Compounds having the general structure I are provided. X and Y are independently selected from the group consisting of CH.sub.2, N, NR.sup.9, C.dbd.O, C.dbd.S, S.dbd.O, SO.sub.2, S, O, (CR.sup.6R.sup.7).sub.n, C(.dbd.O)--(CR.sup.6R.sup.7).sub.n, and C(.dbd.S)--(CR.sup.6R.sup.7).sub.n, where n is 1, 2, or 3. W is selected from the group consisting of (formula I) and L is selected from the group consisting of N, O, S.dbd.O, SO.sub.2, C(O), NC(O), NC(S), OC(O), OC(S), C(NR.sup.10), C(NOR.sup.10), and a covalent bond. Z.sup.1, Z.sup.2, and Z.sup.3 are independently selected from the group consisting of substituted carbon and nitrogen. Compounds of formula I are agonists of the melanocortin-4 receptor ("MC-4r2) and therefore may have useful properties for controlling diseases related to MC-4r action in humans, such as obesity and type II diabetes.