Aliphatic Phosphorus Compounds

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

The deoxygeneration of nitroarenes by trivalent phosphorus compounds in the presence of amines is a useful route to 3/f-azepin-2-amines (cf. compounds 32, Section 3.1.1.4.2.2.). Subsequently, it has been shown, by carrying out the reaction in strongly basic solution, that the process can be extended to the synthesis of 1H-. 3H- and 5//-2-benzazepines from nitronaph-thalenes 43 For example, 1-nitronaphthalenes 3 with dimethyl phosphite in the presence of sodium methoxide and a primary or secondary aliphatic amine, yield the dimethyl 5//-2-ben-zazepin-3-yl phosphonates 4 accompanied, in some cases, by the isomeric 3//-2-bcnzazepin-3-yl phosphonates 5. 

Trinitrochlorobenzene (piciyl chloride) in pyridine-A -mcthylpyrrolidi-none (NMP) solutions were later used for the preparation of polyesters from dicarboxylic acids and diphenols or aliphatic diols,309 but better results have been obtained with sulfonyl chlorides and phosphorus compounds. 

The Tetrahedral Carbon Atom.—We have thus derived the result that an atom in which only s and p eigenfunctions contribute to bond formation and in which the quantization in polar coordinates is broken can form one, two, three, or four equivalent bonds, which are directed toward the corners of a regular tetrahedron (Fig. 4). This calculation provides the quantum mechanical justification of the chemist s tetrahedral carbon atom, present in diamond and all aliphatic carbon compounds, and for the tetrahedral quadrivalent nitrogen atom, the tetrahedral phosphorus atom, as in phosphonium compounds, the tetrahedral boron atom in B2H6 (involving single-electron bonds), and many other such atoms. 

Roundup [AMINES - LOWER ALIPHATIC AMINES] (Vol 2) [GROWTHREGULATIONS - PLANT] (Vol 12) [GENETICENGINEERING - PLANTS] (Vol 12) phosphorus compound [PHOSPHORUS COMPOUNDS] (Vol 18)... 

Many other aliphatic or aromatic amines produce the same reaction. However if N-alkyl (or aryl)2-aniline is made to react with tris-dimethylaminophosphine, tricoordinated phosphorus compounds are obtained. Their analyses and mass spectra show that they are tetramers (5) when the energy of the ionizing electron beam is nearly 70 eV the mass spectra of the oligomers show an intense [M] peak which corresponds to the monomer ion (n = 1) but when the spectra are obtained by field desorption m.s. the molecular ion peak corresponds to a tetramer (n = 4) one sees also smaller peaks for ions n = 3, 2 or 1. 

The percentage of dicoordinated phosphorus compound present depends equally on the substituent R, on the solvent and on the temperature. It has been possible to prepare these oligomers from monosubstituted aliphatic or aromatic diamines, from amidrazones, from semicarbazides, from substituted thiosemicarbazides, from 2-aminophenol, from 2-aminothiophenol and even from the monoimines of orthophenylediamine (Table I). It seems that these oligomers are generally the thermodynamic products of the reaction, except perhaps for the amidrazones, and the 1-phenyl semicarbazide in which case they would be kinetic products (the thermodynamic products being the triazaphospholes). 

Figure 3.16. The Stern-Volmer constant as a function of the half-wave potential E /2 for the reactions with trivalent phosphorus compounds (o), aromatic amines ( ), aliphatic amines ( ), and alkoxybenzenes (A)- The solid broken line represents the diffusional (horizontal) and kinetic branches of Ko for the irreversible reaction, while the dotted line is k from Eq. (3.22). The dashed curve represents Ko for reversible reactions. (From Ref. 121.)...

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. 

The full AM1-SM2 model is discussed in more detail in the final section. Within the context of Tables 2-5, however, it is worth noting that the model enjoys the largest correlation to experimental data for the neutral solutes. All but a few of the molecules listed comprise a subset of a larger data set of 147 neutral solutes spanning many functionalities (e.g., nitro groups, phosphorus compounds, sulfides, bromides, fluoroalkanes, iodides, polyfunctional compounds), not shown because they have not been studied by other methods, for which the AM1-SM2 model has a mean absolute error of 0.6 kcal/mol.203 One apparent flaw illustrated here is that AM1-SM2 consistently underestimates the free energies of solvation for aliphatic and alicyclic ethers. 

A phosphorus analog of aliphatic azo compounds, bis[tris-(trimethylsilyl)methyl]di-phosphene, (Me3Si)3C-P=P-CSiMe3, shows a rapid reversible one-electron reduction to its radical anion at a mercury-coated platinum electrode in DME, MeCN [85], or THF [86]. The arseneous analog is reduced similarly [86] at a potential about 0.5V less negative the anion radical is less stable than that of the phosphorus compound. 

Carbonyl compounds are capable of undergoing another completely different sort of reaction, in which the carbonyl oxygen is replaced, not by a heteroatom as we saw above, but by an sp carbon atom. When triphenylphosphine is treated with a secondary aliphatic halide, a normal substitution reaction occurs, resulting in the replacement of the halide by the phosphorus compound. This phosphonium salt adduct may then be treated with a very strong base, such as phenyllithium, to produce an ylid. An ylid is a compound in which there is a positive charge adjacent to a negative charge. Write down this reaction sequence. 

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