Design of 5-(3,5-di-tert-butyl-4-hydroxyphenyl)-1,3,4-thiadiazoles, -1,3,4-oxadiazoles, and -1,2,4-triazoles as orally active, nonulcerogenic antiinflammatory agents
To discover dual inhibitors of 5-lipoxygenase (LO) and cyclooxygenase (CO) with improved pharmacokinetic properties, we have designed and synthesized series of 1,2,4-triazole, 1,3,4-oxadiazole, and 1,3,4-thiadiazole di-tert-butylphenol derivatives which exhibit a wide range of log P (2.3 to > 4) and pKa (5.5-12) values. From this work 5-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1,3,4-thiadiazole-2(3H)- thione, choline salt (12a, CI-986) was found to be a potent inhibitor of 5-LO (IC50 = 2.8 microM) and CO (IC50 = 0.8 microM), orally active in rat models of inflammation and nonulcerogenic.