- Scope and limitations of reductive amination catalyzed by half-sandwich iridium complexes under mild reaction conditions
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The conversion of aldehydes and ketones to 1° amines could be promoted by half-sandwich iridium complexes using ammonium formate as both the nitrogen and hydride source. To optimize this method for green chemical synthesis, we tested various carbonyl substrates in common polar solvents at physiological temperature (37 °C) and ambient pressure. We found that in methanol, excellent selectivity for the amine over alcohol/amide products could be achieved for a broad assortment of carbonyl-containing compounds. In aqueous media, selective reduction of carbonyls to 1° amines was achieved in the absence of acids. Unfortunately, at Ir catalyst concentrations of 1 mM in water, reductive amination efficiency dropped significantly, which suggest that this catalytic methodology might be not suitable for aqueous applications where very low catalyst concentration is required (e.g., inside living cells).
- Nguyen, Dat P.,Sladek, Rudolph N.,Do, Loi H.
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supporting information
(2020/07/15)
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- Biocascade Synthesis of L-Tyrosine Derivatives by Coupling a Thermophilic Tyrosine Phenol-Lyase and L-Lactate Oxidase
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A one-pot biocascade of two enzymatic steps catalyzed by an l-lactate oxidase and a tyrosine phenol-lyase has been successfully developed in the present study. The reaction provides an efficient method for the synthesis of l-tyrosine derivatives, which exhibits readily available starting materials and excellent yields. In the first step, an in situ generation of pyruvate from readily available bio-based l-lactate catalyzed by a highly active l-lactate oxidase from Aerococcus viridans (AvLOX) was developed (using oxygen as oxidant and catalase as hydrogen peroxide removing reagent). Pyruvate thus produced underwent C–C coupling with phenol derivatives as acceptor substrate using specially designed thermophilic tyrosine phenol-lyase mutants from Symbiobacterium toebii (TTPL). Overall, this cascade avoids the high cost and easy decomposition of pyruvate and offered an efficient and environmentally friendly procedure for l-tyrosine derivatives synthesis.
- Jiang, Yiqi,Ju, Shuyun,Li, Guosi,Lian, Jiazhang,Lin, Jianping,Wu, Mianbin,Xue, Hailong,Yang, Lirong
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supporting information
(2020/02/25)
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- Levodopa methyl ester hydrochloride synthetic method
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The invention relates to a synthesis method of L-dopa methyl ester hydrochloride, which comprises the following steps: by using veratone as a raw material, carrying out amidation to obtain 2-amino-3-(3,4-dimethoxyphenyl)propanamide, carrying out amide oxidation into carboxy group to obtain 2-amino-3-(3,4-dimethoxyphenyl)propionic acid, removing methoxy group to obtain 2-amino-3-(3,4-dihydroxyphenyl)propionic acid, and finally, carrying out methyl ester conversion and acidification to obtain the target product 2-amino-3-(3,4-dimethoxyphenyl)alanine methyl ester hydrochloric acid. The method has the advantages of accessible reaction raw materials, ingenious technique concept, simple steps and no use of virulent reagents, is simple to operate, conforms to the requirements for green chemical industry, and is suitable for industrial production.
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- A versatile approach to noncoded β-hydroxy-α-amino esters and α-amino acids/esters from morita-baylis-hillman adducts
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A simple and straightforward approach to the diastereoselective synthesis of noncoded β-hydroxy-α-amino esters from Morita-Baylis-Hillman (MBH) adducts is described. The strategy is based on a one-pot sequence involving an oxidative cleavage of the double bond of silylated Morita-Baylis-Hillman adducts, followed by the reaction with hydroxylamine hydrochloride/pyridine to form oximes. The stereoselective reduction of the oximes with the mixture MoCl5·nH2O/NaBH3CN led to the corresponding anti-β-hydroxy-α-amino esters in four steps in good overall yield and with diastereoselectivity higher than 95%. A slight modification of the synthetic approach has allowed for the racemic synthesis of a set of noncoded α-amino esters/acids and DOPA
- Ullah, Hamid,Ferreira, Andr V.,Bendassolli, Jos A.,Rodrigues, Manoel T.,Formiga, Andr Luiz B.,Coelho, Fernando
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p. 113 - 123
(2015/02/02)
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- FUNCTIONALIZED FLUORINE CONTAINING PHTHALOCYANINE MOLECULES
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Functionalized fluorine containing phthalocyanine molecules, methods of making, and methods of use in diagnostic applications and disease treatment are disclosed herein. In some embodiments, the fluorine containing phthalocyanine molecules are functionalized with a reactive functional group or at least one cancer-targeting ligand (CTL). The CTL can facilitate more efficient binding and/or internalization to a cancer cell than to a healthy cell. The CTL can inhibit expression of oncoprotein in some embodiments. The pthalocyanine moiety can be used in diagnostic applications, such as fluorescence labeling of a cancer cell, and/or treatment applications, such as catalyzing formation of a reactive oxygen species (ROS) which can contribute to cell death of a cancer cell.
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- Kinetic characteristics of purified tyrosinase from different species of Dioscorea (YAM) in aqueous and non-aqueous systems
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Yam tubers could serve as a cost-effective source of tyrosinase for various applications. Here a novel but cheap method of purification, and some properties of the enzyme from four species of yam tubers having high tyrosinase activity are described. The native and subunit molecular weights of each of the purified tyrosinase were between 41-58 kDa and 24-27 kDa respectively. Optimum pH and temperature were 6.5 and 50 C respectively. Tyrosinase from tubers of Colocasia esculenta retained more than 50% activity in ethanol (≤&60%). All the purified enzymes were activated in 40% ether by between 120 and 170%, and maintained 100% residual activity at up to 65% ether for 17 h. Both the K;bsubesub & and V;bsubesub & increased in 40% ether, leading to a corresponding increase in k;bsubesubbsubesub &. All the enzymes had both monophenolase and diphenolase activities. β- Mercaptoethanol and to a lesser extent, glutathione were good inhibitors. In aqueous systems, the purified tyrosinase catalyzed formation of coloured products in the presence of some substrates such as catechol, pyruvic acid and ammonia. The catalytic properties of these enzymes especially in organic solvents suggest that they may find uses in some biotechnological applications.
- Ilesanmi, Olutosin Samuel,Ojopagogo, Yetunde Adedolapo,Adewale, Isaac Olusanjo
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p. 111 - 117
(2014/11/08)
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- NOVEL MULTIMERIC MOLECULES, A PROCESS FOR PREPARING THE SAME AND THE USE THEREOF FOR MANUFACTURING MEDICINAL DRUGS
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The invention relates to a compound of the formula (I): in which k and j are independently 0 or 1, Y is a macrocycle in which the cycle includes 9 to 36 carbon atoms and is functionalised by three amino functions and by a chain for attaching the spacer arm Z via an X bond, Rc is a binding pattern with a receptor of the TNF superfamily, X is a chemical function for binding the Y group to the space arm, and Z is a bi-, tri- or tetra-functional spacer arm.
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- NOVEL MULTIMERIC CD40 LIGANDS, METHOD FOR PREPARING SAME AND USE THEREOF FOR PREPARING DRUGS
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The invention concerns a compound of formula (I), wherein Y represents a macrocycle whereof the cycle comprises 9 to 36 atoms, and is functionalized by three amine or COOH functions; Rc represents a group of formula H—Xa—Xb—Xc—Xd—Xe—(Xf)i—, wherein i represents 0 or 1, Xn is in particular selected among lysine, arginine, ornithine residues, Xb is in particular selected among glycine, asparagine, L-proline or D-proline residues, Xc et Xd are in particular selected among tyrosine, phenylalanine or 3-nitrotyrosine residues, Xe et Xf are in particular selected among the following amino acid residues: NH2—(CH2)n—COOH, n ranging from 1 to 10 or NH2—(CH2—CH2—O)m—CH2CH2COOH, m ranging from 3 to 6, provided that one at least of the amino acid residues Xa, Xb, Xc and Xd is different from the corresponding amino acid in the sequence of the natural CD40 143Lys-Gly-Tyr-Tyr146 fragment
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- Stereospecificity of mushroom tyrosinase immobilized on a chiral and a nonchiral support
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Mushroom tyrosinase was immobilized from an extract onto glass beads covered with the cross-linked totally cinnamoylated derivates of D-sorbitol (sorbitol cinnamate) and glycerine (glycerine cinnamate). The enzyme was immobilized onto the support by direct adsorption, and the quantity of immobilized tyrosinase was higher for sorbitol cinnamate, the support with the higher number of esterified hydroxyls per unit of monosacharide, than for glycerine cinnamate. The results obtained from the stereospecificity study of the monophenolase and diphenolase activity of immobilized mushroom tyrosinase are reported. The enantiomers L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-α-methyldopa, DL-α-methyldopa, L-isoprenaline, DL-isoprenaline, L-adrenaline, DL-adrenaline, L-noradrenaline, and D-noradrenaline were assayed with tyrosinase immobilized on a chiral support (sorbitol cinnamate), whereas L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-α-methyldopa, and DL-α-methyldopa were assayed with tyrosinase immobilized on a nonchiral support (glycerine cinnamate). The same Vmaxapp values for each series of enantiomers were obtained. However, the Kmapp values were different, the L isomers showing lower values than the DL isomers, whereas the highest K mapp value was obtained with D isomers. No difference was observed in the stereospecificity of tyrosinase immobilized on a chiral (sorbitol cinnamate) or nonchiral (glycerine cinnamate) support.
- Marin-Zamora, Maria Elisa,Rojas-Melgarejo, Francisco,Garcia-Canovas, Francisco,Garcia-Ruiz, Pedro Antonio
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p. 4569 - 4575
(2008/02/09)
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- Derivatives of L-pimaric acid in the synthesis of chiral organophosphorus ligands from decahydrophenanthrene series
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Starting with maleopimaric and fumaropimaric acids were prepared chiral organophosphorus ligands from decahydrophenanthrene series. Cationic complexes of Rh(I) prepared therefrom were tested for catalysts of asymmetric hydrogenation of unsaturated precursors of N-acethylphenylalanine and its derivatives.
- Tolstikov,Karpyshev,Tolstikova,Khlebnikova,Sal'nikov,Mamatyuk,Gatilov,Bagryanskaya
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p. 1134 - 1148
(2007/10/03)
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- Process for the preparation of enantiomers of alpha-amino acid derivatives by asymmetric hydrogenation
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The inventor relates to a process for the preparation of (S)- and (R)-α-amino acid dervatives by asymmetric hydrogenation starting from a substrate of the formula I in which R1denotes hydrogen or an alkyl group R2denotes a protecting group and R3denotes hydrogen, an alkyl, aryl, aralkyl, alkaryl, heteroalkyl or heteroaryl group, which is hydrogenated in the presence of a rhodium(I)complex catalyst of the formula II, , /Rh(Z)(Lk)/ A II, , in which Rhdenotes rhodium Zdenotes a chiral chelating ligand with two trivalent phosphorous atoms as coordination partners for a bond to rhodium Ldenotes a solvent molecule kdenotes 0, 1, 2, or 3 and A denotes an anion of a weakly coordinating acid, such as BF4 , ClO4 , SO4H , PF6 , R4-COO , or R4SO3 , where R4 denotes a fluorinated alkyl or aryl group into an α-amino acid derivative of the formula III in which R1denotes hydrogen or an alkyl group R2denotes a protecting group and R3denotes hydrogen, an alkyl, aryl, aralkyl, alkaryl, heteroalkyl or heteroaryl group in which process an amphiphilic substance of the formula IV, , A-E IV, , in which Adenotes a nonpolar alkyl chain with 5 to 20 carbon atoms or a glycerol dialkylether group and Edenotes a polar (hydrophilic)group, such as -O-SO3Na, -SO3Na, -O(CH2CH2O)nH or -OP?O2/OCH2CH2N⊕(CH3)3/, where n is a number between 3 and 15. The hydrogenation can be carried out in a polar or nonpolar solvent.
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- 3-methoxy-4-hydroxyphenylglycol fluorescence polarization immunoassay
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The present invention is directed to a fluoroescence polarization immunoassay for determining the 3-methoxy-4-hydroxyphenylglycol content in body fluids, to the various components needed for preparing and carrying out such an assay, and to methods of making these components. Specifically, tracers, immunogens and antibodies are disclosed, as well as methods for preparing them. The assay is conducted by measuring the degree of polarization of plane polarized light that has been passed through a sample containing antiserum and tracer.
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- Process for the synthesis of optically active aminoacids
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New process for the synthesis of optically active aminoacids of formula STR1 by treating compounds of formula STR2 which an optically active alcohol of formula To obtain a pair of diastereoiosmer esters of formula STR3 which is resolved in basic medium into the single diastereoisomer esters of formula STR4 from which the desired optically active aminoacid of formula (I) is obtained by treatment in acid medium.
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- Process for the synthesis of the levodopa
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New process for the synthesis of the levodopa, L-(-)-2-amino-3-(3,4-dihydyphenyl)propionic acid, drug used in the treatment of the Parkinson's disease. The process consists in resolving with d-camphorsulfonic acid, or with a salt thereof, the d,l-2-amino-3-(3,4-dimethoxyphenyl)propionitrile, obtained from the 3,4-dimethoxyphenylacetaldehyde, and in the subsequent hydrolysis and demethylation, by means of concentrated solutions of haloid acids, of the d-2-amino-3-(3,4-dimethoxyphenyl)propionitrile and of salts thereof.
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- Method of making a diastereomeric mixture containing two diastereomeric N-acyl-amino acid esters
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In the process of hydrocarboxylating an α-enamide with CO and an organic hydroxyl compound to produce a N-acyl-α-amino acid ester, the improvement comprising using as the organic hydroxyl compound reactant, an organic hydroxyl compound which has a chiral center that is essentially all L or D, thereby producing a reaction mixture having essentially no enantiomeric pairs and containing diastereomeric N-acyl-α-amino acid esters having two chiral centers.
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- Method of making a diastereomeric mixture containing two diastereomeric N-acyl-amino acid esters
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In the process of hydrocarboxylating an α-enamide with CO and an organic hydroxyl compound to produce a N-acyl-α-amino acid ester, the improvement comprising using as the organic hydroxyl compound reactant, an organic hydroxyl compound which has a chiral center that is essentially all L or D, thereby producing a reaction mixture having essentially no enantiomeric pairs and containing diastereomeric N-acyl-α-amino acid esters having two chiral centers.
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- A Convenient Synthesis of 3,4-Dihydroxyphenylalanine (DOPA)
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A modified method for the synthesis of 3,4-dihydroxyphenylalanine (IV) is described.It involves catalytic (Raney Ni or 10percent Pd-C) hydrogenation of 4-(4'-acetoxy-3'-methoxybenzal)-2-phenyl-5-oxazolone (I) followed by hydrolysis of the reduced product N-Benzoyl-β-(4-hydroxy-3-methoxyphenyl)alaninamide (II) to give N-benzoyl-β-(4-hydroxy-3-methoxyphenyl)alanine (III) or IV in high yields under different conditions.
- Ali, Mohammed,Khan, Naseem H.
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p. 868 - 869
(2007/10/02)
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- CHROMATOGRAPHIC AND SPECTROSCOPIC INVESTIGATION OF THE PRODUCTS OF OXIDATION OF TYROSINE WITH OZONE.
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It has been shown that ozone in low concentrations readily oxidizes aromatic amino acids both in solution and when constituents of proteins resulting in the formation of a whole series of oxidation products. Since the oxidation products are physiologically active it was of interest to study them further. In the present work the main molecular products obtained by oxidation of tyrosine with ozone are established, and possible mechanisms of their formation discussed.
- Ignatenko,Cherenkevich,Komyak
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p. 798 - 802
(2007/10/02)
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- One-Electron Redox Potentials of Phenols. Hydroxy- and Aminophenols and Related Compounds of Biological Interest
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The rate constants for reversible electron transfer between a series of substituted phenolate ions and anilines and various substituted phenoxyl or anilino radicals in aqueous solution were measured by observing the formation or depletion of the radicals involved.Nonequilibrium concentrations of the radicals were produced in the presence of the corresponding phenols or anilines by using the pulse radiolysis technique.The relaxation of the system to equilibrium was monitored by optical detection methods.From the equilibrium constants for one-electron transfer, the one-electron redox potentials (E2) for 38 phenolic or anilino type compounds were determined, many of which are natural products.The redox potentials are strongly influenced by electron-donating or -withdrawing substituents at the aromatic system.
- Steenken, S.,Neta, P.
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p. 3661 - 3667
(2007/10/02)
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- Hydroxylation of Phenylalanine by Aqueous H2O2 in the Presence of an Artificial Water-soluble Iron Porphyrin Complex
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Phenylalanine is hydroxylated by aqueous H2O2 in the presence of a catalytic amount of an artificial water-soluble iron porphyrin complex (1) to give monohydroxylated and dihydroxylated products, i.e., tyrosine and dihydroxyphenylalanine, which are obtained in good yields.
- Shimidzu, Takeo,Iyoda, Tomokazu,Kanda, Naoya
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p. 1206 - 1207
(2007/10/02)
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- Method of preparing aldehydes
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A novel method for preparing substituted actaldehydes comprising subjecting a specific sulfoxide derivative to an acidic hydrolysis.
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