Compounds having the formula or a pharmaceutically acceptable salt thereof wherein R1 is (a) hydrogen, (b) loweralkyl, (c) alkenyl, (d) alkoxy, (e) thioalkoxy, (f) halo, (g) haloalkyl, (h) aryl-L2—, and (i) heterocyclic-L2—; R2 is selected from (b) —C(O)NH—CH(R14)—C(O)OR15, (d) —C(O)NH—CH(R14)—C(O)NHSO2R16, (e) —C(O)NH—CH(R14)-tetrazolyl, (f) —C(O)NH-heterocyclic, and (g) —C(O)NH—CH(R14)—C(O)NR17R18; R3 is heterocyclic, aryl, substituted or unsubstituted cycloalkyl; R4 is hydrogen, lower alkyl, haloalkyl, halogen, aryl, arylakyl, heterocyclic, or (heterocyclic)alkyl; L1 is absent or is selected from (a) —L4—N(R5)—L5—, (b) —L4—O—L5—, (c) —L4—S(O)n—L5— (d) —L4—L6—C(W)—N(R5)—L5—, (e) —L4—L6—S(O)m—N(R5)—L5 —, (f) —L4—N(R5)—C(W)—L7—L5 —, (g) —L4—N(R5)—S(O)p—L7—L5—, (h) optionally substituted alkylene, (i) optionally substituted alkenylene, and (j) optionally substituted alkynylene are inhibitors of protein isoprenyl transferases. Also disclosed are protein isoprenyl transferase inhibiting compositions and a method of inhibiting protein isoprenyl transferases.