TMX-67

HTS followed by NMR based counterscreening. Discovery and optimization of pyrimidones as reversible and competitive inhibitors of xanthine oxidase

The identification of novel, non-purine based inhibitors of xanthine oxidase is described. After a high-throughput screening campaign, an NMR based counterscreen was used to distinguish actives, which interact with XO in a reversible manner, from assay artefacts. This approach identified pyrimidone 1 as a reversible and competitive inhibitor with good lead-like properties. A hit to lead campaign gave compound 41, a nanomolar inhibitor of hXO with efficacy in the hyperuricemic rat model after oral dosing.

Febuxostat methanol solvate

In the title compound {systematic name: [2-(3-cyano-4-isobutyl­oxyphen­yl)-4-methyl-1,3-thia­zole-5-carb­oxy­lic acid (febuxostat) methanol monosolvate}, C₁₆H₁₆N₂O₃S·CH₄O, the benzene and thia­zole rings in the febuxostat mol­ecule are twisted at 5.3 (1)°. In the crystal structure, inter­molecular O—H⋯O and O—H⋯N hydrogen bonds link the febuxostat and methanol mol­ecules into helical chains along the 2₁ screw axis.

6-(N-benzoylamino)purine as a novel and potent inhibitor of xanthine oxidase: Inhibition mechanism and molecular modeling studies

The inhibition of xanthine oxidase (XO) activity by the purine analogue 6-(N-benzoylamino)purine was evaluated and compared with the standard inhibitor, allopurinol and the parent compound adenine. 6-(N-benzoylamino)purine is a highly potent inhibitor of XO (IC50 = 0.45 microM) and comparable to allopurinol (IC50 = 0.80 microM). Furthermore, 6-(N-benzoylamino)purine neither produced any enzymatic superoxide nor reduced XO by an electron transfer reaction unlike allopurinol. 6-(N-benzoylamino)purine (Ki = 0.0475 microM) is about 10000-fold more potent as a XO inhibitor compared to the only known purine analogue 8-bromoxanthine (Ki = 400 microM). 6-(N-Benzoylamino)purine is a competitive inhibitor of XO and the inhibition was not completely reversed even at 100 microM xanthine concentration. The calculated interaction energy [Ecomplex - (Eligand + Eprotein)] of -30.5, -22.6, and -17.2 kcal/mol, respectively, of 6-(N-benzoylamino)purine, 8-bromoxanthine and the parent compound adenine provided the rationale for the better enzyme inhibitory activity of 6-(N-benzoylamino)purine. To understand the role of the benzamido group in the inhibition process, molecular docking studies were carried out and it was revealed that the hydrogen bonding interactions involving N-7 of the purine ring and the N-H of Arg880, N-H of the purine ring and OH of Thr1010, as well as non-bonded interactions of the benzamido group of 6-(N-benzoylamino)purine with amino acid residues Gly799, Glu802, Phe914, Ala1078, Ala1079 and Glu1261 in the active site of XO play an important role in the stabilization of the E-I complex.