PHOTOCHEMICAL REACTIONS OF 7-AMINOCOUMARINS. 3. REACTION OF 4-METHYL-7-DIETHYLAMINOCOUMARIN WITH OLEFINS AND ACETYLENES CONTAINING ELECTRON-WITHDRAWING SUBSTITUENTS

Article abstract of DOI:10.1007/BF00472612

The photochemical reactions of 4-methyl-7-diethylaminocoumarin with the dimethyl ester of acetylenedicarboxylic acid, diethyl ester of maleic acid, and N-phenylmaleimide in the presence of oxygen and acetophenone give products of the heterocyclization at C₍₆₎ and C₍₈₎ of coumarin fragment with participation of the diethylamino group.The stereochemical structure of the compounds synthesized was demonstrated using PMR spectroscopy.A mechanism was proposed for this reaction involving the formation of an α-amino radical and its addition to the acetylene or olefin, accompanied by the attack on the aromatic ring with subsequent aromatization.