Alkylphosphonic acids synthesis

The reactions used for synthesis of II-VI (CdSe, CdTe), III-V (InP, InAs), and IV-VI (PbS, PbSe, PbTe) semiconductor nanocrystals are outlined by Schemes 3-5.4,17,30-32 The syntheses are carried out at high temperatures, and in the presence of long-chain alkylphosphines (trioctylphosphine,TOP), alkyl-phosphine oxides (trioctylphosphine oxide, TOPO), alkylamines (hexadecyl-amine, HD A), and alkylphosphonic acids as the stabilizing agents. 

Peptide synthesis. The anhydride effects peptide synthesis as shown in equation (I). Free acid groups arc buffered with a tertiary amine such as N-elhylmorpholine. The reaction is complete after 24 hours at room temperature. No raccmization is detected in the Anderson-Young test. The resulting alkylphosphonic acid derivative is soluble in water and easily removed. 

Hanessian, S., and Bennani, Y.L., A versatile asymmetric synthesis of a-amino a-alkylphosphonic acids of high enantiomeric purity, Tetrahedron Lett., 31, 6465, 1990. 

Aboujaoude, E.E., Colhgnon, N., Savignac, P, and Bensoam, J., Synthesis of m-amino-co-carboxy-alkylphosphonic acids. Phosphorus Sulfur, 34, 93, 1987. 

The zinc and cadmium reagents " " (R0)2P(0)CF2MBr have also proved useful as alkylation substrates for particularly reactive species, e.g. allylic, benzylic or propargylic halides with the last type, some rearrangement to allenic compounds is observed. Scheme 12 illustrates the use of such reagents in the synthesis of a-fluorinated alkylphosphonic acid derivatives. 

An efficient and solvent-free synthesis of O-alkyl alkylphosphonic acids (80) has been described by Dubey et al. (Scheme 25). This methodology involved monoesterification of the corresponding alkyl phosphonic acids using DCC-celite as the condensing reagent system under solvent-free conditions. ... 

Chapters 2-5 focus on the synthesis, spectroscopic analysis, and herbicidal activity of 30 series phosphorus-containing compounds including alkylphosphonates, monosalts of alkylphosphonic acids, alkylphosphinates, monosalts of alkylphosphinic acids, cyclic phosphonates, and caged bicyclic phosphates (Scheme 1.20). Their stmcture-activity relationships are discussed in detail in each chapter. 

Wang J, Chen XY, Liu XF et al (1999) The synthesis and biological properties of a-halogenated phenoxy carbonyloxy alkylphosphonic acids and esters. Chin J Chem Reag 21 301-303... 

In this section, we describe the synthesis, herbicidal activity and structure-activity relationships of alkali metal salts of O-alkyl 1-(substituted phenoxyacetoxy) alkylphosphonic acids IIA-IIE. 

Alkali metal salts of 0-alkyl 1-(substituted phenoxyacetoxy)alkylphosphonic acids IIA-IIE could be easily synthesized by the reaction of (9,(9-dialkyl 1-(substituted phenoxyacetoxy)alkylphosphonates lA or IC with corresponding lithium bromide, sodium iodide, or potassium iodide in refluxing acetone. The synthetic route of IIA-IIE is shown in Scheme 3.5. For the synthesis of IIA-IIE, 1-hydrox-yalkylphosphonates M2, substituted phenoxyacetyl chloride MS, and 0,(9-dialkyl 1-(substituted phenoxyacetoxy)alkylphosphonates lA or IC could be prepared according to the known methods as stated in Chap. 2. 0,0-Dialkyl phosphonate Ml was used directly as obtained commercially or prepared by the reaction of phosphorus trichloride and methanol. Ml reacted with different aldehydes to give 0,0-diaUtyl 1-hydroxyalkylphosphonates M2. The substituted phenoxyacetic acids M4 were prepared in satisfactory yields by the reaction of corresponding substituted phenols with 2-chloroacetic acid or ethyl 2-bromoacetate followed by hydrolysis. The substituted phenoxyacetyl chlorides M5 could be easily obtained by the treatment of M4 with excess thionyl chloride. M2 reacted with MS to provide lA or IC (Scheme 3.5). 

Scheme 3.10 Synthesis of mono alkali metal salts of I-(substituted phenoxyacetoxy) alkylphosphonic acids IIF, IIG and IIH...

Some monosalts of alkylphosphonic acid derivatives like lithium, sodium, and potassium salts could be synthesized under harsh conditions by using metal iodides as catalysts under nitrogen atmosphere [7-12]. However the synthesis of r-butylamin-ium phosphonates could be performed under relatively mild conditions [22, 23]. 

Scheme 9.11 Synthesis of 0,0-bis(trimethylsilyl) alkylphosphonates M8 and alkylphosphonic acids M9...

Scheme 9.12 Synthesis of alkali metal salts of alkylphosphonic acids IIF-IIH...

Razumov, A.L, and Korobkova, E.L. Derivatives of alkylphosphonous and phosphonic acids. Part 11. Synthesis of dicarbethoxymethyl esters of ethyl- and carbethoxymethylphosphonic acids, Trudy Kazan. Khim. Tekhnol. Inst., 23, 215, 1957 Chem. Abstr, 52. 9948d, 1958. 

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