Menadione

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Menadione
Menadione
Chemical name 2-methylnaphthalene-1,4-dione
Other names menadione
vitamin K3
Chemical formula C11H8O2
Molecular mass 172.18 g/mol
CAS number [58-27-5]
Density  ? g/cm3
Melting point 102 °C
Boiling point  ? °C
SMILES O=C(C(C)=C1)C2=C(C=CC=C2)C1=O
Disclaimer and references

Menadione is a polycyclic aromatic ketone, based on 1,4-naphthoquinone, with a 2-methyl substituent.

It is sometimes called vitamin K3, although derivatives of naphthoquinone without the sidechain in the 3-position cannot exert all the functions of the K vitamins. Menadione is a vitamin precursor of K2 which utilizes alkylation in the liver to yield menaquinones (MK-n, n=1-13; K2 vitamers), and hence, is better classified as a provitamin.

Despite the fact that it can serve as a precursor to various types of vitamin K, menadione is generally not used as a nutritional supplement. Large doses of menadione have been reported to cause adverse outcomes including hemolytic anemia due to G6PD deficiency, neonatal brain or liver damage, or neonatal death in some cases. Moreover, menadione supplements have been banned by the FDA because of their high toxicity. Menadione has been used experimentally as a chemotherapic agent for cancer but has lost ground to much safer vitamin K2 vitamers. Low level menadione is still used as an inexpensive micronutrient for livestock in many countries.

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