Our previous structure-affinity relationship study had considered the enantiomers of the naphthodioxane, tetrahydronaphthodioxane, and 2-methoxy-1-naphthoxy analogues ( compounds 1, 3, and 2, respectively) of 2-(2,6-dimethoxyphenoxyethylaminomethyl)-1,4-benzodioxane, the well-known alpha(1)-adrenoceptor (alpha(1)-AR) antagonist WB4101, showing that such modifications significantly modulate the affinity and selectivity profile for alpha(1)-AR subtypes and 5-HT1A receptor. Here, we extend investigations to antagonist activity enclosing new enantiomeric pairs, namely those of the methoxytetrahydronaphthoxy and methoxybiphenyloxy WB4101 analogues (4 and 5-7, respectively) and of a double- modified WB4101 derivative ( 8) resulting from hybridization between 2 and 3. We found that (S)-2 is a very potent (pA(2) 10.68) and moderately selective alpha(1D)-AR antagonist and the hybrid (S)-8 is a potent (pA(2) 7.98) and highly selective alpha(1A)-AR antagonist. Both of these compounds and (S)-WB4101 seem to act as inverse agonists in a vascular model. The results, which generally validate the logic we followed in designing these eight compounds, are acceptably rationalized by comparative SAR analysis of binding and functional affinities.
Our previous structure-affinity relationship study had considered the enantiomers of the naphthodioxane, tetrahydronaphthodioxane, and 2-methoxy-1-naphthoxy analogues ( compounds 1, 3, and 2, respectively) of 2-(2,6-dimethoxyphenoxyethylaminomethyl)-1,4-benzodioxane, the well-known alpha(1)-adrenoceptor (alpha(1)-AR) antagonist WB4101, showing that such modifications significantly modulate the affinity and selectivity profile for alpha(1)-AR subtypes and 5-HT1A receptor. Here, we extend investigations to antagonist activity enclosing new enantiomeric pairs, namely those of the methoxytetrahydronaphthoxy and methoxybiphenyloxy WB4101 analogues (4 and 5-7, respectively) and of a double- modified WB4101 derivative ( 8) resulting from hybridization between 2 and 3. We found that (S)-2 is a very potent (pA(2) 10.68) and moderately selective alpha(1D)-AR antagonist and the hybrid (S)-8 is a potent (pA(2) 7.98) and highly selective alpha(1A)-AR antagonist. Both of these compounds and (S)-WB4101 seem to act as inverse agonists in a vascular model. The results, which generally validate the logic we followed in designing these eight compounds, are acceptably rationalized by comparative SAR analysis of binding and functional affinities.
Our previous structure-affinity relationship study had considered the enantiomers of the naphthodioxane, tetrahydronaphthodioxane, and 2-methoxy-1-naphthoxy analogues ( compounds 1, 3, and 2, respectively) of 2-(2,6-dimethoxyphenoxyethylaminomethyl)-1,4-benzodioxane, the well-known alpha(1)-adrenoceptor (alpha(1)-AR) antagonist WB4101, showing that such modifications significantly modulate the affinity and selectivity profile for alpha(1)-AR subtypes and 5-HT1A receptor. Here, we extend investigations to antagonist activity enclosing new enantiomeric pairs, namely those of the methoxytetrahydronaphthoxy and methoxybiphenyloxy WB4101 analogues (4 and 5-7, respectively) and of a double- modified WB4101 derivative ( 8) resulting from hybridization between 2 and 3. We found that (S)-2 is a very potent (pA(2) 10.68) and moderately selective alpha(1D)-AR antagonist and the hybrid (S)-8 is a potent (pA(2) 7.98) and highly selective alpha(1A)-AR antagonist. Both of these compounds and (S)-WB4101 seem to act as inverse agonists in a vascular model. The results, which generally validate the logic we followed in designing these eight compounds, are acceptably rationalized by comparative SAR analysis of binding and functional affinities.