• vitamin
  • The primary mechanism of the 4-hydroxycoumarin drugs is the inhibition of vitamin K epoxide reductase. (wikipedia.org)
  • As such, these compounds form the most important and widely used subset of vitamin K antagonist drugs, but other such drugs exist which do not have the 4-hydroxycoumarin structure. (wikipedia.org)
  • The MK-7 and other bacterially derived forms of vitamin K2 exhibit vitamin K activity in animals, but MK-7's extra utility over MK-4, if any, is unclear and is a matter of investigation. (wikipedia.org)
  • A review of 2014 concluded that there is positive evidence that monotherapy using MK-4, one of the forms of Vitamin K2, reduces fracture incidence in post-menopausal women with osteoporosis, and suggested further research on the combined use of MK-4 with bisphosphonates. (wikipedia.org)
  • Blood clotting (coagulation) studies in humans using 45 mg per day of vitamin K2 (as MK-4) and even up to 135 mg per day (45 mg three times daily) of K2 (as MK-4), showed no increase in blood clot risk. (wikipedia.org)
  • These early studies also demonstrated that in addition to phylloquinone or vitamin K 1 in green plants, vitamin K activity was present in many bacteria as a series of menaqui-nones, 2-Me-l, 4-naphthoquinones substituted at the 3-position with an unsaturated polyisoprenoid chain. (springer.com)
  • series
  • Furthermore, a series of regioisomeric methylated 4-hydroxycoumarins were synthesised, tested and found to be equally effective as bis-nucleophiles in the Pd-AA cascade with both acyclic and cyclic bis-electrophiles. (nzresearch.org.nz)
  • carbon
  • This happens in the presence of naturally occurring formaldehyde, which allows attachment of a second 4-hydroxycoumarin molecule through the linking carbon of the formaldehyde, to the 3-position of the first 4-hydroxycoumarin molecule, giving the semi-dimer the motif of the drug class. (wikipedia.org)
  • A newer definition, proposed by Kohler, is the 1,4-addition of a doubly stabilized carbon nucleophile to an α,β-unsaturated carbonyl compound. (wikipedia.org)
  • The resulting enolate attacks the activated olefin with 1,4-regioselectivity, forming a carbon-carbon bond. (wikipedia.org)
  • treatment
  • A new generation of triazine-based coupling reagents (TBCRs), designed according to the concept of 'superactive esters', was obtained by treatment of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) chloride with lithium or silver tetrafluoroborate. (biomedsearch.com)
  • base
  • Proton abstraction from protonated base (or solvent) by the enolate 4 to 5 is the final step. (wikipedia.org)