Heterocyclic esters and amides

A non-immunosuppressive compound of formula II:

• ##STR7## or a pharmaceutically acceptable salt, ester, or hydrate thereof, wherein:
• one of A, B and C is S and the other two of A, B and C are CH.sub.2 ;
• R.sub.1 is C.sub.1 -C.sub.5 straight or branched chain alkyl or alkenyl, which is substituted in one or more position(s) with (Ar.sub.1).sub.n, (Ar.sub.1).sub.n connected by a C.sub.1 -C.sub.6 straight or branched chain alkyl or alkenyl, or a combination thereof;
• n is 1 or 2;
• R.sub.2 is either C.sub.1 -C.sub.9 straight or branched chain alkyl or alkenyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.5 -C.sub.7 cycloalkenyl, or Ar.sub.1 ;
• and
• Ar.sub.1 is a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to three position(s) with halo, hydroxyl, nitro, trifluoromethyl, C.sub.1 -C.sub.n straight or branched chain alkyl or alkenyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkenyloxy, phenoxy, benzyloxy, amino, or a combination thereof;
• wherein the individual ring sizes are 5-6 members;
• and wherein the heterocyclic ring contains 1-6 heteroatom(s) selected from the group consisting of O, N, S, and a combination thereof.