Synthesis of ursane-derived isothiocyanates and study of their reactions with series of amines and ammonia

Based on ursolic acid, 3 compounds with isothiocyanate groups located at different distances from C-17 of the triterpenoid core have been synthesized through ursane-derived primary amines. To obtain terpene hybrids thioureas and N,S-containing heterocycles, series amines ammonia were reacted novel isothiocyanates. In reactions propargylamine, 4,5-dihydrothiazol-2-yl-amine selectively obtained in 81%–91% yields. Isothiocyanates containing several bonds between -CNS group backbone (1-aryl-1H-1,2,3-triazole-4-yl)methanamines, as well ammonia, to form thiourea derivatives (78%–94%). The nor-compound a was least reactive due deactivation by donor branched substituent readily only sufficiently strong nucleophiles, such secondary aliphatic reaction nor-derivative 7 elevated temperature led unexpected formation 3β-acetoxy-28-norurs-12-en-17-yl-amine, precursor isothiocyanate, main product (82%).