Reversal agents multidrug resistance.

They ARE PRESENTED compounds with a general formula, which describes R1, R2, R3, R4 and R5. A is a (C2-C12) straight or branched alkyl or portion PHENYL YB is a portion WITH formula specified. The compounds are effective for enhancing the activity of anti-cancer chemotherapeutics SENSITIVITY TO ENHANCE multidrug resistant cells regarding such chemotherapeutics.