26798-33-4Relevant articles and documents
Kinetic effects induced by cellulose on water-catalyzed reactions. Hydrolysis of 2,4-dinitrophenyl cellulose xanthate and some sugar xanthate ester analogues
Humeres, Eduardo,Sequinel, Luiz Fernando,Nunes, Mauricea,Oliveira, Celia M.S.,Barrie, Patrick J.
, p. 960 - 965 (1998)
The hydrolysis of 2,4-dinitrophenyl cellulose xanthate (CelXDNP) was studied in 10% v/v aqueous ethanol at 25°C and μ = 0.1 (KCl). The water- catalyzed hydrolysis showed that, as for p-nitrobenzyl cellulose xanthate, it occurs through two parallel reactions with rate constants k'(H2O) = 4.40 x 10-3 s-1 for the fast hydrolysis, and k''(H2O) = 6.90 x 10-5 s-1 for the slow hydrolysis. The entropy of activation of the fast hydrolysis was 0.7 ± 1.8 cal K-1 mol-1. External nucleophiles such as hydroxide and simple amines show simple first-order kinetics. The spontaneous hydrolysis of CelXDNP in acetone-water mixtures indicates that the fast reaction does not occur through water polymers and that for water molarity higher than 30 M there are no acetone molecules (or very few) in the highly ordered cybotactic region of cellulose. The spontaneous hydrolysis of methyl 4,6-O-benzylidene- α-D-glucopyranoside 3-(S-p-nitrobenzyl-xanthate) although is faster than the 6-isomer, it is slower than the fast hydrolysis of p-nitrobenzyl cellulose xanthate (CelXNB). Also ΔS(+) is highly negative (-41.0 cal K-1 mol-1), as it is for alkyl and sugar analogues. Only for the fast hydrolyses of CelXDNP and CelXNB is the entropy of activation almost zero. It is concluded that there is no neighbouring OH effect on the fast hydrolysis of cellulose xanthate esters. The hydrolysis of 2,4-dinitrophenyl cellulose xanthate (CelXDNP) was studied in 10% v/v aqueous ethanol at 25°C and μ = 0.1 (KCl). The water-catalyzed hydrolysis showed that, as for p-nitrobenzyl cellulose xanthate, it occurs through two parallel reactions with rate constants k′H2O = 4.40 × 10-3 s-1 for the fast hydrolysis, and k″H2O = 6.90 × 10-5 s-1 for the slow hydrolysis. The entropy of activation of the fast hydrolysis was 0.7 ± 1.8 cal K-1 mol-1. External nucleophiles such as hydroxide and simple amines show simple first-order kinetics. The spontaneous hydrolysis of CelXDNP in acetone-water mixtures indicates that the fast reaction does not occur through water polymers and that for water molarity higher than 30 M there are no acetone molecules (or very few) in the highly ordered cybotactic region of cellulose. The spontaneous hydrolysis of methyl 4,6-O-benzylidene-α-D-glucopyranoside 3-(S-p-nitrobenzyl-xanthate) although is faster than the 6-isomer, it is slower than the fast hydrolysis of p-nitrobenzyl cellulose xanthate (CelXNB). Also ΔS≠ is highly negative (-41.0 cal K-1 mol-1), as it is for alkyl and sugar analogues. Only for the fast hydrolyses of CelXDNP and CelXNB is the entropy of activation almost zero. It is concluded that there is no neighbouring OH effect on the fast hydrolysis of cellulose xanthate esters.
Targeted Delivery of Persulfides to the Gut: Effects on the Microbiome
Dillon, Kearsley M.,Morrison, Holly A.,Powell, Chadwick R.,Carrazzone, Ryan J.,Ringel-Scaia, Veronica M.,Winckler, Ethan W.,Council-Troche, R. McAlister,Allen, Irving C.,Matson, John B.
, p. 6061 - 6067 (2021/02/01)
Persulfides (R?SSH) have been hypothesized as potent redox modulators and signaling compounds. Reported herein is the synthesis, characterization, and in vivo evaluation of a persulfide donor that releases N-acetyl cysteine persulfide (NAC-SSH) in response to the prokaryote-specific enzyme nitroreductase. The donor, termed NDP-NAC, decomposed in response to E. coli nitroreductase, resulting in release of NAC-SSH. NDP-NAC elicited gastroprotective effects in mice that were not observed in animals treated with control compounds incapable of persulfide release or in animals treated with Na2S. NDP-NAC induced these effects by the upregulation of beneficial small- and medium-chain fatty acids and through increasing growth of Turicibacter sanguinis, a beneficial gut bacterium. It also decreased the populations of Synergistales bacteria, opportunistic pathogens implicated in gastrointestinal infections. This study reveals the possibility of maintaining gut health or treating microbiome-related diseases by the targeted delivery of reactive sulfur species.
Precise imaging of mitochondria in cancer cells by real-time monitoring of nitroreductase activity with a targetable and activatable fluorescent probe
Gu, Xianfeng,Tan, Jiahui,Wang, Rongchen,Xu, Ge,Zhao, Chunchang,Zhu, Ning,Zhu, Tianli
supporting information, p. 7761 - 7764 (2020/07/27)
An activatable and mitochondrial-targetable fluorescent probe was developed. This designed probe showed ratiometric fluorescence and light-up near-infrared emission responsiveness to nitroreductase, achieving precise imaging of mitochondria in cancer cells by real-time monitoring of nitroreductase activity.
Phosphorus Pentasulfide Mediated Conversion of Primary Carbamates into Thiols
Maurya, Chandra Kant,Gupta, Pradeep Kumar
, p. 1649 - 1651 (2017/08/11)
In this paper, we report a method for the conversion of primary carbamates into thiols in the presence of phosphorus pentasulfide (P 2 S 5) in refluxing toluene. Presently, no method exists in the literature for conversion of carbamates into thiols and, to the best of our knowledge, it is the first report for this type of conversion. This method presents an indirect route for the conversion of alcohols into thiols via their carbamate derivatives that may be useful in the total synthesis of compounds containing a thiol functionality.
Phosphorus pentasulfide mediated conversion of organic thiocyanates to thiols
Maurya, Chandra Kant,Mazumder, Avik,Gupta, Pradeep Kumar
supporting information, p. 1184 - 1188 (2017/07/03)
In this paper we report an efficient and mild procedure for the conversion of organic thiocyanates to thiols in the presence of phosphorus pentasulfide (P2S5) in refluxing toluene. The method avoids the use of expensive and hazardous transition metals and harsh reducing agents, as required by reported methods, and provides an attractive alternative to the existing methods for the conversion of organic thiocyanates to thiols.
Improved syntheses of 5′- S -(2-Aminoethyl)-6- N -(4-nitrobenzyl)- 5′-thioadenosine (SAENTA), analogues, and fluorescent probe conjugates: Analysis of cell-surface human equilibrative nucleoside transporter 1 (hENT1) levels for prediction of the antitumor
Robins, Morris J.,Peng, Yunshan,Damaraju, Vijaya L.,Mowles, Delores,Barron, Geraldine,Tackaberry, Tracey,Young, James D.,Cass, Carol E.
supporting information; experimental part, p. 6040 - 6053 (2010/11/02)
5′-S-(2-Aminoethyl)-6-N-(4-nitrobenzyl)-5′-thioadenosine (SAENTA), 5′-S-(2-acetamidoethyl)-6-N-[(4-substituted)benzyl]-5′- thioadenosine analogues, 5′-S-[2-(6-aminohexanamido)]ethyl-6-N-(4- nitrobenzyl)-5′-thioadenosine (SAHENTA), and related compounds we
Antioxidant-prooxidant properties of a new organoselenium compound library
Plano, Daniel,Baquedano, Ylenia,Ibanez, Elena,Jimenez, Iosu,Palop, Juan Antonio,Spallholz, Julian E.,Sanmartin, Carmen
experimental part, p. 7292 - 7312 (2011/02/24)
The present study describes the biological evaluation of a library of 59 organoselenium compounds as superoxide (O2-) generators and cytotoxic agents in human prostate cancer cells (PC-3) and in breast adenocarcinoma (MCF-7). In orde
Probing the mechanism of electron capture and electron transfer dissociation using tags with variable electron affinity
Sohn, Chang Ho,Chung, Cheol K.,Yin, Sheng,Ramachandran, Prasanna,Loo, Joseph A.,Beauchamp, J. L.
experimental part, p. 5444 - 5459 (2009/09/25)
Electron capture dissociation (ECD) and electron transfer dissociation (ETD) of doubly protonated electron affinity (EA)-tuned peptides were studied to further illuminate the mechanism of these processes. The model peptide FQpSEEQQQTEDELQDK, containing a
Preparation and in-vitro evaluation of 4-benzylsulfanylpyridine-2- carbohydrazides as potential antituberculosis agents
Herzigova, Petra,Klimesova, Vera,Palat, Karel,Kaustova, Jarmila,Dahse, Hans-Martin,Moellmann, Ute
body text, p. 394 - 404 (2009/11/30)
A set of 4-benzylsulfanylpyridine-2-carbohydrazides was synthesized and evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, non-tuberculous mycobacteria, and multidrug-resistant M. tuberculosis. The activities expressed as the minimum inhibitory concentration (MIC) fall into a range of 2 to 125 μmol/L, most often 4 to 32 μmol/L. The results revealed that the substituents on the benzyl moiety do not influence the antimycobacterial efficacy. The substances exhibited similar activities against sensitive and resistant strains of M. tuberculosis. Furthermore, compounds show low antiproliferative effect and cytotoxicity.
Unsymmetric aryl-alkyl disulfide growth inhibitors of methicillin-resistant Staphylococcus aureus and Bacillus anthracis
Turos, Edward,Revell, Kevin D.,Ramaraju, Praveen,Gergeres, Danielle A.,Greenhalgh, Kerriann,Young, Ashley,Sathyanarayan, Nalini,Dickey, Sonja,Lim, Daniel,Alhamadsheh, Mamoun M.,Reynolds, Kevin
, p. 6501 - 6508 (2008/12/21)
This study describes the antibacterial properties of synthetically produced mixed aryl-alkyl disulfide compounds as a means to control the growth of Staphylococcus aureus and Bacillus anthracis. Some of these compounds exerted strong in vitro bioactivity. Our results indicate that among the 12 different aryl substituents examined, nitrophenyl derivatives provide the strongest antibiotic activities. This may be the result of electronic activation of the arylthio moiety as a leaving group for nucleophilic attack on the disulfide bond. Small alkyl residues on the other sulfur provide the best activity as well, which for different bacteria appears to be somewhat dependent on the nature of the alkyl moiety. The mechanism of action of these lipophilic disulfides is likely similar to that of previously reported N-thiolated β-lactams, which have been shown to produce alkyl-CoA disulfides through a thiol-disulfide exchange within the cytoplasm, ultimately inhibiting type II fatty acid synthesis. However, the mixed alkyl-CoA disulfides themselves show no antibacterial activity, presumably due to the inability of the highly polar compounds to cross the bacterial cell membrane. These structurally simple disulfides have been found to inhibit β-ketoacyl-acyl carrier protein synthase III, or FabH, a key enzyme in type II fatty acid biosynthesis, and thus may serve as new leads to the development of effective antibacterials for MRSA and anthrax infections.