Fenbufen, a new anti-inflammatory analgesic: synthesis and structure-activity relationships of analogs.

One hundred analogs of fenbufen were prepared and tested using the carrageenan, polyarthritis, and UV erythema anti-inflammatory tests and the 2-phenyl-1,4-benzoquinone writhing and inflamed paw pressure analgesic tests. Only three retained the same full spectrum of activity as fenbufen: dl-4-(4-biphenylyl)-4-hydroxybutyric acid, dl-4-(4-biphenylyl)-1,4-butanediol, and 4-biphenylacetic acid. Fenbufen had the same spectrum of activity as aspirin, phenylbutazone, and indomethacin in the five tests. In addition, dose-response derived potencies show fenbufen more potent than aspirin and at least as potent as phenylbutazone in all five tests. Two related compounds were generally similar.