M. Cowart et al., A NEW SYNTHESIS OF DOUBLE-LABELED [7,9-C-13(2)]FOLIC ACID, Journal of labelled compounds & radiopharmaceuticals, 34(1), 1994, pp. 67-71
A convenient small scale chemical synthesis of double labeled folic ac
id with C-13 at positions C-7 and C-9 is reported. [1,3-C-13(2)] aceto
ne was converted into folic acid in two steps, with [1, 1, 3]-trichlor
oacetone as the labeled intermediate.