VITAMIN K-LIKE AND ANTIVITAMIN K ACTIVITY OF SUBSTITUTED PARA-BENZOQUINONES

¹ Department of Pharmacology and Therapeutics, University of Manitoba Faculty of Medicine, Winnipeg, Canada

Suitably substituted para-benzoquinones can show vitamin K-like or antivitamin K activity. The type of activity depends on the nature and position of the substituents.

The benzoquinone analogue of vitamin K₁, 2,5,6-trimethyl-3-phytyl-1,4-benzoquinone, shows low vitamin K-like activity and acts as a partial agonist of vitamin K₁.

Replacement of the methyl group in the 2-position by a chlorine on bromine atom results in antivitamin K activity, while replacement by a hydrogen atom or methoxy group gives compounds without vitamin K-like or antivitamin K activity.

The methyl groups in the 5- and 6-position are necessary for both vitamin K-like and antivitamin K activity. Replacement of the methyl groups in these positions by a chlorine atom or methoxy group results in loss of either activity.

Replacement of the phytyl side chain in the 3-position by shorter polyisoprenoid side chains in compounds with vitamin K-like or antivitamin K activity also results in loss of either activity.