New Substituted 1-(2,3-Dihydrobenzo[1,4]dioxin-2-ylmethyl)piperidin-4-yl Derivatives with α2-Adrenoceptor Antagonist Activity

The emergence of a novel theory concerning the role of noradrenaline in the progression and the treatment of neurodegenerative diseases such as Parkinson's and Alzheimer's diseases has provided a new impetus toward the discovery of novel compounds acting at α2-adrenoceptors. A series of substituted 1-(2,3-dihydrobenzo[1,4]dioxin-2-ylmethyl)piperidin-4-yl derivatives bearing an amide, urea, or imidazolidinone moiety was studied. Some members of this series of compounds proved to be potent α2-adrenoceptor antagonists with good selectivity versus α1-adrenergic and D2-dopamine receptors. Particular emphasis is given to compound 33g which displays potent α2-adrenoceptor binding affinity in vitro and central effects in vivo following oral administration.