The CB1 receptor belongs to the G-protein-coupled receptor superfamily. CB1 antagonism has been considered as a new therapeutic target for the treatment of obesity. In this study, we report the synthesis and in vitro binding affinity assay of some 1,5-diarylpyrazole scaffold compounds. The binding results showed that some of the target compounds had an excellent potency toward the CB1 receptor with IC(50) values lying at the nanomole level.
A Novel and Practical Synthesis of Rimonabant Hydrochloride
作者:Zheng Fang、Zhao Yang、Jia-Feng Xu、Kai Guo、Ping Wei
DOI:10.1080/00304948.2012.657564
日期:2012.1.1
H-pyrazole-3-carboxylate (5); hydrolysis of 5 gave 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3carboxylic acid (6) which was subsequently converted to 8 (Scheme 1). Although this method appears to be a viable approach because the reagents are inexpensive and easily obtained, it was irreproducible in our laboratory. In numerous attempts, it was difficult to replicate the result and
3 3 的另一种方法是将 1 的烯醇化物(来自 LiHMDS)酰化以产生 3.3,4 的锂盐 3 与 2,4-氯苯肼缩合得到苯腙中间体 4,该中间体 4 环化为乙基 5-(4 -氯苯基)-1-(2,4-二氯苯基)-4-甲基-1H-吡唑-3-羧酸酯(5);5的水解得到5-(4-氯苯基)-1-(2,4-二氯苯基)-4-甲基-1H-吡唑-3羧酸(6),随后将其转化为8(方案1)。尽管这种方法似乎是一种可行的方法,因为试剂价格低廉且易于获得,但在我们的实验室中却无法重现。在多次尝试中,结果难以复制,产率波动很大。 3 主要问题是难以去除 1 到 2 转化过程中形成的杂质(和未反应的 1)。产物2和原料1的粗混合物的使用导致进一步步骤中的更多杂质。这些粗中间体不容易纯化,因为它们都是油。即使 6 是一种固体并被分离出来,它仍然需要多次重结晶才能得到纯产品。此外,据报道,4的合成也导致苯腙异构体9,因此不可避免地形成副产物10