F:Flammable;
75-08-1Relevant 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.
"dual Layer" Self-Sorting with Cucurbiturils
Barbero, Héctor,Masson, Eric,Thompson, Nathan A.
supporting information, p. 867 - 873 (2020/02/20)
Platinum(II) complexes bearing terpyridyl (tpy) and thiolate ligands were used to test the design of a "dual layer" self-sorting system in the presence of Cucurbit[8]uril (CB[8]). Pt(II) thiolates and CB[8] form 2:1 assemblies, with both metallic centers sitting on top of one another at one of the macrocycle portals. We showed that any pair of these CB[8]-secured Pt(II) complex dimers bearing different tpy "heads" and thiolate "tails" scrambles to afford up to 10 ternary assemblies via two processes: (1) supramolecular exchanges (i.e., the egression and ingression of Pt complexes from and into CB[8]) and (2) ligand exchanges between the Pt thiolates. The mixtures of 10 assemblies were fully characterized by nuclear magnetic resonance spectroscopy. While the thiolate tails do not significantly affect the rate of the supramolecular exchanges, they were found to control (1) the kinetics of ligand exchange, with bulkier thiolates causing dramatic rate retardations, as well as (2) the thermodynamics of the self-sorting process, i.e., the distribution of assemblies at equilibrium, via intra-CB[8] assembly interactions between pairs of thiolates. Ligand exchanges are consistently slower than supramolecular exchanges. An associative pathway that involves the formation of dimers of CB[8]-secured Pt dimers (a total of 4 Pt complexes) during the ligand exchange process was invoked to rationalize the observed kinetics.
Catalytic synthesis of dialkyl sulfides from dialkyl disulfides
Mashkina,Khairulina
, p. 402 - 408 (2017/08/08)
Dialkyl disulfides R2S2 where R = Me, Et, or Pr, both as individual compounds and as their mixtures, isolated from petroleum products can turn into alkanethiols and dialkyl sulfides under the action of catalysts having strong acid sites and medium-strength basic sites on their surface. In a helium atmosphere, the main conversion products are alkanethiols, while dialkyl sulfides form in low yield at a selectivity of no higher than 20%. A much higher dialkyl sulfide selectivity is attained in the reaction involving methanol. The most efficient catalyst for this reaction is alumina, with which the dialkyl sulfide selectivity is up to 99%.
Design, Synthesis, and Characterization of Small-Molecule Reagents That Cooperatively Provide Dual Readouts for Triaging and, When Necessary, Quantifying Point-of-Need Enzyme Assays
Brooks, Adam D.,Mohapatra, Hemakesh,Phillips, Scott T.
, p. 10437 - 10445 (2015/11/18)
A newly designed small molecule reagent provides both qualitative and quantitative readouts in assays that detect enzyme biomarkers. The qualitative readout enables rapid triaging of samples so that only samples that contain relevant concentrations of the target analyte must be quantified. The reagent is accessible in essentially three steps and 34% overall yield, is stable as a solid when heated to 44 °C for >1 month, and does not produce background signal when used in an assay. This paper describes the design and synthesis of the reagent, characterizes its response properties, and establishes the scope of its reactivity.
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.
Heterogeneous photocatalytic degradation of disulfoton in aqueous TiO 2 suspensions: Parameter and reaction pathway investigations
Chen, Ming-Hung,Chen, Chiing-Chang,Wu, Ren-Jang,Lu, Chung-Shin
, p. 380 - 390 (2013/07/27)
The photocatalytic degradation of organophosphorus insecticide disulfoton is investigated by having titanium dioxide (TiO2) as a photocatalyst. About 99% of disulfoton is degraded after UV irradiation for 90 min. The effects of the solution pH, catalyst dosage, light intensity, and inorganic ions on the photocatalytic degradation of disulfoton are also investigated, as well as the reaction intermediates which are formed during the treatment. Eight intermediates have been identified and characterized through a mass spectra analysis, giving insight into the early steps of the degradation process. To the best of our knowledge, this is the first study reporting the degradation pathways of disulfoton. The results suggest that possible transformation pathways may involve in either direct electron or hole transfer to the organic substrate. The photodegradation of disulfoton by UV/TiO2 exhibits pseudo-first-order reaction kinetics and a reaction quantum yield of 0.267. The electrical energy consumption per order of magnitude for photocatalytic degradation of disulfoton is 85 kWh/(m3 order).
Site-specific conjugation of RAFT polymers to proteins via expressed protein ligation
Xia, Yan,Tang, Shengchang,Olsen, Bradley D.
supporting information, p. 2566 - 2568 (2013/04/23)
Site-specific protein conjugates with RAFT polymers were synthesized using expressed protein ligation. Stable micelles were formed from both linear block copolymer and Y-shaped conjugates.
Diels-Alder reactions of perfluoroketene dithioacetals with electron-rich 1,3-dienes: A new access to polysubstituted aromatic sulfides
Bouillon, Jean-Philippe,Mykhaylychenko, Sergiy,Melissen, Sigismund,Martinez, Agathe,Harakat, Dominique,Shermolovich, Yuriy G.
, p. 8663 - 8669 (2012/10/29)
The present paper describes the Diels-Alder reactions of perfluoroketene dithioacetals with electron-rich 1,3-dienes (2,3-dimethylbuta-1,3-diene, isoprene, penta-1,3-diene) followed by spontaneous HF and thiol elimination, leading to polysubstituted aromatic sulfides in moderate to good yields. Reactions seem to be dependent on the substitution patterns of perfluoroketene dithioacetals; the best results were obtained from trifluoromethyl or pentafluoroethyl and ethylsulfanyl derivatives. Theoretical calculations performed at the DFT level are in good agreement with the experimental results and show that the overall process is controlled by the cycloaddition step.
[[(tert-Butyl)dimethylsilyl]oxy]-methylGroup for sulfur protection
Wang, Lihong,Clive, Derrick L. J.
supporting information; experimental part, p. 1734 - 1737 (2011/06/09)
Aromatic and aliphatic thiols can be protected by reaction with t-BuMe 2SiOCH2Cl in DMF in the presence of a base (2,6-lutidine or proton sponge); the resulting t-BuMe2SiOCH2SR or t-BuMe2SiOCH2SAr are deprotected by sequential treatment with Bu4NF and I2 to give symmetrical disulfides. Another mode of deprotection involves reaction with a sulfenyl chloride; this process gives an unsymmetrical disulfide and was examined with Me(CH2) 11SCH2OSiMe2Bu-t and three sulfenyl chlorides.
Standard enthalpies of formation of Li, Na, K, and Cs thiolates
Leal, Joao P.
experimental part, p. 441 - 446 (2010/08/04)
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.
