Agents For Amines Research Articles

Chiral NMR Shift Reagents: Mixtures of Lanthanide Tris (β-diketonates) with Chiral Carboxylate Anions

Chiral carboxylic acids such as N-(R)-1-(1-naphthyl)ethylaminocarbonyl-L-tert-leucine, N-(R)-1-(1-naphthyl)ethylaminocarbonyl-L-valine and N-(3,5-dinitrobenzoyl)-L-leucine are solubilized in chloroform by the addition of triethylamine. The resulting ion pairs are useful chiral resolving agents for sulfoxides, amines and alcohols. For certain substrates, particularly amines, the ion pairs were more effective chiral resolving agents than the corresponding organic-soluble ester derivatives. Addition of lanthanide tris(β-diketonate) complexes to mixtures of the ion pairs causes enhancements in the enantiomeric resolution in the spectra of certain substrates. Evidence indicates that the chiral carboxylate compound bonds directly to the lanthanide tris(β-diketonate) to form an anionic species. Shifts in the spectra of substrates and enhancements in enantiomeric resolution in the presence of the anionic species appear to be dominated by bonding of the substrate to the carboxylate moiety of the lanthanide complex. These new reagents are therefore complementary to mixtures of lanthanide tris(β-diketonate) complexes with the ester forms of the resolving agents. © 1997 John Wiley & Sons, Ltd.

機能性Ｎ‐ヒドロキシアミド含有複素環化合物‐合成・反応・金属錯体形成能

Synthesis, reaction, and metal-chelating property of N-hydroxyamide-containing heterocycles such as 1-hydroxy-2 (1H) -pyrimidinones and -pyrazinones are described. The diazines showed remarkable high water solubility and acidity, which enable them to act as an effective acylating agent for amines, amino acids, and alcohols. The diazines were also found to be an bidentate ligand to a ferric iron in aqueous solution, in particular, under acidic to neutral conditions. The five types of tripodal hexadentate ligands bearing 1-hydroxy-2 (1H) -pyrimidinone or -pyrazinone as bidentate ligands were synthesized, and effects of their structural feature and the chirality on their metal-chelating behavior were also discussed. Among them, a hexadenate ligand bearing 1-hydroxy-2 (1H) -pyrazinone, L-alanine, and tris (2-aminoethyl)amine showed high iron removal ability from human transferrin, and its pseudo-first-order-rate constant was more than five times greater than naturally-occurring siderophore, desferrioxamine B, even in small excess of the ligand concentration to transferrin.

Synthesis, reactivity and X-ray molecular structure of the activated ester complex [( η5-C 5H 4COONS)Co(CO) 2](NS ; N-succinimidyl)

The title compound [( η 5-C 5H 4COONS)Co(CO) 2] ( 2) was prepared in high yield (91%) by treatment of the organometallic carboxylic acid [( η 5-C 5H 4COOH)Co(CO) 2] ( 1) with N-hydroxysuccinimide in the presence of dicyclohexylcarbodiimide. The activated ester complex 2 was identified by spectroscopic methods, in addition its X-ray structure was determined. Compound 2 crystallizes in the triclinic space group P1 with a = 6.1880(8), b = 9.722(1), c = 10.869(1) Å, α = 83.37(1), β = 83.91(1) and γ = 86.30(1)°, V = 645(1) Å3 and Z = 2. The stability of the above species 2 and its reactivity as labelling agent for amines and amino-esters are investigated and discussed.

P(III)-Amines as Phosphorylating Agents for Alcohols and Amines. Modern Aspect of the Problem

P(III)-Amines as Phosphorylating Agents for Alcohols and Amines. Modern Aspect of the Problem

Reactions of Diazomethylphosphonate: The First Synthesis of a Formylphosphonate Hydrate

Abstract: Formylphosphonate hydrate has been synthesised by the oxidation of diazomethylphosphonate with dimethyldioxirane (DMD) and its reactions, including the formation of imines, oximes, and Wittig olefination products, have been investigated. Formylphosphonate also acts as an efficient, selective formylating agent of secondary amines. β-Ketophosphonic acids derived from a range of amino acids have been prepared by the tin (II) chloride-catalysed reaction of diazomethylphosphonate with amino aldehydes and in certain cases shown to be potent inhibitors of leucine aminopeptidase.

N-acetyl-N-acyl-3-aminoquinazolinones as chemoselective acetylating agents

The title compounds, e.g. 3, are highly selective acetylating agents for primary amines in the presence of secondary amines and, in particular, for the less sterically hindered of two different secondary amines.

P(Iii)-Amines as Phosphorylating Agents for Alcohols and Amines. Modern Aspect of the Problem.

Abstract The factors governing the reactivity of P(III)-amines towards protonodonor nucleophiles are discussed. The last data on mechanism of acid catalysis, intramolecular catalysis and possibility of stereoselective phosphorylation by phosphoroamidites are represented.

Occurrence of nitrosatable amines in some Nigerian medicinal plants

The presence of secondary amines; di-methylamine and diethylamine, methylamine, nitroso-methyl-n-propylamine have been reported in plants (Bush i970). Levels found in tobacco samples range between 2 - 100 ppm. The occurrence, metabolism and functions of plant amines have been reviewed by Smith(1971). Nitrate is a normal constituent of human saliva, its concentration in that body compartment isdirectly related to the nitrate intake via food. In the mouth it is partially reduced by microflora present to nitrate, which is swallowed and can serve as nitrosating agent for secondary amines in the stomach. The secondary amines have the imino-group which is very reactive and easily undergoes "nitration" to form the nitrosamines or nitroso compounds which have been shown to be toxic and carcinogenic (IARC 1976). Neurath (1968) reported that the high incidence of oesophageal cancer could be associated with the consumption of crude beers and other liquors in Zambia due to secondary amines, in addition to nitrosamines.

ChemInform Abstract: Dichloronitroacetic Acid Derivatives (I) as Acylating Agents for Primary Amines, Ammonia, and Phenylhydrazine.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Abormal metabolism of [formula omitted] in hypoxic rat liver. Similarities to its abnormal metabolism in alcohol cirrhosis

S-Adenosylmethionine (AdoMet) is an important biologic methylating agent for nucleic acids, phospholipids, biologic amines, and proteins. Previous studies indicated that hepatic AdoMet synthetase and hepatic levels of AdoMet are subnormal in patients with alcoholic cirrhosis. This abnormality limits the patients' capacity to convert phosphatidylethanolamine to phosphatidylcholine by way of phosphatidylethylamine- N-methyltransferase (PEMT). Because alcoholic consumption appears to be associated with hepatic hypoxia, we previously measured AdoMet concentration in liver cells under acute hypoxia and found the level to be decreased substantially. In the present study, we determined whether a similar metabolic abnormality was also observed in rats maintained under physiologic hypoxia for 9 days and administered standard rat chow. The study showed that AdoMet levels in hypoxic rat (ave +- SD) were significantly lower than those in the control (36.8 ± 11.6 vs. 60.4 ± 0.07 vs liver; P < 0.05). Also significantly lower in the hypoxic group were the activities od AdoMet synthetase 0.60 ± 0.07 vs. 0.97 ± 0.20 U; P < 0.05) and PEMT (26.2 ± 4.2 vs. 35.6 ± 5.8 U; P < 0.02). The mRNA levels of AdoMet synthetase also declined in hypoxia indicating that hypoxia may modulate the gene expression of hepatic AdoMet synthetase. Thus, in vivo hypoxia may have an important effect on 1-carbon metabolism.

Urethane protected amino acid N-carboxyanhydrides and fluorides (U-NCAs and U2AAFs)

In order to obtain peptide analogues containing a central pyrrolide bond, as potential mechanism-based inhibitors of the HIV-1 proteinase, activated derivatives of amino acids were required. Treatment of a N,N-bis(Boc) amino acid pyridinium salt with cyanuric fluoride in dichloromethane furnished the correspondingbis(Boc) amino acid fluoride (Boc2AAF). Use of the Vilsmeier reagent in acetonitrile, instead of the cyanuric fluoride, led to a N-Boc amino acid N-carboxyanhydride (Boc-NCA). From a mixed N-Z,N-Boc amino acid salt a N-Z,N-Boc amino acid fluoride and a Z-NCA were respectively obtained. The very sensitive Young test showed that during the coupling of the N-benzoyl-L-Leucine N-carboxyanhydride or the N-benzoyl N-Boc-L-leucyl fluoride with ethyl glycinate the degrees of racemization were weak. Owing to the electronegativity and the small size of the fluorine atom, thebis(urethane) amino acid fluorides are efficient acylating agents for amines and pyrrole anions.

Synthesis of New Ureido Sugars, Derivatives of 2-Amino-2-deoxy-D-glucose and Amino Acids

Abstract Amino acid methyl, ethyl or benzyl esters have been used as amination agents in reaction with methyl 3,4,6-tri-O-acetyl-2-deoxy-2-(4-nitrophenoxycarbonylamino)-β-D-glucopyranoside (1). Fourteen new ureido sugars, derivatives of 2-amino-2-deoxy-D-glucopyranoside and glycine, L-alanine, L-valine, L-leucine, L-phenylalanine, L-pro-line, L-aspartic acid and L-glutamic acid were obtained.

Some Tris[(triorganophosphine)gold(I)]‐oxonium and ‐Organoimonium Tetrafluoroborates with Bulky Substituents

AbstractTris{[tri(2‐methylphenyl)phosphine]gold(I)}‐, tris{[tri(2,4,6‐trimethylphenyl)phosphine]gold(I)}‐ and tris{[tri(cyclohexyl)phosphine]gold(I)}‐oxonium tetra‐fluoroborate (1−3) have been prepared from the corresponding (phosphine)gold(I) chlorides, silver oxide, and sodium tetrafluoroborate in acetone. These oxonium salts are excellent aurating agents for primary amines. Thus in the reaction with 1, t‐butylamine tBuNH2 and aniline PhNH2 are readily converted into the trinuclear imino complexes {[(2‐MeC6H4)3P]Au}3NtBu+BF4− (4) and {[(2‐MeC6H4)3P]Au}3NPh+BF (5) in high yields. With 3, both aniline and 8‐amino‐quinoline also give the trinuclear complexes, i.e. {[(c‐C6H11)3P]Au}3 NPh+BF (6) and {[(c‐C6H11)3P]Au}3N(C9H6N)+BF (7). Auration of aniline with the most sterically hindered reagent 2 yields only the binuclear complex {[2,4,6‐Me3C6H2)3P] · Au}2N(Ph)H+BF (8). The reagents 1−3 and the Products 4–8 have been characterized by analytical and NMR spectroscopic data, and the crystal structures of compounds 4 and 6 have been determined by single crystal x‐ray diffraction. In the cations of 4, a triangle of gold atoms with short Au — Au contacts [3.036(1), 3.107(1), and 3.214(1) Å] forms a steep pyramid with the nitrogen atom, in which the angles AuNAu are all much smaller than the tetrahedral standard of 109.7°: 94.8(4), 98.1(4), and 103.0(4)°. This triangular Au3 unit is staggered relative to the three methyl groups of the tBu substituent at nitrogen. The results for 6 are similar [Au — Au: 3.037(1), 3.071(1), and 3.222(1) Å; AuNAu: 95.3(3), 96.5(3), and 103.6(3)°]. Variable temperature NMR studies of compounds 3 and 8 show hindered rotation of the mesityl groups about the PC bonds of the ligands originating from the steric congestion within each tertiary phosphine.

Determination of the chiral purity of benzylic amines using marfey's reagent

1-Fluoro-2,4-dinitrophenyl-5-(S)-alanine amide (Marfey's reagent) was used as a chiral derivatizing agent for benzylic amines in order to determine optical purities.

Chloroisothiocyanatoquinolines as fluorogenic derivatizing agents for primary and secondary amines.

Two new prechromatographic LC fluorogenic derivatizing agents, 2- and 4-chloro-3-isothiocyanatoquinoline (4 and 5) have been synthesized and shown to react smoothly with primary and secondary amines to produce fluorescent thiazoloquinolines. Compounds 4 and 5 hydrolyse in aqueous base and the rates of this reaction compared with the rates of derivatizations with amino acids indicate that the hydrolysis reaction interferes with derivatization when UV detection is used. The kinetics of derivatization with ordinary amines indicate that this reaction is quite facile, although less nucleophilic amines, e.g. aniline, react slowly. The pKas for first protonations indicate that derivatives of 4 would be unprotonated and those of 5 would be protonated with typical RP-LC mobile phases. The Stokes shift for protonated derivatives of 5 is nearly 200 nm. The excess of unreacted derivatizing reagent interferes with UV detection of some analytes; but when fluorescence detection is used this excess produces only a small negative peak. With fluorescence detection the sensitivity of this method is about 0.8 microM at S/N of 2, and the response of peak height to concentration is linear over at least two decades of concentration.

Dichloronitroacetic acid derivatives as acylating agents for primary amines, ammonia, and phenylhydrazine

The corresponding carbamic acid derivatives were obtained (28–91% yields) as a result of the reaction of dichloronitroacetic acid derivatives, O2NCCl2COR, (1a–c, R = OEt, OCH2Ph, NH2) with ammonia, methylamine, benzylamine, glycine, phenylhydrazine, and aniline. The probable mechanism of the process and factors that affect the nature of the departing group were discussed.

Analysis by liquid chromatography of desipramine in aqueous solutions and plasma application of dichlorotriazinylaminofluorescein (DTAF) as a pre-column fluorescent derivatising agent for selected secondary amines

Dichlorotriazinylaminofluorescein (DTAF) has been proposed as a fluorescent derivatising agent for secondary aliphatic amines. In this report, its applicability as a pre-column reagent is demonstrated by its use in the analysis of aqueous solutions and plasma samples of the tricyclic antidepressant, desipramine. Samples were processed by liquid—solid extraction onto XAD-2 resin, followed by DTAF derivatisation of the fraction of the column effluent containing analyte. The reaction mixture was then subjected to HPLC using a dual column switching configuration that was designed to (a) separate excess DTAF from the reaction product, and to (b) achieve the necessary analytical resolution. Fluorometric detection of the analyte in column effluent afforded a sensitivity of 150 fmol of desipramine injected on-column, a 2–3 order of magnitude increase in sensitivity relative to previously described methods. DTAF appears to be a convenient reagent for fluorescence derivatisation of N-methyl secondary amines prior to their HPLC analysis.

Syntheses of New Optically Active Organosilanes and Their Applications for the Optical-Purity-Determining Agents

Abstract New optically active organosilicon compounds such as (benzylmethylphenylsilyl)acetic acid (1) and (ethylmethylphenylsilyl)acetic acid (2) were synthesized. Application of these acids as the optical purity determining agents for chiral amines and alcohols were successfully carried out. In addition, it was also revealed that optically active (benzylmethylphenylsilyl)methylamine (3) and [benzylmethyl(o-tolyl)silyl]methylamine (4) are able to be used as the optical purity determining agents for chiral carboxylic acids.

Optically active perfluorocarboxylic acids and their applications

Perfluoropropoxypropionic acid (PPPA), obtained by the hydrolysis of the dimer of hexafluoropropene oxide (HFPO), was optically resolved into enantiomers via its cinchonidine salt. Perfluoroisopropoxypropionic acid (PIPA), carrying a more bulky group on its chiral center, was also resolved into enantiomers. ▪ These optically active perfluorocarboxylic acids are thermally, chemically and optically very stable and are vesatile derivatizing agents for chiral alcohols and amines. Some applications in 19F nmr and chromatographic analysis will be mentioned.

ChemInform Abstract: PREPARATION AND SOME REACTIONS OF PHENYLMERCURY THIO‐ AND DITHIOCARBOXYLATES

AbstractDiphenyl‐Hg (II) bildet mit äquimolaren Mengen der Mono‐ und Dithiocarbonsäuren (I) die Phenyl‐Hg‐(di)thiocarboxylate (III), die mit weiteren Säuremengen die′ Hg‐bis‐ [(di).thiocarboxylate (IV) ergeben.