Application of the Goldilocks Effect to the Design of Potent and Selective Inhibitors of Phenylethanolamine <i>N</i>-Methyltransferase: Balancing p<i>K</i><sub>a</sub> and Steric Effects in the Optimization of 3-Methyl-1,2,3,4-tetrahydroisoquinoline Inhibitors by β-Fluorination
作者:Gary L. Grunewald、Mitchell R. Seim、Jian Lu、Mariam Makboul、Kevin R. Criscione
DOI:10.1021/jm051262k
日期:2006.5.1
inhibitors of phenylethanolamine N-methyltransferase (PNMT), but are not selective due to significant affinity for the alpha(2)-adrenoceptor. Fluorination of the methyl group lowers the pK(a) of the THIQ amine from 9.53 (CH(3)) to 7.88 (CH(2)F), 6.42 (CHF(2)), and 4.88 (CF(3)). This decrease in pK(a) results in a reduction in affinity for the alpha(2)-adrenoceptor. However, increased fluorination also results
3-甲基-1,2,3,4-四氢异喹啉 (3-甲基-THIQ) 是苯乙醇胺 N-甲基转移酶 (PNMT) 的强效抑制剂,但由于对 α(2)-肾上腺素受体具有显着亲和力,因此不具有选择性。甲基的氟化将 THIQ 胺的 pK(a) 从 9.53 (CH(3)) 降低到 7.88 (CH(2)F)、6.42 (CHF(2)) 和 4.88 (CF(3))。pK(a) 的这种降低导致对 α(2)-肾上腺素受体的亲和力降低。然而,增加氟化也会导致 PNMT 抑制效力降低,这显然是由于空间和静电因素。一系列 3-氟甲基-THIQ 和 3-三氟甲基-THIQ 的生化评估表明,前者是 PNMT 的高效抑制剂,但由于对 α(2)-肾上腺素受体具有显着的亲和力,因此通常是非选择性的,虽然后者缺乏 α(2)-肾上腺素受体亲和力,但也失去了 PNMT 的效力。3-二氟甲基-7-取代-THIQ 具有空间位阻和 pK(a)