2365-48-2Relevant articles and documents
Side-chain pairing preferences in the parallel coiled-coil dimer motif: Insight on ion pairing between core and flanking sites
Steinkruger, Jay D.,Woolfson, Derek N.,Gellman, Samuel H.
, p. 7586 - 7588 (2010)
A new strategy for rapid evaluation of sequence-stability relationships in the parallel coiled-coil motif is described. The experimental design relies upon thiol-thioester exchange equilibria, an approach that is particularly well suited to examination of heterodimeric systems. Our model system has been benchmarked by demonstrating that it can quantitatively reproduce previously reported trends in interhelical a-a′ side-chain pairing preferences at the coiled-coil interface. This new tool has been used to explore the role of Coulombic interactions between a core position on one helix and a flanking position on the other helix (a-g′). This type of interhelical contact has received relatively little attention to date. Our results indicate that such interactions can influence coiled-coil partner preferences.
S-Carboxyanhydrides: Ultrafast and Selective Ring-Opening Polymerizations Towards Well-defined Functionalized Polythioesters
Wang, Yanchao,Li, Maosheng,Wang, Shixue,Tao, Youhua,Wang, Xianhong
, p. 10798 - 10805 (2021)
Aliphatic polythioesters are popular polymers because of their appealing performance such as metal coordination ability, high refractive indices, and biodegradability. One of the most powerful approaches for generating these polymers is the ring-opening polymerization (ROP) of cyclic monomers. However, the synthesis of precisely controlled polythioesters via ROP of thiolactones still faces formidable challenges, including the minimal functional diversity of available thiolactone monomers, as well as inevitable transthioesterification side reactions. Here we introduce a hyperactive class of S-carboxyanhydride (SCA) monomers derived from amino acids that are significantly more reactive than thiolactones for ultrafast and selective ROP. Inclusion of the initiator PPNOBz ([PPN]=bis(triphenylphosphine)-iminium) with chain transfer agent benzoic acid, the polymerizations that can be operated in open vessels reach complete conversion within minutes (1–2 min) at room temperature, yielding polythioesters with predictable molecular weight, low dispersities, retained stereoregularity and chemical recyclability. Most fascinating are the functionalized SCAs that allow the incorporating of functional groups along the polythioester chain and thus finely tune their physicochemical performance. Computational studies were carried out to explore the origins of the distinctive rapidity and exquisite selectivity of the polymerizations, offering mechanistic insight and explaining why high polymerizability of SCA monomer is able to facilitate exquisitely selective ring-opening for enchainment over competing transthioesterification and backbiting reactions.
ADDITION OF METHYL MERCAPTOACETATE TO N-VINYLPYRROLES
Trofimov, B. A.,Sobenina, L. N.,Mikhaleva, A. I.,Sergeeva, M. P.,Nesterenko, R. N.,et al.
, p. 403 - 405 (1992)
Methyl esters of 2-(pyrryl-1)ethylthioacetic acid were synthesized in 53-71percent yield by addition of methyl mercaptoacetate to N-vinylpyrroles.Their reactions with ammonia and hydrazine hydrate were investigated.
An antiparallel α-helical coiled-coil model system for rapid assessment of side-chain recognition at the hydrophobic interface
Hadley, Erik B.,Gellman, Samuel H.
, p. 16444 - 16445 (2006)
Both parallel and antiparallel α-helical coiled-coil dimers are common among proteins; however, biophysical scrutiny has focused almost entirely on parallel dimers. We describe the development of a model system that enables efficient and systematic analysis of hydrophobic packing between antiparallel α-helices. Our findings reveal significant differences in packing preferences between parallel and antiparallel coiled-coils. Copyright
Method for producing methyl thioglycolate based on sodium hydrosulfide method
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Paragraph 0041-0071, (2021/03/24)
The invention relates to a method for producing methyl thioglycolate based on a sodium hydrosulfide method, which belongs to the technical field of organic synthesis. The method comprises the step ofdistilling and concentrating thioglycolic acid acidified liquid, and adding CaCl2 to obtain distilled and concentrated liquid containing molten salt hydrate, an esterification reaction step in which the molten salt hydrate is used as a reaction medium, and the step of settling and layering to obtain methyl thioglycolate. The separation of thioglycolic acid, the treatment of the extraction tail wastewater and the esterification reaction are integrated, the production process is greatly simplified, the water and the solid salt can be effectively separated, the content of organic matters in the water and the solid salt is low, the separated water can be recycled, and the solid salt can also be used as a byproduct. The side reaction in the production process of the methyl thioglycolate is greatly reduced, the discharge of wastewater and the dosage of a catalyst are reduced, and the resource recycling is realized.
The novel method to synthesis of cantharidin intermediate
Tan, Chunbin,Liu, Xiaoling,Du, Hongfei
, p. 271 - 276 (2019/07/31)
Sulfur-containing dehydrocantharidin(SD) was yielded (76% to 96%) by Diels-Alder reaction in an ionic-liquid system under ordinary pressure and temperature. We explored the influences of different ionic-liquid types, reaction temperatures, and reaction times in this reaction. We found that the optimal reaction temperature was about 35°C, the reaction time was 20 h, and the most suitable ionic liquid was 1-butyl-3-methylimidazolium tetrafluoroborate. Furthermore, in the recycling process of ionic liquid, we found that CH3CN was the most suitable extraction solvent. We explored four steps in the synthetic route to SD and achieved a good yield of 38% in total. We envisage that this process could be further developed at an industrial scale for the synthesis of Cantharidin and is destined to be an environmentally friendly way to solve the lack of cantharis as a natural resource.
Unusual multistep reaction of C70Cl10 with thiols producing C70[SR]5H
Khakina, Ekaterina A.,Peregudov, Alexander S.,Yurkova, Anastasiya A.,Piven, Natalya P.,Shestakov, Alexander F.,Troshin, Pavel A.
, p. 1215 - 1219 (2016/03/01)
We report a reaction of the chlorofullerene C70Cl10 with thiols producing C70[SR]5H with all organic addends attached around one central pentagon at the pole of the C70 cage. This reaction was shown to proceed via a complicated radical pathway, presumably involving addition, substitution, rearrangement, and/or elimination steps. The obtained C70[SR]5H products were shown to be very unstable and undergo quantitative decomposition to pristine C70, RSSR, and RSH at elevated temperatures (e.g., 50 °C). Quantum chemical calculations and NMR spectroscopy data showed that cleavage of organic addends from the fullerene cage could be induced by solvation effects in solution.
Development and evaluation of ST-1829 based on 5-benzylidene-2-phenylthiazolones as promising agent for anti-leukotriene therapy
Lill, Andreas P.,R?dl, Carmen B.,Steinhilber, Dieter,Stark, Holger,Hofmann, Bettina
, p. 503 - 523 (2014/12/11)
Different inflammatory diseases and allergic reactions are mediated by leukotrienes, which arise from the oxygenation of arachidonic acid catalyzed by 5-lipoxygenase (5-LO). One promising approach for an effective anti-leukotriene therapy is the inhibition of this key enzyme. This study presents the synthesis and development of a potent and direct 5-LO inhibitor based on the well characterized 5-benzylidene-2-phenylthiazolone C06, whose further pharmacological investigation was precluded due to its low solubility. Through optimization of C06, evaluation of structure-activity relationships including profound assessment of the thiazolone core and consideration of the solubility, the 5-benzyl-2-phenyl-4-hydroxythiazoles represented by 46 (ST-1829, 5-(4-chlorobenzyl)-2-p-tolylthiazol-4-ol) were developed. Compound 46 showed an improved 5-LO inhibitory activity in cell-based (ICinf50/inf values 0.141/4M) and cell-free assays (ICinf50/inf values 0.03 1/4M) as well as a prominent enhanced solubility. Furthermore, it kept its promising inhibitory potency in the presence of blood serum, excluding excessive binding to serum proteins. These facts combined with the non-cytotoxic profile mark a major step towards an effective anti-inflammatory therapy.
Polyisocyanate compound, process for producing the same and optical materials using the same
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, (2008/06/13)
A novel polyisocyanate compound, which compound is useful as a starting material for an optical material having excellent optical characteristics such as a high refractive index and a low dispersion, and a process for producing this compound at good efficiency. Specifically, a polyisocyanate compound represented by general formula (I): wherein Z represents a direct bond, or —CH2—. The invention also relates to processes for producing the desired polyisocyanate compound through a tricarboxylic acid ester and a tricarbonyl hydrazide using a dihalogeno-aliphatic carboxylic acid lower alkyl ester and a thioglycolic acid lower alkyl ester. In addition, the invention relates to optical materials, such as lenses, etc., made by a polyaddition reaction of compounds of formula (I) and other monomers.
Acid-catalyzed breakdown of alkoxide and thiolate ion adducts of benzylidene Meldrum's acid, methoxybenzylidene Meldrum's acid and thiomethoxybenzylidene Meldrum's acid
Bernasconi, Claude F.,Ketner, Rodney J.,Brown, Shoshana D.,Chen, Xin,Rappoport, Zvi
, p. 8829 - 8839 (2007/10/03)
A kinetic study of the acid-catalyzed loss of alkoxide and thiolate ions from alkoxide and thiolate ion adducts, respectively, of benzylidene Meldrum's acid (1-H), methoxybenzylidene Meldrum's acid (1-OMe), and thiomethoxybenzylidene Meldrum's acid (1-SMe) is reported. The reactions appear to be subject to general acid catalysis, although the catalytic effect of buffers is weak and the bulk of the reported data refers to H+-catalysis. α-Carbon protonation and, in some cases, protonation of one of the carbonyl oxygens to form an enol compete with alkoxide or thiolate ion expulsion. This rendered the kinetic analysis more complex but allowed the determination of pK(a) values and of proton-transfer rate constants at the α-carbon. In conjunction with previously reported data on the nucleophilic addition of alkoxide and thiolate ions to the same Meldrum's acid derivatives, rate constants for nucleophilic addition by the respective neutral alcohols and thiols could also be calculated. Various structure-reactivity relationships are discussed that help define transition-state structures. Comparisons with similar reactions of alkoxide ion adducts of β-alkoxy-α-nitrostilbenes provide additional insights.
