AbstractN‐Pyrazolylcarboxamides and N‐pyrazolylureas represent promising lead compounds for the development of novel antileishmanial drugs. Herein, we report the late‐stage diversification of 3‐bromopyrazoles 10 A/B and 14 A by Pd‐catalyzed Sonogashira and Suzuki‐Miyaura cross coupling reactions. The electron‐withdrawing properties of the cyano moiety in 4‐position of the pyrazole ring limited the acylation of the primary amino moiety in 5‐position. A large set of pyrazoles bearing diverse aryl and alkynyl substituents in 3‐position was prepared and the antileishmanial and antitrypanosomal activity was recorded. The urea 38 lacking the electron withdrawing cyano moiety in 4‐position and containing the large 4‐benzylpiperidinoo moiety exhibited a modest antileishmanial (IC50=19 μM) and antitrypanosomal activity (IC50=7.9 μM)). However, its considerable toxicity against the PMM and MRC‐5 cells indicates low selectivity, i. e. a small gap between the desired antiparasitic activity and undesired cytotoxicity of <2‐ to 4‐fold.
摘要N-吡唑羧酰胺和 N-吡唑脲类是开发新型抗利什曼病药物的有前途的先导化合物。在此,我们报告了通过钯催化的 Sonogashira 和 Suzuki-Miyaura 交叉偶联反应对 3-溴吡唑 10 A/B 和 14 A 进行后期多样化的情况。吡唑环 4 位氰基的吸电子特性限制了 5 位伯氨基的酰化。我们制备了一大批在 3 位具有不同芳基和炔基取代基的吡唑,并记录了它们的抗利什曼病和抗锥虫活性。脲 38 在 4-位上缺少撤电子氰基,但含有大的 4-苄基哌啶基,具有适度的抗利什曼病活性(IC50=19 μM)和抗锥虫活性(IC50=7.9 μM)。然而,它对 PMM 和 MRC-5 细胞的毒性相当大,这表明它的选择性很低,也就是说,在所需的抗寄生虫活性与 2-4 倍的非预期细胞毒性之间存在着很小的差距。