Vitamin K <sub> 2 </ Sub> (20) Of The Synthesis

Menaquinone(vitamin K₂) is a high efficiency counteractant bleeding medicament. Menaquinone was prepared by catalytical hydrogenation, methoxy protection, bromization, Grignard reaction, and released protection by the reaction of oxidation. At last, vitamin K₂₍₂₀₎ been synthesized.In the experiment, the high yield can be gained through making optimized condition to the several reactions. The first catalytical hydrogenation with palladium/activated carbon as the catalyst can gain the production with ration almost. The second reaction, 2-methyl-l,4-naphthohydroquione reacted with dimethyl sulfate in aqueous alkali. The optimized conditions of the second reaction are: the bound of pH is 9 to 10, reaction temperature is 50℃, the consistence of sodium hydroxide is 30%, yield 95.1%. The optimized conditions of the third reaction are: reaction temperature is -10°C, reaction time is 4 hours, the mole ratio of 2-methyl-l,4-dimethoxynaphthalene to bromine to 1:1.05, 90.1% yield can be gained. The fourth reaction is Grignard reaction. The reaction can being solicitation successfully via four methods: magnesium activation, the solvent is dry THF, bromoethane is solicitation reagent, N₂ protection. The optimized conditions of the reaction is: the mole ratio of Cuprous bromide is 0.5eq, yield 85.7%. The fifth reaction is released protection, yield 86.9%. At last, synthesized the menaquinone successfully.In the synthesis of geranylgeranyl bromide, the innovation been bring forward in the step of desulfonylation, the yield is 90%.