Catalytic Synthesis Process Of Vitamin K₂ With A Environmentally Benign Route

Vitamin K2 which is fat-dissolved,has an important role in medical industry,healthy care and feeding field,is a kind of polyeniccompounds contained 2-methyl-1,4-naphthalenedione.The application and improvement of Vitamin K2 are hindered by higher cost for its biological extraction.So it is being atached more and more importance that how to develop a chemical method to synthesize Vitamin K2 and put it into industrialization.The cognitive history,properties,application field and synthetical method of Vitamin K2 were summarized and the previous synthetical process was improved in this dissertation.A new synthetical method of Vitamin K2 which was economical,fine stereoselectivity and fiting to industrialization was studied.Vitamin K2 can be synthesized in only three steps,when 2-methyl-1,4-dihydroxynaphthalene was obtained by catalysing and hydrogenation from menadione as initiative material used Pd/C in room temperature,the molar yield reached 83.96%;after that,Vitamin K2(20)can be obtained by alkylation from the former substance with geranyl linalool and oxidated with FeCl3.The molar yield of the second step is 55.80%based on 2-methyl-1,4-naphthalenedione,the total molar yield is 56.55%.The optimal conditions of synthesizing 2-methyl-1,4-dihydroxynaphthalene by catalysing and hydrogenating 2-methyl-1,4-naphthalenedione used Pd/C were researched.The dose of Pd/C was 50mg,by which the catalysing efficiency can be improved and the amount of Pd/C can be reduced.MTBE which can be removed by vacuum distillation easily in a lower temperature was used as solvent.The velocity and efficiency of reaction can be balanced beter in a hour.Furthermore,the reaction is mild in room temperature.The optimal conditions of synthesizing deoxidized Vitamin K2(20)which can be obtained by alkylation from 2-methyl-1,4-dihydroxynaphthalene with geranyl linalool were researched.Dry ZnCl2 as catalyst made the cost relatively lower.The molar ratio of ZnCl2 and Geranyl linalool to 2-Methyl-1,4-Naphthalenedione was 1:1.8:1;reaction temperature was 50?;reaction time was 2h and dose of CH3COOH was 0.8mmol.Deoxidized Vitamin K2(20)can be oxidized by FeCl3 to produce Vitamin K2(20),the reaction time was short and the process was safe with no byproduct.The purity of product after treatment was higher and luster.The troublesome separation of column chromatography would be avoided as crude product recrystallized secondly in ethanol.The purity of product analyzed by HPLC was 79.76%.