The probabilities of the occurrence of photochemical processes in some
3-substituted derivatives of coumarin I and coumarin IH as well as in
4-trifluoromethylcoumarin I were studied by quantum-chemical methods.
The probabilities for different pathways of die photoreactions of alk
ylaminocoumarins appear to be a function of the type and position of a
substituent and of the nature of orbitals in the electronically excit
ed state, as found from the values of relevant bond energies calculate
d in the electrostatic approximation.