Potent and Orally Bioavailable 8-Bicyclo[2.2.2]octylxanthines as Adenosine A<sub>1</sub> Receptor Antagonists
作者:William F. Kiesman、Jin Zhao、Patrick R. Conlon、James E. Dowling、Russell C. Petter、Frank Lutterodt、Xiaowei Jin、Glenn Smits、Mary Fure、Andrew Jayaraj、John Kim、Gail Sullivan、Joel Linden
DOI:10.1021/jm0605381
日期:2006.11.30
In the search for a selective adenosine A(1) receptor antagonist with greater aqueous solubility than the compounds currently in clinical trials as diuretics, a series of 1,4- substituted 8-cyclohexyl and 8-bicyclo-[2.2.2] octylxanthines were investigated. The binding affinities of a variety of cyclohexyl and bicyclo[2.2.2]octylxanthines for the rat and human adenosine A(1), A(2A), A(2B), and A(3) receptors are presented. Bicyclo[ 2.2.2] octylxanthine 16 exhibited good pharmaceutical properties and in vivo activity in a rat diuresis model (ED50=0.3 mg/ kg po). Optimization of the bridgehead substituent led to propionic acid 29 ( BG9928), which retained high potency ( hA(1), K-i=7 nM) and selectivity for the adenosine A1 receptor (915-fold versus adenosine A2A receptor; 12-fold versus adenosine A2B receptor) with improved oral efficacy in the rat diuresis model (ED50=0.01 mg/ kg) as well as high oral bioavailability in rat, dog, and cynomolgus monkey.