58-27-5

Irritant to skin and mucous membranes, especially the alcoholic solution.

A general term referring to a group of naphthoquinone derivatives required in the diet for blood clotting. Vitamin K5 or medadione and its derivatives are synthetic, lipid-soluble compounds.

Appearance: phylloquinone is a yellow oil at room temperature, but the other vitamers K are yellow crystals. Solubility: the vitamers K and MK and most forms of menadione are insoluble in water, slightly soluble in ethanol, and readily soluble in ether, chloroform, fats, and oils. Stability: the vitamers K are sensitive to light and alkali, but are relatively stable to heat and oxidizing environments.
Menadione, the formal parent compound of the menaquinone series does not occur naturally but is a common synthetic form called menadione (2-methyl-1,4- naphthoquinone). This compound forms a water-soluble sodium bisulfite addition product, menadione sodium bisulfite, whose practical utility is limited by its instability in complex matrices such as feeds. However, in the presence of excess sodium bisulfite, it crystallizes as a complex with an additional mole of sodium bisulfite (i.e., menadione sodium bisulfite complex), which has greater stability, therefore, is used widely as a supplement to poultry feeds. A third water-soluble compound is menadione pyridinol bisulfite (MPB).

Kappaxin,Sterling Winthrop

ChEBI: A member of the class of 1,4-naphthoquinones that is 1,4-naphthoquinone which is substituted at position 2 by a methyl group.

Vitamin K activity is associated with several quinones, including phylloquinone (vitamin K₁), menadione (vitamin K₃), and a variety of menaquinones (vitamin K₂). These quinones promote the synthesis of proteins that are involved in the coagulation of blood.These proteins include prothrombin, factor VII (proconvertin), factor IX (plasma thromboplastin). The vitamin K quinones are obtained from three major sources.Vitamin K is present in various plants, especially green vegetables. The menaquinones that possess vitamin K₂ activity are synthesized by bacteria, particularly gram-positive organisms; the bacteria in the gut of animals produce useful quantities of this vitamin.Vitamin K₃ is a chemically synthesized quinone that possesses the same activity as vitamin K₁.

Menadione can be prepared by oxidizing 2-methylnaphthalene with chromic acid or hydrogen peroxide.

Dissolve 100 g of β-methylnaphthalene in 500 g of carbon tetrachloride. Dissolve 500 g of commercial sodium dichromate in 175 g of hot water. Pour these two solutions into a 3-liter 3-necked flask, equipped with an efficient stirrer, a reflux condenser, and a dropping funnel. The flask should be put into a water bath held at 50°C. The contents of the flask agitated as violently as possible at adding (through the dropping funnel) 896 g of 77% (by weight) sulfuric acid. The rate of dropping depends on the efficiency of the reflux condenser. If the reaction tends to get out of hand due to overheating, cold water should be run into the water bath. After the addition of acid has been completed, keep the water bath at 70°C, for 1% to 2 hours. Then stop the agitation, cool the mixture and decant therefrom as much of the carbon tetrachloride layer as possible. Pour water into the flask; add 100 g more of carbon tetrachloride and stir for an additional ten minutes. The carbon tetrachloride layer will now settle to the bottom. The acid layer can be decanted and discarded, or worked up for those components desired. A complete separation of the acid from the carbon tetrachloride is effected by means of a separatory funnel. All of the carbon tetrachloride solutions are pooled and filtered to clarity through filter paper. The carbon tetrachloride may be distilled off from the quinone in a vacuum, using a water bath heated to 50°C.
The quinone is concentrated to a point where crystallization begins. Thereupon the concentrated solution is transferred to a beaker and allowed to crystallize at room temperature. Further crops of crystals are obtained by allowing the mother liquor to cool in an icebox, or by reducing it still further. If the β-methylnaphthalene starting material was pure, the 2-methyl-1,4- naphthoquinone obtained will have a melting point of 100°-104°C, without further purification. Vacuum sublimation has been found most effective to produce quinones of a very high purity. There is a rapid method of oxygenation of β-methylnaphthalene: 3 g of β-methylnaphthalene is dissolved in 180 grams of carbon tetrachloride. To this is added 15 grams of commercial sodium dichromate dissolved in 6 grams of hot water. The above solutions are placed in a 1-liter 3-necked flask equipped with an efficient stirrer, a dropping funnel, and a distilling condenser of large bore. The mixture is agitated energetically, and 25 grams of 77% sulfuric acid added through the dropping funnel. The time of addition need not be over 30 seconds. The flask is not subjected to exterior cooling, as the distilling carbon tetrachloride should hold the heat to the proper temperature, which should not exceed 85°C. After five minutes the reaction may be discontinued and the product handled similarly to the method outlined in above. The yield of 2-methyl-1,4-naphthoquinone will be around 80% of theoretical by the use of this rapid method.

Kappaxin (Sterling Winthrop); Kayquinone.

Prothrombogenic vitamin

Menadione is an oxidative stress inducer.

The typical role of vitamin K is to maintain normal blood coagulation function. Its role is related to the metabolic processes.

Vitamin K deficiency results in increased bleeding time. This hypoprothrombinemia may lead to hemorrhage from the gastrointestinal tract, urinary tract, and nasal mucosa. In normal, healthy adults, deficiency is rare. The two groups at greatest risk are newborn infants and patients receiving anticoagulant therapy; hypoprothrombinemia preexists in these two groups. Any disease that causes the malabsorption of fats may lead to deficiency. Inhibition of the growth of intestinal bacteria from extended antibiotic therapy will result in decreased vitamin K synthesis and possible deficiency.

Toxicity of vitamin K has not been well defined. Jaundice may occur in a newborn if large dosages of vitamin K are given to the mother before birth. Although kernicterus may result, this can be prevented by using vitamin K.

Recrystallise it from 95% EtOH, or MeOH after filtration. It forms bright yellow crystals which are decomposed by light. Its solubility in EtOH is 1.7% and in *C6H6 it is 10%. It IRRITATES mucous membranes and skin. [Fieser J Biol Chem 133 391 1940, Beilstein 7 IV 2430.]