2，6-二氨基-3，5-二硝基-1-氧吡嗪合成中的氧化方法改进

以磁性Fe3O4负载质子化过氧钨酸盐为催化剂，在不用三氟乙酸的情况下，以双氧水为氧化剂，将2，6-二甲氧基吡嗪、2，6-二氯吡嗪和2-氯-6-甲氧基吡嗪高效地氧化为其相应的氮氧化物2，6-二氨基-3，5-二硝基-1-氧吡嗪(LLM-105)。 典型条件为：底物10 mmol，CH3CN 30 mL，催化剂Fe3O4/CS/HWO 0.1 g(约0.1 mmol)，60 ℃分5次逐滴加入30%双氧水5 mL。 反应混合物溶液经萃取和柱色谱法提纯，得产物，收率一般为60%~73%。 使用高斯03量化计算程序对氧化过程进行了理论计算，结果与实验数据相符。

Improvement of the Oxidation Process in the Synthesis of 2,6-Diamino-3,5-dinitropyrazine-1-oxide

A new catalytic system was applied to the oxidation reactions involved in the synthesis of 2,6-diamino-3,5-dinitropyrazine-1-oxide(LLM-105), in which protonated peroxotungstate immobilized into the network of cross-linked chitosan with the superparamagnetic Fe3O4 core(Fe3O4/CS/HWO) was used as the catalyst. With H2O2 as the oxidant, good to excellent yields could be achieved with pyrazine, 2,6-dimethoxypyrazine, 2,6-dichloropyrazine and 2-chloro-6-methoxypyrazine as the substrates without addition of trifluoracetic acid. A representative procedure for the oxidation process is as following: to 30 mL of CH3CN containing substrate(10 mmol) and Fe3O4/CS/HWO(0.1 mmol, about 0.1 g), 30%H2O2(5 mL) was added dropwisely by 5 times at 60 ℃ temperature. The oxidation process was monitored by TLC. Product could be obtained with a yield ranging from 60% to 73%. Theoretical studies were also carried out with Gaussian 03 to evaluate the oxidation process. All of the calculated data matched well with the experimental results.