Synthesis of L-Menthyl β-D-Glucoside

In order to improve the thermal stability of L-menthol,several coupling methods and their related protection and deprotection reactions for L-menthyl β-Dglucoside synthesizing were investigated,the coupling reaction conditions of β-D-glucose pentaacetate with L-menthol were discussed,and the melting point,optical rotation,NMR,MS and TG of the synthesized product were analyzed.The results showed that:1) it is feasible to synthesize L-menthyl β-D-glucoside from glucose and L-menthol through three-step reaction of acetylation,coupling,and deprotection;2) the synthesized product is the target product;3) the optimized condition of coupling reaction was solvent CH₂Cl₂,n(β-D-glucose pentaacetate):n(L-menthol):n(BF₃·Et₂O)=1:3:5,reaction temperature 25℃,and reaction time 10 hours,at which the yield reached 40%;4) the synthesized product,L-menthyl β-D-glucoside,featured high thermal stability.