This invention relates to: (a) compounds of formula Ia (with R1, R4, R5, R6, n and A as defined herein) and pharmaceutically acceptable salts or solvates thereof that are useful as dopamine-β-hydroxylase inhibitors; (b) pharmaceutical compositions comprising such compounds, salts or solvates; (c) the use of such compounds, salts or solvates in therapy; (d) therapeutic methods of treatment using such compounds, salts or solvates; and (e) processes and intermediates useful for the synthesis of such compounds.本發明涉及:(a)可用作多巴胺-β-羥化酶抑制劑的式Ia化合物(其中R1、R4、R5、R6、n和A如本文所定義)和其藥學上可接受的鹽或溶劑合物;(b)包含所述化合物、鹽或溶劑合物的藥物組合物;(c)所述化合物、鹽或溶劑合物在療法中的用途;(d)使用所述化合物、鹽或溶劑合物治療的治療性方法;和(e)可用於合成所述化合物的方法和中間體