatives. Some of the photoproducts considered responsible for the yellowing of the examined materials were identified. The effect exerted by two additives generally considered to have an inhibiting action toward radical processes was also evaluated.
Alberti, Angelo,Campredon, Mylene,Demadrille, Renaud
experimental part
p. 552 - 561
(2011/06/25)