56-17-7Relevant academic research and scientific papers
Synthesis of reversible cyclic peptides
Ortiz-Acevedo, Alfonso,Dieckmann, Gregg R.
, p. 6795 - 6798 (2004)
Reversible cyclic peptides were synthesized by introducing a disulfide bond into the backbone of a peptide containing alternating d/l amino acids. The peptides exist in two distinct conformations (linear/cyclic) that are controlled by reduction/oxidation of the disulfide bond. A novel approach for the synthesis of cyclic peptides that can exist in either linear or cyclized conformations is described. Synthesis of the peptides was achieved via a modified solid phase methodology. The reversible linear/cyclized (i.e., open/closed) states are controlled via the reduction/oxidation of a disulfide bond incorporated into the backbone of the peptide chain.
Functionalized selenium nanoparticles with nephroprotective activity, the important roles of ROS-mediated signaling pathways
Li, Yinghua,Li, Xiaoling,Zheng, Wenjie,Fan, Cundong,Zhang, Yibo,Chen, Tianfeng
, p. 6365 - 6372 (2013/12/04)
The most frequent adverse effect of cisplatin-based chemotherapy is nephrotoxicity. Oxidative stress has been implicated as an important mechanism in the pathogenesis of cisplatin-induced nephrotoxicity. In the present study, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox) surface-functionalized selenium nanoparticles (Se@Trolox) with enhanced antioxidant activity have been prepared by self-assembly of trolox on the surface of the nanoparticles, and their nephroprotective effects have been investigated. Functionalization by trolox significantly enhanced cell uptake and in vitro antioxidant activities of the nanoparticles. In addition, pretreatment with Se@Trolox dose-dependently blocked cisplatin-induced cell growth inhibition against HK-2 cells. Mechanistic investigation suggested that Se@Trolox markedly prevented cisplatin-induced apoptosis in HK-2 cells, as evidenced by inhibition of chromatin condensation, DNA fragmentation, PARP cleavage and activation of caspase-3. Furthermore, Se@Trolox effectively blocked the cisplatin-induced reactive oxygen species (ROS) accumulation, activation of AKT and MAPK signaling and DNA damage-mediated p53 phosphorylation in HK-2 cells. Taken together, our findings suggest that Se@Trolox is a promising Se species with potential application in prevention of cisplatin-induced renal injury.
Stereoselective synthesis of 4-substituted azetidine-2,3-diones by ring opening of 1,3-thiazolidine-derived spiro-β-lactams
Cremonesi, Giuseppe,Croce, Piero Dalla,Fontana, Francesco,Rosa, Concetta La
, p. 554 - 561 (2008/09/20)
New 3-heterocycle substituted 1,3-thiazolidine-derived 4-spiro-β-lactams with a relative trans-configuration were stereoselectively synthesised by means of a Staudinger ketene-imine reaction between the ketene generated from the (2S,4R)-1,3-thiazolidine-2,3,4-tricarboxylic acid 3-(1,1-dimethylethyl) 4-methyl ester 1 and imines 2b-e. The 1,3-thiazolidine-derived 4-spiro-β-lactams were transformed into the corresponding enantiomerically pure 4-heterocycle substituted azetidine-2,3-diones by means of an oxidative cleavage of the 1,3-thiazolidine ring. The opening of the 1,3-thiazolidine ring was studied under different experimental conditions and a consistent mechanism is proposed.
[2 + 2] Cycloaddition reactions of imines with cyclic ketenes: Synthesis of 1,3-thiazolidine derived spiro-β-lactams and their transformations
Cremonesi, Giuseppe,Dalla Croce, Piero,La Rosa, Concetta
, p. 1580 - 1588 (2007/10/03)
Unsymmetric cyclic ketenes were generated from N-acyl-1,3-thiazolidine-2- carboxylic acids 1a-c by means of Mukaiyama's reagent, and then reacted with imines 2a-c to the new, isomeric spiro-β-lactams 3 and 4 via [2 + 2] cycloaddition (Staudinger ketene-imine reaction; Scheme 1). The reactions were stereoselective (Table 1) and mainly afforded the spiro-β-lactams with a relative trans configuration. The spiro-β-lactams could be transformed into the corresponding monocyclic β-lactams by means of thiazolidine ring opening or into substituted thiazolidines via hydrolysis of the β-lactam ring.
Organosulfur compounds as pre-exposure therapy for threat agents.
Ternay Jr.,Brzezinska,Sorokin,Cook,Lyaschenko
, p. S31-34 (2007/10/03)
A series of symmetric (Ar-S-S-Ar) and unsymmetric (Ar-S-S-CH2CH2NH3+Cl-) disulfides have been prepared and evaluated as potential cyanoprotective agents. Target compounds have been prepared by known methods and/or methods developed by us specifically for this program, e.g. reaction of a thiol with 2,2'-dithiobis(benzothiazole) (BT-S-S-BT) followed by reaction with a second thiol. Both 4-methoxyphenyl disulfide and 2-aminoethyl-4-methoxyphenyl disulfide hydrochloride are cyanoprotective against 2-LD50 of injected cyanide. Evaluation of both symmetric and unsymmetric related disulfides indicates that structural requirements for cyanoprotective activity are stringent and strongly suggest that protection is enzyme mediated. In addition to cyanoprotective action, initial results suggest that unsymmetric disulfides may evolve into effective antimustard agents.
Disulfides. 1. Syntheses Using 2,2'-Dithiobis(benzothiazole)
Brzezinska, Ewa,Ternay, Andrew L.
, p. 8239 - 8244 (2007/10/02)
2,2'-Dithiobis(benzothiazole) produces unsymmetric disulfides containing the 2-benzothiazolyl fragment in both high yield and purity when reacted with 1 equiv of a variety of alkane and arene thiols under mild conditions.In turn, these unsymmetric disulfides react with a variety of thiols to produce either symmetric disulfides or new unsymmetric disulfides in excellent yields.At room temperature, 2 equiv of most thiols are oxidized essentially quantitatively to the corresponding symmetric disulfide by 2,2'-dithiobis(benzothiazole).Thiols employed at various stages include 1-propanethiol, 2-propanethiol, 2-methyl-2-propanethiol, phenylmethanethiol, 2-mercaptoethanol, 2-mercaptoethylamine (MEA) hydrochloride, 2-methoxybenzenethiol, 4-methoxybenzenethiol, 4-aminobenzenethiol, 4-acetamidobenzenethiol, 4-bromobenzenethiol, 4-methylbenzenethiol, N-acetyl-L-cysteine, and sodium 2-mercaptoethanesulfonate (MESNA).Various disulfides were inactive in vivo against cyanide poisoning.
Process for the preparation of compounds with antiulcer action
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, (2008/06/13)
For the preparation of compounds such as ranitidine, niperotidine and cimetidine a urea of the formula: which is synthesized by reaction with a compound of formula STR1 is converted in a first stage into the corresponding bis-carbodiimide by reaction with triphenylphospine and bromine in the presence of a strong base and in a second stage the diimide thus obtained is reacted with nitromethane or a saline derivative of the cyanamide. The product thus obtained is reduced at the disulfide bridge obtaining a compound of formula: STR2 which is reacted with: STR3 to obtain ranitidine and niperotidine or cimetidine respectively depending on whether the first or the second of the described reactants is used.
Synthesis of antiulcer compounds
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, (2008/06/13)
To synthesize molecules with antiulcer action, specifically ranitidine, niperotidine and cimetidine, having the formula: STR1 wherein R1 is hydrogen or together with R2 represents the rest of a cycloaliphatic or heterocyclic optionally substituted ring with 5 or 6 carbon atoms, R2 represents H, alkyl, alkyl substituted with a simple or substituted aromatic ring or with a single or substituted heterocyclic ring, Ar represents a simple or substituted phenyl group, a simple or substituted heterocyclic aromatic group, N=1, 2, 3, 4, 5 or 6 and X represents CH--NO2, S, N--C N, the compound (II) is prepared through the following process sequence: STR2 wherein Z=H, NO2, halogen and R3 =--(CH2)n Ar, --(CH2)n --SH, --(CH2)n --S--S--(CH2)n, --(CH2)n --S--CH2 Ar Y being halogen. The urea of formula STR3 is converted in a first stage into the corresponding carbodiimide STR4 by reaction with triphenylphosphine and bromine in the presence of a strong base and in a second stage is obtained the desired compound by reaction with nitromethane or with a saline derivative of cynamide.
Reaction of β-mercaptoethylamine with α-acetylenic ketones
Glotova, T. E.,Nakhmanovich, A. S.,Skvortsova, G. G.,Komarova, T. N.,Kalikhman, I. D.,Voronkov, M. G.
, p. 653 - 658 (2007/10/02)
Bis(acylvinylaminoethyl) disulfides were synthesized by the reaction of α-acetylenic ketones with β-mercaptoethylamine in alcohol in the presence of sodium methoxide or in chloroform in the presence of potassium carbonate. 1,4-Bis(acylvinyl)-1-thia-4-azabutanes were obtained in the same way for acetylenic ketones with an aryl radical at the triple bond.
