THERMAL BEHAVIOR OF BICYCLO[2.2.2]OCTADIENE-INSTALLED PRECURSORS FOR 2H-ANTHRA[2,3-c]PYRROLES AND ANTHRA [2,3-c] THIOPHENE

4,11-Ethano-4,11-dihydro-2H-anthra[2,3-c]pyrrole and 4,11-ethano-4,11-dihydroanthra[2,3-c]thiophene derivatives were prepared from the corresponding bicyclo[2.2.2]octadiene-fused five-membered heterocycles by the Diels-Alder reaction with in situ generated α,α'-dibromo-o-xylylene derivatives. Their thermogravimetric analyses showed evapolation without formation of 2H-anthra[2,3-c]pyrrole and anthra[2,3-c]thiophene derivatives under the atmospheric pressure.