A short and convenient synthesis of [1-18O] and [4-18O] vitamin K1

Abstract

Vitamin K1 was quantitatively reduced by Na2S2O4 to dihydrovitamin K1 (2). The hydroquinone 2 was partially methylated by CH3I/K2CO3 to give a mixture of 1 and 4 monomethylethers which were separated by HPLC. Each monoether was oxidized by ceric ammonium nitrate in the presence of [18O] H2O to afford the specifically labelled [1‐18O] or [4‐18O] vitamin K1 with isotopic enrichments of 93–95%. © 1998 John Wiley & Sons, Ltd.