Leishmanicidal evaluation of novel synthetic chromenes.

In the present paper, twelve chromenes were synthesized by coupling of 2,2,8,8-tetramethyl-8H-pyrano[2,3-f]chroman-4-one 1 with various aryl and benzylmagnesium chlorides. The synthetic compounds were examined for in-vitro activity against Leishmania major, and some of them displayed efficient anti-leishmanial activity. Among the compounds tested, compounds 9 (4-(2-chloro-benzylidene)-2,2,8,8-tetramethyl-3,4-dihydro-2H,8H-pyrano[2,3-f]chromene 9a and 4-(2-chloro-benzyl)-2,2,8,8-tetramethyl-2H,8H-pyrano[2,3-f]chromene 9b) were the most active with an inhibitory activity of 73.4%.