Abstract Recently, we identified highly potent agonists of the human histamine H 4 receptor (hH 4 R) among a series of imidazolylbutylcyanoguanidines. Aiming at improved selectivity for the hH 4 R relative to the H 3 receptor (hH 3 R), the flexible tetramethylene linker connecting imidazole ring and cyanoguanidine group was replaced by conformationally restricted carbocycles. Introduction of a para-or a meta-phenylene spacer yielded only ...
![4-methyl-N-[(3-nitrophenyl)methylidene]benzenesulfonamide结构式](https://image.chemsrc.com/caspic/233/73845-02-0.png)
