Alajos Grün*, István Greiner and György Keglevich* Pages 968 - 973 ( 6 )
The addition of phosphorous acid on the C=O group of substituted benzaldehydes in the presence of hydrochloric acid in water affords a mixture of the corresponding α - chlorophosphonic acid and α-hydroxyphosphonic acid. The selectivity towards the α-chloro derivatives may be increased to 92% by the excess of HCl applying forcing conditions. α- Hydroxyphosphonic acids may be synthesized better in yields of 83-92% by the hydrolysis of the corresponding dimethyl α-hydroxyphosphonates. α-Chlorophosphonic acids may also be obtained in yields of 66-79% from α -hydroxyphosphonic esters by reaction with thionyl chloride followed by hydrolysis. The α -chlorophosphonic acids and esters are useful intermediates for other phosphonic derivatives.
Phosphorous acid, dimethyl phosphite, substituted benzaldehydes, α-chlorophosphonic acid, α -hydroxyphosphonic acid, organophosphorus compounds.
Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, 1521 Budapest, Gedeon Richter Plc. 1475 Budapest, Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, 1521 Budapest