Monodealkylation esters

Dealkylation of phosphonates. Vigorous acid treatment is usually required for this reaction. To circumvent this difficulty, both bromo- and chloro-trimethylsilane have been used with limited success. lodotrimethylsilane is more selective the parent phosphonic acids can be obtained under very mild conditions without modification of a variety of other functional groups. However, monodealkylation is not practical with this reagent. Aryl esters are not cleaved hence selective dealkylation of alkyl aryl esters of phosphonic acids may be possible. 

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

Phosphite or pyrophosphite esters undergo dealkylation by protonic acids with decreasing ease in the series hydrogen halide, carboxylic acid, alcohol, or phenol. The carboxylic acid reaction (18,31,171), which stops at monodealkylation, has been utilized (141) for the synthesis of aryl esters of amino acid derivatives. 

The 2-oxoazetidine-l-phosphonic acids (22) have been prepared by monodealkylation of the corresponding dialkyl esters with thiourea. The acid (22 R = R = H) was obtained, as its monoanilinium salt, by reaction of its bis-(trimethylsilyl) ester with aniline in ether. ... 

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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