A method for identifying compounds binding to HCV polymerase comprising
the steps of: contacting said HCV polymerase or an analog thereof with a
probe formula I: ##STR00001## wherein A is O, S, N, NR.sup.1, or
CR.sup.1, wherein R.sup.1 is defined herein; ----- represents either a
single or a double bond; R.sup.2 is selected from: H, halogen, R.sup.21,
OR.sup.21, SR.sup.21, COOR.sup.21, SO.sub.2N(R.sup.22).sub.2,
N(R.sup.22).sub.2, CON(R.sup.22).sub.2, NR.sup.22C(O)R.sup.22 or
NR.sup.22C(O)NR.sup.22 wherein R.sup.21 and each R.sup.22 is defined
herein; B is NR.sup.3 or CR.sup.3, wherein R.sup.3 is defined herein;
with the proviso that, when A is not N, then one of A or B is either
CR.sup.1 or CR.sup.3, K is N or CR.sup.4, wherein R.sup.4 is defined
herein; L is N or CR.sup.5, wherein R.sup.5 has the same definition as
R.sup.4 defined above; M is N or CR.sup.7, wherein R.sup.7 has the same
definition as R.sup.4 defined above; R.sup.5 is C(Y.sup.1)Z wherein
Y.sup.1 is O or S; and Z is N(R.sup.6a)R.sup.6 or OR.sup.6, wherein
R.sup.6a is H or alkyl or NR.sup.61R.sup.62 wherein R.sup.61 and R.sup.62
are defined herein; and R.sup.6 is H, alkyl, cycloalkyl, alkenyl, Het,
alkyl-aryl, alkyl-Het; or R.sup.6 is ##STR00002## wherein R.sup.7 and
R.sup.8 and Q are as defined herein; Y.sup.2 is O or S; R.sup.9 is H,
(C.sub.1-6 alkyl), (C.sub.3-7)cycloalkyl or
(C.sub.1-6)alkyl-(C.sub.3-7)cycloalkyl, aryl, Het, (C.sub.1-6)alkyl-aryl
or (C.sub.1-6)alkyl-Het, all of which optionally substituted with
R.sup.90; or R.sup.9 is covalently bonded to either of R.sup.7 or R.sup.8
to form a 5- or 6-membered heterocycle; or a salt thereof; where the
probe comprises a detectable label attached to any suitable position,
whereby said probe binds to an HCV polymerase or an analog thereof and is
capable of being displaced by an inhibitor thereof.
