- Chemical and Theoretical Comparison between Phosphido (X = PR2) and Thiolato (X = SR) Bent Niobocenes of the Type . Structure of >
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The hydrido complexes reacted with MeI to afford the iodo derivatives 1.The reaction of 1 with Na(SEt) led to the terminal thiolato complexes 2.Compounds 2 were used to bind the metal carbonyl fragments Fe(CO)4 and M(CO)5 from and (thf = tetrahydrofuran) respectively.The corresponding monothiolato-bridged complexes n>> 3 (M = Fe, n = 4; M = Mo or W, n = 5) were obtained only in the case of L = CO and no dibridged μ-SEt, μ-Co complex was formed.The new complexes 1-3 were characterized by IR, 1H and 31P NMR spectroscopies.The X-ray analysis of > showed an endo position of the ethyl group with respect to the CO ligand bound to the niobium.The results of extended-Hueckel molecular orbital (EHMO) conformational calculations carried out on the model complexes and are compared, and the importance of electronic and steric effects deduced.An explanation for the non-formation of dibridged μ-SEt, μ-CO complexes is attempted on the basis of EHMO and X-ray results.
- Kubicki, Marek M.,Oudet, Pascal,Martin, Christine,Barre, Christophe
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Read Online
- NHC-CDI Betaine Adducts and Their Cationic Derivatives as Catalyst Precursors for Dichloromethane Valorization
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Zwitterionic adducts of N-heterocyclic carbene and carbodiimide (NHC-CDI) are an emerging class of organic compounds with promising properties for applications in various fields. Herein, we report the use of the ICyCDI(p-Tol) betaine adduct (1a) and its cationic derivatives2aand3aas catalyst precursors for the dichloromethane valorization via transformation into high added value products CH2Z2(Z = OR, SR or NR2). This process implies selective chloride substitution of dichloromethane by a range of nucleophiles Na+Z-(preformed or generatedin situfrom HZ and an inorganic base) to yield formaldehyde-derived acetals, dithioacetals, or aminals with full selectivity. The reactions are conducted in a multigram-scale under very mild conditions, using dichloromethane both as a reagent and solvent, and very low catalyst loading (0.01 mol %). The CH2Z2derivatives were isolated in quantitative yields after filtration and evaporation, which facilitates recycling the dichloromethane excess. Mechanistic studies for the synthesis of methylal CH2(OMe)2rule out organocatalysis as being responsible for the CH2transfer, and a phase-transfer catalysis mechanism is proposed instead. Furthermore, we observed that1aand2areact with NaOMe to form unusual isoureate ethers, which are the actual phase-transfer catalysts, with a strong preference for sodium over other alkali metal nucleophiles.
- Sánchez-Roa, David,Mosquera, Marta E. G.,Cámpora, Juan
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p. 16725 - 16735
(2021/11/18)
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- Synthesis and reactivity of thiolate-bridged multi-iron complexes supported by cyclic (alkyl)(amino)carbene
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The combined utilization of Me2-cAAC (Me2-cAAC =:C(CH2)(CMe2)2N-2,6-iPr2C6H3) and thiolates as supporting ligands enables the access of unprecedented carbene coordinated thiolate-bridged diiron(ii) complexes [(Me2-cAAC)Fe(μ-SR)(Br)]2 (R = Me, 3; R = Et, 4). The coordination environment of each tetrahedral iron(ii) center in complexes 3 and 4 is composed of one terminal bromide atom, one carbene carbon atom and two thiolate sulfur atoms, which is similar to the carbide-containing sulfur-rich environment of iron centers in the belt region of the FeMo-cofactor. Interestingly, when NaSCPh3 was chosen as the thiolate ligand, C-S bond homolysis occurred to form a rare [3:1] site-differentiated cubane-type cluster [(Me2-cAAC)Fe4S4(Br)3][Me2-cAACH] (5). Furthermore, complexes 3 and 4 exhibit good exchange reactivity toward the azide anion to give novel thiolate-bridged diiron complexes with two azido ligands in a trans arrangement.
- Zhang, Yanpeng,Mei, Tao,Yang, Dawei,Zhang, Yixin,Wang, Baomin,Qu, Jingping
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p. 15888 - 15896
(2017/12/02)
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- A method for preparing phthalic of the dithiol
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The invention provides a method for preparing benzene-1,2-dithiol. The method includes the steps that metal sodium, ethyl mercaptan and 1,2-dichlorobenzene serve as starting raw materials, two halogen atoms of the 1,2-dichlorobenzene are completely substituted in polar solvents N,N-dimethyl formamide by controlling the molecular proportion of the reactants through the high nucleophilic substitution capacity of sodium thioethylate, 1,2-2 ethyl petrol phenyl sulfide is obtained with the high yield, then sulphur atom deprotection is carried out under the reducing action of the metal sodium and naphthalene, and the target product benzene-1,2-dithiol is produced in an almost-quantitative mode after acidizing is carried out through hydrochloric acid. The preparing method is simple, convenient to operate, low in price and high in yield, and has the broad application prospects in the fine chemical engineering and the pharmaceutical industry.
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Paragraph 0020-0026
(2020/05/05)
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- One-pot synthesis and characterization of chalcopyrite CuInS2 nanoparticles
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We synthesized tetragonal chalcopyrite CuInS2 (CIS) nanoparticles from molecular single source precursors, (Ph3P) 2Cu-(μ-SEt)2In(SEt)2, by a one-pot reaction in the presence of 3-mercaptopropionic acid at reaction times of 3 hours or less with high yields. In our approach, NaCl as a by-product was used as a heat transfer agent via a conventional convective heating method. We tuned the sizes of nanoparticles through manipulation of the reaction temperature, reaction time, precursor, and thiol concentration. The sizes of nanoparticles from 1.8 nm to 5.2 nm were obtained as reaction temperatures were increased from 150 °C to 190 °C. The method developed in this study is scalable to achieve production of ultra-large quantities of tetragonal chalcopyrite CIS nanoparticles. The resulting nanoparticles were analyzed by UV-vis spectroscopy, X-ray diffraction, EDAX, and HRTEM.
- Sun, Chivin,Cevher, Zehra,Zhang, Jin,Gao, Bo,Shum, Kai,Ren, Yuhang
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p. 10629 - 10633
(2014/07/07)
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- Preparation and use of enantioenriched 2-aryl-propylsulfonylbenzene derivatives as valuable building blocks for the enantioselective synthesis of bisabolane sesquiterpenes
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We have demonstrated that different enantioenriched 2-arylpropylsufonylbenzene derivatives are very useful building blocks for the synthesis of aromatic bisabolane sesquiterpenes. Their preparation and the exploitation of their chemical reactivity have been comprehensively investigated. Accordingly, the naturally occurring bisabolane sesquiterpenes (-)-curcuphenol, (-)-xanthorrhizol, (+)-glandulone A, (+)-curcudiol, (+)-turmerone and (+)-curcudiol-10-one were synthesized in high enantiomeric purity. It is worth noting that the compounds (+)-curcudiol-10-one and (+)-glandulone A were prepared in enantioenriched form for the first time. Through the proposed synthetic approaches, we were able to confirm both chemical structures and the absolute configurations previously assigned to the two aforementioned sesquiterpenes.
- Serra, Stefano
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p. 1561 - 1572
(2015/02/05)
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- METHOD FOR PRODUCING 1,2-BENZISOTHIAZOL-3-ONE COMPOUND
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The present invention provides a method for producing a 1,2-benzisothiazol-3-one compound by reacting a 2-(alkylthio)benzonitrile compound with a halogenating agent in the presence of water, wherein an alkyl halide that is generated as by-product is reacted with a sulfide to form an alkylthiol, which is converted into an alkali metal salt, and then the resulting alkali metal salt is reacted with a 2-halobenzonitrile compound to be converted into a 2-(alkylthio)benzonitrile compound and reused as a starting material for the production of a 1,2-benzisothiazol-3-one compound. By means of the present invention, it is possible to efficiently use the by-product that is generated during the production of a 1,2-benzisothiazol-3-one compound and economically produce a 1,2-benzisothiazol-3-one compound without placing a burden on the environment.
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Paragraph 0075; 0076; 0077
(2014/02/15)
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- METHODS OF FORMING SINGLE SOURCE PRECURSORS, METHODS OF FORMING POLYMERIC SINGLE SOURCE PRECURSORS, AND SINGLE SOURCE PRECURSORS AND INTERMEDIATE PRODUCTS FORMED BY SUCH METHODS
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Methods of forming single source precursors (SSPs) include forming intermediate products having the empirical formula ?{L2N(μ-X)2M′X2}2, and reacting MER with the intermediate products to form SSPs of the formula L2N(μ-ER)2M′(ER)2, wherein L is a Lewis base, M is a Group IA atom, N is a Group IB atom, M′ is a Group IIIB atom, each E is a Group VIB atom, each X is a Group VIIA atom or a nitrate group, and each R group is an alkyl, aryl, vinyl, (per)fluoro alkyl, (per)fluoro aryl, silane, or carbamato group. Methods of forming polymeric or copolymeric SSPs include reacting at least one of HE1R1E1H and MER with one or more substances having the empirical formula L2N(μ-ER)2M′(ER)2 or L2N(μ-X)2M′(X)2 to form a polymeric or copolymeric SSP. New SSPs and intermediate products are formed by such methods.
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Page/Page column 9; 10; 11
(2011/07/06)
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- Synthesis of sulfanyl-, sulfinyl-, and sulfonyl-substituted bicyclic dioxetanes and their base-induced chemiluminescence
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(Chemical Equation Presented) The singlet oxygenation of 4-tert-butyl-3,3-dimethyl-5-(3-oxyphenyl)-2,3-dihydrothiophenes 5c-e bearing an acetoxy or methoxy group at the 2-position exclusively gave the corresponding sulfanylsubstituted bicyclic dioxetanes 2c-e, while that of 5a without 2-substituent mainly gave sulfoxide 11 alongwith a small amount of dioxetane 2a. These dioxetanes were sufficiently stable thermally to permit handling at room temperature. Sulfanyl-substituted dioxetanes, 2c and 2e, were further oxidized with m-chloroperbenzoic acid to afford the corresponding sulfinyl-substituted dioxetanes 3c, 3e and sulfonylsubstituted dioxetanes 4c, 4e. X-ray single crystallographic analysis was performed for 2c and 4e. Baseinduced decomposition of the dioxetanes in DMSO gave light with a maximum wavelength λmaxCL at 554 nmfor 2a and 565 nmfor 2e in moderate light yields,while sulfinyl-derivative 3e gaveweak light with λmaxCL = 795 nm and sulfonyl-derivative 4e gave very weak light with λmaxCL = 848 nm. 2010 American Chemical Society.
- Watanabe, Nobuko,Kikuchi, Masato,Maniwa, Yuusuke,Ijuin, Hisako K.,Matsumoto, Masakatsu
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supporting information; experimental part
p. 879 - 884
(2010/05/18)
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- Total synthesis of (-)-isopisiferin: Confirmation of absolute configuration
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Starting from 4,4-dimethyl-2-cyclohexenone, an enantioselective synthesis of (-)-isopisiferin has been accomplished in 15 steps with an overall yield of 11.4 %. This work not only provides synthetic evidence for confirming the absolute configuration of natural isopisiferin itself, but also serves as an additional correlation origin to which many related icetexane-type diterpenes, particular for the pisiferin family, can be referred.
- Jan, Ning-Wei,Liu, Hsing-Jang,Hsieh, Min-Tsang,Shia, Kak-Shan
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experimental part
p. 4271 - 4275
(2010/09/20)
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- Standard enthalpies of formation of Li, Na, K, and Cs thiolates
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The standard enthalpies of formation of alkaline metals thiolates in the crystalline state were determined by reaction-solution calorimetry. The obtained results at 298.15 K were as follows: δfH°m(MSR, cr)/kJ mol-1 = -259.0 ± 1.6 (LiSC2H5), -199.9 ± 1.8 (NaSC2H5), -254.9 ± 2.4 (NaSC4H9), -240.6 ± 1.9 (KSC2H 5), -235.8 ± 2.0 (CsSC2H5). These results where compared with the literature values for the corresponding alkoxides and together with values for δfH° m(MSR, cr) were used to derive a consistent set of lattice energies for MSR compounds based on the Kapustinskii equation. This allows the estimation of the enthalpy of formation for some non-measured thiolates.
- Leal, Joao P.
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experimental part
p. 441 - 446
(2010/08/04)
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- USE OF KINASE INHIBITORS TO PROMOTE NEOCHONDROGENESIS
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This invention provides methods for utilizing compounds that inhibit cyclin-dependent kinase and tyrosine kinase enzymes in the promotion of neochondrogenesis and the enhancement, protection and repair of cartilage. In certain embodiments the invention relates to methods of using compounds of formula (I): and pharmaceutically acceptable salts thereof, to promote neochondrogenesis, wherein, R1,R2, R3, R4, R5, R6, A, B, D, and E have any of the values defined therefor in the specification.
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Page/Page column 43; 44
(2010/10/20)
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- Kinase inhibitors
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This invention provides phenyl-substituted pyrimidopyrimidines, dihydropyrimido-pyrimidines, pyridopyrimidines, naphthyridines, and pyridopyrazines of the general formula: that inhibit cyclin-dependent kinase and tyrosine kinase enzymes, methods and intermediate compounds for their synthesis, as well as pharmaceutical compositions and methods for their use in treating, inhibiting or preventing maladies associated with cell proliferative disorders, including angiogenesis, atherosclerosis, restenosis, and cancer.
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- Streptogramins for preparing same by mutasynthesis
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The invention provides a method for preparing streptogramins using genetically-modified microorganisms to influence the biosynthesis of at least one of the precursors of the group B streptogramins. Cultures of the genetically-modified microorganisms are supplemented with a least one precursor that is different from the streptogramin precursor whose biosynthesis is altered and the streptogramins produced are recovered.
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- Solvent effects on reactions of hydroxide ion with phosphorus (V) esters. A quantitative treatment
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Second-order rate constants of reactions of HO- with phosphate, phosphinate and thiophosphinate esters, (PhO)2PO.OC6H4NO2-p, Ph2PO.OC6H4NO2-p, Ph2PO.SPh, Ph2PO.SC6H4NO2-p and Ph2PO.SEt, go through minima with decreasing water content of H2O-MeCN or H2O-t-BuOH. The rate decrease is due to stabilization of the non-ionic ester on addition of organic solvent to H2O. This inhibition is partially offset by stabilization of the anionic transition states and in the drier solvents partial desolvation of HO- increases rates.
- Bunton, Clifford A.,Gillitt, Nicholas D.,Kumar, Anurag
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p. 145 - 151
(2007/10/03)
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- Thiolate, Thioether, and Thiol Derivatives of Iron(0) Carbonyls
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A new series of anionic complexes of iron tetracarbonyl monofunctionalized with the ligand ->,-> (R = Ph, Et, Me, H), have been synthesized and characterized.The compound was formed in the reaction of and PhSSPh.The -> anion was characterized by X-ray diffraction as its +> salt and found to be a typical trigonal-bipyramidal complex in which the phenylthiolate ligand occupies an axial position with a Fe-S bond distance of 2.332(5) Angstroem and Fe-S-C(Ph) = 111.3(6) deg.The salt crystallized inthe orthorhombic space group Pbc21, with a = 9.529(4) Angstroem, b = 21.493(9) Angstroem, c = 20.185(9) Angstroem, V = 4134(3) Angstroem3, and Z = 2.Other members of the series of complexes, ->, were best obtained by ligand exchange of -> and the labile thioether complex (PhSMe)Fe(CO)4.The latter was produced from the low-temperature alkylation of the ->.Protonation of the thiolates (R = Ph, Et, Me, H) ultimately leads to formation of H2 and Fe2(μ-SR)2(CO)6; however, the intermediate thiol, (RSH)Fe(CO)4, could be observed at -78 to -40 deg C for R = Et, Me.The PhSH and HSH derivatives were unstable even at -78 deg C.
- Liaw, Wen-Feng,Kim, Christine,Darensbourg, Marcetta Y.,Rheingold, Arnold L.
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p. 3591 - 3597
(2007/10/02)
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- SYNTHESIS OF MONO(ALKYLTHIO)-SUBSTITUTED KETONES
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In the reaction of 2-propanone in the presence of sodium bicarbonate with a mixture of formaldehyde and the corresponding alkaline hydrolyzates of S-alkylthiuronium salts (thioalcoholates) β-keto sulfides (1-alkylthio-3-butanones) were obtained.Ketalization of the products with glycerol gave the cyclic derivatives alkylthio-1,3-dioxolanes.
- Sabirov, S. S.,Gnevasheva, L. M.,Ismailov, M. I.,Isobaev, M. D.
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p. 1239 - 1243
(2007/10/02)
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- Synthesis and Electronic and Redox Properties of "Double-Cubane" Cluster Complexes Containing MoFe3S4 and WFe3S4 Cores
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The reaction system MS42-/3-3.5FeCl3/9-12NaSR (M = Mo,W) in methanol or ethanol affords as principal products four "double-cuban" cluster anions, 3- (1), 3- (2), 3- (3),and 4- (4), which are isolable as appropriate quaternary ammonium salts.Synthesis of cluster types 1 (M = W), 3, and 4 are described together with spectroscopic and voltammetric properties of the four cluster types.All clusters exhibit isotropically shifted 1H NMR spectra which serve as criteria for adequate purity, reveal from shift patterns contact and dipolar mechanisms at terminal and bridge substituents, respectively, and support the existence of single geometrical isomers in solution.Cluster types 1 and 2 form three-membered electron-transfer series in wich individual MFe3S4(SR)3 clusters are reduced in weakly coupled steps.Cluster type 3 affords a four-membered series in which the initial reduction is FeIII -> FeII in the Fe(SR)6 bridge unit and subsequent reductions occur at individual clusters.Potential separations for the latter two steps (ca. 0.10 V) more closely approach the statistical value of 36 mV than do those of types 1 and 2 (ca. 0.19 V), owing to larger intercluster separations.The pressence of FeIII and FeII in the bridge units of type 3 and 4 clusters, respectively, is demonstrated by Moessbauer spectroscopy.From observations of narrow intervals of 57Fe isomer shifts, hyperfine magnetic fields at Fe sites, terminal methylene proton contact shifts, and redox potentials of 1 and 2 it is concluded that the Fe3 portions of MFe3S4 core units are electronically delocalized and, within and among all cluster types 1-4, are virtually equivalent electronically.Core Fe isomer shifts are considered to accord best with the mean oxidation state Fe2.67+.This conclusion, together with prior observations of a pronounced structural core similarity in all clusters, leads to the core formal electronic descriptions 4+Fe3+2Fe2+S4>4+ + 3+Fe3+2Fe2+S4>3+ (type 1) and 23+Fe3+2Fe2+S4>3+ (types 2-4), thereby difining total oxidation levels of the cores in each cluster type.Full tabulations of Moessbauer spectral parameters and 1H NMR isotropic shifts are presented together with representative Moessbauer and NMR spectra and cyclic voltammograms.
- Wolff,Thomas E.,Power, Philip P.,Frankel, Richard B.,Holm, R. H.
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p. 4694 - 4703
(2007/10/02)
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- 9-Alkoxy-5-methyl-6,7-benzomorphans
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N-Substituted-9-alkoxy-5-methyl-6,7-benzomorphans have been found to possess potent narcotic agonist and/or antagonist activity. In particular, the compound 2-cyclopropylmethyl-2'-hydroxy-9α-methoxy-5-methyl-6,7-benzomorphan has been found to possess potent narcotic agonist and antagonist activity. These compounds are prepared by total synthesis and are not derived from opium alkaloids.
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