The synthesis and pharmacology of a new analgesic, ID-1229.

A new non-narcotic analgesic, 2-[3-(p-fluorobenzoyl)-n-propy]-5alpha,9alpha-dimethyl-2'-hydroxy-6,7-benzomorphan (ID-1229) has been prepared from 5alpha,9alpha-dimethyl-2'-hydroxy-6,7-benzomorphan. The analgesic activities of ID-1229 were several times more potent than those of pentazocine in the acetic acid writhing test in mice, bradykinin test in rats, Randall-Selitto's test in rats, and the electrical stimulation test in mice, while, ID-1229 showed little activity in both the tail pinch test and the hot plate test. ID-1229 did not show anti-narcotic activity in the morphine-combined test, and the Straub tail phenomenon was not observed in ID-1229. ID-1229 showed CNS activities in some tranquilizing tests, but did not show activity in several other CNS tests. The CNS potency is condiserably weaker as compared with haloperidol or diazepam, and the pattern of CNS activities in ID-1229 is quite different from those of both compounds. ID-1229 is a potent non-narcotic analgesic with tranquilizing activity, which is quite free from the undersirable side effects of morphine or morphine-like compounds including pentazocine.