The Ritter reaction between monoterpenoid (–)-isopulegol and nitriles in the presence of concentrated sulfuric acid or trifluoromethanesulfonic acid yielded a series of chiral 1,3-oxazine derivatives. When studying the analgesic activity of the synthesized compounds in vivo, it was found that 1,3-oxazine synthesized by the reaction of (–)-isopulegol with benzyl cyanide increases the time of latency of the animal in the hot plate test of thermal pain irritation, not inferior in effectiveness to the comparison drug diclofenac sodium.

中文翻译：

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Ritter反应合成基于（-）-异胡薄荷醇的1,3-恶嗪衍生物及其镇痛活性的研究

在浓硫酸或三氟甲磺酸的存在下，单萜类化合物（–）-异薄荷醇与腈之间的Ritter反应产生了一系列手性1,3-恶嗪衍生物。在研究合成化合物的体内止痛活性时，发现在热痛热板试验中，由（-）-异薄荷醇与苄基氰化物反应合成的1,3-恶嗪增加了动物的潜伏时间。刺激性，疗效不逊于比较药物双氯芬酸钠。