Synthesis and analgesic activity of monoterpenoid-derived alkyl-substituted chiral hexahydro-2H-chromenes

A set of new 2-alkyl-substituted 4,7-dimethyl-3,4,4a,5,8,8a-hexahydro-2H-chromene-4,8-diols was obtained by reactions of monoterpenoid (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol with aliphatic aldehydes in the presence of montmorillonite clay K10. Synthesized compounds were evaluated for their analgesic activity in vivo using the acetic acid-induced writhing test and the hot-plate test. Five compounds showed a significant analgesic activity in the acetic acid-induced writhing test; two of them also demonstrated analgesic activity in the hot-plate test. These compounds seem to be most promising for further development.