Phosphoric monodealkylation

Savignac, P, and Lavielle, G., Monodealkylation of phosphoric and phosphonic esters by thiolates and thiophenates. Bull. Soc. Chim. Fr., 1506, 1974. 

Oximes, which are valuable intermediates for the conversion of oxoalkyl phosphonic diesters into those of aminoalkylphosphonic acids (Chapter 4, Section IV.C. 1. d), are also readily available, although it is necessary to prepare them with some care. Nevertheless, the feature of interest here is their ready degradability, particularly under aqueous conditions, and which has been intensively investigated by Breuer and coworkers. The necessity for care in the preparation of oximes of acylphosphonic diesters, is illustrated by the synthesis of dimethyl [a-(hydroxyimino)benzyl]phosphonate this compound exists in the thermodynamically more stable ( ) form which, under the influence of acid is converted into the less stable (Z) form, and both forms have been separately characterized by X-ray crystallography. The geometric isomers of the oxime differ in their behaviour under basic conditions with NaOH-MeOH, the ( ) form undergoes monodealkylation, whereas the (Z) isomer decomposes to dimethyl phosphate and benzonitrile. In aqueous solution, ( )-[a-(hydroxyimino)benzyl]phosphonic acid also decomposes into benzonitrile together with phosphoric acid, in a manner which is pH dependent, and consistent with a dissociative mechanism that involves the early formation of monomeric metaphosphate. ... 

Aminophosphatides—Monodealkylation of phosphoric acid esters s. 19, 26 Selective removal from peptide hy dr azides—Preferential removal s. 76, 31 Alkoxylamines from N-acylalkoxylamines ONHAc ONHg... 

Removal of N-carbo-lerf-butoxy protective groups Monodealkylation of phosphoric acid esters... 

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