Novel phenylacetic derivatives are provided of the general formula ##STR1## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as defined herein, and pharmaceutically acceptable salts thereof. These have anti-inflammatory or analgetic activity. The invention also provides a process for the production of these compounds from a ketone of the structure: ##STR2## It also provides pharmaceutical compositions including phenylacetic derivatives.