- Cationic–anionic palladium complexes: effect of hydrogen bond character on their stability and biological activity
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The solution state of palladium cationic–anionic complexes (AmHn)k[PdCl4] prepared for the first time, where Am is morpholine, methylmorpholine, aminoethylmorpholine, 5-aminovaleric acid, L-1-phenyl-2-methylaminopropanol, and m-xylilenediamine, has been studied by electronic absorption spectroscopy, NMR, and pH measurements. The agreement of obtained results for the state of the complexes in water and NaCl solutions with IR and X-ray diffraction data for these complexes has allowed us to substantiate the principle for designing patent formulation (C5H12NO)2[PdCl4], a new type of palladium complexes, palladium(II) cationic–anionic complexes showing high antitumor and antimetastatic activity. Crystallographic data for six obtained complexes have been presented.
- Efimenko,Churakov,Ivanova,Erofeeva,Demina
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- An efficient enzymatic synthesis of 5-aminovaleric acid
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The title compound was prepared enzymatically from l-lysine in an excellent yield and under buffer-free conditions. l-Lysine was oxidized by the action of l-lysine α-oxidase from Trichoderma viride followed by spontaneous oxidative decarboxylation of the intermediate 6-amino-2-oxocaproic acid in the reaction medium. l-Lysine α-oxidase was immobilized on an epoxy-activated solid support (Sepabeads EC-EP) and the activity of both solution-based and immobilized enzyme in this reaction was determined.
- Pukin, Aliaksei V.,Boeriu, Carmen G.,Scott, Elinor L.,Sanders, Johan P.M.,Franssen, Maurice C.R.
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Read Online
- An Integrated Cofactor/Co-Product Recycling Cascade for the Biosynthesis of Nylon Monomers from Cycloalkylamines
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We report a highly atom-efficient integrated cofactor/co-product recycling cascade employing cycloalkylamines as multifaceted starting materials for the synthesis of nylon building blocks. Reactions using E. coli whole cells as well as purified enzymes produced excellent conversions ranging from >80 and 95 % into desired ω-amino acids, respectively with varying substrate concentrations. The applicability of this tandem biocatalytic cascade was demonstrated to produce the corresponding lactams by employing engineered biocatalysts. For instance, ?-caprolactam, a valuable polymer building block was synthesized with 75 % conversion from 10 mM cyclohexylamine by employing whole-cell biocatalysts. This cascade could be an alternative for bio-based production of ω-amino acids and corresponding lactam compounds.
- Sarak, Sharad,Sung, Sihyong,Jeon, Hyunwoo,Patil, Mahesh D.,Khobragade, Taresh P.,Pagar, Amol D.,Dawson, Philip E.,Yun, Hyungdon
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p. 3481 - 3486
(2020/12/17)
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- Synthetic studies towards N-substituted 3-vinyl-4-piperidineacetic acid derivatives
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The synthesis and full characterization of two new (E)-2-butenyl)-5-amino-2-pentenoates, (Z)-4-[N-(3-buten-1-yl)benzamido]-2-buten-1-ol, and (Z)-1-chloro-4-[N-(3-buten-l-yl)benzamido]-2-butene are reported. These were designed as substrates for a projected thermal ene cyclization leading to the N-substituted 3-vinyl-4-piperidineacetic acid scaffold. Although conditions for this ene-cyclization have not yet been uncovered, the ease of preparation of these ene-cyclization substrates gives promise for their future use.
- Johnson, David A.,Gribble, Gordon W.
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p. 178 - 195
(2019/05/15)
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- General Synthesis of Amino Acid Salts from Amino Alcohols and Basic Water Liberating H2
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An atom-economical and environmentally friendly method to transform amino alcohols to amino acid salts using just basic water, without the need of pre-protection or added oxidant, catalyzed by a ruthenium pincer complex, is developed. Water is the solvent, the source of the oxygen atom of the carboxylic acid group, and the actual oxidant, with liberation of dihydrogen. Many important and useful natural and unnatural amino acid salts can be produced in excellent yields by applying this new method.
- Hu, Peng,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 6143 - 6146
(2016/06/09)
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- Immunomodulatory peptides
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The invention relates to peptides derivatized with a hydrophilic polymer which, in some embodiments, bind to human FcRn and inhibit binding of the Fc portion of an IgG to an FcRn, thereby modulating serum IgG levels. The disclosed compositions and methods may be used in some embodiments, for example, in treating autoimmune diseases and inflammatory disorders. The invention also relates, in further embodiments, to methods of using and methods of making the peptides of the invention.
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- The chemistry of escapin: Identification and quantification of the components in the complex mixture generated by an L-amino acid oxidase in the defensive secretion of the sea snail Aplysia Californica
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Escapin is an L-amino acid oxidase in the ink of a marine snail, the sea hare Aplysia californica, which oxidizes L-lysine (1) to produce a mixture of chemicals which is antipredatory and antimicrobial. The goal of our study was to determine the identity
- Kamio, Michiya,Ko, Ko-Chun,Zheng, Shilong,Wang, Binghe,Collins, Stacy L.,Gadda, Giovanni,Tai, Phang C.,Derby, Charles D.
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experimental part
p. 1597 - 1603
(2009/11/30)
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- Design and synthesis of novel sulfonamide-containing bradykinin hB 2 receptor antagonists. 2. Synthesis and structure-activity relationships of α,α-cycloalkylglycine sulfonamides
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Recently we reported on the design and synthesis of a novel class of selective nonpeptide bradykinin (BK) B2 receptor antagonists (J. Med. Chem. 2006, 3602-3613). This work led to the discovery of MEN 15442, an antagonist with subnanomolar affinity for the human B2 receptor (hB2R), which also displayed significant and prolonged activity in vivo (for up to 210 min) against BK-induced bronchoconstriction in the guinea-pig at a dose of 300 nmol/kg (it), while demonstrating only a slight effect on BK-induced hypotension. Here we describe the further optimization of this series of compounds aimed at maximizing the effect on bronchoconstriction and minimizing the effect on hypotension, with a view to developing topically delivered drugs for airway diseases. The work led to the discovery of MEN 16132, a compound which, after intratracheal or aerosol administration, inhibited, in a dose-dependent manner, BK-induced bronchoconstricton in the airways, while showing minimal systemic activity. This compound was selected as a preclinical candidate for the topical treatment of airway diseases involving kinin B2 receptor stimulation.
- Fattori, Daniela,Rossi, Cristina,Fincham, Christopher I.,Caciagli, Valerio,Catrambone, Fernando,D'Andrea, Piero,Felicetti, Patrizia,Gensini, Martina,Marastoni, Elena,Nannicini, Rossano,Paris, Marielle,Terracciano, Rosa,Bressan, Alessandro,Giuliani, Sandro,Maggi, Carlo A.,Meini, Stefania,Valenti, Claudio,Quartara, Laura
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p. 550 - 565
(2007/10/03)
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- [2+2] Photocycloadditions with chiral uracil derivatives: Access to all four stereoisomers of 2-aminocyclobutanecarboxylic acid
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Starting from a single, chiral, bicyclic derivative of uracil, all four stereoisomers of 2-aminocyclobutanecarboxylic acid have been prepared in enantiomerically pure form, using a synthetic sequence which begins with a key photochemical [2+2] cycloaddition reaction and includes a practical cis to trans β-amino acid isomerisation procedure. Georg Thieme Verlag Stuttgart.
- Fernandes, Carlos,Gauzy, Christine,Yang, Yi,Roy, Olivier,Pereira, Elisabeth,Faure, Sophie,Aitken, David J.
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p. 2222 - 2232
(2008/03/28)
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- 15N/14N position-specific isotopic analyses of polynitrogenous amino acids
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15N/14N isotope ratios are widely used to study processes and systems involving amino acids. Nitrogen isotope fractionation in biological processes occurs primarily at sites of bond-breaking and formation; the finest discrimination for "isotopic fingerprinting" and studies of isotopic fluxes is thus obtained at the position-specific level. While there are numerous reports of natural intramolecular carbon isotope variability, there are no literature reports of 15N/14N position-specific isotopic analysis (N-PSIA) of biologically relevant molecules. We report a methodology for high-precision N-PSIA of four polynitrogenous α-amino acids (asparagine, glutamine, lysine, histidine) and the first survey of natural intramolecular 15N/14N in these biomolecules. Selective liberation of N-atoms from multiple commercial standards of each parent amino acid was achieved by an appropriate enzymatic reaction or by acid hydrolysis. 15N/14N measurements were performed on N-ethoxycarbonyl ethyl ester derivatives of the parent amino acids and their analogues by gas chromatography combustion isotope ratio mass spectrometry, and the average precision for replicate injections was found to be SD(δ15N) = 0.3‰. Position-specific δ15N values of the parent amino acid were directly observed or indirectly calculated using mass balance. The average precision obtained for directly measured positions was SD(δ15N) = 0.2-0.4‰. The average precision for indirectly obtained positions was SD(δ15N) = 0.6-1.3‰ as a result of propagation of errors. Enrichment in the side chain-N with respect to the peptide-N was observed in nearly all of the amino acid sources, most notably in asparagine (average Δδside-peptide = +11‰), which may be indicative of its method of production. In some cases, it was possible to distinguish commercial sources by N-PSIA that could not be distinguished at the compound-specific level.
- Sacks, Gavin L.,Brenna, J. Thomas
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p. 1013 - 1019
(2007/10/03)
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- Studies on the stability of the cyclobutane β-aminoacid skeleton: A cautionary tale
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The 2-amino-1-cyclobutanecarboxylic acid skeleton undergoes facile retro-Mannich type ring opening in solution, which may lead to unexpected by-products during its synthesis or manipulation.
- Aitken, David J.,Gauzy, Christine,Pereira, Elisabeth
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p. 2359 - 2361
(2007/10/03)
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- Lactams in sulfuric acid. The mechanism of amide hydrolysis in weak to moderately strong aqueous mineral acid media
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Reaction rate constants obtained in moderately concentrated sulfuric acid for the hydrolysis of simple lactams of ring sizes five, six, seven, and eight as a function of acidity and temperature have been analyzed using the excess acidity kinetic method. The basicity constants for these substrates have been recalculated; the 13C NMR spectra used to obtain these values are very sensitive to medium effects. It was found that the basicities of the lactams at 0.003-0.1 M lactam concentration were over half a pK unit more basic than they were at 0.5 M lactam, presumably because of the medium effect. Apart from this, the rate constant results obtained at different times by different groups using different techniques for monitoring the kinetics are in adequate agreement. The excess acidity analysis showed that the kinetics could be fitted according to the 'three-water-molecule followed by one-water-molecule' mechanistic scenario previously found, or could just as well be fitted by a 'one-water-molecule followed by unknown mechanism' scenario, with the mechanistic change taking place at 50 wt.% sulfuric acid for all the substrates. Other evidence makes the latter seem the more likely possibility of the two, and activation parameters based upon the 'one-water- molecule' process were determined. Sufficient data points to enable the unknown mechanism to be established were not present; possible mechanisms applicable in media more concentrated than 50 wt.% sulfuric acid are discussed. Previously obtained values of the parameter r, the number of water molecules involved with the substrate in A2 processes, are now questionable.
- Cox, Robin A.
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p. 649 - 656
(2007/10/03)
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- BIOSYNTHESIS OF PIPERLONGUMINE
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The incorporation of L-lysine and L-phenylalanine into piperlongumine has been demonstrated in Piper longum.The subsequent stepwise degradation to methyl-(3,4,5-trimethoxyphenyl)-propanoate and δ-aminovaleric acid revealed that the C6-C3 moiety of the alkamide arises from phenylalanine; the heterocyclic ring is biosynthesized from lysine.It has also been shown that DL-tyrosine and sodium acetate are poor precursors for piperlongumine. Key Word Index - Piper longum; Piperaceae; alkamides; piperlongumine; biosynthesis.
- Prabhu, Bharathi R.,Mulchandani, Newand B.
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p. 2589 - 2592
(2007/10/02)
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- FLAME-INDUCED CARBOXYLATION OF UNSATURATED AMINES IN AN AQUEOUS FORMIC ACID SOLUTION
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When a hydrogen-oxygen flame was kept in contact with an aqueous formic acid solution of unsaturated amines, carboxylation onto a double bond took place.This reaction revealed to be initiated by addition of a hydrogen atom to the double bond followed by coupling of the resulted substrate radical with a carboxyl radical.
- Nomoto, Shinya,Harada, Kaoru
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p. 145 - 148
(2007/10/02)
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- The kinetics and mechanism of acid catalysed hydrolysis of lactams
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The acid-catalysed hydrolysis of lactams of ring size 4-7, and of N-ethylacetamide, has been studied at various temperatures in 0-70percent aqueous sulfuric acids.The kinetics have been analysed by means of the r-hydration parameter treatment and the transition-state activity coefficient (TSAC) approach.Except for the β-lactam, all substrates show a strong positive rate dependence on water activity, indicating a tetrahedral intermediate type of mechanism (A0T2), similar to that found for simple (acyclic) amide hydrolyses; only the β-lactam shows a negative rate - water activity dependence, which is interpreted in terms of a unimolecular (AND1) mechanism, involving rate-determining acylium ion formation.Similarly, all substrates except the β-lactam show a pronounced destabilization of the transition-state as acidity is increased, typical of oxonium ion species.The behaviour of the β-lactam resembles that of methyl mesitoate hydrolysis.Basicity constants for lactams of ring size 4-9 show a definite dependence on ring size, with the δ-lactam being unusually basic.Both rate and pK dependence on ring size are discussed in terms of ring strain and steric effects.The activation parameters, particularly ΔS, are fully consistent with the conclusions drawn concerning transition-state hydration.
- Wan, Peter,Modro, Tomasz A.,Yates, Keith
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p. 2423 - 2432
(2007/10/02)
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