Abstract: Using low molecular weight chitooligosaccharide and dialkyl phosphite as raw materials, the site-controlled diethoxy phosphoryl chitooligosaccharides were synthesized through varying the amount of triethlamine. Then, N-diethoxy phosphoryl chitooligosaccharide and N,O,O-diethoxy phosphoryl chitooligosaccharide were obtained. The optimal synthetic conditions were studied by the single factor variable method. And the optimum reaction conditions of N-diethoxy phosphoryl chitooligosaccharide were as follows: 2 g COS, n_COS∶n_TEA=1∶6, n_COS∶n_DEPH=1∶3, 2 h for the time of dropwise for the solution of DEPH in CCl₄, 2 h for the time at the low temperature. The maximum phosphorus content achieves 1.50% under the optimum conditions. The optimum reaction conditions of N,O,O-diethoxy phosphoryl chitooligosaccharide were as follows: 2 g COS, n_COS∶n_TEA=1∶6, n_COS∶n_DEPH=1∶5, 2 h for the time of dropwise for the solution of DEPH in CCl₄, 4 h for the time at the low temperature, 8 h for the reaction time at the room temperature. The maximum phosphorus content achieves 3.42% under the optimum conditions. Moreover, a possible reaction mechanism was proposed to explain the formation of diethoxy phosphoryl chitooligosaccharides.

Key words: Chitooligosaccharide, Locus control, Diethoxy phosphoryl chitooligosaccharide