SYNTHESIS OF THE FIRST [1,3]BENZOXAZINO[3,2-B][1,2]BENZOXAZINE AND ITS TANDEM RETRO-DIELS-ALDER DIELS-ALDER REARRANGEMENT TO A NOVEL [1,3]BENZOXAZINO[2,3-B][1,3]BENZOXAZINE
Z. Goldschmidt et al., SYNTHESIS OF THE FIRST [1,3]BENZOXAZINO[3,2-B][1,2]BENZOXAZINE AND ITS TANDEM RETRO-DIELS-ALDER DIELS-ALDER REARRANGEMENT TO A NOVEL [1,3]BENZOXAZINO[2,3-B][1,3]BENZOXAZINE, Tetrahedron letters, 35(39), 1994, pp. 7273-7276
Thermolysis of 3-methyl-4H-1,2-benzoxazine gave the tetracyclic ,12aH,
13H-[1,3]benzoxazino[3,2-b][1,2]benzoxazine, which further rearranged
to the isomeric H,11H,13H-[1,3]benzoxazino[2,3-b][1,3]benzoxazine. The
rmolysis of the benzoxazinobenzoxazines gave 2-methyl-4H-1,3-benzoxazi
ne, and o-quinone methide which was trapped by ethyl vinyl ether to gi
ve 2-ethoxy-dihydrobenzopyran.