Folates isotopologues

The first deuterated folate to be used as internal standard was [ H4]-folic acid labelled in the 4-aminobenzoate moiety the latter was the base for the first folate analogues for naturally occurring folates (Freisleben et al. 2002). The latter were the first to be used as internal standards for folates in foods not fortified with folic acid (Freisleben et al. 2003b). Further folate isotopologues were synthesized thereafter, and an extensive synthetic study was presented by Maunder et al. (1999) with routes to pH4]-folic acid and [ Csl-folic acid labelled in the glutamate moiety and the benzene moiety, respectively. 

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