The subject invention provides compounds having the structure: ##STR00001## wherein R.sub.1 is H, OH, a photoactivatable moiety, a fluorescent moiety, or a radioactive moiety; R.sub.2 is H, OH, a photoactivatable moiety, a fluorescent-moiety, or a radioactive moiety; R.sub.3 is H or OH; R.sub.4 is H, OH, a photoactivatable moiety, a fluorescent moiety, or a radioactive moiety; and wherein at least one of R.sub.1, R.sub.2, R.sub.3, or R.sub.4 is a photoactivatable moiety, a fluorescent moiety, or a radioactive moiety, or an optically pure enantiomer of the compound or wherein R1 is H or OH; R2 is H, OH, halogen, unsubstituted or substituted, straight or branched (C.sub.1 C.sub.5) alkyl group, (C.sub.2 C.sub.5) alkenyl, or a (C.sub.2 C.sub.5) alkynyl, (C.sub.1 C.sub.5) alkoxy, (C.sub.2 C.sub.5) alkenyloxy, or (C.sub.2 C.sub.5) alkynyloxy, --N3, --COR5, --CONR5R6, --CO2R5, --OCOR5, --NH(OH), --NR5R6, --NHCOR5, --N(OH)COR5, --CH2OR5, --OCH2CO2R5, --CH2SR5, --CH2NR5R6, --SR5, --OSR5, or --NR5SO2R6, where R5 and R6 are each independently hydrogen, substituted or unsubstituted (C.sub.1 C.sub.5) alkyl, (C.sub.2 C.sub.5) alkenyl, or (C.sub.2 C.sub.5) alkynyl, or a cycloalkyl or aryl group having 3 to 10 carbon atoms; R3 is H or OH; R4 is H, (C1 C10) alkyl, (C1 C10) alkenyl, (C1 C10) alkynyl, -A-Ar, -A-Z-Ar, --SO.sub.2--Ar, or -A-NR.sub.5, or --R.sub.7, where A, Z and Ar are as defined herein, and the use of the compounds for detecting or identifying a receptor which binds the compounds of the invention or for treating a PAF associated condition in a subject.