63581-66-8Relevant academic research and scientific papers
Selective esterification of phosphonic acids
Brodzka, Anna,Koszelewski, Dominik,Ostaszewski, Ryszard,Trzepizur, Damian
, (2021/09/27)
Here, we report straightforward and selective synthetic procedures for mono-and diesteri-fication of phosphonic acids. A series of alkoxy group donors were studied and triethyl orthoacetate was found to be the best reagent as well as a solvent for the performed transformations. An important temperature effect on the reaction course was discovered. Depending on the reaction temperature, mono-or diethyl esters of phosphonic acid were obtained exclusively with decent yields. The sub-strate scope of the proposed methodology was verified on aromatic as well as aliphatic phosphonic acids. The designed method can be successfully applied for small-and large-scale experiments without significant loss of selectivity or reaction yield. Several devoted experiments were performed to give insight into the reaction mechanism. At 30?C, monoesters are formed via an intermediate (1,1-diethoxyethyl ester of phosphonic acid). At higher temperatures, similar intermediate forms give diesters or stable and detectable pyrophosphonates which were also consumed to give diesters.31P NMR spectroscopy was used to assign the structure of pyrophosphonate as well as to monitor the reaction course. No need for additional reagents and good accessibility and straightforward purification are the important aspects of the developed protocols.
Investigation of reactive intermediates and reaction pathways in the coupling agent mediated phosphonamidation reaction
Fredriksen, Kim Alex,Amedjkouh, Mohamed
supporting information, p. 474 - 482 (2016/02/18)
The preparation of carboxamides through the coupling agent mediated reaction of carboxylic acids and amines is one of the most frequently employed reaction types of modern organic synthesis and has largely replaced older methods of amide formation based on reactive acyl chloride intermediates. However, the preparations of analogous phosphonamidates still rely on the use of phosphonochloridate intermediates - a method that is incompatible with sensitive functional groups. Herein, we present a comprehensive study in which different coupling agents are tested in the phosphonamidation reaction. The procedures, parallel to those typically applied to the preparation of carboxamides, were generally unsuccessful with regard to the coupling reactions of monoesters of phosphonic acids and amines, with the exception of those mediated by (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyBOP). The implementation of a preactivation period in the absence of the amine coupling partner allowed for efficient phosphonamidate formation with coupling agents such as (1-cyano-2-ethyoxy-2-oxoethylideneaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU), [ethyl cyano(hydroxyimino)acetato-O2]tri-1-pyrrolidinylphosphonium hexafluorophosphate (PyOxim), dicyclohexyl carbodiimide (DCC), N,N′-diisopropylcarbodiimide (DIC), and N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uronium hexafluorophosphate (HBTU). The reactive intermediates observed by 31P NMR analysis were individually synthesized and examined to understand their influence on the reaction. A phosphonamidation reaction that uses (1-cyano-2-ethyoxy-2-oxoethylideneaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU) to mediate the coupling of monoalkyl esters of phosphonic acids and amines was developed. A preactivation period without the amine was needed to obtain the product. Using this step allowed for other coupling agents to be successfully used in the reaction.
Palladium(II)-catalyzed ortho-arylation of benzylic phosphonic monoesters using potassium aryltrifluoroborates
Meng, Xiangjian,Kim, Sunggak
, p. 11247 - 11254 (2013/12/04)
The new monophosphonic acid directing group was successfully utilized in the Pd (II)-catalyzed ortho-arylation of benzylic phosphonic monoesters using potassium aryltrifluoroborates. A wide range of benzylic phosphonic monoesters underwent clean ortho-ary
Phosphonic acid analogs of GABA through reductive dealkylation of phosphonic diesters with lithium trialkylborohydrides
Chowdhury, Sarwat,Muni, Niraj J.,Greenwood, Nicholas P.,Pepperberg, David R.,Standaert, Robert F.
, p. 3745 - 3748 (2008/02/13)
Lithium trialkylborohydrides were found to effect rapid monodealkylation of phosphonic diesters, and this reaction was applied to the synthesis of alkylphosphonic acid 2-aminoethyl esters [H2N(CH2)2OP(OH)R, 4], a little-ex
Phosphonosulfates. Metal Ion Catalysis in the Hydrolysis of 2-Pyridyl- and 2-Pyridylmethylphosphonosulfate
Eiki, Toshio,Horiguchi, Tetsuo,Ono, Michimasa,Kawada, Shuji,Tagaki, Waichiro
, p. 1986 - 1991 (2007/10/02)
The hydrolysis rates of phosphonosulfates, having a neighboring 2-pyridyl group, 2-pyridyl- (1) and 2-pyridylmethylphosphonosulfate (2), have been compared with those of the corresponding phenyl- (3) and benzylphosphonosulfate (4) in a pH range of 1-9.All
