IMPROVED SYNTHESIS OF [3',5'-(H-2)2]FOLIC ACID - EXTENT AND SPECIFICITY OF DEUTERIUM LABELING

As an extension of research concerning stable-isotopic labeling of folates, this report describes a modification of our previous procedure for the preparation of folic acid labeled with deuterium at the 3',5'-positions. The major procedural changes were (a) preliminary removal of exchangeable protons from the substrate, 3',5'-dibromofolate, and (b) the catalytic dehalogenation reaction conducted in an aprotic solvent of NaOD in D2O. Proton NMR examination of the resulting [3',5'-2H2]folic acid indicated complete labeling of the 3',5'-positions. Labeling of other positions of the folate molecule was not detected. © 1990, American Chemical Society. All rights reserved.