This invention provides sulfonamide derivatives useful in the treatment of susceptible neoplasms in warm-blooded animals of formula (I): in which A is -O-, -@CH3, -CH2-, -CH2CH2-, or -CH2O-; D is -CH2- or -O-; R1 is hydrogen or halo, and R2 is halo or trifluoromethyl. E.g., N-([(4-chlorophenyl)amino]carbonyl)-2,3-dihydro-1H-indene-5-sulfonamide, m.p. 169-172 DEG C, is prepared by reacting 2,3-dihydro-5-indenylsulfonamide with 4-chlorophenylisocyanate.