The acridinone derivative 3,4-dihydro-3,3-dimethyl-1(2H)-acridinone (4
) has been prepared in a two step fashion and the molecular structure
confirmed by X-ray diffraction. Compound 4 crystallizes in the space g
roup P2(1)/n with a = 6.022(2), b = 21.111(2), c = 9.604(2) Angstrom,
beta = 99.97(2)degrees, and Z = 4. The single crystal analysis showed
the acridinone tricyclic ring is virtually planar except in the gem-di
methyl position of C(3) which presented a half-chair conformation.