- Synthesis of a new disulfide Fmoc monomer for creating biologically susceptible linkages in peptide nucleic acid oligomers
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Peptide nucleic acids (PNA) are one of many synthetic mimics of DNA and RNA that have found applications as biological probes, as nano-scaffold components, and in diagnostics. In an effort to use PNA as constructs for cellular delivery we investigated the possibility of installing a biologically susceptible disulfide bond in the backbone of a PNA oligomer. Here we report the synthesis of a new abasic Fmoc monomer containing a disulfide bond that can be incorporated into a PNA oligomer (DS-PNA) using standard solid phase peptide synthesis. The disulfide bond survives cleavage from the resin and DS-PNA forms duplexes with complementary PNA oligomers. Initial studies aimed at determining if the disulfide bond is cleavable to reducing agents while in a duplex are explored using UV thermal analysis and HPLC.
- Campbell, Brandon,Hood, Taylor,Shank, Nathaniel
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Read Online
- THIOL-BASED FLUORESCENT PROBE FOR REACTIVE SPECIES
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Detection of nitroxyl (HNO), the transient one-electron reduced form of nitric oxide, is a significant challenge owing to its high reactivity with biological thiols (rate constants as high as 109M?1 s?1). Reported herein is a new thiol-based HNO-responsive trigger that can compete against reactive thiols for HNO. This process forms an N-hydroxysulfenamide intermediate which cyclizes to release a masked fluorophore leading to fluorescence enhancement. To ensure a rapid cyclization step, the disclosed design capitalizes on two established physical organic phenomena: the alpha-effect and the Thorpe-Ingold effect. Using this new trigger, NitroxylFluor was developed; a selective HNO-responsive fluorescent probe. Treatment of NitroxylFluor with an HNO donor results in a 16-fold turn-on. This probe also exhibits excellent selectivity over various reactive nitrogen, oxygen, and sulfur species and efficacy in the presence of thiols (e.g., glutathione in mM concentrations). Also, live cell imaging of HNO using NitroxylFluor was performed.
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Paragraph 0157
(2020/05/29)
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- Preparation method of 2-mercaptoisobutyric acid
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The invention relates to a preparation method of 2-mercaptoisobutyric acid, which comprises the following steps: carrying out a reaction with methyl (ethyl) 2-bromoisobutyrate with thiourea to prepareisothiourea salt, and carrying out alkaline hydrolysis and acidification to obtain the 2-mercaptoisobutyric acid. The method has the advantages of low cost, mild reaction conditions and high yield, and is suitable for industrial production.
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Paragraph 0021; 0022
(2020/05/08)
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- Novel preparation method of 2-mercaptoisobutyric acid
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The invention provides a novel preparation method of 2-mercaptoisobutyric acid. Raw materials used in the method comprise 2-ethyl bromoisobutyrate, thiourea, an alkali solution, a solvent, and a hydrolyzate. Compared with other synthetic methods, the method provided by the invention has the advantages of a high yield, high purity, cheap and easy-availability reagents, mild reaction conditions, a simple technological process and environmental friendliness.
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Paragraph 0025; 0026
(2019/10/01)
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- NitroxylFluor: A Thiol-Based Fluorescent Probe for Live-Cell Imaging of Nitroxyl
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Detection of nitroxyl (HNO), the transient one-electron reduced form of nitric oxide, is a significant challenge owing to its high reactivity with biological thiols (with rate constants as high as 109 M-1 s-1). To address this, we report a new thiol-based HNO-responsive trigger that can compete against reactive thiols for HNO. This process forms a common N-hydroxysulfenamide intermediate that cyclizes to release a masked fluorophore leading to fluorescence enhancement. To ensure that the cyclization step is rapid, our design capitalizes on two established physical organic phenomena; the alpha-effect and the Thorpe-Ingold effect. Using this new trigger, we developed NitroxylFluor, a selective HNO-responsive fluorescent probe. Treatment of NitroxylFluor with an HNO donor results in a 16-fold turn-on. This probe also exhibits excellent selectivity over various reactive nitrogen, oxygen, and sulfur species and efficacy in the presence of thiols (e.g., glutathione in mM concentrations). Lastly, we successfully performed live cell imaging of HNO using NitroxylFluor.
- Pino, Nicholas W.,Davis, Jerome,Yu, Zhengxin,Chan, Jefferson
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supporting information
p. 18476 - 18479
(2018/01/08)
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- Site-specific conjugation of RAFT polymers to proteins via expressed protein ligation
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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.
- Xia, Yan,Tang, Shengchang,Olsen, Bradley D.
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supporting information
p. 2566 - 2568
(2013/04/23)
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- Synthesis and crystal structure of 3,3,6,6-tetramethylmorpholine-2,5-dione, and its 5-monothioxo and 2,5-dithioxo derivatives
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The synthesis of 3,3-dimethylmorpholine-2,5-diones 4a was achieved conveniently via the 'direct amide cyclization' of the linear precursors of type 3, which were prepared by coupling of 2,2-dimethyl-2H-azirin-3-amines 2 with 2-hydroxyalkanoic acids 1. Thionation of 4a with Lawesson's reagent yielded the corresponding 5-thioxomorpholin-2-ones 10 and morpholine-2,5-dithiones 11, respectively, depending on the reaction conditions. The structures of 3aa, 4aa, 10a, and 11a were established by X-ray crystallography. All attempts to prepare S-containing morpholine-2,5-dione analogs or thiomorpholine-2,5-diones by cyclization of corresponding S-containing precursors were unsuccessful and led to various other products. The structures of some of them have also been established by X-ray crystallography.
- Mawad, Nasser,Ghorbani-Salman Pour, Fatemeh,Linden, Anthony,Heimgartner, Heinz
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scheme or table
p. 2326 - 2346
(2011/02/18)
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- Diagnostic radiopharmaceutical compounds (That)
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Tetradentate ligands are used to form neutral 99m-technetium complexes which may be useful as radiopharmaceuticals e.g. as brain imaging agents. The ligands have the structure STR1 where n is 2 or 3, m is 0-4, R is H or substituted or unsubstituted C1 -C6 alkyl, provided that one CR2 group adjacent the starred nitrogen atom represents CO and forms with the adjacent N atom, a --CONH-- amide group, Y is unsubstituted or substituted C1 -C6 alkyl, and one of X and X' represents H or a labile thiol protecting group while the other is unsubstituted or substituted C1 -C6 alkyl, alkenyl or alkynyl.
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- A facile, high-yielding method for the conversion of halides to mercaptans
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An efficient, high-yield, one-pot preparation of alkyl and activated aryl mercaptans is presented. The method relies on sodium thiophosphate displacement of the halide, followed by mild hydrolysis of the intermediate phosphorothioate.
- Bieniarz,Cornwell
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p. 939 - 942
(2007/10/02)
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- Organotin-containing composition for the stabilization of polymers of vinyl chloride
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An organotin-containing composition for the stabilization of polymers or copolymers of vinyl chloride in which there is incorporated a stabilizing amount of an organotin compound containing at least two tin atoms and which is a mercapto, hydroxy or alkoxy substituted ester of a mercapto acid substituted organotin mercapto acid diester.
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- 2-Mercaptoaldehyde dimers and 2,5-dihydrothiophenes from 1,3-oxathiolan-5-ones
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Representative 1,3-oxathiolan-5-ones (6), prepared from 2-mercaptoacids, have been reduced to 2-mercaptoaldehydes 1 with diisobutylaluminum hydride.The aldehydes 1, which appear to exist in several dimeric forms, react with vinyltriphenylphosphonium bromide to give 2,5-dihydrothiophenes.
- McIntosh, John M.,Siddiqui, Maqbool A.
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p. 1872 - 1875
(2007/10/02)
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- Azole derivatives
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Azole derivatives of the formula SPC1 Wherein R1 is free or esterified carboxyl or other functionally modified carboxyl group, R2 and R3 each are aryl; A is Cn H2n in which n is an integer from 1 to 10, inclusive; and Z is O or S; and the physiologically acceptable salts thereof, possess, with good compatibility, excellent antiphlogistic activity and, in particular, influence favorably the chronic progressive diseases of the joints, e.g., arthritis. They can be prepared from compounds of the formula SPC2 Wherein X1 is a group convertible into the group --S--A--R1, and R2 and R3 have the values given above.
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