Synthesis of Eosinophil Infiltration Inhibitors with Antihistaminic Activity.
作者:Michiyo Gyoten、Hideaki Nagaya、Shigeru Fukuda、Yasuko Ashida、Yasuhiko Kawano
DOI:10.1248/cpb.51.122
日期:——
A series of [1, 2, 4]triazolo[1, 5-b]pyridazines (5) and imidazo[1, 2-b]pyridazines (6) having cyclic amines was synthesized and evaluated for antihistaminic activity and inhibitory effect on eosinophil infiltration. When a piperidine or a piperazine containing a benzhydryl group and a suitable spacer was incorporated at the 6-position, the fused pyridazines were found to exhibit both antihistaminic activity and an inhibitory effect on eosinophil chemotaxis. Above all, 6a showed potent antihistaminic activity, but little blockade of central H1 receptors in contrast with its complete blockade of peripheral H1 receptors as determined by an ex vivo binding assay. Furthermore, 6a inhibited eosinophil infiltration of the skin caused by a topical antigen challenge in sensitized guinea pigs, while an antihistamine terfenadine was not effective. After the pharmacokinetic study, 6a was found to be rapidly hydrolyzed to 6o, which was also orally active. Compound 6o, 2-[6-[[3-[4-(diphenylmethoxy)piperidino]propyl]amino]imidazo[1, 2-b]pyridazin-2-yl]-2-methylpropionic acid dihydrate (TAK-427), having both antihistaminic and antiinflammatory activity, is currently undergoing clinical trials as a therapeutic agent for atopic dermatitis and allergic rhinitis.
合成了一系列含有环状胺的[1, 2, 4]三唑[1, 5-b]吡唑啉(5)和咪唑[1, 2-b]吡唑啉(6),并评估了其抗组胺活性和对嗜酸性粒细胞浸润的抑制作用。当在6位引入含有苯基苄基团和合适连接子的哌idine或哌唑时,发现这些融合的吡唑啉同时展现了抗组胺活性和对嗜酸性粒细胞趋化的抑制作用。特别是,化合物6a展现了强大的抗组胺活性,但在外周H1受体上的完全阻断与中央H1受体的轻微阻断形成对比,后者是通过ex vivo结合实验确定的。此外,6a还抑制了在敏感豚鼠皮肤上由局部抗原挑战引起的嗜酸性粒细胞浸润,而抗组胺药物特非那定则无效。在药代动力学研究后,发现6a迅速水解为6o,后者也具有口服活性。化合物6o,即2-[6-[[3-[4-(二苯基甲氧基)哌啶基]丙氨]氨基]咪唑[1, 2-b]吡唑啉-2-基]-2-甲基丙酸二水合物(TAK-427),同时具有抗组胺和抗炎活性,目前正在作为特应性皮炎和过敏性鼻炎的治疗药物进行临床试验。