| abstract |
A process for the preparation of (2R)-methyl-4,4,4- -trifluorobutylamine, or an acid addition salt thereof which comprises a) acylating an optically active amine with 2-methyl- -4,4,4-trifluorobutanoic acid or a reactive derivative thereof to afford a butyramide; b) separating (R)-diastereomeric butyramide from (S)-diastereomeric butyramide; and c) converting the (R)-diastereomeric butyramide into the desired (2R)-methyl- -4,4,4-trifluorobutylamine, or an acid addition salt thereof. The product may be acylating with a carboxylic acid of formula (III) wherein U is carboxy, or a reactive derivative thereof to afford (R)-4-[5-(N-[4,4,4-trifluoro-2-methylbutyl]carbamoyl)-1- -methylindol-3-yl-methyl]-3-methoxy-N-o-tolylsulphonylbenzamide. The indole is useful as a leukotriene antagonist, for example in the treatment of asthma or allergic rhinitis. |