Abstract: Novel benzologs or pyrazolo-quinazoline derivatives of the formula (I) ##STR1## wherein X and Y are independently selected from oxygen, sulphur and imino and wherein ring (C) is a pyrazole ring fused to ring (B) via one of the three ortho positions or sides of ring (B); the fused pyrazole ring (C) is either in the 4,3- or the 3,4-arrangement; and tautomers of formula (I) compounds; when X is not oxygen, i.e. stands for sulphur or imino, Y may stand for a covalent bond that links the hydrogen directly to the carbon atom in position 2.Two methods for producing the novel formula (I) compounds are disclosed. The first or indazole method starts from a precursor having a benzene moiety (ring B) and a pyrazolo moiety (ring C) fused therewith, i.e. the indazole structure; ring (B) carries two vicinal substituents for forming the pyrimidine moiety or ring (A) by cyclization. The second or quinazoline method starts from a precursor having the pyrimidine moiety (A) and the benzene moiety (B) fused therewith, i.e.

Abstract: Novel quinazoline derivatives of the formula (1) ##STR1## wherein ring C is a pyrazole ring fused to ring B in two vicinal positions thereof that are not fused with ring A. The novel formula (1) compounds or pyrazolo-quinazoline-ones are structurally related to allopurinol, a well known drug useful in the treatment of gout and are expected to replace or complement allopurinol in the therapeutic use thereof. The generic name Benzoallopurinol is suggested for the novel formula (1) compounds; formula (1) includes angular and linear structures of the interfused rings A, B and C.Two methods for producing the novel formula (1) compounds are disclosed. The first method starts from the indazole structure that includes the interfused rings B and C, and ring A is formed on the indazole moiety. The second method starts from the quinazoline structure that includes interfused rings A and B, and the pyrazole ring C is formed on the benzo moiety (ring B) of the quinazoline structure.