Synthesis of 1,3-Oxazine Derivatives Based on (–)-Isopulegol using the Ritter Reaction and Study of their Analgesic Activity

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.