- Design and development of the first peptide-chelating bisphosphane bioconjugate from a novel functionalized phosphorus(III) hydride synthon
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Remarkable oxidative stability is shown by the carboxylate- functionalized primary bisphosphane 1. Compound 1 can be used in conjugation reactions with biomolecules for functionalization through the COOH group without prior protection of PH2 groups. A novel water-soluble bisphosphane was obtained by reaction of the PH2 groups of 1 with formaldehyde under mild conditions.
- Gali, Hariprasad,Karra, Srinivasa R.,Reddy, V. Sreenivasa,Katti, Kattesh V.
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- Enhancing the stability and biological functionalities of quantum dots via compact multifunctional ligands
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We have designed and synthesized a series of modular ligands based on poly(ethylene glycol) (PEG) coupled with functional terminal groups to promote water-solubility and biocompatibility of quantum dots (QDs). Each ligand is comprised of three modules: a PEG single chain to promote hydrophilicity, a dihydrolipoic acid (DHLA) unit connected to one end of the PEG chain for strong anchoring onto the QD surface, and a potential biological functional group (biotin, carboxyl, and amine) at the other end of the PEG. Water-soluble QDs capped with these functional ligands were prepared via cap exchange with the native hydrophobic caps. Homogeneous QD solutions that are stable over extended periods of time and over a broad pH range were prepared. Surface binding assays and cellular internalization and imaging showed that QDs capped with DHLA-PEG-biotin strongly interacted with either NeutrAvidin immobilized on surfaces or streptavidin coupled to proteins which were subsequently taken up by live cells. EDC coupling in aqueous buffer solutions was also demonstrated using resonance energy transfer between DHLA-PEG-COOH-functionalized QDs and an amine-terminated dye. The new functional surface ligands described here provide not only stable and highly water-soluble QDs but also simple and easy access to various biological entities.
- Susumu, Kimihiro,Uyeda, H. Tetsuo,Medintz, Igor L.,Pons, Thomas,Delehanty, James B.,Mattoussi, Hedi
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- Metal ion induced fluorescence resonance energy transfer between crown ether functionalized quantum dots and rhodamine B: Selectivity of K+ ion
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We report a ratiometric fluorescent metal ion sensor based on the mechanism of fluorescence resonance energy transfer (FRET) between synthesized 15-crown-5-ether capped CdSe/ZnS quantum dots (QDCE) and 15-crown-5-ether attached rhodamine B (RBCE) in pH 8.3 buffer solution. Fluorescence titration with different metal ions in pH 8.3 buffer solution of the QDCE-RBCE conjugate showed a decrease and an increase in the fluorescence intensity for QDCE and RBCE moieties respectively due to FRET from QDCE to RBCE. This sensor system shows excellent selectivity towards K+ ions resulting in increasing efficiency of FRET. Energy transfer efficiency depends on the affinity between metal ions and crown ether functionalized with QDCE/RBCE. The detailed analysis of FRET was explored. This water soluble ratiometric sensor system can act as a good FRET probe for sensing applications especially in biological systems.
- Lee, Hsin-Lung,Dhenadhayalan, Namasivayam,Lin, King-Chuen
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- PH-Responsive quantum dots via an albumin polymer surface coating
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Multifunctional peptide?polymer hybrid materials have been applied as efficient and biocompatible quantum-dot coating materials. Significant pH responsiveness (e.g., an influence of the pH on the quantum yields of the peptide?polymer/QDs) was found and is attributed to conformational rearrangements of the peptide backbone.
- Wu, Yuzhou,Chakrabortty, Sabyasachi,Gropeanu, Radu A.,Wilhelmi, Joerg,Xu, Yang,Er, Kai Shih,Kuan, Seah Ling,Koynov, Kaloian,Chan, Yinthai,Weil, Tanja
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- Design and characterization of α-lipoic acyl shikonin ester twin drugs as tubulin and PDK1 dual inhibitors
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Shikonin exhibits powerful anticancer activities for various cancer cells, but its poor solubility and strong toxicity hinder its development as clinical anticancer agent. We previously confirmed that shikonin and its derivatives can disturb mitosis through targeting tubulin. In this study, α-lipoic acid, the naturally-occurring co-factor of pyruvate dehydrogenase (PDH), was introduced into shikonin to design the twin drugs against both mitosis (tubulin) and glycolysis (PDK). 18 kinds of α-lipoic acid shikonin ester derivatives were achieved through three rounds of screening process performed by computer assistant drug design method, being designated as the outstanding compounds. Among them, 1c displayed the most potent cytotoxicity towards cervical cancer cells (HeLa) with an IC50 value of 3.14 ± 0.58 μM and inhibited xenotransplanted tumor growth in a dose-dependent manner. Further pharmacologic study demonstrated that 1c can cause cell cycle arrest in G2/M phase as tubulin polymerization inhibitor. Moreover, it also showed good PDK1 inhibitory activity, promoting PDH activity and forced HeLa cells to process more aerobic metabolism to undergo cell apoptosis. We reported here the first dual inhibitors of tubulin and PDK1 based on shikonin. It may form a basis for shikonin optimization through twin drug design framework for the discovery of new and potent shikonin derivatives in the study of targeted cancer therapy.
- Lin, Hong-Yan,Han, Hong-Wei,Sun, Wen-Xue,Yang, Yu-Shun,Tang, Cheng-Yi,Lu, Gui-Hua,Qi, Jin-Liang,Wang, Xiao-Ming,Yang, Yong-Hua
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- Driving oxygen coordinated ligand exchange at nanocrystal surfaces using trialkylsilylated chalcogenides
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A general, efficient method is demonstrated for exchanging native oxyanionic ligands on inorganic nanocrystals with functional trimethylsilylated (TMS) chalcogenido ligands. In addition, newly synthesized TMS mixed chalcogenides leverage preferential reactivity of TMS-S bonds over TMS-O bonds, enabling efficient transfer of luminescent nanocrystals into aqueous media with retention of their optical properties.
- Caldwell, Marissa A.,Albers, Aaron E.,Levy, Seth C.,Pick, Teresa E.,Cohen, Bruce E.,Helms, Brett A.,Milliron, Delia J.
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- Facile synthesis of water-soluble fluorescent silver nanoclusters and HgII sensing
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A single step facile synthesis of highly emissive, water-soluble, fluorescent Ag nanoclusters has been reported using a small molecule, dihydrolipoic acid. These clusters were characterized using ultraviolet/visible (UV/vis) spectroscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD) studies. Mass spectrometric analysis shows the presence of a few atoms in nanoclusters containing only Ag4 and Ag5. The reported fluorescent Ag nanoclusters show excellent optical properties, including narrow emission profile, larger Stokes shift (more than 200 nm), and good photostability. Interestingly, these nanoclusters also exhibit semiconducting property. Moreover, as-prepared fluorescent Ag nanoclusters have been utilized as an indicator for selective and ultrasensitive detection of highly toxic Hg II ions in water, even at subnanomolar concentrations.
- Adhikari, Bimalendu,Banerjee, Arindam
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- Synthesis of compact multidentate ligands to prepare stable hydrophilic quantum dot fluorophores
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We describe a simple and versatile scheme to prepare an array of heterofunctional multidentate ligands that permit strong and stable interactions with colloidal semiconductor nanocrystals (quantum dots, QDs) and render them soluble in aqueous environments. These ligands were synthesized by reacting various chain length poly(ethylene glycols) with thioctic acid, followed by ring opening of the dithiolane moiety, creating a bidentate thiol motif with enhanced affinity for CdSe-ZnS core-shell QDs. Functionalization with these ligands permits processability of the nanocrystals not only in aqueous but also in many other polar solvents. These ligands provide a straightforward means of preparing QDs that exhibit greater resistance to environmental changes, making them more amenable for use in live cell imaging and other biotechnological applications.
- Uyeda, H. Tetsuo,Medintz, Igor L.,Jaiswal, Jyoti K.,Simon, Sanford M.,Mattoussi, Hedi
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- Highly chemiluminescent gold nanopopcorns functionalized by N-(aminobutyl)-N-(ethylisoluminol) with lipoic acid as a co-stabilizing reagent
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Herein we report a novel facile synthesis of Au nanopopcorns (AuNPCs) with high chemiluminescent yield by reducing (±)-α-lipoic acid (LA) and HAuCl4 with N-(aminobutyl)-N-(ethylisoluminol) (ABEI) in ethyl alcohol solution at room temperature through a seed growth method. The morphologies of AuNPCs could be changed by adjusting the mole ratios of ABEI, LA and HAuCl4. The characterization results demonstrated that ABEI and the reduction product of LA as stabilizers were coated on the surface of AuNPCs during the synthesis. The AuNPCs, functionalized with ABEI, could react with various oxidants (H2O2, KMnO4, NaClO, Fe(CN)63- and AgNO3) to produce chemiluminescence (CL). The special morphology of AuNPCs maintains the large specific surface area, inherited from its shape and demonstrated excellent catalytic property when involved in CL reaction with H2O2. Thus the CL efficiency of AuNPCs was more than two orders of magnitude higher than that of ABEI functionalized gold nanoparticles in our previous work. The AuNPCs are capable of direct conjugation with protein and DNA while maintaining their luminescent properties, thus they could be potentially useful as a bio-probe for immunoassays and DNA assays. The Royal Society of Chemistry 2013.
- Zhang, Hongli,Liu, Mengxiao,Huang, Guangming,Yu, Yuqi,Shen, Wen,Cui, Hua
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- One-pot development of water soluble copper nanoclusters with red emission and aggregation induced fluorescence enhancement
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One-pot synthesis of water-soluble Cu NCs using DHLA protection ligands by different reducing reagents including NaBH4, N2H4 and THPC was developed. Furthermore, it was found that the as prepared Cu NCs using THPC as a reducing reagent describe fluorescence enhancement in the presence of Zn2+ and Al3+. It is proposed that the binding of Zn2+ and Al3+ to OH on the copper core of Cu NCs promotes the formation of CuNC-OH-Zn-OH-Cu NCs and CuNC-OH-Al-OH-Cu NCs aggregates respectively, which enables aggregation induced fluorescence enhancement. Additionally, it was found that the fluorescence enhancement were partly reversible by the introduction of an alkaline buffer solution and Zn2+.
- Li, Dan,Chen, Zhenhua,Wan, Zhanghui,Yang, Tiezhu,Wang, Hao,Mei, Xifan
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- NOVEL LIPOIC ACID-HETEROCYCLE THIOACETAL COMPOUNDS AND USES OF THE SAME
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The present invention relates to a novel lipoic acid - heterocycle thioacetal compound which converts a lipoic acid having an unstable disulfide structure into a thioacetal, and to the use thereof. The present invention relates to a pharmaceutical composition comprising a lipoic acid - heterocyclic thioacetal compound for preventing or treating degenerative diseases and a health supplement food composition for preventing or alleviating a degenerative disease.
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Paragraph 0107-0110
(2021/05/04)
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- Novel bifunctional [16]anes4-derived chelators for soft radiometals
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The field of targeted radionuclide therapy is rapidly growing, highlighting the need for wider radionuclide availability. Soft Lewis acid ions, such as radioisotopes of platinum, rhodium and palladium, are particularly underdeveloped. This is due in part to a lack of compatible bifunctional chelators. These allow for the practical bioconjugation to targeting vectors, in turn enabling radiolabeling. The [16]andS4 macrocycle has been reported to chelate a number of relevant soft metal ions. In this work, we present a procedure for synthesizing [16]andS4 in 45% yield (five steps, 12% overall yield), together with a selection of strategies for preparing bifunctional derivatives. An ester-linked N-hydroxysuccimide ester (NHS, seven steps, 4% overall yield), an ether-linked isothiocyanate (NCS, eight steps, 5% overall yield) and an azide derivative were prepared. In addition, a new route to a carbon-carbon linked carboxylic acid functionalized derivative is presented. Finally, a general method for conjugating the NHS and NCS derivatives to a polar peptide (octreotide) is presented, by dissolution in water:acetonitrile (1:1), buffered to pH 9.4 using borate. The reported compounds will be readily applicable in radiopharmaceutical chemistry, by facilitating the labeling of a range of molecules, including peptides, with relevant soft radiometal ions.
- Jensen, Andreas I.,Magnus, Charlotte B.,Straathof, Natan J. W.,Zhuravlev, Fedor
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supporting information
(2021/08/17)
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- Preparation method of lipoic acid impurity A
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The invention relates to a preparation method of a lipoic acid impurity A, and belongs to the field of compound synthesis. The invention aims to overcome the defects of complex operation and harsh reaction conditions in the prior art, and provides the preparation method of the lipoic acid impurity A. The preparation method is mild in condition and high in product purity. The preparation method comprises the following steps: (1) dissolving lipoic acid in a reaction solvent, adding an oxidant for reaction, and removing solids and the solvent after the reaction is completed to obtain a compound B; (2) respectively adding the compound B, sodium thiosulfate and a catalyst into water, then adding hydrochloric acid, carrying out hydrolysis ring-opening reaction, and filtering after the reaction is completed to obtain a compound C; and (3) respectively adding the compound C, sodium sulfide and formaldehyde into the reaction solvent for reaction, extracting after the reaction is completed, drying, and purifying to obtain a compound D lipoic acid impurity A. The method is mild in condition, and the prepared lipoic acid impurity A is high in purity.
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- Thioctic acid aldehyde derivatives, and preparation method and application thereof
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The invention belongs to the technical field of chemical pharmacy, and concretely relates to thioctic acid aldehyde derivatives, a preparation method thereof, and an application of the thioctic acid aldehyde derivatives in the preparation of antitumor drugs as a histone deacetylase inhibitor. Aldehyde compounds are introduced into thioctic acid molecules by chemical synthesis to obtain the thioctic acid aldehyde compounds with a novel structure, and a result of in-vitro antitumor activity study shows that the thioctic acid aldehyde derivative has a significant inhibition effect on the tumor cells OVCaR-3, A549 and NCI-H460. From the perspective of the activity results and the preparation possibility, the thioctic acid aldehyde derivatives can be processed to prepare high-efficiency and low-toxicity antitumor drugs, and have broad drug development prospects.
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Paragraph 0048-0050
(2019/11/20)
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- PROCESS FOR THE PRODUCTION OF DIHYDROLIPOIC ACID
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The present invention relates to a multi-step process for the production of dihydrolipoic acid, which can particularly be carried out as a one-pot reaction and without isolation of intermediates.
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Paragraph 0058
(2019/09/20)
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- TAXIFOLIN DERIVATIVE WITH SUPERIOR ANTIOXIDANT EFFECT AND COSMETIC COMPOSITION CONTAINING THE SAME
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Disclosed are taxifolin derivative with superior antioxidant effect, a method of synthesizing the same and a cosmetic composition containing the same. In accordance with the method, taxifolin derivatives having higher antioxidant activity than taxifolin can be synthesized using lipoic acid. As such, a novel taxifolin derivative synthesized according to the present invention can exhibit anti-aging effects when used for cosmetics and the like.
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Paragraph 0049; 0050
(2017/08/26)
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- Circularly polarized luminescence in chiral silver nanoclusters
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Silver nanoclusters (NCs) capped with enantiomeric bidentate ligands exhibited mirror image circularly polarized luminescence (CPL) spectra with an anisotropy factor of 0.2%. Chirality in the ligand staples is most likely responsible for the induction of optical activity in the emissive state.
- Kumar, Jatish,Kawai, Tsuyoshi,Nakashima, Takuya
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supporting information
p. 1269 - 1272
(2017/02/05)
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- CPI-613: Antimitochondrial metabolism agent Treatment of hematological malignancies and solid tumors
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Metabolic changes specifically associated with cancer may constitute an excellent opportunity for the identification of new biomarkers and targets for novel drugs. The coenzyme lipoate is a key player in the control of cell metabolic fluxes and occupies a central position in tumor biology. Previous observations suggested that systemically delivered lipoate analogues might selectively disrupt cancer mitochondrial metabolism, potentially resulting in cancer cell death. CPI-613, the first member of a large set of lipoate analogues, specifically inhibits mitochondrial metabolism in a wide range of tumor cell lines, but not in normal cells, by mechanisms involving pyruvate dehydrogenase and α-ketoglutarate dehydrogenase enzyme complexes. There are 14 ongoing or completed phase I and phase II clinical trials on CPI-613, alone or in combination, showing promising results for several hematological malignancies and solid tumors, particularly for the treatment of acute myeloid leukemia, myelodysplastic syndrome and pancreatic cancer.
- Moro
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p. 209 - 214
(2017/05/17)
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- Taxifolin derivative with high anti-oxidant effect and cosmetic composition therefrom
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The present invention relates to a taxifolin derivative with an excellent anti-oxidant effect, a synthesizing method thereof, and a cosmetic composition comprising the same. In the present invention, the taxifolin derivative showing higher anti-oxidant activity than that of taxifolin is synthesized by using lipoic acid. The taxifolin derivative newly synthesized in the present invention is used by being added in cosmetics, thereby exhibiting an anti-aging effect, etc. The taxifolin-7-lipoate has a structure represented by chemical formula 8, and is referred to as (7-(5-(1,2-dithiolan-3-yl)pentyloxy)-2-(3,4-dihydroxyphenyl)-3,5-dihydroxychroman-4-one).COPYRIGHT KIPO 2016
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Paragraph 0052-0055
(2018/03/07)
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- Aqueous-phase hydrogenation and hydroformylation reactions catalyzed by a new water-soluble [rhodium]-thioligand complex
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Rh(DHTANa) is a new water-soluble catalyst easily obtained by mixing in water the catalytic precursor [Rh(COD)Cl]2 and the dihydrothioctic acid sodium salt (DHTANa). This catalyst showed to be very active in the hydrogenation of unsaturated substrates as 2-cyclohexen-1-one, the biomass-derived furfural and acetophenone. In this last case the catalytic system obtained by using as water-soluble ligand (R)-(DHTANa) afforded (R)-1-phenylethanol with very modest enantioselectivity. Rh(DHTANa) was active also in the aqueous biphase hydroformylation of styrene producing exclusively the two corresponding aldehydes with 80-86% selectivity toward the branched aldehyde 2-phenylpropanal. This new catalytic system was easily recycled in both hydrogenation and hydroformylation processes and no leaching phenomenon was observed.
- Paganelli,Piccolo,Pontini,Tassini,Rathod
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- Synthesis of novel aryl dithian valeryl podophyllotoxin ester derivatives as potential antitubulin agents
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Microtubules are among the most successful targets for anticancer therapy. In this study, we described the synthesis routes of the lipoyl podophyllotoxin ester derivatives and found that they can selectively inhibit the proliferation of cancer cells without damaging the non-cancer cells. Among them, L4 showed the best antiproliferation activity with IC50 = 2.68 μM against A549 cells. This effect of L4 was similar to that of CA-4 (IC50 = 2.78 μM), a typical microtubule inhibitor, but better than podophyllotoxin (IC50 = 6.57 μM) itself. Furthermore, cell cycle analysis revealed that L4 can remarkably cause cell cycle arrest in the G2/M phase in a time- and dose-dependent manner. But the effect of L4 on apoptosis inducing was not apparent enough. Moreover, confocal microscopy and western blot analysis results indicated that L4 can perturb microtubule polymerization, thus causing tumor growth inhibition.
- Lin, Hong-Yan,Li, Zi-Kang,Han, Hong-Wei,Qiu, Han-Yue,Gu, Hong-Wei,Yang, Yong-Hua,Wang, Xiao-Ming
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p. 47511 - 47521
(2015/06/16)
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- Thiolates of arsenic(III), antimony(III), and bismuth(III) with dl-α-dihydrolipoic acid
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Lipoic acid can be reduced to dihydrolipoic acid free of lipoic acid without using deoxygenated solvents. Dihydrolipoic acid reacted with phenylarsine oxide, As2O3, and AsCl3, SbCl 3 but not Sb2O3, and Bi2O 3, BiCl3, and Bi(NO3)3· 5H2O in various solvents giving thiolates. When the reactions were done in methanol, the HCl and HNO3 released caused esterification of the -COOH group. The reaction with As(III) compounds was sensitive to dioxygen, leading to production of lipoic acid derivatives as well, arsenite being particularly active for the autoxidation. Physical (1H NMR) and chemical [reactivity of >M-Cl and >Bi(NO3)] properties of the adducts are described. The six-membered dihydrolipoic acid complexes reacted with stoichiometric amounts of British Anti-Lewisite releasing the dihydrolipoic acid by forming the corresponding complexes of British Anti-Lewisite. Graphical Abstract: [Figure not available: see fulltext.]
- Ioannou, Panayiotis V.,Tsivgoulis, Gerasimos M.
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p. 897 - 909
(2014/06/09)
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- Effects of lipoic acid, caffeic acid and a synthesized lipoyl-caffeic conjugate on human hepatoma cell lines
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Hepatocellular carcinoma (HCC) is among the most aggressive and fatal cancers. Its treatment with conventional chemotherapeutic agents is inefficient, due to several side effects linked to impaired organ function typical of liver diseases. Consequently, there exists a decisive requirement to explore possible alternative chemopreventive and therapeutic strategies. The use of dietary antioxidants and micronutrients has been proposed for HCC successful management. The aim of this work was to test in vitro the effects of lipoic acid, caffeic acid and a new synthesized lipoylcaffeic conjugate on human hepatoma cell lines in order to assess their effect on tumor cell growth. The results of cytotoxicity assays at different times showed that the cell viability was directly proportional to the molecule concentrations and incubation times. Moreover, to evaluate the pro- or anti-inflammatory effects of these molecules, the cytokine concentrations were evaluated in treated and untreated cellular supernatants. The obtained cytokine pattern showed that, at the increasing of three molecules concentrations, three pro-inflammatory cytokines such as IL-1α, IL-8 and TNF-α decreased whereas the antiinflammatory cytokine such as IL-10 increased.
- Guerriero, Eliana,Sorice, Angela,Capone, Francesca,Costantini, Susan,Palladino, Pasquale,D'Ischia, Marco,Castello, Giuseppe
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experimental part
p. 6365 - 6377
(2011/11/12)
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- Synthesis of new macromolecular, functionalized carboxylic-acid-PEG-DHLA surface ligands
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An efficient method for the synthesis of new macromolecular surface ligands for quantum dots functionalization has been developed. The new ligands contain a dihydrolipoic acid unit which is connected to either a mono- or a diacid terminal function by a PEG chain.
- Mignani, Serge,Aszodi, Jozsef,Babin, Didier,Liutkus, Mélanie,Bedel, Olivier
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scheme or table
p. 5364 - 5367
(2010/11/02)
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- Synthesis and anticancer evaluation of α-lipoic acid derivatives
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α-Lipoic acid derivatives were synthesized and evaluated for their in vitro anticancer activities against NCI-460, HO-8910, KB, BEL-7402, and PC-3 cell lines. The results, for most compounds exhibited dose-dependent inhibitory property and several compounds had good inhibitions at the dose of 100 μg/mL. Compound 17m was further selected for in vivo evaluation against S180 xenograft in ICR mice, which had 24.7% tumor-weight inhibition through intragastric administration of 200 mg/kg of body weight. Moreover, the LD50 in mice for 17m through ig exceeded 1000 mg/kg of body weight.
- Zhang, Shi-Jie,Ge, Qiu-Fu,Guo, Dian-Wu,Hu, Wei-Xiao,Liu, Hua-Zhang
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scheme or table
p. 3078 - 3083
(2010/07/18)
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- LIPOIC ACID DERIVATIVES
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Lipoic acid derivatives and pharmaceutical formulations containing lipoic acid derivatives are useful in the treatment and prevention of disease characterized by disease cells that are sensitive to lipoic acid derivatives.
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Page/Page column 11
(2008/12/04)
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- Lipoic acid derivatives and their use in treatment of disease
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This invention relates to the identification of a novel class of therapeutic agents which selectively target and kill tumor cells and certain other types of diseased cells, and to compositions comprising lipoic acid derivatives which poison the pyruvate dehydrogenase complex specifically in such cells. This invention also provides for methods of using therapeutically effective amounts of the lipoic acid derivatives for the treatment of cancer and other diseases. The lipoic acid derivatives described herein have a wide range of preventive and therapeutic applications.
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- A short and productive synthesis of racemic α-lipoic acid
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Racemic α-lipoic acid is synthesized in four steps from the base chemicals vinyl ethyl ether and cyclohexanone. The total yield is 40%.
- Balkenhohl, Friedhelm,Paust, Joachim
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p. 649 - 654
(2007/10/03)
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- Synthesis and in vitro anthelmintic properties of some new dithiaarsanes
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Fifteen new trivalent organoarsenicals were synthesized and evaluated for anthelmintic properties on three in vitro models, infective larvae of the filaria Molinema dessetae, infective larvae of an intestinal nematode, Nippostrongylus brasiliensis and adults and larvae of Rhabditis pseudoelongata a free living nematode. On the M. dessetae model, the most active compound after a 24 h incubation period had an EC50 of 0.02 μmol/l (compound 3a). Twelve compounds had an EC50 lower than 1 μmol/l whereas potassium melarsonyl exhibited an EC50 of 45.6 μmol/l. After 7 days incubation time, compound 1d had an EC50 of 2 nmol/l. On the N. brasiliensis model, compound 1d was also the most efficient after a 4 day incubation period (EC50 of 1 μmol/l). This compound was 100 times more active than potassium melarsonyl used as a reference compound. Nevertheless, no compound had an EC50 less than 100 μmol/l on Rhabditis pseudoelongata. Concerning the effect of dithiol ligands on the anthelmintic activity of these trivalent organoarsenicals on M. dessetae and N. brasiliensis, 2,2'- dimercaptodiethyloxide was more efficient as dithiol ligand than 1,3- dimercaptopropane which was more efficient than 1,2-dimercaptoethane. Moreover, the para-amino haptophore was more efficient than the melaminyl haptophore. These results showed that the use of new dithiol ligands for trivalent arsenicals enhanced greatly the anthelmintic activity compared with potassium melarsonyl.
- Loiseau, Philippe-Marie,Lubert, Patrick,Wolf, Jean-Gerard
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p. 944 - 950
(2007/10/03)
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- Production and use of salts of 6, 8-bis (amidiniumthio) -octanoic acid
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The invention relates to the production and purification of salts of 6,8-bis(amidiniumthio) octanoic acid, its enantiomers (+)-6,8-bis(amidiniumthio)octanoic acid and (-)-6,8-bis (amidiniumthio)octanoic acid and of the esters of these compounds as well as to their use to produce dihydrolipoic acid and α-lipoic acid.
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- Equilibrium Constants for Thiol-Disulfide Interchange Reactions: A Coherent, Corrected Set
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Equilibrium constants (Keq) for the thiol-disulfide interchange reactions between dithiothreitol (DTT) and lipoic acid (14.2 +/- 0.7), lipoic acid (Lip) and mercaptoethanol (13.3 M +/- 1.0 M), and mercaptoethanol (ME) and glutathione (GSH or GSSG) (1.20 +/- 0.10) were measured in D2O at pD 7.0 by 1H NMR spectroscopy.Two of these equilibrium constants were also measured in D2O/CD3OD.These values are compared with those obtained by other methods.A coherent set of values for the equilibrium constants between DTT or ME and thiols having a range of structures was assembled (Table III).The recommended value for the equilibrium constant between DTT and GSH is 210 M (Keq = ox>2/(red>)).
- Lees, Watson J.,Whitesides, George M.
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p. 642 - 647
(2007/10/02)
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- A Reagent for Reduction of Disulfide Bonds in Proteins That Reduces Disulfide Bonds Faster Than Does Dithiothreitol
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We have synthesized a new reagent - N,N'-dimethyl-N,N'-bis(mercaptoacetyl)hydrazine (DMH) - for the reduction of disulfide bonds in proteins.DMH reduces disulfide bonds 7 times faster than does dithiothreitol (DTT) in water at pH 7.DMH reduces mixed disulfides of cysteine proteases (papain and ficin) especially rapidly (30 times faster than DTT).DMH (ε0 = -0.300 V) reduces noncyclic disulfides completely, although it is less strongly reducing than DTT (ε0 = -0.356 V).
- Singh, Rajeeva,Whitesides, George M.
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p. 2332 - 2337
(2007/10/02)
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- Process for the production of 1,2-dithiolan-3-pentanoic acid (thioctic acid) and intermediate compounds therefor
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1,2-Dithiolane-3-pentanoic acid (D,L-thioctic acid) of the formula STR1 is prepared by a process comprising (a) reacting a 2-(3-alkylthiopropionyl)-cyclopentanone-1 of the formula STR2 where R is a C1 -C4 alkyl, phenyl or benzyl in aqueous alkaline solution at a temperature of about 20° C. to about 90° C. to form the corresponding carboxylic acid of formula VI STR3 (b) reacting the compound of formula VI with an alkyl mercaptan at a temperature between -20° C. and 0° C. to form the corresponding thioketal of formula VII STR4 (c) reacting the compound of formula VII with sodium in liquid ammonia at a temperature between -60° C. and -10° C. to form the 6,8-dimercaptooctanoic acid of formula VIII STR5 (d) reacting the 6,8-dimercaptooctanoic acid of formula VIII in alkaline solution with an iron (III) salt and oxygen to form the 1,2-dithiolane-3-pentanoic acid of formula IX, or in place of steps (a) through (c) reacting an acid of formula XII STR6 where R1 and R2 are hydrogen, C1 -C4 -alkyl, phenyl or benzyl, with the proviso that both R1 and R2 cannot be benzyl, with sodium in liquid ammonia at a temperature between -60° C. and -10° C. to form the corresponding 6,8-dimercaptooctanoic acid of formula VIII. The compounds of formulae VI, VII, XII are new.
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- STEREOSELECTIVE REDUCTION OF RACEMIC N-HYDROXYAMINO ACIDS BY OPTICALLY ACTIVE THIOLS-IRON(II)
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Kinetic resolution of racemic N-hydroxyamino acids by the reduction with optically active thiols and a catalytic amount of ferrous ion gave optically active amino acids presumably through enantiodifferentiating coordination of substrates to thiol-Fe(II) complexes.
- Nambu, Yoko,Endo, Takeshi
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p. 999 - 1002
(2007/10/02)
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