6-dihydro-4H-1,2,5-oxadiazines. Analogous reactions with arylglyoxals in the presence of trifluoroacetic acid afforded 6-aroyl-5,6-dihydro-4H-1,2,5-oxadiazines. It was found that phenylglyoxal in the absence of the acid yielded N-substituted α-aroylnitrone which undergoes cyclization into the corresponding oxadiazine under the action of CF3COOH.
烷基芳族 1,2-羟基
氨基
肟(在伯或仲碳原子上含有羟基
氨基)的 Z-异构体与
甲基乙二醛反应得到 6-乙酰基-5,6-二氢-4H-1,2,5-恶二嗪. 在
三氟乙酸存在下与芳基
乙二醛的类似反应得到 6-芳酰基-5,6-二氢-4H-1,2,5-恶二嗪。发现在不存在酸的情况下苯
乙二醛产生 N-取代的 α-芳酰基硝酮,其在 CF3COOH 的作用下环化成相应的恶二嗪。