Menadione is analog of?

The principal role of vitamin K is in the posttranslational modification of various blood clotting factors, in which it serves as a coenzyme in the carboxylation of ceain glutamic acid residues present in these proteins.Vitamin K exists in several forms, for example, in plants as phylloquinone (or vitamin K1), and in intestinal bacterial flora as menaquinone (or vitamin K2). A synthetic form of vitamin K, menadione, is availableReference: Lippincott edition 5; page no: 389