- Practical and efficient recyclable oxidative system for the preparation of symmetrical disulfides under aerobic conditions
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An efficient and practical oxidative coupling of thiols to symmetrical disulfides is developed at room temperature under aerobic conditions. The commercially available sodium methoxide solution 30 wt. % in methanol together with the air was used as a retrievable promoter system and green oxidant, respectively, for the preparation of symmetrical disulfides. The desired products were obtained in good to high yields by an economical procedure. No overoxidation of the symmetrical disulfides was observed, and various functional groups were well tolerated in the current protocol. Moreover, the new reagent reduces the generation of hazardous waste due to its high reusability. The reaction proceeded in the absence of light, and it was not inhibited by TEMPO. Also, the low yield of TEMPO-benzyl thiol adduct was detected under these conditions. Based on our experiments, a possible mechanism was proposed in the absence and presence of TEMPO.
- Ling, Ong Chiu,Heidelberg, Thorsten,Ching, Juan Joon,Khaligh, Nader Ghaffari
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p. 281 - 294
(2020/12/13)
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- Direct sequential C-H iodination/organoyl-thiolation for the benzenoid A-ring modification of quinonoid deactivated systems: A new protocol for potent trypanocidal quinones
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We report a sequential C-H iodination/organoyl-thiolation of naphthoquinones and their relevant trypanocidal activity. Under a combination of AgSR with a copper source, sulfur-substituted benzenoid quinones were prepared in high yields (generally >90%). This provides an efficient and general method for preparing A-ring modified naphthoquinoidal systems, recognized as a challenge in quinone chemistry.
- Jardim, Guilherme A. M.,Oliveira, Willian X. C.,De Freitas, Rossimiriam P.,Menna-Barreto, Rubem F. S.,Silva, Thaissa L.,Goulart, Marilia O. F.,Da Silva Júnior, Eufranio N.
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supporting information
p. 1686 - 1691
(2018/03/21)
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- SYNTHETIC VACCINES AGAINST STREPTOCOCCUS PNEUMONIAE TYPE 1
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The present invention relates to the total synthesis of saccharide structures contained in the capsular polysaccharide of Streptococcus pneumoniae type 1, to glycoconjugates containing said saccharide structures obtained by total synthesis and to use of s
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Page/Page column 83; 117
(2015/02/02)
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- Influence of the diamine on the reactivity of thiosulfonato ruthenium complexes with hydrosulfide (HS-)
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We have recently reported that cationic thiosulfonato ruthenium complexes [(p-cymene)Ru(bipy)(SSO2Ar)]+ (bipy: 2-2′- bipyridine, Ar: phenyl or p-tolyl) react with thiolates (RS-, R = alkyl or aryl) by cleavage of the S-SO
- Galardon, Erwan,Daguet, Hombeline,Deschamps, Patrick,Roussel, Pascal,Tomas, Alain,Artaud, Isabelle
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p. 2817 - 2821
(2013/04/10)
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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 10; 11
(2011/07/06)
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- (Neocuproin)zinc Thiolates: Attempts at Modeling Cobalamin-Independent Methionine Synthase
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Several new complexes [(neo)Zn(SR)2] [neo = neocuproin (2,9-dimethylphenanthroline)] have been synthesized and structurally characterised. They react in a stepwise fashion with the alkylating agents CH3I and (CH3)2SO4 to afford the thioethers CH3SR and first the mixed complexes [(neo)Zn(SR)X] (X = I, CH3SO4) and then [(neo)ZnX2]. Similar alkylations occur with benzyl iodide, but not with trimethyl phosphate in nonpolar media. Under these conditions, thiolate exchange with [PPN]SR does not occur which indicates that the alkylations take place at the zinc-bound thiolates. In polar solvents (methanol, DMSO), thiolate exchange occurs readily, and at higher temperatures (CH3)3PO4 also acts as an alkylating agent which indicates that under these conditions free thiolate is available in solution. Qualitative kinetic data support the associative alkylation mechanism in nonpolar media and the change of mechanism in polar media. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Seebacher, Jan,Ji, Mian,Vahrenkamp, Heinrich
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p. 409 - 417
(2007/10/03)
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- Nucleophilic Opening of the Aziridine Ring in 1-Alkyl-1-azoniatricyclo[2.2. 1.02,6]heptanes
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Opening of the aziridine ring in 3-bromo-1-alkyl-1-azoniatricyclo[2.2.1. 02,6]heptane bromides by the action of various nucleophiles leads to formation of the corresponding 6-substituted 2-alkyl-2-azabicyclo-[2.2.1] heptanes.
- Bulanov,Sosonyuk,Zyk,Zefirov
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p. 415 - 421
(2007/10/03)
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- Sulfur containing compounds
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This invention is directed to novel and known stufur containing compounds and pharmaceutically acceptable salts thereof that have utility as antifungals and as antiproliferative agents against mammalian cells, in particular cancer cells and most particularly leukemia-derived cells. The invention provides a method for synthesizing certain of the sulfur containing compounds that is more efficient than previously known methods.
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Page/Page column 26
(2010/11/30)
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- Synthesis and reactions of 2-(alkylthio)-4,4-dimenthyl-1,3-thiazole-5(4H)-thiones
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Six 2-(alkylthio)-substituted 4,4-dimethyl-1,3-thiazole-5(4H)-thiones were synthesized according to a new method. The reactions of these compounds with allyl- and benzyllithium reagents, 1,3-dipoles, and dimethyl acetylenedicarboxylate proceeded in a similar manner to 2-alkyl-substituted analogues, while methyllithium reacted in a different way yielding trithio-orthoester derivatives.
- Shi,Linden,Heimgartner
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p. 1903 - 1920
(2007/10/02)
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- N-(amino)alkyl)-1-pyrrolidine, 1-piperidine and 1-homopiperidinecarboxamides (and thiocarboxamides) with sulfur linked substitution in the 2, 3 or 4-positions
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Novel pyrrolidine, piperidine and homopiperidinecarboxamide and thiocarboxamide compounds having the formula: STR1 wherein X is --S--, --S(O)-- or --S(O)2 --; A is a loweralkalene chain and A1 and A2 are alkalene chains when p and d are one; R, R1 and R2 are hydrogen, loweralkyl, phenyl cycloalkyl or phenylalkyl and R1 and R2 may form a heterocyclic residue with the adjacent nitrogen atom; Q is a selected aromatic radical, and the pharmaceutically acceptable acid addition salts useful as cardiac antiarrhythmia agents are disclosed. Novel chemical intermediates, unsubstituted on pyrrolidine, piperidine and homopiperidine nitrogen but with --(A2)p --X--(A2)d --Q side chain are also disclosed.
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- N-[(amino)alkyl]-1-pyrrolidine, 1-piperidine and 1-homopiperidinecarboxamides (and thiocarboxamides) with sulfur linked substitution in the 2, 3 or 4-position
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Novel pyrrolidine, piperidine and homopiperidinecarboxamide and thiocarboxamide compounds having the formula: STR1 wherein X is --S--, --S(O)-- or --S(O)2 --; A is a loweralkalene chain and A1 and A2 are alkalene chains when p and d are one; R, R1 and R2 are hydrogen, loweralkyl, phenyl cycloalkyl or phenylalkyl and R1 and R2 may form a heterocyclic residue with the adjacent nitrogen atom; Q is a selected aromatic radical, and the pharmaceutically acceptable acid addition salts useful as cardiac antiarrhythmia agents are disclosed. Novel chemical intermediates, unsubstituted on pyrrolidine, piperidine and homopiperidine nitrogen but with --(A2)p --X--(A2)d --Q side chain are also disclosed.
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- Quinones. Part 9. Side-chain Alkylthiolation of Methyl-1,4-naphthoquinones
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2-Methyl-1,4-naphthoquinones react with an excess of sodium methanethiolate to give methylthiomethyl derivatives.Corresponding products were obtained, but in lower yield, using α-toluene- and toluene-p-thiolates.With 3-chloro-2-methyl-1,4-naphthoquinone and methanethiolate, replacement of chlorine occurs before reaction with the side chain, while the minor products formed provide evidence that the side-chain alkylation proceeds by addition of thiolate to the tautomeric quinone methide form of the methylquinone.
- Thomson, Ronald H.,Worthington, Roger D.
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p. 282 - 288
(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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