| abstract |
Compounds of the formula: <IMAGE> in which R, R1, R2 and R3 have the meanings given in Claim 1, or their pharmaceutically acceptable acid addition salts are prepared. A compound of the formula: <IMAGE> is reacted in an inert solvent with chlorine or bromine or a derivative of hypochlorous or hypobromous acid. The compounds of the formula I can easily be obtained in high purity. They have useful pharmacological properties, such as e.g. anti-inflammatory, analgesic or antiviral activities. |