The reaction of natural isoflavones formononetin and cladrin with primary amines and formalin in the presence of a base catalyst was studied. Several novel substituted 9,10-dihydro-4H,8H-chromeno[8,7-e][1,3]oxazin-4-ones containing alkyl, benzyl, or heterylalkyl substituents in the N-9 position were synthesized.
The behavior of 7-hydroxy-4'-fluoroisoflavones under the conditions of the Mannich reaction with primary amines was studied. New 9-alkyl-substituted 3-(4-fluorophenyl)-9,10-dihydro-4H,8H-chromeno-[8,7-e][1,3]oxazin-4-ones were synthesized. A method was developed for the synthesis of 8-amino- methyl derivatives of isoflavones.
