Electronic control of stereoselectivity. 6. Directionality of singlet oxygen addition to 1,4-dimethoxynaphthalenes laterally fused to bridged bicyclic systems
A composition is provided that, when utilized in combination with warfarin, greatly improves the anticoagulant effects of warfarin in mammalian subjects. The composition is a compound having a naphthohydroquinone ring system substantially similar to the ring system of the reduced form of vitamin K
1
and has the general formula:
where R
1
and R
4
are hydrogen or acyl, R
2
is a saturated or unsaturated alkyl group with up to 6 carbons, and R
3
is a saturated or unsaturated alkyl group with up to 20 carbons, or R
2
and R
3
are part of a cyclic or polycyclic ring system.