TOWARDS A UNITARY DESCRIPTION OF THE PHOTOCHEMICAL ISOMERIZATION REACTIONS IN PENTAATOMIC AROMATIC HETEROCYCLES:THE CASE OF FURAN,THIOPHENE,PYRROLE,ISOXAZOLE,IMIDAZOLE,AND PYRAZOLE DERIVATIVES

摘要

Abstract-The photochemical behaviour of furan,thiophene,pyrrole,isoxazole,imidazole,and pyrazole derivatives appears to be very complex and ,apparently,no common description of the reactivity of these heterocycles is possible .On the basis of PM3-PHF-CI semiempiricla calculation an unitary description of the behaviour of these moleculer can be made.