75-66-1Relevant articles and documents
Photoactivatable Odorants for Chemosensory Research
Gore, Sangram,Ukhanov, Kirill,Herbivo, Cyril,Asad, Naeem,Bobkov, Yuriy V.,Martens, Jeffrey R.,Dore, Timothy M.
, p. 2516 - 2528 (2020/10/02)
The chemosensory system of any animal relies on a vast array of detectors tuned to distinct chemical cues. Odorant receptors and the ion channels of the TRP family are all uniquely expressed in olfactory tissues in a species-specific manner. Great effort has been made to characterize the molecular and pharmacological properties of these proteins. Nevertheless, most of the natural ligands are highly hydrophobic molecules that are not amenable to controlled delivery. We sought to develop photoreleasable, biologically inactive odorants that could be delivered to the target receptor or ion channel and effectively activated by a short light pulse. Chemically distinct ligands eugenol, benzaldehyde, 2-phenethylamine, ethanethiol, butane-1-thiol, and 2,2-dimethylethane-1-thiol were modified by covalently attaching the photoremovable protecting group (8-cyano-7-hydroxyquinolin-2-yl)methyl (CyHQ). The CyHQ derivatives were shown to release the active odorant upon illumination with 365 and 405 nm light. We characterized their bioactivity by measuring activation of recombinant TRPV1 and TRPA1 ion channels expressed in HEK 293 cells and the electroolfactogram (EOG) response from intact mouse olfactory epithelium (OE). Illumination with 405 nm light was sufficient to robustly activate TRP channels within milliseconds of the light pulse. Photoactivation of channels was superior to activation by conventional bath application of the ligands. Photolysis of the CyHQ-protected odorants efficiently activated an EOG response in a dose-dependent manner with kinetics similar to that evoked by the vaporized odorant amyl acetate (AAc). We conclude that CyHQ-based, photoreleasable odorants can be successfully implemented in chemosensory research.
COPPER PROTECTIVE AGENT
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Paragraph 0042-0043, (2019/05/24)
A copper protective agent is provided. The copper protective agent is represented by a general formula (GI): HS—R (GI); and R is a linear or branched alkyl group having 1 to 20 carbon atoms.
Quantitative Reactivity Scales for Dynamic Covalent and Systems Chemistry
Zhou, Yuntao,Li, Lijie,Ye, Hebo,Zhang, Ling,You, Lei
supporting information, p. 381 - 389 (2016/01/26)
Dynamic covalent chemistry (DCC) has become a powerful tool for the creation of molecular assemblies and complex systems in chemistry and materials science. Herein we developed for the first time quantitative reactivity scales capable of correlation and prediction of the equilibrium of dynamic covalent reactions (DCRs). The reference reactions are based upon universal DCRs between imines, one of the most utilized structural motifs in DCC, and a series of O-, N-, and S- mononucleophiles. Aromatic imines derived from pyridine-2-carboxyaldehyde exhibit capability for controlling the equilibrium through distinct substituent effects. Electron-donating groups (EDGs) stabilize the imine through quinoidal resonance, while electron-withdrawing groups (EWGs) stabilize the adduct by enhancing intramolecular hydrogen bonding, resulting in curvature in Hammett analysis. Notably, unique nonlinearity induced by both EDGs and EWGs emerged in Hammett plot when cyclic secondary amines were used. This is the first time such a behavior is observed in a thermodynamically controlled system, to the best of our knowledge. Unified quantitative reactivity scales were proposed for DCC and defined by the correlation log K = SN (RN + RE). Nucleophilicity parameters (RN and SN) and electrophilicity parameters (RE) were then developed from DCRs discovered. Furthermore, the predictive power of those parameters was verified by successful correlation of other DCRs, validating our reactivity scales as a general and useful tool for the evaluation and modeling of DCRs. The reactivity parameters proposed here should be complementary to well-established kinetics based parameters and find applications in many aspects, such as DCR discovery, bioconjugation, and catalysis.
A di-tert-butyl-terminated chain multi-sulfide synthesis method
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Paragraph 0017; 0041; 0041, (2017/03/24)
The invention provides a synthesis method for di-tert-butyl terminated chain polythiaether. The method is characterized by comprising the steps of: putting elemental sulfur and a catalyst (amino based metal-organic framework microporous material) into a reaction kettle, replacing the air in the reaction kettle with nitrogen, then injecting hydrogen sulfide, conducting stirring heating to 120-160DEG C, slowly injecting isobutene into the reaction kettle, then carrying out reaction at a pressure of 4-7MPa for 2-6 h, then cooling the reaction product to 100DEG C, performing purging with nitrogen, condensing the low-boiling point by-product tert-butyl mercaptan and di-tert-butyl sulfide, then performing recovery for reuse as a raw material, conducting filtering when the product is cooled to room temperature to obtain a di-tert-butyl terminated chain polythiaether product, and using the catalyst obtained by filtering repeatedly. The synthesis method provided by the invention has the characteristics of high yield, reusable catalyst, and reaction atom economy near 100%, realizes zero pollution and zero emission, and belongs to an environment-friendly synthesis method.
C-S bond cleavage by a polyketide synthase domain
Ma, Ming,Lohman, Jeremy R.,Liu, Tao,Shen, Ben
, p. 10359 - 10364 (2015/09/01)
Leinamycin (LNM) is a sulfur-containing antitumor antibiotic featuring an unusual 1,3-dioxo-1,2-dithiolane moiety that is spiro-fused to a thiazole-containing 18-membered lactam ring. The 1,3-dioxo-1,2- dithiolane moiety is essential for LNM's antitumor activity, by virtue of its ability to generate an episulfonium ion intermediate capable of alkylating DNA. We have previously cloned and sequenced the lnm gene cluster from Streptomyces atroolivaceus S-140. In vivo and in vitro characterizations of the LNM biosynthetic machinery have since established that: (i) the 18-membered macrolactam backbone is synthesized by LnmP, LnmQ, LnmJ, LnmI, and LnmG, (ii) the alkyl branch at C-3 of LNM is installed by LnmK, LnmL, LnmM, and LnmF, and (iii) leinamycin E1 (LNM E1), bearing a thiol moiety at C-3, is the nascent product of the LNM hybrid nonribosomal peptide synthetase (NRPS)-acyltransferase (AT)-less type I polyketide synthase (PKS). Sulfur incorporation at C-3 of LNM E1, however, has not been addressed. Here we report that: (i) the bioinformatics analysis reveals a pyridoxal phosphate (PLP)-dependent domain, we termed cysteine lyase (SH) domain (LnmJ-SH), within PKS module-8 of LnmJ; (ii) the LnmJ-SH domain catalyzes C-S bond cleavage by using L-cysteine and L-cysteine S-modified analogs as substrates through a PLP-dependent β-elimination reaction, establishing L-cysteine as the origin of sulfur at C-3 of LNM; and (iii) the LnmJ-SH domain, sharing no sequence homology with any other enzymes catalyzing C-S bond cleavage, represents a new family of PKS domains that expands the chemistry and enzymology of PKSs and might be exploited to incorporate sulfur into polyketide natural products by PKS engineering.
Kinetics and mechanism of the nucleophilic substitution of tellurium(II) dialkanethiolates, Te(SR1)2 with thiols, HSR2
Fleischer, Holger
, p. 815 - 825 (2007/10/03)
The equilibrium reaction between tellurium(II) dithiolates and thiols, Te(SR1)2 + 2 HSR2 ? Te(SR 2)2 + 2 HSR1 was studied by means of 1H- and 125Te NMR spectroscopy and ab initio quantum chemical methods. It was found that the reaction is catalyzed by Bronsted acids and bases, the catalytic activity corresponding to the strength of the respective acid or base. Investigation of the initial step of the reaction, Te(SR1)2 + HSR2 ? Te(SR 1)(SR2) + HSR1, showed it to proceed according to first order kinetics for Te(SR1)2, HSR2 and for the catalyst. Ab initio geometry optimizations and frequency calculations suggest [Te(SR1)(HSR1)(HSR2)]+ and [Te(SR1)2(SR2)]- to be stable intermediates and not transition states in the acid and base catalyzed reactions, respectively. The reaction hence proceeds via an additional elimination rather than an SN2 mechanism. The catalytic activity displayed by acids and bases can be applied to reduce the temperature in synthesis of thermally labile tellurium(II) dithiolates. Copyright Taylor & Francis Inc.
Remarkably fast direct synthesis of thiols from alcohols under mild conditions
Bandgar,Sadavarte,Uppalla
, p. 1304 - 1305 (2007/10/03)
One pot rapid synthesis of thiols from alcohols via trifluoroacetates using polymer supported hydrosulfide in acetonitrile under mild conditions has been described.
Solid Supported Reagents and Reactions. Part 21.1 Rapid and Clean Synthesis of Thiols from Halides Using Polymer-supported Hydrosulfide
Bandgar, Babasaheb P.,Pawar, Sanjay B.
, p. 212 - 213 (2007/10/03)
A variety of thiols are prepared from corresponding halides using polymer-supported hydrosulfide in excellent yields. Isolation of pure products by simple filtration and evaporation is an important feature of this method.
Mechanism of the Solution-Phase Reaction of Alkyl Sulfides Atomic Hydrogen. Reduction via a 9-S-3 Radical Intermediate
Tanner, Dennis D.,Koppula, Sudha,Kandanarachchi, Pramod
, p. 4210 - 4215 (2007/10/03)
The low selectivity of benzyl alkyl sulfide fragmentation subsequent to its reaction with atomic hydrogen is indicative of a reaction that proceeds via an early transition state. The competitive reduction of a series of substituted-benzyl alkyl sulfides was insensitive to the substituent on the aromatic ring (ρ = -0.13, r = 0.99). The relative rates of fragmentation of a series of the substituted-benzyl alkyl sulfides gave a V-shaped Hammett plot. Both electron-donating and electron-withdrawing groups destabilized the transition state (ρ = +0.99, r = 0.999; ρ = -0.82, r = 0.992). Since the relative rates of disappearance of the alkyl benzyl sulfides are not substituent dependent, but the relative rates of fragmentation are, a 9-S-3 intermediate is preferred as the structure leading to products.
Investigation of the direct and indirect reduction processes of some disulfides by electrochemical means
Bo Christensen, Torben,Daasbjerg, Kim
, p. 307 - 317 (2007/10/03)
The free energy relationship for the reaction between aromatic radical anions A.- having about the same intrinsic barrier and three disulfides RSSR (diphenyl disulfide, dimethyl disulfide and di-tert-butyl disulfide) in N,N-dimethylformamide has been obtained. For each RSSR second-order rate constants were measured electrochemically in the interval 10-3-105 M-1 s-1 by changing the nature of A.- and thereby the driving force. In the case of diphenyl disulfide the standard potential ERSSR/RSSR.-? and the self-exchange reorganization energy λ(0) of the RSSR/RSSR.- couple could be extracted from the free energy relationship to values of -1.4 (±0.1) V vs. SCE and 65 kcal mol-1, respectively. This knowledge may be combined with the kinetic features of the heterogeneous reduction process of diphenyl disulfide to obtain, among other parameters, the standard heterogeneous rate constant. The cleavage rate constant kc of the corresponding radical anion was estimated from kinetic measurements to be about 5 × 108 s-1. No such information was accessible for the aliphatic disulfides due to a high self-exchange energy of the RSSR/RSSR.- couple but still a maximum value of kc could be determined at 2x108 s-1. The minimum values of ERSSR/RSSR.-? and λ(0) were estimated to be -1.9 V vs. SCE and 75 kcal mol-1 and -2.2 V vs. SCE and 75 kcal mol-1 for dimethyl disulfide and di-tert-butyl disulfide, respectively. ? Acta Chemica Scandinavica 1997.
