The Study On Synthesis Of Methocarbamol

Methocarbamol is a kind of muscle relaxant. This article describes achemical method of synthesizing methocarbamol, which adopts glycerylguaiacolate and glycerinα-chlorohydrin as main material.The synthesisof glyceryl guaiacolate included reactions of salt formation,additionreaction and etherifying obtained. Methocarbamol was synthesized bysteps of cyclization and ammoniation starting from glyceryl guaiacolate.A HPLC method was established for the determination of methocarbamol.It is fitted to commercial production.The structure of the intermediates was confirmed by IR and NMR.The conditions of the above reactions are optimized according to possiblereaction mechanisms. Glycerinα-chlorohydrin is main raw materials inthe synthesis of glyceryl guaiacolate. By selecting suitable conditions,Glycerinα-chlorohydrin was obtained in good yield and good quality;The material ratio 1:1.1:1.07 of guaiacol,Glycerinα-chlorohydrinand alkali was confirmed.Optimizing reaction conditions and the yield ofglyceryl guaiacolate is 81.4%. Qualitity of the objective compoundsaccorded the standard of USP26. In the synthesizing of methocarbamol,the suitable process, was confirmed by the investigation of the selectionand a amount of catalyst, the ratio of materials, crystal solvent,ect. Thebetter confirmed ratio of glyceryl guaiacolate: diethylcarbonate: sodiumethoxide was 1:2.1:0.24 by optimizing reaction conditions. The crude methocarbamol was obtained by reacting guaiacol with aqueous ammoniain dichloroethane and recrystallized from the acetone-water. With yield ofmethocarbamol is 77.5%(based on glyceryl guaiacolate), Qualitity of theobjective compounds accorded the standard of USP28.According toabove mentioned process conditions,the total yield of methocarbamol is63.9%(based on guaiacol).