Aliphatic phosphorus esters

Aliphatic phosphorus esters that do not cause delayed neurotemidty include phosphorothioates, phosphonothioates, phosphinates, phosphinofluoridates, and phosphorochloridates. 

FIGURE 18-2. Stmctures of phosphate esters that produce delayed neurotoxicity. (A) Aliphatic phosphorus ester. 

Polycondensation between allg l/atyl phosphoric dichlorides with diols or bisphenols (Scheme 6.2) is one of the oldest methods for obtaining PPEs. The earliest works about polycondensation were summarized more than 50 years ago in a book by Gefter. Beside traditional melt and solution polycondensation in the presence of a tertiary amine as HCl scavenger,this route also includes interfacial polycondensation. The molecular weights of PPEs obtained through polycondensation between allq l phosphoric dichlorides and aliphatic diols are often limited by side reactions (Scheme 6.3), such as chlorination of the diol, acidolysis of the side chain, and competitive formation of cyclic phosphorus esters in the case of 1,2- and l,3-diols. ... 

Phosphorus acids and esters possess P-OH groups which produce one or two broad bands in the 2700-2100 cm region. Aliphatic phosphorus compounds... 

Serbezeanu Diana, Vlad-Bubulac Tachita, and Hamciuc Corneliu. Synthesis and characterization of new aromatic-aliphatic poly(ester-imide)s containing phosphorus. Rev. Roum. Chim. 55 no. 10 (2010a) 667-672. 

Phosphated and Polyphosphated Alcohols In most cases aliphatic alcohols with a chain length in the range of 10-20 carbon atoms are converted with phosphorus pentoxide. A mixture of alkyl dihydrogen esters (primary) and dialkyl hydrogen esters (secondary) are yielded. 

In the Diels-Alder reaction with inverse electron demand, the overlap of the LUMO of the 1-oxa-l,3-butadiene with the HOMO of the dienophile is dominant. Since the electron-withdrawing group at the oxabutadiene at the 3-position lowers its LUMO dramatically, the cycloaddition as well as the condensation usually take place at room or slightly elevated temperature. There is actually no restriction for the aldehydes. Thus, aromatic, heteroaromatic, saturated aliphatic and unsaturated aliphatic aldehydes may be used. For example, a-oxocarbocylic esters or 1,2-dike-tones for instance have been employed as ketones. Furthermore, 1,3-dicarbonyl compounds cyclic and acyclic substances such as Meldmm s acid, barbituric acid and derivates, coumarins, any type of cycloalkane-1,3-dione, (1-ketoesters, and 1,3-diones as well as their phosphorus, nitrogen and sulfur analogues, can also be ap-... 

The kinetics of oxidation of several para-substituted anilines and aliphatic acetals by peroxomonosulfate in aqueous acetic acid have been investigated. In the oxidation of sulfides to sulfoxides by peroxymonosulfate (Oxone), the observed increase in second-order rate constants with increasing concentration of H2SO4 has been shown to be due to the increasing polarity of the medium, rather than to acid catalysis. Similar conclusions were arrived at for the oxidation of aryl thiobenzoates and thiol-phosphorus(V) esters. 

The optical purity of a- and /J-thiol carboxylic esters, a-thiolamides, secondary benzylic thiols and aliphatic thiols can be measured by l3PNMR using a nonchiral divalent phosphorus... 

General methods for the preparation of acid halides from aliphatic carboxylic acids are described in Section 5.12.1, p. 692. Phosphorus pentachloride is the preferred chlorinating agent for aromatic acids which contain electron-withdrawing substituents, and which do not react readily with thionyl chloride. The preparation of both p-nitrobenzoyl chloride and 3,5-dinitrobenzoyl chloride is described in Expt 6.161. These particular acid chlorides are valuable reagents for the characterisation of aliphatic alcohols and simple phenols, with which they form crystalline esters (see Section 9.6.4, p. 1241 and Section 9.6.6, p. 1248). 

Plasticizers include the esters of a few aliphatic and aromatic mono and dicarboxylic acids, aliphatic and aromatic phosphorus acid esters, ethers, alcohols, ketones, amines, amides, and non-polar and chlorinated hydrocarbons. These additives are used in various mixtures. For their separation and qualitative detection, thin-layer chromatography (TLC) is preferred. Usually Kieselgur plates, 0.25 mm thick, activated at 110°C for 30 min, in the saturated vapor are used. Methylene chloride and mixtures of diisopropyl ether/petether at temperatures between 40 to 60°C have been successfully used as the mobile phase. Refer to Table 1. 

Different OP compounds have structural similarities within classes. The phosphorus compounds have the characteristic phosphoryl bond, P=0. Most OP compounds have a phosphoryl bond or a thiophosphoryl bond (P=S). All OP compounds are esters of phosphorus with varying combinations of oxygen, carbon, sulfur, and nitrogen attached. These are classified as (1) phosphates (2) phos-phonates (3) phosphorothioates (4) phosphorodithioates (5) phosphorothiolates and (6) phosphoramidates. Further, the OP compounds are categorized as (1) aliphatic (2) phenyl and (3) heterocyclic derivatives. The aliphatic are carbon chainlike in structure. TEPP, which was used in agriculture for the first time in 1946, is a member of this group. Others include malathion, trichlorfon, monocrotophos, dimethoate, oxydemetonmethyl, dimethoate, dicrotophos, disulfoton, dichlorvos, mevinphos, methamidophos, and acephate. 

A one-pot synthesis of 3,5-disubstituted 7-hydroxy-3//-l,2,3-triazolo[4,5-d]pyrimidines (130) has been carried out by using benzyl azide, cyano-acetamide, ethyl or methyl esters of the appropriate carboxylic acid, and sodium ethoxide as catalyst. The reaction proceeds via a 5-amino-l-benzyltriazole-4-carboxamide intermediate (85JHC1607). 7-Amino-3H-l,2,3-triazolo[4,5-d]pyrimidines 133 (R2 = H) were prepared starting from benzyl azide, malononitrile, and an aliphatic or aromatic nitrile, or by reaction of 130 with phosphorus oxychloride followed by amination. Compound 132 was formed in most reactions from two molecules of the 5-amino-4-cyano-l-benzyltriazole intermediate by an intermolecular nucleophilic at-... 

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