| 摘要 |
<p>1476110 Obtaining optically pure D-p-hydroxyphenylglycine PFIZER Inc 20 Nov 1975 [9 Jan 1975] 47870/75 Heading C2C The invention comprises a process for separating D-p-hydroxyphenylglycine from a mixture containing D and DL-p-hydroxyphenylglycine and/or the C 1-10 alkyl esters thereof wherein (a) said mixture is dissolved in aqueous hydrobromic acid (b) insoluble DL-p-hydroxyphenylglycine HBr is separated from the solution, (c) the pH of the solution is adjusted to a value in the range 4À0 to 6À0 and (d) isolating the D- isomer from the solution in crystalline form. The hydrobromide of D-p-hydroxyphenylglycine may be isolated from stage (b) after separation of the DL isomer by, e.g. evaporation of the HBr and then dissolved to form an aqueous solution from which the free amino acid can be obtained by treatment with alkali. When the starting material is or includes C 1-10 alkyl esters these are hydrolysed during the reaction.</p> |
