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N-三芳基硼氮六环可以较易地由芳胺盐酸盐及硼氢化锂在四氢呋喃中来制备。由于硼氢化锂在四氢呋喃中的溶解度较大,且易于在四氢呋喃中用硼氢化钾来转化。此外,四氢呋喃的沸点又较低,溶剂易于蒸出。我们认为这方法较硼氢化钠在一缩乙二醇二甲醚中的反应要缓和。在制备N-三脂基硼氮六环时,硫醇,例如正丁硫醇可以加速反应。但在制备N-三芳基硼氮六环时,正丁硫醇的催化效应不明显。在苯基对位的不同性质取代基,可以影响脱氢速度。一般-I<+C效应基团影响速度不大,-I>+C效应基团加速反应。+I及+C效应基团阻碍反应。-I及-C效应基团进一步加速反应。但由于形成的硼氮六环不稳而未能分离。
The N-triarylborazine ring can be more easily prepared from the aromatic amine hydrochloride and lithium borohydride in tetrahydrofuran. Lithium borohydride is highly soluble in tetrahydrofuran and is readily converted to potassium borohydride in tetrahydrofuran. In addition, tetrahydrofuran has a lower boiling point and the solvent is easily distilled off. We think this method is more responsive than sodium borohydride in glyme. Thiols, such as n-butanethiol, can accelerate the reaction in the preparation of N-tris-alkylborazine. However, the catalytic effect of n-butanethiol was not obvious in the preparation of N-triarylborane and hexacycle. Substituents of different nature at the para position of the phenyl group can affect the dehydrogenation rate. Generally -I <+ C effect group effect is not big, -I> + C effect group to accelerate the reaction. + I and + C effect groups impede the reaction. -I and -C effect groups further accelerate the reaction. However, due to the formation of boron-nitrogen ring instability and failed to separate.