The present invention provides the compound having the formula: wherein each of R1 and R2 is, substituted or unsubstituted, aryl, cycloalkyl, cycloalkylamino, naphtha, pyridineamino, piperidino, t-butyl, aryloxy, arylalkyloxy, or pyridine group wherein A is an amido moiety, -O-, -S-, -NH-, or -CH2- and wherein n is an integer from 3 to 8. The present invention also provides a method of selectively inducing growth arrest, terminal differentiation and/or apoptosis of neoplastic cells and thereby inhibiting proliferation of such cells. Moreover, the present invention provides a method of treating a patient having a tumor characterized by proliferation of neoplastic cells. Lastly, the present invention provides a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a therapeutically acceptable amount of the compound above.