Abstract The esters of 4-hydroxy-5-phosphinyl-2-imidazolidinone were prepared by reaction of urea with the esters of 2-hydroxy-2-phosphinylethanal in acidic medium. The ir, 1 H nmr and 31 P nmr spectral data of the products are reported. All the isolated products had cis configuration. The stereochemistry of their formation is discussed.
