In the title structure, 5-fluoro-3-phenyl-2-[(1S)-1-(9H-purin-6-yl-amino)-prop-yl]quinazolin-4(3H)-one (= idelalisib) tert-butanol monosolvate dihydrate, C22H18FN7O·C4H10O·2H2O, the idelalisib mol-ecule displays planar quinazoline and purine systems which are nearly perpendicular to one another. Seven distinct hydrogen-bonding inter-actions link the idelalisib, t-BuOH and water mol-ecules into a complex chain structure with the topology of a 2,3,4,5-connected 4-nodal net having the point symbol (3.4.52.62)(3.4.52.64.72)(3.5.6)(5).
Keywords: crystal structure; hydrate; hydrogen bonding; pharmaceuticals; solvate.