Oxygen → 1-Methyl-1-oxophospholanyl methyl phosphinic acid methyl ester

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Reaction Steps

6 g of tert.-butyl peroctoate in 30 g of methane phosphonous acid methyl ester and 116 g of 1-methyl-1-oxophospholine are added dropwise to 282 g of oxygen-free methane phosphonous acid methyl ester at 120° C. with stirring. The reaction time is 90 minutes. Excess methane phosphonous acid methyl ester and a small quantity of 1-methyl-oxophospholine are distilled off. The residue, consisting of 205 g of 1-methyl-1-oxophospholanyl-methyl phosphinic acid methyl ester is purified by distillation under vacuum (bp1 mm : 210° to 220° C.) to yield 186 g of pure product which solidifies very slowly to stellate crystals which begin to reliquefy at 70° C. Acid saponification leads to isomeric 1-methyl-1-oxophospholanylmethyl phosphinic acids of the idealized constitution: ##STR17##

Provenance & Evidence