organic compounds
Photolysis of 11,12-dibenzoyl-9,10-dihydro-9,10-dimethoxy-9,10-ethenoanthracene, (1), in a mixture of benzene and methanol gives the dibenzofuranopentalene (3), whereas irradiation of (1) in a mixture of benzene and aqueous methanol gives a mixture of the dibenzopentalenone (4) and the dibenzofuranopentalene derivative (5). The structures of two of these photoproducts, namely, the methanol solvate of 8c-benzoyl-8b,8c-dihydro-4b,8b-dimethoxy-4bH-dibenzo[a,f]furano [3,4,5c,d-]pentalene, C32H24O4.0.5CH3OH, (3), and 8c-benzoyl-8b,8c,8d,9-tetrahydro-8b,8d,9-trimethoxy-4bH-dibenzo[a,f]furano [3,4,5-c,d]pentalene, C33H28O5, (5), have been determined by X-ray diffraction methods.