3-arylquinazoline derivatives as selective estrogen receptor beta modulators

Novel quinazoline derivatives possessing activity as estrogen receptor beta (ERbeta) modulators are provided which have the general formula I wherein X is O or S; A and B are each independently CR''' or N; R, R' and R'' are each independently hydrogen, alkyl, benzyl, p-methoxybenzyl, allyl, or Si(R4)3, wherein at least one of R, R' and R'' is hydrogen; R''' is hydrogen, halogen, CF3, OR5, S(O)nR6, NR7R8, cycloalkyl or alkyl; R1, R2 and R3 are each independently hydrogen, halogen, CF3, OR5, S(O)nR6, NR7R8, cycloalkyl or alkyl; R4 is a alkyl; R5, R6, R7 and R8 in each functional group are each independently hydrogen, cycloalkyl or alkyl; and n is an integer from 0 to 2. In addition, a method is provided for preventing, inhibiting or treating the progression or onset of pathological conditions associated with the estrogen receptor and to pharmaceutical compositions containing such compounds.