A Study of Plant Coumarins. 18. Conjugates of Coumarins with Lupane Triterpenoids and 1,2,3-Triazoles: Synthesis and Anti-Inflammatory Activity

In the reaction of coumarin peuruthenicin with α,ω-dibromoalkanes, the corresponding 7-(ω-bromoalkyloxy)coumarins have been synthesized. The interaction of the resulting compounds with sodium azide has yielded 7-(ω-azidoalkyl)-substituted peuruthenicin derivatives, which exhibited high activity in the Cu(I)-catalyzed Huisgen cycloaddition reaction with the propargyl ester of betulonic acid. As a result of the reaction, 28-O-(chromenoalkyl-triazolylmethyl)lupenones have been synthesized. The reaction of betulonic acid propargyl ester with 2-azidooreoselones in the presence of aqueous copper sulfate and sodium ascorbate has led to the corresponding (furochromen-triazolyl)-20(29)-lupen-3-ones. The newly synthesized hybrid compound triterpenoid furocoumarin containing a triazole linker exhibits anti-inflammatory activity in a model of histamine inflammation.