| abstract |
A novel histidine derivative represented by the following formula (I), and a pharmaceutically acceptable salt and hydrate thereof, useful as a pharmaceutical agent such as analgesics for the treatment of various kinds of acute or chronic pain diseases and of neuropathic pain diseases: n n n n n n n n n n n n wherein, R 1 is hydrogen, alkyl having 1 to 6 carbon(s) or benzyl which may be substituted with alkyl having 1 to 4 carbon(s) or halogen; R 2 is hydrogen or alkyl having 1 to 4 carbon(s); R 3 and R 4 are same or different and each is hydrogen, alkyl having 1 to 4 carbon(s) or phenyl which may be substituted with any one or two of alkyl having 1 to 6 carbon(s), alkoxy having 1 to 6 carbon(s), halogen, trifluoromethyl, nitro and cyano; and R 5 is hydrogen or an alkyl group having 1 to 4 carbon(s). |