The radical alkylation of 1,4-naphthoquinone with various lengths of fatty acids [H(CH2)nCO2H] in the presence of (NH4)2S2O8 and AgNO3 was studied. A simple and effective method was found for the synthesis of vitamin-K derivatives with different lengths of alkyl side chain. Two types of vitamin-K derivatives were synthesized. The first type, 2-alkyl-1,4-naphthoquinones, was synthesized by a single step of radical alkylation of 1,4-naphthoquinone with different lengths of fatty acids. The second type, 2-alkyl-3-methyl-1,4-naphthoquinones, was synthesized by radical alkylation of 2-methyl-1,4-na...
