- Maleimide conjugates of saxitoxin as covalent inhibitors of voltage-gated sodium channels
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(+)-Saxitoxin, a naturally occurring guanidinium poison, functions as a potent, selective, and reversible inhibitor of voltage-gated sodium ion channels (NaVs). Modified forms of this toxin bearing cysteine-reactive maleimide groups are available through total synthesis and are found to irreversibly inhibit sodium ion conductance in recombinantly expressed wild-type sodium channels and in hippocampal nerve cells. Our findings support a mechanism for covalent protein modification in which toxin binding to the channel pore precedes maleimide alkylation of a nucleophilic amino acid. Second-generation maleimide-toxin conjugates, which include bioorthogonal reactive groups, are also found to block channel function irreversibly; such compounds have potential as reagents for selective labeling of NaVs for live cell imaging and/or proteomics experiments.
- Parsons, William H.,Du Bois
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- Maleimide-functionalised platinum(IV) complexes as a synthetic platform for targeted drug delivery
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Maleimide-functionalised Pt(iv) complexes with highly selective binding properties to thiol groups were synthesised as precursors for binding of thiol-containing tumour-targeting molecules like human serum albumin.
- Pichler, Verena,Mayr, Josef,Heffeter, Petra,D?m?t?r, Orsolya,Enyedy, éva A.,Hermann, Gerrit,Groza, Diana,K?llensperger, Gunda,Galanksi, Markus,Berger, Walter,Keppler, Bernhard K.,Kowol, Christian R.
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- Regioselective β-Csp3-Arylation of β-Alanine: An Approach for the Exclusive Synthesis of Diverse β-Aryl-β-amino Acids
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An approach for the synthesis of a variety of new β-aryl-β-amino acids has been developed via a palladium-catalyzed auxiliary-directed regioselective Csp3-H arylation of the unactivated β-methylene bond of β-alanine. The use of 8-aminoquinoline amide as an auxiliary efficiently directs the desired regioselective β-Csp3-H functionalization. The developed protocol enables the easy and straightforward access to several high-value β-aryl-β-amino acids useful for peptide engineering, starting from inexpensive and readily available β-alanine precursors in moderate to excellent yields.
- Chowdhury, Sushobhan,Vaishnav, Roopal,Panwar, Namita,Haq, Wahajul
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p. 2512 - 2522
(2019/03/07)
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- Tri-n-butyl(N-maleoyl-β-alaninato)tin
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The Sn atom in [Sn(C4H9)3(C7H6NO 4)]n adopts a distorted trigonal-bipyramidal geometry, with three n-butyl groups defining the trigonal plane [mean Sn-C distance 2.145 (1) A] and the axial positions occupied by the O atoms of different carboxylate groups having significantly different Sn-O bond lengths [2.215 (5) and 2.424 (5) A]. The structure forms a polymeric chain of complex molecules linked via carboxylate moieties. ? Alternative name: catena-poly[[trimethyltin(IV)]-μ-[3-(2,5-dioxo-3-pyrazolin-1-yl)propionoato- O:O′]].
- Parvez, Masood,Ali, Saqib,Bhatti, Moazzam Hussain,Khokhar, Muhammad Nawaz,Mazhar, Muhammad,Qureshi, Sajid Iqbal
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p. 1427 - 1429
(2007/10/03)
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- Sulfonium ylides 7. Influence of substituents in the imide fragment on the regioselectivity of intramolecular cyclization of phthalimido-containing keto-stabilized sulfonium ylides
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The intramolecular cyclization of keto-stabilized sulfonium ylides obtained from β-alanine and containing various imide fragments was studied. On heating in toluene in the presence of PhCO2H, ylides containing a phthalimide moiety are converted into indolizidine-2,6-dione derivatives, whereas those incorporating a 4-methyl-1,2,3,6-tetrahydrophthalimide or pyrrolidine-2,5-dione moieties do not undergo cyclization.
- Galin,Lakeev,Tolstikov
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p. 1904 - 1908
(2007/10/03)
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- Synthesis and hypotensive activity of some succinimide derivatives
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A series of 1--2,5-pyrrolidinedione (3) has been prepared and tested for hypotensive activity on cats and dogs.The compound 3b showed better hypotensive activity. 1--2,5-pyrrolidinediones (6) and 1--2,5-pyrrolidinediones (9) have also been synthesised and tested for their hypotensive activity.Compounds 6b, 6e, 9b and 9e showed very mild hypotensive activity.While attempting the synthesis of 12 the unexpected 11 is obtained.
- Khadilkar, B M,Bhayade, S R
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p. 338 - 342
(2007/10/02)
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- Comparison of the hypolipidemic activity of cyclic vs. acyclic imides
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Two series of nitrogen-substituted cyclic and acyclic imides were examined for hypolipidemic activity in mice after dosing for 16 days at a dose of 20 mg/kg per day. The hypolipidemic activity of the unsubstituted, N-butyl, N-3-oxobutyl, and N-2-carboxyethyl derivatives of diacetimide and succinimide were compared as well as the unsubstituted and N-substituted dibenzimide and diphenimide. It was shown that an imide functionally incorporated into a ring was not necessary for hypocholesterolemic activity. Good hypocholesterolemic activity was observed in both series of acyclic and cyclic imides. However, a cyclic imido structure was a necessary requirement for good hypotriglyceridemic activity. A decrease in hypotriglyceridemic activity was noted when comparing the cyclic imides to their respective acyclic congeners.
- Voorstad,Chapman,Cocolas,Wyrick,Hall
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- Asymmetric Hydroformylation and Hydrocarboxylation of Enamides. Synthesis of Alanine and Proline
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Carbonyltris(triphenylphosphine)hydridorhodium (1) catalyzed the hydroformylation of N-vinylimides in the presence of optically active 2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane (DIOP) or 2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(5H-dibenzophospholyl)butane (DIPHOL) to afford optically active α-amido aldehydes.Linear disubstituted N-vinylimides or -amides reacted very sluggishly, while the cyclic N-acyl-2-pyrroline (19) was very reactive.In the unsubstituted N-vinylimides moderate (20-40percent ee) asymmetric induction was observed.The optically active α-amido aldehydes were readily converted to the corresponding α-amino acids.Asymmetric hydrocarboxylation of the same substrates in the presence of bis(triphenylphosphine)palladium chloride (2) produced α-amido esters in low optical purity.
- Becker, Y.,Eisenstadt, A.,Stille, J. K.
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p. 2145 - 2151
(2007/10/02)
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