Search results for "phosphonate"

Poly(phosphonate)-mediated Horner–Wadsworth–Emmons reactions

2015

A novel, general protocol for a polymer-mediated Horner–Wadsworth–Emmons (HWE) reaction is reported. The polyvalent polymeric reagent was prepared via acyclic diene metathesis (ADMET) polymerization. Homo- and copolymers of reactive poly(phosphonate)s with molecular weights up to 40 000 g·mol−1 and molecular weight dispersities Đ < 2 were successfully synthesized. Subsequent application of these polymers in the HWE reaction to prepare a library of aromatic α,β-unsaturated ketones (chalcons) has proven to be an efficient synthetic pathway to minimize purification efforts, as the polymeric side-product can be removed by simple precipitation. In this paper we also demonstrate for the first tim…

Rapid characterization of alkylpolyphosphonates by CZE with indirect photometric and mass spectrometric detection.

2006

Methods for the rapid characterization of industrial alkylpolyphosphonates (APPs) by infusion MS and CZE with indirect photometric (IPD) and MS detection are described. Technical-grade APPs, including alkylaminepolyphosphonates with 3-5 phosphonate groups and different hydrocarbon skeletons, hydroxyethyl-amino-bis(methylenephosphonic acid), hydroxyethylidene-diphosphonic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid, were examined. A 10 mM solution of adenosine triphosphate disodium salt at pH 2.2 was used as BGE. The nominal compounds of the industrial APPs and their impurities were well resolved in less than 15 min. The peaks were identified by using extracted ion electropherograms…

Synthesis of N-methyl alkylaminomethane-1,1-diphosphonic acids and evaluation of their complex-formation abilities towards copper(II)

2015

Abstract A series of N -methyl alkylaminomethane-1,1-diphosphonic acids ( 3a – g ) with a common tertiary nitrogen atom (CH 3 –N–R) bearing linear or branched alkyl, cycloheptyl or phenylalkyl R substituents was synthesized in the reaction of diethylphosphonate with triethyl orthoformate and secondary amine followed by hydrolysis, and by the Eschweiler–Clarke methylation of the alkylaminomethane-1,1-diphosphonic acids with formic acid and formaldehyde. Complex-formation abilities of 3a – g towards copper(II) in solution were studied by means of pH-potentiometry, ESI-MS spectrometry, UV–Vis and EPR methods. Evaluation of stability constants for the Cu(II) complexes of 3a – g has revealed the…

Herbicidally Active Derivatives of Aminomethylenebis-Phosphonic Acid-Mode of Action and Structure - Activity Relationship

1996

Abstract: (N-pyridylamino)methylenebisphosphonates exhibit strong herbicidal activity which may be reversed by supplementation of the growth media with aromatic amino acids. They appeare to be the inhibitors of aromatic amino acids biosynthesis acting as inhibitors of DAHP synthase the first enzyme of shikimate pathway. Over 40 analogues of these acids were synthesized in order to determine the structure-activity relationship.

Supported liquid membrane separation of amine and amino acid derivatives with chiral esters of phosphoric acids as carriers

2003

Studies on the possible use of phosphate and phosphonate esters bearing chiral menthol or nopol moieties as carriers for the transport of amines, amino acids, and amino acid esters through supported liquid membranes (SLM) are presented. Additionally, the enantioselectivity of the SLM transport of alkyl esters of aromatic amino acids and a non‐protein amino acid was also evaluated. It could be concluded that the extent of transport strongly depends on the hydrophobicity of the amino compound. Moreover, the carrier structure also influences the transport of those compounds through SLM: chiral phosphate and phosphonate esters appear to be poor or moderate carriers for enantioselective SLM tran…

Characterization of industrial alkylpolyphosphonates by infusion electrospray ionization-ion trap mass spectrometry with identification of the impuri…

2005

Technical grade diethylene-triaminepentakis(methylenephosphonic acid) (I), dihexamethylene-triaminepentakis(methylenephosphonic acid) (II), ethylene-diaminetetrakis(methylenephosphonic acid) (III), hexamethylene-diaminetetrakis(methylenephosphonic acid) (IV), amino-tris(methylenephosphonic acid) (V), hydroxyethyl-aminobis(methylenephosphonic acid) (VI), 1-hydroxyethylidene-1,1-diphosphonic acid (VII), and 2-phosphonobutane-1,2,4-tricarboxylic acid (VIII) were characterized by ion trap mass spectrometry with electrospray ionization (ESI-ITMS). Using the negative ion mode and acid and alkaline media, peak series corresponding to the nominal compounds and to impurities with a lower number of p…

Separation of aromatic aminophosphonic acid enantiomers by capillary electrophoresis with the application of cyclodextrins

2002

The detailed studies concerning capillary electrophoresis separation of aminophosphonic acid enantiomers with various commercially available cyclodextrins are presented. The obtained results show that the separation of these stereoisomers is dependent on pH of background electrolyte, concentration of cyclodextrin as well as on the type of applied chiral selector. The separation mechanism is based on the co-operative effect of hydrogen bond type interactions enhanced by hydrophobic forces and sterical constrains between aminophosphonate and cyclodextrin. With application of elaborated method, enantiomeric baseline or partial separation of 18 alpha-aminophosphonic acids was achieved. This sep…

Tetramethylguanidine (TMG)-catalyzed addition of dialkyl phosphites to α,β-unsaturated carbonyl compounds, alkenenitriles, aldehydes, ketones and imi…

1998

Abstract Tetramethylguanidine-catalyzed addition of dialkyl phosphites to α,β-unsaturated carbonyl compounds, alkenenitriles, aldehydes and ketones constitutes a practical route to a variety of phosphonate synthons. The very mild conditions employed, together with the short reaction times, make the procedure highly versatile and tolerant to a range of functionalities. The proposed methodology is also convenient for the preparation of α-aminophosphonates.

Magnetization Relaxation in a Three‐Dimensional Ligated Cobalt Phosphonate Containing Ferrimagnetic Chains

2010

Herbicidal Derivatives of Aminomethylenebisphosphonic Acid. Part IV. Hydroxyalkylidenebisphosphonates, Iminomethylenebisphosphonates and Ureidomethyl…

2000

Derivatives of aminomethylenebisphosphonic acids constitute a class of promising herbicides. Replacement of the amino group by hydroxyl, ureido, thioureido, or imino moieties leads to compounds of significant herbicidal properties. This indicates that protonated amino function is not a requirement for phytotoxic action of bisphosphonates.