Synthesis and Recyclization of Methylenebisflavonoids Based on Heterocyclic Analogs of Umbelliferone and Formononetin

The methylenebisflavonoids 7-hydroxy-3-hetaryl-8-(4-oxo-4 H -3-chromenylmethyl)-4 H -4-chromenones and 7-hydroxy-3-hetaryl-8-(4-oxo-4 H -3-chromenylmethyl)-2 H -2-chromenones were synthesized via the reaction of 7-hydroxy-8-dialkylaminomethyl-3-hetarylcoumarins and chromones with 3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one. Recyclization of 3-(1,3-benzthiazol-2-yl)-7-hydroxy-8-(4-oxo-4 H -3-chromenylmethyl)-2 H -2-chromenone through the action of N , N - and N , O -binucleophiles produced new 3-benzthiazolylcoumarin derivatives modified by pyrazole, isoxazole, and pyrimidine heterocycles.