1981 Volume 45 Issue 4 Pages 831-838
5-(4-Hydroxyphenyl)hydantoin (p-HPH), an important intermediate in production of D-2-(4- hydroxyphenyl)glycine, was synthesized by employing new amidoalkylation reaction of phenol with glyoxylic acid and urea under acidic conditions, accompanied by formation of the isomer, i.e. 5-(2- hydroxyphenyl)hydantoin (o-HPH).
The ratio of p-HPH was found to be mainly influenced by the reaction method (the manner of charging raw materials) and reaction conditions, particularly reaction temperature, although more p-HPH was always produced than o-HPH (p-HPH/o-HPH= 3-7).
The reaction mechanism of HPH formation was also examined using possible the intermediates glyoxylurea, allantoin and p-hydroxymandelic acid.
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