PHOTOCHEMICAL REACTIONS OF 7-AMINOCOUMARINS 2. -CYCLOADDUCTS WITH STYRENE

Article abstract of DOI:10.1007/BF00474038

The photocycloaddition of styrene to 4-methyl-7-aminocoumarin, 4-methyl-7-diethylaminocoumarin, 7-(N-morpholino)coumarin, 3-ethoxycarbonylmethyl-4-methyl-7-diethylaminocoumarin, and coumarin-102 (2,3,6,7-tetrahydro-9-methyl-1H,5H,11H--benzopyrano<6,7,8-ij>quinolizin-11-one) was investigated.Adducts of regio- and stereospecific <2+2>-cycloaddition to the 3-4 bond were isolated.It was established by means of x-ray diffraction analysis that the phenyl group in the cycloadducts occupies the 1-endo position.The participation of the singlet excited states of the 7-aminocoumarin molecules in <2+2>-cycloaddition was demonstrated.