Novel 5-Hydroxytryptamine (5-HT3) Receptor Antagonists. IV. Synthesis and Pharmacological Evaluation of the Oxidation Products of (-)-(R)-5-((1-Methyl-1H-indol-3-yl)carbonyl)-4,5,6,7 tetrahydro-1H-benzimidazole Hydrochloride (YM060: Ramosetron).
作者:Mitsuaki OHTA、Takeshi SUZUKI、Shinya NAGASHIMA、Tatsuhiro TOKUNAGA、Keiji MIYATA、Toshiyasu MASE
DOI:10.1248/cpb.44.1717
日期:——
In physicochemical and pharmacokinetic evaluations of (-)-(R)-5-[(1-methyl-1H-indol-3-yl)carbonyl]-4, 5, 6, 7-tetrahydro-1H-benzimidazole hydrochloride 1 (YM060 : ramosetron), which is a highly potent 5-hydroxytryptamine (5-HT3) receptor antagonist, 4-hydroxy-6-[(1-methyl-1H-indol-3-yl)carbonyl]-4, 5, 6, 7-tetrahydro-1H-benzimidazole 2 was identified as a degradation product and metabolite of 1. The (-)-(4R, 6S)-isomer 2 was synthesized from the diketone derivative 3, via the stereoselective reduction of 3 followed by the stereocontrolled epimerization of the (-)-(4S, 6S)-isomer 10, the epimer of 2. The stereochemistry of 2 and 10 was determined by NMR and HPLC studies. Compounds 2 and 10 were found to be potent 5-HT3 receptor antagonists, like 1. Among the other oxidation products, the diketone derivatives 3 and 7 and the dihydroxylated derivative 4 retained antagonistic activity similar to that of ondansetron. This is of interest, because they do not possess the amine group which is known to be necessary for high affinity to the 5-HT3 receptor.
在对(-)-(R)-5-[(1-甲基-1H-吲哚-3-基)羰基]-4, 5, 6, 7-四氢-1H-苯并咪唑盐酸盐1(YM060:拉莫司特龙)的物理化学和药物动力学评估中,发现4-羟基-6-[(1-甲基-1H-吲哚-3-基)羰基]-4, 5, 6, 7-四氢-1H-苯并咪唑2是1的降解产物和代谢物。(-)-(4R, 6S)-异构体2是通过二酮衍生物3的立体选择性还原以及(-)-(4S, 6S)-异构体10(2的对映体)的立体控制的表异构化反应合成的。通过核磁共振(NMR)和高效液相色谱(HPLC)研究确定了2和10的立体化学。化合物2和10被发现具有与1相似的强效5-羟色胺(5-HT3)受体拮抗活性。在其他氧化产物中,二酮衍生物3和7以及二羟基衍生物4也保持了与昂丹司琼相似的拮抗活性。这一点值得关注,因为它们不具有已知对5-HT3受体高亲和力必需的氨基组。