Phosphinic acid amides anhydrides

A variety of compounds have been examined which are in the phosphinic acid class. They include a phenyl cyclopentyl ester,184 a phosphinothioic anhydride,185 a dipheny1phosphinamide, 86 a red bis(di-t-buty1thiophosphinamide) and its selenide analogue,187 the anisylphosphor inane (67),1 88 the thioamide (68),1 89 and the phospholenium amide (69, Y = i-Pr2N).190... 

With these considerations in mind it was decided to investigate phosphinic-carboxylic mixed anhydrides in peptide methodology. .Mechanistic consideration of the reactants (2) and (3) and products shown above would suggest regiospecific nucleophilic attack by the amine component due to the formation of an amide bond with concomitant generation of a new P-0 bond.As in the study of phosophinamidates discussed above,a series of phosphinic acids were selected for preparation of the mixed anhydrides (2) because of the intimate steric and electronic... 

A different approach toward preparation of phosphinous and phosphonous iodides uses the reaction of iodoalkanes with either PI3 or PI5. This reaction is specific for iodoalkanes and phosphorus iodides and is not applicable to other halides. From the resultant highly reactive phosphinous and phosphonous iodides, the full range of the parent acid derivatives may be prepared (esters, other acid halides, anhydrides, amides). We will not be concerned here with these preparations of derivatives of the parent acids, topics that are considered in other reports. ... 

A-Phosphorylated imidazoles and benzimidazoles can be made by direct phosphorylation by halides, esters, amides, amidoesters, isocyanates, and thiocyanates of phosphorus-containing acids, or from reaction of phosphonic or phosphinic imidazolides with a sulfonic acid or anhydride <82CB1636>. Stable charge transfer complexes are produced when a 1 1 or 1 2 ratio of imidazole (or benzimidazole) and sulfur trioxide are refluxed in ether, dioxane, THE, or 1,2-dichloroethane. These complexes are stable on storage in the absence of water and have sharp melting points. Indeed, the benzimidazole SO3 complex must be boiled for five hours in water to decompose it. On fusion, the complexes form the C-sulfonic acids (see Section 3.02.5.3.3) <87CHE1084>. Sulfonyl chlorides readily A-sulfonate imidazoles <94JMC332>. 

Dehydration reactions using the tertiary phosphine-carbon tetrachloride adduct have appeared quite regularly in the literature again this year. Among those reported have been the dehydrations of oximes to nitriles, carboxylic acids to anhydrides, and the amides (37) to the cumulenes (38). Further reaction of the dehydration product from treatment of the... 

A related technique involves a tris(dimethylamino)phosphine-carbon tetrachloride reagent, where interaction with carboxylic acids gives anhydrides and tris(dimethylamino)phosphonium chloride (95), which can, in turn, activate remainingacid for furtherreaction, e.g. tocomplete anhydride formation, giving the overall process shown in Scheme 31. Alternatively, it can be used to effect amide-bond formation, when nucleophilic attack by amine on... 

A-Tosylsulphimides (90) are reduced to sulphides (92) in DMF in high yields by the action of phosphines or cyanide ion " (Scheme 5). This reaction proceeds by initial attack of the nucleophile on tervalent sulphur (5n2-S mechanism). The intermediate 1,3-dipoles (91) were shown to be powerful dehydrating reagents which converted carbonic acids into anhydrides, or, in the presence of alcohols and amines, into esters and amides, respectively." The use of alcohols alone led to alkyl-exchanged sulphides (93). Thiophenolate ion and (90) gave quantitatively the sulphide arising by a SN2-type reaction on the carbon atom... 

Geranyl chloride can be prepared from geraniol by the careful use of triphenylphosphine in carbon tetrachloride. Tris(dimethylamino)phosphine reacts with carbon tetrachloride to form the complex (42) which can be used to form the enol esters (43) from acid anhydrides. Similarly, aldehydes form the alkenes (44), and esters or amides of trichloroacetic acid are converted to glycidic esters. ... 

The phosphinic isocyanates (116) and isothiocyanates (117) react with oxygen, nitrogen, and phosphorus nucleophiles by attack at carbon rather than phosphorus. Phenyl phosphonodichloridate has been recommended as a useful reagent for the activation (presumably by mixed anhydride formation) of carboxylic acids for conversion to amides and hydrazides. ... 

The use of polymer-bound triphenylphosphine has also been described in combination with carbon tetrachloride for the condensation of carboxyhc acids with primary amines to give amides via the corresponding in situ formed mixed phosphinic anhydride, and for the conversion of aliphatic alcohols to the corresponding alkyl chlorides [38]. 

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