- Synthesis and acid-base properties of α-aminophosphoryl compounds
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α-Aminophosphoryl compounds of the phosphonate, phosphine oxide, and α,ω-bis(phosphine oxide) series and some of their thiophosphoryl analogs were synthesized. Potentiometric measurements of the pKa of the conjugate acids revealed an insignificant effect of variation of substituents on the phosphorus, nitrogen, and α-carbon atoms on the basicity of the phosphorylated amines. The latter are weak bases. Organophosphorus groups decrease the basicity of the amines by almost 5 pK a units. The role of the hydrophobic effect and intramolecular H-bonding in the obtained substances was discussed.
- Zakharov,Nuriazdanova,Garifzyanov,Galkin,Cherkasov
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- Catalyst-Free and Selective C-N Bond Functionalization: Stereospecific Three-Component Coupling of Amines, Dichloromethane, and >P(O)H Species Affording α-Aminophosphorus Compounds
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Catalyst-free and selective C-N bond functionalization has been achieved through three-component coupling of amines, dihalomethane, and >P(O)H species. This reaction takes place stereospecifically with retention of configuration at phosphorus, which can produce various new optically active phosphorus analogues of α-amino acids.
- Zhao, Yalei,Chen, Xiuling,Chen, Tieqiao,Zhou, Yongbo,Yin, Shuang-Feng,Han, Li-Biao
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- Copper-catalyzed α-amination of phosphonates and phosphine oxides: A direct approach to α-amino phosphonic acids and derivatives
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A direct approach to important α-amino phosphonic acids and its derivatives has been developed by using copper-catalyzed electrophilic amination of α-phosphonate zincates with O-acyl hydroxylamines. This amination provides the first example of C=N bond formation which directly introduces acyclic and cyclic amines to the α-position of phosphonates in one step. The reaction is readily promoted at room temperature with as little as 0.5 mol % of catalyst, and demonstrates high efficiency on a broad substrate scope. A direct approach to important α-amino phosphonic acids and derivatives, by using copper-catalyzed electrophilic amination of α-phosphonate zincates using O-acylhydroxylamines, is described. This amination is the first example of C=N bond formation which directly introduces acyclic and cyclic amines to the α-position of phosphonates in one step. The reaction proceeds at room temperature with as little as 0.5 mol % of the catalyst. Copyright
- McDonald, Stacey L.,Wang, Qiu
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supporting information
p. 1867 - 1871
(2014/03/21)
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- Efficient synthesis of phosphono- and phosphinoxidomethylated N-heterocycles under solvent-free microwave conditions
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Simple N-heterocycles were converted to N-phosphono- and phosphinoxidomethyl derivatives by a solvent-free microwave-assisted condensation of the heterocycle, paraformaldehyde, and diethylphosphite or diphenylphosphine oxide in a convenient and, in most cases, efficient way. In contrast to an earlier report, imidazole proved to be unreactive in this type of phospha-Mannich reaction. Copyright Taylor & Francis Group, LLC.
- Prauda, Ibolya,Greiner, Istvan,Ludanyi, Krisztina,Keglevich, Gyoergy
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p. 317 - 322
(2007/10/03)
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- Design and synthesis of macrocyclic ligands for specific interaction with crystalline ettringite and demonstration of a viable mechanism for the setting of cement
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Cementitious materials are among those most widely used by mankind while being among the least well understood. The detailed physicochemical processes involved in the hydration and setting of cement slurries are very complex, and a clearly defined quantitative account is still lacking: indeed, even the composition of the cement powder itself is not known exactly. Still less has there been any understanding of the mechanism by which numerous known retarders of the cement setting process act. In this article, we detail the synthesis of novel macrocyclic organophosphonate retarders 1a and 2a which were developed by rational methods. Attempts to synthesise these compounds as phosphonate ester derivatives were universally unsuccessful, however direct modification of the parent hexaaza-(3) and trioxatriaza-18-crown-6 (5) derivatives was successful, to provide the phosphonic acids 1b and 2b respectively. Subsequent testing of these compounds showed their ability to inhibit the growth of crystalline ettringite and delay the setting of cement. These results support the hypothesis that the formation of crystalline ettringite is the rate determining step in the setting of cement.
- Griffin, Jonathan L. W.,Coveney, Peter V.,Whiting, Andrew,Davey, Roger
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p. 1973 - 1981
(2007/10/03)
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- Participation of Phosphonate Neighbour Groups with Dehydrogenations of Amines
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Aminophosphonates 1-5 are dehydrogenated with mercury EDTA to the corresponding lactams 6-9 and suprisingly to the formamide derivative 10.The different rate of ester hydrolysis of these acylamine compounds, the steric requirements and the reaction mechanisms are discussed. - Keywords: Aminomethanephosphonate, Mercury EDTA Dehydrogenation, Lactam, Formamide, Aminoalkylation
- Moehrle, Hans,Vetter, Wolfgang
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p. 1662 - 1671
(2007/10/02)
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- Enamine synthesis using the Horner-Wittig reaction. Part 1. (Aminomethyl)diphenylphosphine oxides, new formyl anion equivalents
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Using the Horner-Wittig reagent (morpholinomethyl)diphenylphosphine oxide (7), aromatic, aliphatic and α,β-unsaturated aldehydes are converted into morpholino enamines of their homologous aldehydes.With diphenylphosphine oxide (12), the same aldehydes, together with the ketones (cyclic as well as acyclic, both saturated and α,β-unsaturated), are converted into enamines of their homologous aldehydes.Both types of enamines are converted into the corresponding aldehydes by mild, acid-catalyzed hydrolysis, showing the utility of 7 and 12, as formyl anion equivalents.Preparation of each geometrical isomer of the N-methylanilino enamines is possible since the intermediate diastereoisomeric adducts 13 can be separated.
- Broekhof, N. L. J. M.,Gen, A. van der
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p. 305 - 312
(2007/10/02)
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