or an alkyl group of for example 1 to 4 carbon atoms; [0036] 2. ???CH2OH; [0037] 3. ???CH2OCH2CH(OH)CH2OH; [0038] 4. ???COOCH2CH(OH)CH2OH; and [0039] 5. ???CONRd???(CH2)mOH [0040] 6. ???N(CH2CH2OH)CH2CH2OH [0041] 7. ???C(O)F [0042] 8. ???C(O)ORd [0043] 9. ???CO2H [0044] where Rd is hydrogen or an alkyl group such as methyl, ethyl, propyl, butyl, or hexyl and m is 2-12. [0045] Compounds according t