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Vitamin K 2 is a highly active anti- bleeding drugs. Paper with 2 - methyl- naphthoquinone, geraniol and geranyl acetate as a starting material , a catalytic hydrogenation , a methoxy group protection, bromination, Grignard reaction and oxidation of deprotection reaction, the ultimate synthesis of the vitamin K 2 (20) . Through experiments , on which the reaction steps of the optimization experiments , found the optimum reaction conditions , to obtain a high reaction yield . The first step for the catalytic hydrogenation reaction , the Pd / C catalyst 2 - menaquinone hydrogenation reaction can be completed almost quantitatively . The second step is a methoxy group deprotection reaction , under alkaline conditions to react with dimethyl sulfate , the orthogonal experimental design study of the reaction conditions , preferably the reaction conditions : pH = 9-10 , the reaction temperature is 50 ℃, sodium hydroxide concentration of 30 % yield of 95.1% . The third step is carried out on a single factor bromination reaction optimization experiments , to get a better reaction conditions as follows: reaction temperature of -10 ℃, dropping time of 4 hours bromine and Material 2 - methyl -1,4 - dimethoxy naphthalene : bromide = 1.05 ( molar ratio ) 90.1% higher when compositing target yield product 2 - bromo-3 - methyl-1 ,4 - dimethoxy- naphthalene. The fourth step is the Grignard reaction , fully activated by magnesium , the choice of dry tetrahydrofuran as solvent, ethyl bromide as the initiator of the reaction system and to ensure that such method throws an inert atmosphere to prepare a Grignard reagent , and through the single factor experiment showed that the amount of cuprous bromide 0.5eq highest yield when the target product , was 85.7% . The fifth step is oxidative deprotection reaction yield of 86.9% of the final synthesis of vitamin K 2 (20) . This geranylgeranyl bromide synthesis , based on the research of others on removal step reaction sulfone proposed innovative improvements that will yield the step from 26 % to 90%.
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