A compound of the structure STR1 wherein R1 and R2 are each, independently, hydrogen, or --CONH--O--(CR3 R4)m Z; R3 and R4 are each, independently, hydrogen, alkyl, cycloalkyl, --CF3, or F; Z is hydrogen, alkyl, --OR5, --SR5, --NRSR6, --CN, --CF3, --OAr, --Ar, or R7 ; R5 and R6 are each, independently, hydrogen, alkyl, arylalkyl, alkenyl, alkynyl, alkoxyalkyl, alkylthioalkyl, alkylaminoalkyl, dialkylaminoalkyl, cycloalkyl, or Ar; R7 STR2 or --C C--R11 ; R8, R9, R10, and R11 are each, independently, hydrogen, alkyl of 1-6 carbon atoms, halogen, or phenyl, wherein the phenyl group may be optionally mono-, di-, or tri-substituted; Ar is an aryl radical that may be optionally mono-, di-, or tri-substituted; and m=1-6; with the proviso that R1 and R2 are both not hydrogen, or a pharmaceutically acceptable salt thereof which is useful as an immunosuppressive, antiinflammatory, antifungal, antiproliferative, and antitumor agent.