Synthesis of phosphonylmethyl analogues of diribonucleoside monophosphates containing modified internucleotide bond

1987 ◽  
Vol 52 (10) ◽  
pp. 2572-2588 ◽  
Author(s):  
Ivan Rosenberg ◽  
Antonín Holý
Keyword(s):  
Methyl Esters ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Oligonucleotide Synthesis ◽  
Amino Groups ◽  
Methyl Group ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Methylene Group ◽  
Phosphotriester Method

Two types of (2'-5')- and (3'-5')-isomers of analogues of diribonucleoside monophosphates derived from O-phosphonylmethyl derivatives of ribonucleosides, differing in the position of the methylene group in the internucleotide bond (type A, B, C, and D) have been synthesized. The compounds were prepared from methyl esters of O-phosphonylmethylribonucleosides I and XVII by a procedure analogous to the phosphotriester method of oligonucleotide synthesis. The phosphonate moiety was protected with the methyl group. After protection of the hydroxyl or amino groups, the compounds I or XVII were condensed with protected ribonucleosides VIII, XI, XIV, XXIII to afford the neutral diesters IX, XII, XV, XXIV, XXVI, and XXVIII which were isolated by short column chromatography on silica gel. Deprotection, ion-exchange chromatography, and semipreparative HPLC gave (2'-5')- and (3'-5')-isomers of both types of O-phosphonylmethyl analogues of diribonucleoside monophosphates (X, XIII and XXV, XXVII). All these compounds are resistant towards cleavage with ribonucleases A and T2 and with snake venom exonuclease. Under conditions of alkaline hydrolysis of RNA, the analogues of the type A and B are completely stable whereas compounds of the type C and D are degraded to form 2'- or 3'-O-phosphonylmethylribonucleosides and 3'-terminal ribonucleosides.

scholarly journals Novel Amino Acid Derivatives of Quinolines as Potential Antibacterial and Fluorophore Agents

2020 ◽  
Vol 88 (4) ◽  
pp. 57
Author(s):  
Oussama Moussaoui ◽  
Rajendra Bhadane ◽  
Riham Sghyar ◽  
El Mestafa El Hadrami ◽  
Soukaina El Amrani ◽  
...  
Keyword(s):  
Amino Acid ◽  
Methyl Esters ◽  
Amino Acid Derivatives ◽  
Bacterial Strains ◽  
Fluorescent Properties ◽  
Topoisomerase Iv ◽  
Microdilution Method ◽  
Hydrolysis Of ◽  
Derivatives Of

A new series of amino acid derivatives of quinolines was synthesized through the hydrolysis of amino acid methyl esters of quinoline carboxamides with alkali hydroxide. The compounds were purified on silica gel by column chromatography and further characterized by TLC, NMR and ESI-TOF mass spectrometry. All compounds were screened for in vitro antimicrobial activity against different bacterial strains using the microdilution method. Most of the synthesized amino acid-quinolines show more potent or equipotent inhibitory action against the tested bacteria than their correspond esters. In addition, many of them exhibit fluorescent properties and could possibly be utilized as fluorophores. Molecular docking and simulation studies of the compounds at putative bacterial target enzymes suggest that the antimicrobial potency of these synthesized analogues could be due to enzyme inhibition via their favorable binding at the fluoroquinolone binding site at the GyrA subunit of DNA gyrase and/or the ParC subunit of topoisomerase-IV.

scholarly journals Isolation, purification and structure of exochelin MS, the extracellular siderophore from Mycobacterium smegmatis

1995 ◽  
Vol 305 (1) ◽  
pp. 187-196 ◽  
Author(s):  
G J Sharman ◽  
D H Williams ◽  
D F Ewing ◽  
C Ratledge
Keyword(s):  
Amino Acids ◽  
Mycobacterium Smegmatis ◽  
Methyl Esters ◽  
Three Dimensional ◽  
Iron Chelation ◽  
Peptide Bond ◽  
Exchange Chromatography ◽  
Peptide Bonds ◽  
Hydrolysis Of ◽  
Gallium Complex

The extracellular siderophore from Mycobacterium smegmatis, exochelin MS, was isolated from iron-deficiently grown cultures and purified to > 98% by a combination of ion-exchange chromatography and h.p.l.c. The material is unextractable into organic solvents, is basic (pI = 9.3-9.5), has a lambda max at 420 nm and a probable Ks for Fe3+ of between 10(25) and 10(30). Its structure has been determined by examination of desferri- and ferri-exochelin and its gallium complex. The methods used were electrospray-m.s. and one- and two-dimensional (NOESY, DQF-COSY and TOCSY) 1H n.m.r. The constituent amino acids were examined by chiral g.l.c analysis of N-trifluoroacetyl isopropyl and N-pentafluoropropionyl methyl esters after hydrolysis, and reductive HI hydrolysis, of the siderophore. The exochelin is a formylated pentapeptide: N-(delta-N-formyl,delta N-hydroxy-R-ornithyl) -beta-alaninyl-delta N-hydroxy-R-ornithinyl-R-allo-threoninyl-delta N-hydroxy-S-ornithine. The linkages involving the three ornithine residues are via their delta N(OH) and alpha-CO groups leaving three free alpha-NH2 groups. Although there are two peptide bonds, these involve the three R (D)-amino acids. Thus the molecule has no conventional peptide bond, and this suggests that it will be resistant to peptidase hydrolysis. The co-ordination centre with Fe3+ is hexadenate in an octahedral structure involving the three hydroxamic acid groups. Molecular modelling shows it to have similar features to other ferric trihydroxamate siderophores whose three-dimensional structures have been established. The molecule is shown to have little flexibility around the iron chelation centre, although the terminal (Orn-3) residue, which is not involved in iron binding except at its delta N atom, has more motional freedom.

scholarly journals Unusual Regularity in GC Retention of Simple Amino Acid Derivatives

2019 ◽  
Vol 6 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Igor G. Zenkevich ◽  
Nino G. Todua ◽  
Anzor I. Mikaia
Keyword(s):  
Gas Chromatography ◽  
Retention Index ◽  
Methyl Esters ◽  
Elution Order ◽  
Alkyl Esters ◽  
Methyl Group ◽  
The Difference ◽  
Direct Use ◽  
Derivatives Of

Background: Application of simple regularities and general principles along with direct use of reference gas chromatography retention index data for reliable structure determination of compounds can be enhanced by determination of new regularities that are specific to certain structural elements. Objective: Revelation and interpretation of an anomaly in the elution order of alkyl esters of alkoxycarbonyl derivatives of glycine and alanine on standard and semi-standard non-polar phases. Method: Preliminary derivatization of amino acids to alkyl esters of N-alkoxycarbonyl analogs and interpretation of their gas chromatographic characteristics. Results: Alkyl esters of N-alkoxycarbonyl derivatives of alanine (Alkyl = C2H5, n- and iso-C3H7) elute prior to the same derivatives of glycine, despite the presence of an additional methyl group at C(2) in the molecule. Elution order is reversed for methyl esters of N-methoxycarbonyl derivatives. Conclusion: It is established that the peculiar behavior of alkyl esters of N-alkoxycarbonyl derivatives of glycine and alanine agrees with the concepts of gas chromatography and the known retention index regularities of organic compounds. A decrease of retention index values is a result of an introduction of an additional methyl group to a carbon atom connected to two polar fragments in a molecule like CH2XY. The dependence of the difference of retention index values for homologs of the types of CH3-CHXY and CH2XY vs. the total mass of fragments (X + Y) is similar to those for other sub-groups of analytes.

scholarly journals Persistence of methylated bases in ribonucleic acid of syrian golden hamster liver after administration of dimethylnitrosamine

1979 ◽  
Vol 177 (3) ◽  
pp. 967-973 ◽  
Author(s):  
G P Margison ◽  
J M Margison ◽  
R Montesano
Keyword(s):  
Ribosomal Rna ◽  
Golden Hamster ◽  
Excision Repair ◽  
Experimental System ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Syrian Golden Hamster ◽  
Low Doses ◽  
Enzymic Hydrolysis ◽  
Hydrolysis Of

1. Syrian golden hamster liver ribosomal RNA was isolated up to 96 h after administration of [14C]dimethylnitrosamine at 25 mg/kg or 2.5 mg/kg body weight. 2. The chemical alkyation products, 7-methylguanine, 3-methylcytosine, O6-methylguanosine and 1-methyladenosine, were measured after acidic or enzymic hydrolysis of the RNA to bases or mononucleosides followed by ion-exchange chromatography. 3. Between 7 and 96 h, the relative amounts of alkylation products did not change with time even though the absolute amounts fell by approx. 80% and 51% after the high and low doses respectively. 4. The results suggest that base specific excision repair does not exist for RNA alkylation products in this experimental system.

Darstellung, 11B-, 13C-NMR- und Schwingungsspektren von Cs2[B6H5(p-C6H4(NO2))] und Cs2[B6H5(C6H3-l-(CH3)-5-(NO2))] sowie Kristallstruktur von (CH2Py2)[B6Cl5(p-C6H4(NO2))]·CH3CN / Preparation, 11B , 13C-NMR and Vibrational Spectra of Cs2[B6H5(p-C6H4(NO2))], Cs2[B6H5 (C6H3-1 -(CH3 )-5-(NO2))] and Crystal Structure of (CH2Py2)[B6Cl5(p-C6H4(NO2))]·CH3CN

2000 ◽  
Vol 55 (11) ◽  
pp. 1031-1036
Author(s):  
S. Zander ◽  
W. Preetz
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Deae Cellulose ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Derivatives Of ◽  
Ir And Raman

The first aryl derivatives of c/oso-hexahydrohexaborate are formed by reaction of [B6H6]2- with 1-bromo-4-nitrobenzene and 2-bromo-5-nitrotoluene in acetonitrile at 80 °C. Cs2[B6H5- (1,4-C6H4(NO2))] and Cs2[B6H5(C6H3-1-(CH3)-5-(NO2))] can be isolated by ion exchange chromatography on diethylaminoethyl (DEAE) cellulose. Further treatment with /V-chlorosuccinimide yields the perhalogenated derivative (CH2Py2)[B6Cl5(1,4-Ph(NO2))]CH3CN which has been characterized by X-ray diffraction analysis (orthorhombic, space group P2( 2,2t, a = 9.810(4), b - 14.412(3), c - 18.586(9) A, Z = 4). The 11B NMR spectra of all compounds are consistent with a monosubstituted B6-cluster. The IR and Raman spectra exhibit characteristic BB, BH, CH, CC and NO vibrations, respectively.

Intestinal Absorption of Dipeptides Containing Glycine, Phenylalanine, Proline, β-Alanine or Histidine in the Rat

1973 ◽  
Vol 45 (6) ◽  
pp. 849-858 ◽  
Author(s):  
D. J. Boullin ◽  
R. F. Crampton ◽  
Christine E. Heading ◽  
D. Pelling
Keyword(s):  
Intestinal Absorption ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Peptide Absorption ◽  
Physiological Conditions ◽  
Anaesthetized Rats ◽  
Tissue Homogenates ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

1. The intestinal absorption of carnosine, glycylglycine, glycyl-d-phenylalanine, glycyl-l-phenylalanine, glycyl-l-proline and l-prolylglycine were investigated after intraluminal injection of dipeptide into anaesthetized rats. 2. With all six dipeptides, the intact substance was detected by ion-exchange chromatography in blood samples taken from the superior mesenteric vein. 3. The rate of hydrolysis of the dipeptides in tissue homogenates was measured in vitro. 4. The relative rates of hydrolysis varied by a factor of 300; there was an apparent inverse relationship between rate of hydrolysis and detection of intact peptide. 5. Peptide absorption was accompanied by increases in venous concentrations of the component amino acids, which appeared in proportions appropriate to the view that peptide absorption preceded hydrolysis. 6. It is suggested that slowly hydrolysed dipeptides may pass intact through the intestine wall under physiological conditions.

BIOCHEMISTRY OF THE USTILAGINALES: VIII. THE STRUCTURES AND CONFIGURATIONS OF THE USTILIC ACIDS

1953 ◽  
Vol 31 (4) ◽  
pp. 396-417 ◽  
Author(s):  
R. U. Lemieux
Keyword(s):  
Methyl Esters ◽  
Active Form ◽  
Aluminum Hydride ◽  
Optically Active ◽  
Lithium Aluminum ◽  
Acid Oxidation ◽  
Chromic Acid Oxidation ◽  
Pure Compounds ◽  
Hydrolysis Of ◽  
Derivatives Of

Methanolysis of ustilagic acid and hydrolysis of the methyl esters formed yielded a crystalline acidic fraction which was essentially a mixture of two substances termed the ustilic acids A and B. The acids were separated as their iso-propylidene derivatives. The ustilic acids cocrystallize to mixtures with melting points intermediate between those of the pure compounds. Conversion of ustilic acid A, m.p. 112–113 °C, [α]D −8° in methanol, which made up about 70% of the mixture, by hydrogenolysis to palmitic acid, by oxidation with chromic oxide to pentadecanedioic acid, and by lead tetraacetate oxidation followed by hydrogenation to 15-hydroxypentadecanoic acid showed the substance to be an optically active form of 15,16-dihydroxyhexadecanoic acid. Conversion of ustilic acid B, m.p. 140–141 °C, [α]D−10° in methanol, by sodium bismuthate oxidation followed by hydrogenation to 1,14-dihydroxytetradecane, by chromic acid oxidation of its methyl ester followed by hydrolysis of the product, and peroxide oxidation of the α-keto acid thus formed to tetradecanedioic acid, and by hydrogenolysis of the C2-carbon atom through a series of reactions to ustilic acid A, showed the substance to be an optically active form of 2,15,16-trihydroxy-hexadecanoic acid. Optically active forms of 2,15-dihydroxypentadecanoic and 2-hydroxypentadecanoic acids were prepared from ustilic acid B. Application of certain empirical rules of rotation to derivatives of these 2-hydroxyacids showed them to possess the D-configuration. Reduction of ustilic acid B with lithium aluminum hydride gave meso-1,2,15,16-tetrahydroxyhexadecane. Thus, ustilic acid B was the 2D,15D,16-trihydroxyhexadecanoic acid and the ustilic acid A was the 15D,16-dihydroxyhexadecanoic acid. Several derivatives of the above described acids were prepared.

scholarly journals PEMISAHAN ASAM AMINO DARI LIMBAH CAIR PABRIK KELAPA SAWIT DENGAN KROMATOGRAFI PENUKAR ION

2018 ◽  
Vol 6 (2) ◽  
pp. 69
Author(s):  
Indah Rahmi Sari ◽  
Ade Ayu Oksari ◽  
Irma Kresnawaty
Keyword(s):  
Amino Acid ◽  
Ion Exchange ◽  
Liquid Waste ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Enzyme Hydrolysis ◽  
Protease Enzyme ◽  
Absorbance Reading ◽  
Amino Acid Levels ◽  
Hydrolysis Of

Separation of Amino acid from Liquid waste of Oil palm Factory with Ion Exchange Chromatography Research on Separation of Amino Acid Liquid Waste mills with Ion Exchange Chromatography was carried out from October to November 2015. The results of  hydrolysis of 6 N HCl results showed  that the highest absorbance reading was obtained at a concentration of eluent of 0,2 and 0,6 M NaCl, while the results of the protease enzyme hydrolysis the highest absorbance reading at NaCl eluent 0,2 and 1 M. There was no significant difference in the results of separation by ion exchange chromatography, showed that the concentration of NaCl eluent is not very influential, so for subsequent analysis used only one concentration of the eluent. Results of linear regression obtained was equal to 0,9946, these results indicate that the series standard amino acid lysine has a value that is linear as it approaches 1. The amino acid levels obtained on the sample results LCPKS hydrolysis with 6 N HCl which was about 0 to 8.82 ppm and samples of the protease enzyme hydrolysis of about 0 to 4.31 ppm. Amino acid levels obtained were still far from the expected.Keywords: Amino Acid, Oil Palm, Liquid Waste, Ion Exchange Chromatography ABSTRAKPenelitian mengenai Pemisahan Asam Amino dari Limbah Cair Pabrik Kelapa Sawit dengan Kromatografi Penukar Ion telah dilaksanakan dari bulan Oktober sampai November 2015. Hasil hidrolisis HCl 6 N menunjukkan bahwa pembacaan absorbansi tertinggi diperoleh pada konsentrasi eluen NaCl 0,2 dan 0,6 M, sedangkan hasil hidrolisis enzim protease pembacaan absorbansi tertinggi pada eluen NaCl 0,2 dan 1 M. Tidak ada perbedaan yang signifikan pada hasil pemisahan dengan kromatografi penukar ion ini, menunjukkan bahwa konsentrasi eluen NaCl tidak terlalu berpengaruh, sehingga untuk analisis selanjutnya digunakan hanya satu konsentrasi eluen. Hasil regresi linear yang diperoleh yaitu sebesar 0,9946, hasil tersebut menunjukkan bahwa deret standar asam amino lisin mempunyai nilai yang linear karena mendekati 1. Kadar asam amino yang diperoleh pada sampel hasil hidrolisis LCPKS dengan HCl 6N yaitu sekitar 0 – 8,82 ppm dan sampel hasil hidrolisis enzim protease sekitar 0 – 4,31 ppm. Kadar asam amino yang diperoleh masih jauh dari yang diharapkan.Kata Kunci: Asam Amino, Minyak Kelapa Sawit, Limbah Cair, Kromatografi Penukar Ion

DERIVATIVES OF DEHYDROABIETIC AND PODOCARPIC ACIDS

1963 ◽  
Vol 41 (8) ◽  
pp. 1924-1936 ◽  
Author(s):  
Ernest Wenkert ◽  
Peter Beak ◽  
Richard W. J. Carney ◽  
James W. Chamberlin ◽  
David B. R. Johnston ◽  
...  
Keyword(s):  
Methyl Esters ◽  
Resin Acid ◽  
Aluminum Hydride ◽  
Resin Acids ◽  
Lithium Aluminum ◽  
Hydride Reduction ◽  
Rate Of Hydrolysis ◽  
Keto Derivative ◽  
Hydrolysis Of ◽  
Derivatives Of

The lithium aluminum hydride reduction of nitriles in the aromatic resin acid series to aldimines and the conversion of the products to other derivatives are described. The effect of the stereochemistry of the nitriles on the rate of reduction is noted. The transformation of dehydroabietane into a dehydro product is indicated. The syntheses of a desoxydecarboxy-5,6-dehydro-7-keto derivative of podocarpic acid and its optical antipode are discussed. The stereochemistry of hydrogenation of 5,6-dehydro derivatives of podocarpic acid is reported. The effect of a 7-keto group on the rate of hydrolysis of methyl esters of aromatic resin acids is illustrated. The reactions of 6-bromo-7-keto derivatives of methyl podocarpate with bases are portrayed.

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