cas 91-04-3, 2,6-Bis(hydroxymethyl)-p-cresol

Articles about 91-04-3Total 33 be found

Article title
Article abstract
Author
Journal number and time
Download

The preparation of dicompartmental multifunctional group ligands
A convenient method for the preparation of the phenol-based ligands 1,6-bis(2-thiophenyl)-2,5-bis(2-hydroxy-3-hydroxymethyl-5-methylbenzyl)-2, 5-diazahexane and 1,6-bis(5-methyl-2-thiophenyl)-2,5-bis(2-hydroxy-3- hydroxymethyl-5-methyl-benzyl)-2,5-diazahexane possessing two dissimilar compartments having multifunctional groups is reported. To synthesize these ligands, an equivalent of 1,6-bis(2-thiophene)-2,5-diazahexane or 1,6-bis(5-methyl-2-thiophene)-2,5-diazahexane and two equivalents of 2,2-dimethyl-6-methyl-8-(chloromethyl)benzo-1,3-dioxin were reacted in the presence of Na2CO3 in 1,4-dioxane, followed by acid hydrolysis of an acetonide-protecting group. Characterization data for the new compounds is reported. Copyright Taylor & Francis Group, LLC.
Khaniani, Yeganeh,Golchoubian, Hamid
p. 2817 - 2823
(2006)
Read Online

DINUCLEATING LIGAND OR DINUCLEAR METAL COMPLEX
To provide a dinuclear metal complex that can be synthesized simply and easily and has a proper anticancer action.SOLUTION: The present disclosure provides a dinucleating ligand represented by the following formula (I) and a dinuclear metal complex thereof (where each X may be the same or different to represent H, Cl, OMe, or, Me, Y is H, a phenyl group, a substituted carbamoyl group or the like).SELECTED DRAWING: None
-
Paragraph 0048-0049

(2021/03/19)

DINUCLEATING LIGAND OR DINUCLEAR METAL COMPLEX
To provide a dinuclear metal complex that can be synthesized simply and easily and has a proper anticancer action.SOLUTION: The present disclosure provides a dinucleating ligand represented by the following formula (I) and a dinuclear metal complex thereof (where X is H or a substituted carbamoyl group, R1, R2, R3, and R4 independently represent H or a C1-8 linear or branched alkyl group).SELECTED DRAWING: None
-
Paragraph 0048; 0060-0061

(2021/03/19)

Process preparation method of 4-substituted-2, 6-dimethylphenol
The present invention discloses a process preparation method of 4-substituted-2, 6-dimethyl phenol. According to the process preparation method, a preparation route method is improved and optimized, reaction conditions are optimized, post-treatment and purification methods are improved, so that the danger grade of operation and the production cost are reduced; and the requirement for the corrosionresistance grade of reaction container equipment is low, the operation is safe, and the post-treatment is environment-friendly; and the prepared 4-substituted-2, 6-dimethyl phenol has less impurities, thus, the purity and the quality of an intermediate product are greatly improved while the yield is improved as well, the difficulty of process control in the production process of a subsequent rawmaterial medicine product is improved, and the quality and qualification rate of the subsequent raw material medicine product are improved; and the steps of the preparation method is simple to operate, the solvent and the process conditions are safe and easy to achieve, environment-friendly production is achieved, and the preparation method has wide application prospect.
-
Paragraph 0106-0108

(2019/07/11)

Electronic Effects of Ligand Substitution in a Family of CoII2 PARACEST pH Probes
We report three new Co2-based paramagnetic chemical exchange saturation transfer (PARACEST) probes with the ability to ratiometrically quantitate pH. A CoII2 complex, [LCo2(etidronate)]-, featuring tetra(carboxamide) and OH-substituted etidronate ligands with opposing pH-dependent CEST peak intensities, was previously shown to exhibit a linear correlation between log(CESTOH/CESTNH) and pH in the pH range 6.5-7.6 that provided a sensitivity of 0.99(7) pH unit-1 at 37 °C. Here, we demonstrate through a series of CF3-functionalized CoII2 complexes [(XL′)Co2(etidronate)]- (X = NO2, F, Me), that modest changes in the electronic structure of CoII centers through remote ligand substitution can significantly affect the NMR and CEST properties of Co2-based PARACEST probes. Variable-pH NMR and CEST analyses reveal that the chemical shifts of the ligand protons are highly affected by the nature of the X substituent. The ratios of OH and NH CEST peak intensities at 115 and 88, 93 and 79, and 88 and 76 ppm for X = NO2, F, and Me, respectively, afford pH calibration curves with remarkably high sensitivities of 1.49(9), 1.48(7), and 2.04(5) pH unit-1 across the series. The 1.5-2-fold enhancement in pH sensitivity for the CF3-functionalized Co2 probes stems from the complete separation of the OH and NH CEST peaks. Furthermore, incorporation of electron-withdrawing CF3 groups shifts the detection window to a more acidic range of pH 6.2-7.4. Finally, the CoII2 complexes are found to be extremely robust toward substitution and oxidation in aqueous solutions. Taken together, these results highlight the unique ability of transition metal-based PARACEST probes to provide a highly sensitive concentration-independent measure of pH and demonstrate that modest ligand modifications can be a powerful tool for optimizing the pH sensing performance of these probes.
Thorarinsdottir, Agnes E.,Tatro, Scott M.,Harris, T. David
supporting information
p. 11252 - 11263
(2018/09/14)

Highly enantioselective asymmetric reactions involving zinc ions promoted by chiral aziridine alcohols
Enantiomerically pure, chiral secondary and tertiary aziridine alcohols (including the aziridine analogue of ProPhenol—AziPhenol) have proven to be highly effective catalysts for enantioselective asymmetric reactions in the presence of zinc ions, including arylation of aromatic aldehydes, epoxidation of chalcone and addition of diethylzinc to aldehydes, leading to the desired chiral products in high chemical yields (up to 90%) and with ee's up to 90%. A higher catalytic activity of Prophenol-type bis(aziridine alcohol) in the aforementioned asymmetric transformations has been demonstrated.
Jarzyński, Szymon,Utecht, Greta,Le?niak, Stanis?aw,Rachwalski, Micha?
p. 1774 - 1779
(2017/11/16)

A CuII2 Paramagnetic Chemical Exchange Saturation Transfer Contrast Agent Enabled by Magnetic Exchange Coupling
The ability of magnetic exchange coupling to enable observation of paramagnetic chemical exchange saturation transfer (PARACEST) in transition metal ions with long electronic relaxation times (s) is demonstrated. Metalation of the dinucleating, tetra(carboxamide) ligand HL with Cu2+ in the presence of pyrophosphate (P2O7)4- affords the complex [LCuII2(P2O7)]-. Solution-phase variable-temperature magnetic susceptibility data reveal weak ferromagnetic superexchange coupling between the two S = 1/2 CuII centers, with a coupling constant of J = +2.69(5) cm-1, to give an S = 1 ground state. This coupling results in a sharpened NMR line width relative to a GaCu analogue, indicative of a shortening of s. Presaturation of the amide protons in the Cu2 complex at 37 °C leads to a 14% intensity decrease in the bulk water 1H NMR signal through the CEST effect. Conversely, no CEST effect is observed in the GaCu complex. These results provide the first example of a Cu-based PARACEST magnetic resonance contrast agent and demonstrate the potential to expand the metal ion toolbox for PARACEST agents through introduction of magnetic exchange coupling.
Du, Kang,Harris, T. David
p. 7804 - 7807
(2016/07/07)

Hydrogenolysis of glycerol using Fe-Fe/Al2O3 complex catalyst
Macrocyclic complex catalyst Fe-FeL1 complex of L1 (L1 = C24H26O2N4.) was synthesized and studied in the hydrogenolysis reaction of glycerol reaction in a high pressure batch reactor. The catalyst was well characterized i.e. FTIR, XRD, TGA and BET surface area. The study of hydrogenolysis was found that the selectivity of 1,2-propane diol 80 % at 220°C temperature and 0.35 MPa pressure in presence of hydrogen gas and Fe-Fe/Al2O3 and 30 % glycerol concentration in water gives 1,2-propane diol as the only product and conversion was 36 % at 220°C. It is further seen that if the concentration of glycerol in water is increased beyond 40 % there is a decrease in the total conversion and carbon is produced as coke during the reaction.
Lal, Sunder,Thakur, Ramswaroop Singh
p. 2596 - 2600
(2016/10/17)

Nickel-catalyzed one-pot deoxygenation and reductive homocoupling of phenols via C-O activation using TCT reagent
A new method for C-O bond activation of phenolic compounds has been achieved using 2,4,6-trichloro-1,3,5-triazine to utilize in one-pot Ni-catalyzed deoxygenation and reductive homocoupling reactions. With this simple method, phenolic compounds were converted to their corresponding arenes or biaryl compounds under mild conditions. The introduced methodology has a broad scope and demonstrates good functional group compatibility.
Iranpoor, Nasser,Panahi, Farhad
supporting information
p. 214 - 217
(2015/01/30)

Visual and near IR (NIR) fluorescence detection of Cr3+ in aqueous media via spirobenzopyran ring opening with application in logic gate and bio-imaging
A new spirobenzopyran derivative (SPNH) was designed and synthesized which was applied in simultaneous colorimetric and NIR fluorescence detections for Cr3+. This spirobenzopyran receptor is normally colorless in aqueous organic media but the formation of merocyanine occurs by Cr3+ showing a yellow color. Here the formation of yellow color in UV-vis spectra and strong NIR fluorescence emission at 675 nm makes SPNH a good sensor for Cr 3+ ion. It is also found to be useful in cell imaging and in construction of logic gate. It shows INHIBIT gate in fluorescence and OR gate in absorption. To the best of our knowledge, this is the first report of NIR fluorescence emission of a spirobenzopyran derivative by Cr3+ and its application to cell-biology and also in the logic gate.
Goswami, Shyamaprosad,Das, Avijit Kumar,Maity, Anup Kumar,Manna, Abhishek,Aich, Krishnendu,Maity, Sibaprasad,Saha, Partha,Mandal, Tarun Kanti
p. 231 - 239
(2014/01/06)

(ArO)TiR3 complexes for highly syndiospecific styrene polymerization
A kind of (ArO)TiR3 (ArO = 2,6-(R′)2-4- methylphenolate, R′ = Me, tBu, CH2SPh, CH 2N(iPr)2, CH2NPh2) complexes was synthesized and characterized. X-ray analysis of 6a and 7 shows that neither CH2SPh (6a) nor CH2N(iPr) 2 group (7) coordinates to titanium. Large bond angles C(Ar)-O(1)-Ti(1) angel (152.9(2) in 6a and 175.33 in 7 indicate that the bond have partial sp-hybridized character. Upon treatment with modified methylaluminoxane (MMAO), the titanium complexes exhibit significant thermal stability, and prove useful as styrene syndiotactic polymerization catalysts. Comparisons between different complexes on the styrene polymerization were discussed. Steric instead of electronic properties at 2,6-positions of phenol affect the polymerization activity. (2-tert-Butyl)-4-methylphenoxytitanium(IV) chloride 5e was established the most efficient one. High activity (1.11 × 105 g sPS/mol(Ti) h) was achieved when styrene polymerization was carried out in the presence of 5e/MMAO at 130 C for 2 h.
Xu, Chongjie,Chen, Zhou,Ji, Gang,Sun, Xiu-Li,Li, Jun-Fang,Tang, Yong
p. 77 - 82
(2014/01/06)

A rhodamine B-based "turn-on" fluorescent sensor for detecting Cu2+ and sulfur anions in aqueous media
A novel selective fluorescent chemosensor L based on rhodamine B derivative has been designed and synthesized to optically detect Cu2+ and S2- in aqueous buffer solution. The fluorescence of L was excited by Cu2+ with a 1:1 binding ratio, and could be used as a "turn-on" type sensor. Otherwise, the emission band would undergo a slight red-shift. Once binding with Cu2+, the copper complex can exhibit high selectivity for S2-. Upon addition of Cu2+, the color of the chemosensor L changes from colorless to pink. Additionally, the resulting pink solution changes to colorless immediately upon the addition of S2-. However, no phenomenon change could be observed in the presence of other anions. Conclusively, the color changes suggest that sensor L could serve as a "naked-eye" sensor for Cu2+ and S2-.
Guo, Dan,Dong, Zhengping,Luo, Chao,Zan, Wenyan,Yan, Shiqiang,Yao, Xiaojun
p. 5718 - 5725
(2014/01/23)

An "off-on-off" fluorescent probe for the sequential detection of Zn2+ and hydrogen sulfide in aqueous solution
A novel selective fluorescent chemosensor (L1) based on 8-aminoquinoline was synthesized and characterized. The sensor exhibited remarkable selectivity for Zn2+ in the presence of other cations in aqueous solution. Density functional theory calculations on L1 and the L1-Zn complex are consistent with the experimental results. Once combined with Zn2+, the complex L1-Zn displayed high specificity for H2S. As HS - is equivalent to H2S in physiological solution, HS - was selected to represent H2S in this work. Among various anions, only HS- induced revival of the fluorescence of L1. Signal transduction occurs via reversible formation-separation of complex L1-Zn and ZnS. L1 and the sequential complex L1-Zn have ideal chemical and spectroscopic properties that satisfy the criteria for further Zn2+ and H2S sensing in biological and environmental applications.
Dong, Zhengping,Le, Xuanduong,Zhou, Panpan,Dong, Chunxu,Ma, Jiantai
p. 1802 - 1808
(2014/05/06)

Oxidation-responsive poly(amino ester)s containing arylboronic ester and self-immolative motif: Synthesis and degradation study
We report the synthesis of a new type of amphiphilic poly(amino ester)s which can be completely degraded in aqueous media via H2O2 oxidation. The polymers were prepared by the controlled Michael-type addition polymerization of a phenylboronic pinacol ester-containing diacrylate and N-aminoethylpiperazine, followed by postmodification with mPEG5K-succinimide ester. Upon oxidation, the side chain phenylboronic esters will be transformed into phenol groups which can trigger the sequential self-immolative process to degrade the polymer main chain. Meanwhile, the amino groups on the polymer main chain are capable of trapping the highly active quinone methides generated in situ during the oxidative degradation of the polymers. Based on the detailed oxidation kinetics and products of several model compounds, the H 2O2-triggered degradation of nanoparticles of these copolymers was investigated by NMR spectroscopy, GPC, and Nile red fluorescence probe. The results demonstrate that the poly(amino ester) backbones were completely degraded by H2O2, resulting in the dissociation of nanoparticles. Oxidative degradation rates of the nanoparticles could be accelerated by increasing the concentration of H2O2, the PEGylation degree, or the pH of the buffer. Interestingly, the in situ formed quinone methides could be captured by secondary amines due to their higher nucleophilicity than H2O. Of potential importance, these amphiphilic oxidation-responsive copolymers are sensitive to stimulation of 200 μM H 2O2; therefore, they may find application in the field of intelligent drug/gene delivery systems.
Song, Cheng-Cheng,Ji, Ran,Du, Fu-Sheng,Li, Zi-Chen
p. 8416 - 8425
(2013/12/04)

Remarkable ESIPT induced NIR emission by a selective colorimetric dibenzimidazolo diimine sensor for acetate
A new dibenzimidazolo diimine sensor (DDS) has been designed and synthesized for selective detection of acetate ion. Significant naked eye recognized color change of DDS solution from light yellow to pink upon addition of only acetate ion is accompanied with near infra red (NIR) emission exploiting excited state intramolecular proton transfer (ESIPT).
Goswami, Shyamaprosad,Maity, Sibaprasad,Das, Avijit Kumar,Maity, Annada C.,Mandal, Tarun Kanti,Samanta, Siddhartha
supporting information
p. 5232 - 5235
(2013/09/02)

Transition metal complexes of 2, 6-di ((phenazonyl-4-imino) methyl)-4-methylphenol: Structure and biological evaluation
A symmetric ligand 2, 6-di ((phenazonyl-4-imino)methyl)-4-methylphenol (Dpmp) and its cobalt dinuclear complex (Co2(Dpmp) 2(NO3)2(H2O)2·NO3· EtOH, (1) and zinc mononuclear complex Zn(Dpmp)(NO3)2, (2) have been prepared. The crystal structures were determined by single-crystal X-ray diffraction. The biological activity has been evaluated by examining their anti-oxidative activity and ability to bind to bovine serum albumin (BSA) and calf-thymus DNA (CT DNA) with UV-vis absorption, fluorescence, viscosity measurements and circular dichroism (CD) spectroscopies. The complexes exhibit good binding propensity to BSA and CT DNA. Both 1 and 2 have been found to promote cleavage of pUC19 DNA in the absence of any reducing agent. Antioxidant tests in vitro show the compounds possess significant antioxidant activity against superoxide and hydroxyl radicals.
Liu, Hongyan,Shi, Xiaoyan,Xu, Min,Li, Zhengpeng,Huang, Liang,Bai, Decheng,Zeng, Zhengzhi
scheme or table
p. 1638 - 1647
(2011/05/06)

Mononuclear copper(ii) complexes with 3,5-substituted-4-salicylidene-amino- 3,5-dimethyl-1,2,4-triazole: Synthesis, structure and potent inhibition of protein tyrosine phosphatases
Six copper complexes of Schiff base ligands containing 3,5-substituted-4- salicylideneamino-3,5-dimethyl-1,2,4-triazole have been synthesized and well characterized. The structures of complexes 1 and 2 were determined by X-ray crystal analysis. Fluorescence and potentiometric study indicated that in the physiological pH range, one ligand was dissociated from the complexes to form 1:1 mononucleus copper complexes. The complexes potently inhibit protein tyrosine phosphatase 1B (PTP1B), T-cell protein tyrosine phosphatase (TCPTP), megakaryocyte protein tyrosine phosphatase 2 (PTP-MEG2) and Src homology phosphatase 1 (SHP-1) with 3-4 fold selectivity against PTP1B over TCPTP and PTP-MEG2, and 3-9 fold over SHP-1, but display almost no inhibition against Src homology phosphatase 2 (SHP-2). Complex 1 inhibits PTP1B with a competitive model with Ki of 30 nM. Substitution with small groups at the phenyl of the ligand does not obviously influence the inhibitory ability of the complexes.
Ma, Ling,Lu, Liping,Zhu, Miaoli,Wang, Qingming,Li, Ying,Xing, Shu,Fu, Xueqi,Gao, Zengqiang,Dong, Yuhui
experimental part
p. 6532 - 6540
(2011/08/03)

Self-assembly from metal-organic vesicles to globular networks: Metallogel-mediated phenylation of indole with phenyl boronic acid
Self-assembly of the conformationally flexible bismethylimidazolyl ligands with Pd(OAc)2 is described. Depending on whether the ligands provide the hydrogen bonding donor, a switching of metal-organic vesicles to globular networks gelating solvents is achieved. The metallogels exhibit catalytic activity for the cross-coupling of indole with phenyl boronic acid.
Yang, Li,Luo, Liang,Zhang, Shuai,Su, Xiaoyu,Lan, Jingbo,Chen, Chi-Tien,You, Jingsong
supporting information; scheme or table
p. 3938 - 3940
(2010/07/14)

The enantiomeric recognition of chiral organic ammonium salts by chiral pyridino-macrocycles bearing aminoalcohol subunits
Pyridine-based macrocycles were prepared by treating 2,6-bis[[2′6′-bis(bromomethyl)-4′-methylphenoxy]methyl]pyridine 3 with the appropriate chiral aminoalcohols. The enantiomeric recognition of these macrocycles bearing aminoalcohol subunits of the pyridinocrown type ligand was evaluated for chiral organic ammonium salts by UV titration. The important differences were observed in the Ka values of (R)-Am2 and (S)-Am2 for (S,S,S)-1, (S,S,S)-2 and (S,S,S)-3 hosts, KS/KR = 5.0, KS/KR = 2.4 and KS/KR = 5.0, respectively. There seems to be a general tendency for hosts to recognise (S)-enantiomers for both Am1 and Am2.
Ozer, Hayriye,Kocakaya, Safak Ozhan,Akgun, Abuzer,Hosgoeren, Halil,Togrul, Mahmut
scheme or table
p. 1541 - 1546
(2009/11/30)

Synthesis and molecular orbital calculations of some benzo-substituted macrocyclic diamides and their corresponding macrocyclic dithiodiamides
A new series of benzo-substituted macrocyclic diamides were prepared by nucleophilic reaction of the appropriate dipotassium salts with the corresponding bis(halo) compounds in refluxing DMF. Treatment of the novel macrocyclic diamides with Lawesson's reagent in refluxing toluene led to the formation of the corresponding macrocyclic dithiodiamides in good yields. Molecular orbital calculations were performed at the semi-empirical level AM1 on some of the studied macrocycles. Thermodynamic functions show that the most stable structures in gas phase that have internal amine groups are less in energy than the other ones that have internal carbonyl groups. The solvent polarity does not appreciably affect the stability trend of the three conformers of each compound due to their comparable dipole moments. A complete and thorough survey of proton affinity (PA) and proton detachment energies (PDE) on each of the possible sites has been performed.
Mohamed, Adel A.,Masaret, Ghada S.,Elwahy, Ahmed H.M.
p. 4000 - 4010
(2007/10/03)

Asymmetric synthesis of hydrobenzofuranones via desymmetrization of cyclohexadienones using the intramolecular Stetter reaction
Dearomatization of phenols followed by oxidation affords cyclohexadienyloxyacetaldehydes, which produce hydrobenzofuranones via asymmetric intramolecular Stetter reaction in good to excellent yield. Quaternary as well as up to three contiguous stereocenters may be formed in good to excellent enantioselectivities and high diastereoselectivities. Copyright
Liu, Qin,Rovis, Tomislav
p. 2552 - 2553
(2007/10/03)

Synthesis and characterisation of a high valent dinuclear Mn(III,III) complex of a triphenolate ligand [N4O3]3- with two extra functional groups
A new high valent complex [Mn2(III,III)L(μ-OAc) 2]·PF6 7 was prepared, where L was the tri-anion of 2,6-Bis {[(2-hydroxy-5-tert-butylbenzyl)(pyridyl-2-methyl)amino]methyl}-4-methylphenol which contained two additional phenolate groups and two tert-butyl groups compared to its parent [Mn2(II,II)(bpmp)(μ-OAc) 2]·PF6. These improvements narrowed the disparity between the new model and (Mn)4 cluster (OEC in nature).
Li, Hongyang,Shi, Feng,Gao, Yan,Zhang, Rong,Peng, Xiaojun,Sun, Licheng
p. 57 - 58
(2007/10/03)

Synthesis and conformational behaviour of new intra-annularly linked cyclophane possessing a 1,6-dioxahexa-2,4-diyne spacer
The new intra-annularly linked cyclophane 1 was synthesized in five steps from p-cresol by intramolecular Eglington coupling of precyclophane 5. From the 1H NMR data, it was evident that the cyclophane 1 exists predominantly as conformer 1a rather than 1b at room temperature.
Rajakumar, Perumal,Murali, Venghatraghavan
p. 7695 - 7698
(2007/10/03)

Effect of ligand structure on the zinc-catalyzed Henry reaction. Asymmetric syntheses of (-)-denopamine and (-)-arbutamine
(Matrix presented) Syntheses of variously modified ligands for the dinuclear zinc catalysts for the asymmetric aldol and nitroaldol (Henry) reactions are reported. Catalytic enantioselective nitroaldol reactions promoted by these modified ligands led to efficient syntheses of the β-preceptor agonists (-)-denopamine and (-)-arbutamine.
Trost, Barry M.,Yeh, Vince S. C.,Ito, Hisanako,Bremeyer, Nadine
p. 2621 - 2623
(2007/10/03)

Synthesis, magnetism, 1H NMR and redox activity of dicopper(II) complexes having a discrete {Cu2(μ-phenoxide)2}2+ unit supported by a non-macrocyclic ligand environment. Crystal structure of [Cu2(L)2(OCIO3)2] [HL = 4-methyl-2,6-bis(pyrazol-1-ylmethyl)-phenol]
Reaction between 4-methyl-2,6-bis(pyrazol-l-ylmethyl)phenol (HL) or its 3,5-dimethylpyrazole derivative (HL′) and Cu(ClO4)2·6H2O afforded [CuII2(L/L′)2(OClO3) 2] 1 and 2. Complex 1 has been structurally characterized showing that each copper(II) centre is square pyramidal with two bridging phenoxide oxygens and two terminal pyrazole nitrogens in the equatorial plane and a perchlorate oxygen atom axially co-ordinated. Variable-temperature magnetic susceptibility measurements revealed that the dicopper(II) centres are strongly antiferromagnetically coupled [singlet-triplet energy separation, 2J (in cm-1): -1204 for 1 and -798 for 2]. The complexes exhibit 1H NMR spectra within δ 0-10 due to their S = 0 ground state. In MeCN solution they exhibit ligand field transitions in the range 14 300-16 600 cm-1 and phenolate-to-copper(II) charge-transfer transition at ≈22 700 cm-1. In MeCN solution each complex displays three consecutive irreversible responses (scan rate of 50 mV s-1) with Epc values (V vs. SCE) at -0.02, -0.54 and -0.86 (1) and 0.00, -0.42 and -0.80 (2). The first two responses are due to CuIICuI and the most cathodic response to CuI-Cu0 redox processes, respectively. The Royal Society of Chemistry 1999.
Gupta, Rajeev,Mukherjee, Sumitra,Mukherjee, Rabindranath
p. 4025 - 4030
(2007/10/03)

Synthesis and binding behavior of an artificial receptor based on 'upper rim' functionalized calix[5]arene
A new calix[5]arene possessing two benzoic acid moieties was synthesized as an artificial receptor and its ability of binding to a variety of amine guests was investigated. The structures of the complexes with the mines were proposed by the molecular mechanics calculation using MacroModel V. 4.0.
Haino, Takeharu,Matsumura, Kazumi,Harano, Tetsuya,Yamada, Kaori,Saijyo, Yoshikazu,Fukazawa, Yoshimasa
p. 12185 - 12196
(2007/10/03)

Alkyl- and aryl-oxygen bond activation in solution by rhodium(I), palladium(II), and nickel(II). Transition-metal-based selectivity
Reaction of [RhCl(C8H14)2]2 (C8H14 = cyclooctene) with 2 equiv of the aryl methyl ether phosphine 1 in C6D6 results in an unprecedented metal insertion into the strong sp2-sp3 aryl-O bond. This remarkable reaction proceeds even at room temperature and occurs directly, with no intermediacy of C-H activation or insertion into the adjacent weaker ArO-CH3 bond. Two new phenoxy complexes (8 and 9), which are analogous to the product of insertion into the ArO-CH3 bond (had it taken place) were prepared and shown not to be intermediates in the Ar-OCH3 bond cleavage process. Thus, aryl-O bond activation by the nucleophilic Rh(I) is kinetically preferred over activation of the alkyl-O bond. The phenoxy Rh(I)-η1-N2 complex (8) is in equilibrium with the crystallographically characterized Rh(I)-μ-N2-Rh(I) dimer(12). Reaction of [RhClC8H14)2]2 with 2 equiv of the aryl methyl ether phosphine 2, PPh3, and excess HSiR3 (R = OCH2CH3, CH2CH3) results also in selective metal insertion into the aryl-O bond and formation of (CH3O)SiR3. Thus, transfer of a OCH3 group from carbon to silicon was accomplished, showing that hydrosilation of an unstrained aryl-O single bond by a primary silane is possible. The selectivity of C-O bond activation is markedly dependent on the transition-metal complex and the alkyl group involved, allowing direction of the C-O bond activation process at either the aryl-O or alkyl-O bond. Thus, contrary to the reactivity of the rhodium complex, reaction of NiI2 or Pd(CF3CO2)2 with 1 equiv of 1 in ethanol or C6D6 at elevated temperatures results in exclusive activation of the sp3-sp3 ArO-CH3 bond, while reaction of the analogous aryl ethyl ether 4 and Pd(CF3CO2)2 results in both sp3-sp3 and sp2-sp3 C-O bond activation. The resulting phenoxy Pd(II) complex (18) is fully characterized by X-ray analysis. Heating the latter under mild dihydrogen pressure results in hydrodeoxygenation to afford an aryl-Pd(II) complex (19).
Van Der Boom, Milko E.,Liou, Shyh-Yeon,Ben-David, Yehoshoa,Shimon, Linda J. W.,Milstein, David
p. 6531 - 6541
(2007/10/03)

Synthesis of macrocyclic polyhydroxy tetralactams derived from L-tartaric acid and β-hydroxyglutaric acid
The synthesis of new 16-, 18-, 19- or 20-membered secondary tetralactams with L-tartaric acid or β-hydroxyglutaric acid moieties is investigated. The stepwise synthesis with an intermediate diamide diamine provides overall good yields (30-55%) compared with other processes using an intermediate diamide diacid or direct macrocyclization. This synthetic pathway leads to symmetrical or unsymmetrical polyhydroxytetralactams with variable hydroxyl group number. Use of mild acylating agents in this approach allows to avoid the protection-deprotection steps of hydroxyl groups.
Arnaud, Nathalie,Picard, Claude,Cazaux, Louis,Tisnes, Pierre
p. 13757 - 13768
(2007/10/03)

Facile synthesis of calix[4]arenes in ABAC type upper rim substitution
Calix[4]arenes with three different substituents in ABAC pattern at the upper rim of calix are synthesized by '3 + 1' fragmentation condensation reaction between trimer of p-substituted phenol (ABA) and 2,6-bishydroxymethylated p-substituted phenol (C).
Kwanghyun, No,Jong, Eun Kim,Kyoung, Mee Kwon
p. 8453 - 8456
(2007/10/02)

A New Synthesis of Oxacalixarene Macrocycles and Alkali-Metal-Binding Studies
The title oxacalixarene macrocycles 1 have been synthesized in yields of 12-32percent by an acid-catalyzed, high-dilution condensation of 2,6-bis(hydroxymethyl)-p-subtituted-phenols, where R = t-Bu, i-Pr, Et, Me, and Cl.The macrocycles are isolated in high purity without chromatography, as the sodium or potassium salts of their monoanions.Metal-binding studies indicate that, like the related calixarenes, the oxacalixarenes bind alkali metals only in the presence of base (Na(1+) ca.K(1+) > Li(1+)).
Hampton, Philip D.,Bencze, Zsolt,Tong, Weidong,Daitch, Charles E.
p. 4838 - 4843
(2007/10/02)

Process for producing alkylphenols
There is disclosed a process for producing an alkylphenol comprising reacting a phenol with an aldehyde and hydrogen in the presence of (a) an alkaline or alkaline earth metal catalyst selected from a hydroxide of an alkaline metal, hydroxide of an alkaline earth metal, a carbonate of an alkaline metal, and a hydrogencarbonate of an alkaline metal and (b) a hydrogenation catalyst. By the use of the process, the alkylphenols can be produced in good yield in one stage method.
-
(2008/06/13)

Process for producing alkylphenols
There is disclosed a process for producing an alkylphenol comprising reacting a phenol with an aldehyde and hydrogen in the presence of (a) an alkaline or alkaline earth metal catalyst selected from a hydroxide of an alkaline metal, hydroxide of an alkaline earth metal, a carbonate of an alkaline metal, and a hydrogencarbonate of an alkaline metal and (b) a hydrogenation catalyst. By the use of the process, the alkylphenols can be produced in good yield in one stage method.
-
(2008/06/13)

The Synthesis, Redox Properties, and Ligand Binding of Heterobinuclear Transition-Metal Macrocyclic Ligand Complexes. Measurement of an Apparent Delocalization Energy in a Mixed-Valent CuICuII Complex
A series of binuclear complexes MAIIMBIIL2+ have been synthesized and characterized.The binuleating macrocyclic ligand L2+ is a symmetric Schiff base derived by condensing 2 equiv. of 2,6-diformyl-4-methylphenol with 2 equiv of 1,3-diaminopropane, resulting in two identical N2O2 coordination sites.In all cases, MA(II) = Cu(II) while MB was varied across the series MB(II) = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II).The electrochemical properties of these species were examined by cyclic voltammetry, differential pulse polarography, sampled DC polarography, and coulometry.In each case reversible to quasi-reversible Cu(II)C(I) electrochemistry was observed.The Cu(II)Cu(I) reduction potential was, within experimental error, invariant with respect to the remote metal MB; Ef(Cu(II)Cu(I)) = -1.068 V vs. ferrocene/ferrocinium(1+).The one exception is the homonuclear complex MA(II) = MB(II) = Cu(II); the homobinuclear complex was more readily reduced, Ef = -0.925 V vs.Fc/Fc+, than the heteronuclear species.After a correction due to magnetic stabilization the difference between the heteronuclear and homonuclear reduction potantials, 143 mV = 3.3 kcal/mol, has been ascribed to a special stability associated with the mixed-valent CuIICuIL+ species, where some electronic delocalization has been previously demonstrated.In addition, the electrochemical properties of homonuclear complexes (MA = MB) are reported.The ligand-binding properties of the species CuIMBIIL+, MB(II) = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II), have been examined.Cu(I) shows an affinity for the axial bases carbon monoxide, ethylene, tris(o-methoxyphenyl)phosphine, and 4-ethylpyridine.In contrast to the Cu(II)/Cu(I) reduction potentials, the binding of axial bases to Cu(I) does seem to depend on the nature of the remote metal, Mb.
Gagne, R. R.,Spiro, C. L.,Smith, T. J.,Hamann, C. A.,Thies, W. R.,Shiemke, A. K.
p. 4073 - 4081
(2007/10/02)