- Active Controlled and Tunable Coacervation Using Side-Chain Functional α-Helical Homopolypeptides
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We report the development of new side-chain amino acid-functionalized α-helical homopolypeptides that reversibly form coacervate phases in aqueous media. The designed multifunctional nature of the side-chains was found to provide a means to actively control coacervation via mild, biomimetic redox chemistry as well as allow response to physiologically relevant environmental changes in pH, temperature, and counterions. These homopolypeptides were found to possess properties that mimic many of those observed in natural coacervate forming intrinsically disordered proteins. Despite ordered α-helical conformations that are thought to disfavor coacervation, molecular dynamics simulations of a polypeptide model revealed a high degree of side-chain conformational disorder and hydration around the ordered backbone, which may explain the ability of these polypeptides to form coacervates. Overall, the modular design, uniform nature, and ordered chain conformations of these polypeptides were found to provide a well-defined platform for deconvolution of molecular elements that influence biopolymer coacervation and tuning of coacervate properties for downstream applications.
- Barun, Ehab,Bell, Alexandra G.,Deming, Timothy J.,Evans, Declan,Gharakhanian, Eric G.,Houk, K. N.,Scott, Wendell A.
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supporting information
p. 18196 - 18203
(2021/11/12)
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- TFA-protected α-amino acid N-hydroxysuccinimide ester: Application for inter- And intramolecular acylation
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The utilization of N-trifluoroacetyl (TFA)-α-amino acid N-hydroxysuccinimide ester (OSu) derivatives, a promising acylating agent with high storage stability, is reported for Friedel-Crafts acylation into arenes and N-heterocycles. The reaction between TF
- Tachrim, Zetryana Puteri,Oida, Kazuhiro,Ohashi, Fumina,Wakasa, Haruna,Ikemoto, Haruka,Kurokawa, Natsumi,Sakihama, Yasuko,Hashidoko, Yasuyuki,Suzuki, Takeyuki,Hashimoto, Makoto
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p. 877 - 893
(2019/04/26)
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- The: Ortho -substituent on 2,4-bis(trifluoromethyl)phenylboronic acid catalyzed dehydrative condensation between carboxylic acids and amines
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2,4-Bis(trifluoromethyl)phenylboronic acid is a highly effective catalyst for dehydrative amidation between carboxylic acids and amines. Mechanistic studies suggest that a 2:2 mixed anhydride is expected to be the only active species, and the ortho-substituent of boronic acid plays a key role in preventing the coordination of amines to the boron atom of the active species, thus accelerating the amidation. This catalyst works for α-dipeptide synthesis.
- Wang, Ke,Lu, Yanhui,Ishihara, Kazuaki
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supporting information
p. 5410 - 5413
(2018/05/30)
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- PRODUCTION OF N-ACYL COMPOUNDS
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The invention relates to the production of compounds containing an acylated nitrogen atom. According to said method, the N-protonated adduct of the compounds is reacted with a chloride, bromide or iodide anion, or the free nitrogen base is reacted with acyl halogenide, preferably acyl chloride, in the presence of an acid that expulses the released HCl or Hl.
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Page/Page column 4; 5
(2008/06/13)
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- Use of N-trifluoroacetyl-protected amino acid chlorides in peptide coupling reactions with virtually complete preservation of stereochemistry
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The use of protected amino acid chlorides for peptide coupling reactions has long been avoided due to the extensive racemization that commonly occurs during either the acid chloride formation or the coupling reaction itself. Conditions are described which
- Jass, Paul A.,Rosso, Victor W.,Racha, Saibaba,Soundararajan, Nachimuthu,Venit, John J.,Rusowicz, Andrew,Swaminathan, Shankar,Livshitz, Julia,Delaney, Edward J.
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p. 9019 - 9029
(2007/10/03)
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- Chemoselective N-deprotection of tert-butyl 2-(trifluoroacetylamino) esters under PTC conditions: Synthesis of tert-butyl 2-aminocarboxylates
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Trifluoroacetamide 1 is alkylated in good yields (77-83%) by tert-butyl 2-bromocarboxylates 3 under solid-liquid phase transfer catalysis (PTC) conditions [anhydrous K2CO3, triethyl(benzyl)ammonium chloride (TEBA; 10%), MeCN, 80°C]. The resulting tert-butyl 2-(trifluoroacetylamino) carboxylates 5 are chemoselectively hydrolysed in 75-95% yields to the corresponding tert-butyl 2-amino carboxylates, isolated as hydrochlorides 8, under liquid-liquid PTC conditions [CH2Cl2 or Et2O, aqueous 20% KOH, TEBA (10%), 25-40°C].
- Albanese, Domenico,Corcella, Francesco,Landini, Dario,Maia, Angelamaria,Penso, Michele
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p. 247 - 249
(2007/10/03)
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- Affinity Modification of Amino Acid Derivatives of Oligonucleotides in Complementary Complex
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Intracomplex photochemical interaction of photoactive derivatives R-CONH(CH2)3NH-pGATACCAA, where R = p-azidotetrafluorophenyl (I) or 2-nitro-5-azidophenyl (II), and 5'-phospho-p-azidoanilide pGATACCAA (III) with a target - oligonucleotide *pGG
- Godovikova, T. S.,Berezovskii, M. V.,Knorre, D. G.
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p. 742 - 750
(2007/10/03)
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- THE INCLUSION OF THE ENANTIOMERS OF N-TRIFLUOROACETYL-4-FLUOROPHENYLALANINE AND N-TRIFLUOROACETYLPHENYLALANINE BY CYCLOMALTOHEXAOSE: A 2H- AND 19F-N.M.R. STUDY
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19F-N.m.r. studies show that N-trifluoroacetyl-D- and -L-4-fluorophenylalanine and N-trifluoroacetyl-D- and -L-phenylalanine form 1:1 inclusion complexes with cyclomaltohexaose (α-cyclodextrin) characterised by stability constants of 11.44 +/- 1.13, 11.40 +/- 1.09, 6.15 +/- 0.59, and 6.37 +/- 0.81 M-1, respectively, in aqueous 0.1M NaCl at pH 6.5 and 25 deg C.Under similar conditions, the correlation time of N-trifluoroacetyl-phenylalanine changed from 65 +/- 4 ps in the free state to 320 +/- 40 ps in the complex, consistent with there being little freedom of movement of the guest in the inclusion complex.
- Smith, Nicholas J.,Spotswood, Thomas M.,Lincoln, Stephen F.
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- Effect of N-trifluoroacetyl derivatives of amino acids and amino acid analogs on microbial antitumor screen
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Eighteen trifluoroacetyl derivatives of amino acids and of amino acid analogs were prepared and tested for growth-inhibitory activity. Of the compounds tested, the trifluoroacetyl derivatives of o-, m-, and p-fluorophenylalanine and β-3-thienylalanine showed modest activity; trifluoroacetyl derivatives of phenylalanine and of β-2-thienylalanine showed marginal activity. The activity exhibited by the active trifluoroacetyl compounds was equal to that noted for most active chloroacetyl derivatives reported previously, as judged by comparison of their activity with that of chloroacetyl-m-fluorophenylalanine. No reversal of inhibition was noted when a representative of these inhibitors was challenged with a corresponding natural metabolite, both as free amino acid and as a noninhibitory acylated compound.
- Otani,Briley
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p. 496 - 499
(2007/10/05)
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