Phosphonolipids. XXVII. Synthesis of O-(2-Aminoethyl)phosphono-L-serine and its Stereoisomer

1974 ◽  
Vol 52 (8) ◽  
pp. 718-722 ◽  
Author(s):  
Erich Baer ◽  
Jeno T. Eber
Keyword(s):  
Sulfuric Acid ◽  
Phosphonic Acid ◽  
Benzyl Ester ◽  
Palladium Black ◽  
Simultaneous Removal ◽  
Reaction Products ◽  
Naturally Occurring ◽  
Phosphate Diester ◽  
Serine Phosphate

The synthesis of O-(2-aminoethyl)phosphono-L-serine and O-(2-aminoethyl)phosphono-D-serine is described. The phosphonic acid analogues were obtained by the reaction of O-(2-N,N-dibenzylaminoethyl)phosphonic acid monochloride and triethylamine with N-carbobenzoxy-L-serine benzyl ester and N-carbobenzoxy-D-serine benzyl ester, respectively, followed by the simultaneous removal of the protective carbobenzoxy- and benzyl groups of the reaction products, i.e. O-(2-N,N-dibenzylaminoethyl)phosphono-N-carbobenzoxy-L-serine benzyl ester and its stereoisomer, by hydrogenolysis in 95% ethanol with palladium black catalyst in the presence of sulfuric acid. The O-(2-aminoethyl)phosphono-L-serine and its stereoisomer were obtained in overall yields of about 40% of theory. They are phosphonic acid analogues of the naturally occurring O-(ethanolamine)-O-(L-serine)phosphate diester and its stereoisomer, respectively.

Phosphonolipids. XV. Synthesis of a dihydroceramide aminoethylphosphonate

1968 ◽  
Vol 46 (3) ◽  
pp. 525-532 ◽  
Author(s):  
Erich Baer ◽  
Bimal C. Pal
Keyword(s):  
Chemical Synthesis ◽  
Acid Chloride ◽  
Phosphonic Acid ◽  
Steam Distillation ◽  
Free Acid ◽  
Reaction Products ◽  
New Class ◽  
Naturally Occurring ◽  
Benzoyl Group ◽  
Complex Lipids

The first chemical synthesis of a dihydroceramide aminoethylphosphonate is described. It is a saturated representative of a new class of recently discovered, naturally occurring complex lipids derived from phosphonic acid. The compound, viz. erythro-N-palmitoyl-DL-dihydrosphingosyl-1-(2-aminoethyl)-phosphonate, was obtained by two procedures: phosphonylation of erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosine with (2-N,N-dibenzylammoethyl)phosphonic acid chloride (hydrochloride) and triethylamine, or with (2-phthalimidoethyl)phosphonic acid monochloride and triethylamine, and freeing the reaction products of both procedures, viz. erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosyl-1-(2-N,N-dibenzylaminoethyl)phosphonate and erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosyl-1-(2-phthalimidoethyl)phosphonate, from their protective benzyl or phthaloyl group by hydrogenolysis or hydrazinolysis, respectively, followed in both cases by removal of the benzoyl group by saponification.The (2-N,N-dibenzylaminoethyl)phosphonic acid was obtained by treating (2-bromoethyl)phosphonic acid with N,N-dibenzylamine and converting the reaction product, viz. the dibenzylammonium salt of (2-N,N-dibenzylaminoethyl)phosphonic acid, into the free acid by steam distillation.

scholarly journals Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

2006 ◽  
Vol 40 (35) ◽  
pp. 6863-6878 ◽  
Author(s):  
Rebecca M. Garland ◽  
Matthew J. Elrod ◽  
Kristi Kincaid ◽  
Melinda R. Beaver ◽  
Jose L. Jimenez ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Reaction Products ◽  
Acid Catalyzed ◽  
Catalyzed Reactions

The Absorption and Fluorescence of Isoflavones and the Effect of Shift Reagents

1984 ◽  
Vol 39 (2) ◽  
pp. 238-243 ◽  
Author(s):  
Otto S. Wolfbeis ◽  
Eva Fiirlinger ◽  
Hem Chandra Jha ◽  
Fritz Zilliken
Keyword(s):  
Sulfuric Acid ◽  
Absorption Band ◽  
Absorption Maximum ◽  
Structure Elucidation ◽  
Sodium Acetate ◽  
Methanol Solution ◽  
Aluminium Chloride ◽  
Sodium Borate ◽  
Naturally Occurring ◽  
Aluminium Trichloride

The absorption and fluorescence maxima of 20 isoflavones have been determined in methanol solution and the effect of addition of water, 50% sulfuric acid, aluminium trichloride, borax, sodium acetate, ammonia and sodium hydroxide has been studied. The following findings may be useful in the structure elucidation of naturally occurring isoflavones: (a) 5-Hydroxyisoflavones have band I absorption maxima around 335 nm. 6-hydroxyisoflavones between 310 and 330 nm, and others below 310 nm. (b) Addition of water produces practically no shift in the absorption spectra, but - unlike other hydroxyisoflavones - can give distinctly longwave shifted new fluorescence bands with 7-hydroxyisoflavones. (c) Addition of sodium acetate gives rise to anion absorption of 7-hydroxyisoflavones and to partial anion absorption of 6-hydroxyisoflavones; the spectral maxima of 5-hydroxyisoflavones remain practically unchanged, (d) Ammonia gives rise to anion absorption of both 6- and 7-hydroxyisoflavones, but not of the 5-hydroxy isomers, (e) Sodium borate is a useful reagent to identify 6,7-dihydroxyisoflavones by virtue of its ability to form a chelate complex with an absorption maximum that is different from the anion absorption, (f) Aluminium trichloride forms complexes with both 5-hydroxy- and 6,7-dihydroxyisoflavones with distinct absorption maxima, (g) 5,7-D ihydroxyisoflavones may be recognized by addition of ammonia, which does not result in a longwave shift, but rather in an intensification of the longwave absorption band, (h) 6-H ydroxyisoflavones can be differentiated from the 7-hydroxy isomers by their longwave shifts (4 0-60 nm) following addition of ammonia. The respective shifts of the 7-hydroxy isomers are smaller, (i) 5-H ydroxyisoflavones are practically non-fluorescent. while others have fairly strong fluorescences, (j) The absorption and fluorescence maxima of isoflavones give unique combinations which may be useful in their identification, (k) Addition of aluminium chloride makes the non-fluorescent 5-hydroxyisoflavones fluorescent. (1) As in the case of absorption, 6,7-dihydroxyisoflavones form complexes with borate possessing fluorescence bands with maxima different from those of the anion bands

scholarly journals Effect of Soil Washing Solutions on Simultaneous Removal of Heavy Metals and Arsenic from Contaminated Soil

2020 ◽  
Vol 17 (9) ◽  
pp. 3133 ◽  
Author(s):  
Kanghee Cho ◽  
Eunji Myung ◽  
Hyunsoo Kim ◽  
Cheonyoung Park ◽  
Nagchoul Choi ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Soil Washing ◽  
Metal Extraction ◽  
Simultaneous Removal ◽  
Removal Of Heavy Metals ◽  
Removal Efficiencies

In this study, we investigated the feasibility of using a solution of sulfuric acid and phosphoric acid as an extraction method for soil-washing to remove Cu, Pb, Zn, and As from contaminated soil. We treated various soil particles, including seven fraction sizes, using sulfuric acid. In addition, to improve Cu, Pb, Zn, and As removal efficiencies, washing agents were compared through batch experiments. The results showed that each agent behaved differently when reacting with heavy metals (Cu, Pb, and Zn) and As. Sulfuric acid was more effective in extracting heavy metals than in extracting As. However, phosphoric acid was not effective in extracting heavy metals. Compared with each inorganic acid, As removal from soil by washing agents increased in the order of sulfuric acid (35.81%) < phosphoric acid (62.96%). Therefore, an enhanced mixture solution using sulfuric acid and phosphoric acid to simultaneously remove heavy metals and As from contaminated soils was investigated. Sulfuric acid at 0.6 M was adopted to combine with 0.6 M phosphoric acid to obtain the mixture solution (1:1) that was used to determine the effect for the simultaneous removal of both heavy metals and As from the contaminated soil. The removal efficiencies of As, Cu, Pb, and Zn were 70.5%, 79.6%, 80.1%, and 71.2%, respectively. The combination of sulfuric acid with phosphoric acid increased the overall As and heavy metal extraction efficiencies from the contaminated soil samples. With the combined effect of dissolving oxides and ion exchange under combined washings, the removal efficiencies of heavy metals and As were higher than those of single washings.

ChemInform Abstract: Reaction of 5,5,6-Trimethylbicyclo(2.2.1)heptan-2-one with Acetonitrile and Sulfuric Acid and NMR Spectra of the Reaction Products.

ChemInform ◽  
1989 ◽  
Vol 20 (25) ◽  
Author(s):  
N. G. KOZLOV ◽  
L. A. POPOVA ◽  
V. I. BIBA ◽  
T. N. POTKINA ◽  
E. F. KORSHUK
Keyword(s):  
Sulfuric Acid ◽  
Nmr Spectra ◽  
Reaction Products

The synthesis of β-mannopyranosides by intramolecular aglycon delivery: scope and limitations of the existing methodology

1994 ◽  
Vol 72 (6) ◽  
pp. 1447-1465 ◽  
Author(s):  
Frank Barresi ◽  
Ole Hindsgaul
Keyword(s):  
Reaction Products ◽  
The Core ◽  
Naturally Occurring ◽  
Reaction Proceeds ◽  
Synthesis Approach

The synthesis of β-mannopyranosides by intramolecular aglycon delivery is shown to proceed with complete stereoselectivity in six separate cases. This strategy has been successfully applied to the synthesis of several disaccharides, including octyl 3,6-di-O-benzyl-4-O-(3,4,6-tri-O-benzyl-β-D-mannopyranosyl)-2-deoxy-2-phthalimido-β-D-glucopyranoside, a precursor of the naturally occurring β-D-Man-(1→4)-β-D-GlcNAc linkage, present in all N-linked glycoproteins. Exclusive formation of the β-mannosidic linkage has been confirmed in all six cases, since independently synthesized α-linked mannopyranoside standards were shown to be absent from the reaction products. The intramolecular stereocontrolled reaction proceeds even in the presence of competing methanol. The extension of this strategy to the synthesis of the core pentasaccharide of N-linked glycoproteins has revealed limitations to the methodology, especially when a block synthesis approach is investigated.

Peptide models for protein-mediated cation transport

1980 ◽  
Vol 58 (10) ◽  
pp. 865-870 ◽  
Author(s):  
Charles M. Deber
Keyword(s):  
Calcium Transport ◽  
Calcium Ionophore ◽  
Cation Transport ◽  
Benzyl Ester ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Design And Synthesis ◽  
Cellular Processes ◽  
Naturally Occurring ◽  
Peptide Models

Substances which can perturb the transmembrane cation balance in a predictable manner have wide-ranging uses in the study of cellular processes. We have undertaken to examine transmembrane calcium transport on the molecular level through the design and synthesis of a series of ionophoric peptides as models for protein-mediated calcium transport. General mechanisms for carrier-mediated membrane transport are discussed. Cation transport profiles are presented for transport by synthetic peptides of structure cyclo(Glu(OR)-Sar-Gly-(N-R1)-Gly)2, where R = benzyl ester or H; R1 = n-decyl or cyclohexyl. Transport of physiologically abundant cations across "liquid membranes" in Pressman cells mediated by cyclo(Glu-Sar-Gly-(N-decyl)Gly)2 was observed to be essentially calcium specific, as long as calcium ions were present in the system. Multilamellar and unilamellar phosphatidylcholine vesicles were each found to be emptied of internal 45Ca2+ ions upon addition of cyclo(Glu(OBz)-Sar-Gly-(N-cyclohexyl)Gly)2 to the vesicle suspension. The results are compared with the naturally occurring calcium ionophore A23187.

scholarly journals Hygroscopic growth and droplet activation of soot particles: uncoated, succinic or sulfuric acid coated

2012 ◽  
Vol 12 (10) ◽  
pp. 4525-4537 ◽  
Author(s):  
S. Henning ◽  
M. Ziese ◽  
A. Kiselev ◽  
H. Saathoff ◽  
O. Möhler ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Succinic Acid ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Hygroscopic Growth ◽  
Reaction Products ◽  
Carrier Gas ◽  
Soot Particles ◽  
Polycyclic Aromatic ◽  
Droplet Activation

Abstract. The hygroscopic growth and droplet activation of uncoated soot particles and such coated with succinic acid and sulfuric acid were investigated during the IN-11 campaign at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) facility. A GFG-1000 soot generator applying either nitrogen or argon as carrier gas and a miniCAST soot generator were utilized to generate soot particles. Different organic carbon (OC) to black carbon (BC) ratios were adjusted for the CAST-soot by varying the fuel to air ratio. The hygroscopic growth was investigated by means of the mobile Leipzig Aerosol Cloud Interaction Simulator (LACIS-mobile) and two different Hygroscopicity Tandem Differential Mobility Analyzers (HTDMA, VHTDMA). Two Cloud Condensation Nucleus Counter (CCNC) were applied to measure the activation of the particles. For the untreated soot particles neither hygroscopic growth nor activation was observed at a supersaturation of 1%, with exception of a partial activation of GFG-soot generated with argon as carrier gas. Coatings of succinic acid lead to a detectable hygroscopic growth of GFG-soot and enhanced the activated fraction of GFG- (carrier gas: argon) and CAST-soot, whereas no hygroscopic growth of the coated CAST-soot was found. Sulfuric acid coatings led to an OC-content dependent hygroscopic growth of CAST-soot. Such a dependence was not observed for activation measurements. Coating with sulfuric acid decreased the amount of Polycyclic Aromatic Hydrocarbons (PAH), which were detected by AMS-measurements in the CAST-soot, and increased the amount of substances with lower molecular weight than the initial PAHs. We assume that these reaction products increased the hygroscopicity of the coated particles in addition to the coating substance itself.

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