Horner-Emmons condensation of benzazepinone (I) with triethyl phosphonoacetate gave unsaturated ester (II). Subsequent reductive treatment of (II) with Mg in MeOH produced the saturated ester (III) with concomitant cleavage of the tosyl group. 2-Chloro-4-(1-pyrrolidinyl)benzoyl chloride (V) (prepared by reaction of the corresponding carboxylic acid (IV) with SOCl2) was then condensed with benzazepine (III) to produce benzamide (VI). Hydrolysis of the methyl ester function of (VI) yielded the racemic carboxylic acid (VII), which was resolved by means of esterification with (R)-2-heptanol, followed by chromatographic separation of the diastereomeric mixture. After saponification of the required diastereoisomeric ester (VIII), the resulting (R)-carboxylic acid was finally coupled with isopropylamine using diethylcyanophosphate as the condensing reagent.

Horner-Emmons condensation of benzazepinone (I) with triethyl phosphonoacetate gave unsaturated ester (II). Subsequent reductive treatment of (II) with Mg in MeOH produced the saturated ester (III) with concomitant cleavage of the tosyl group. 2-Chloro-4-(1-pyrrolidinyl)benzoyl chloride (V) (prepared by reaction of the corresponding carboxylic acid (IV) with SOCl2) was then condensed with benzazepine (III) to produce benzamide (VI). Hydrolysis of the methyl ester function of (VI) yielded the racemic carboxylic acid (VII), which was resolved by means of esterification with (R)-2-heptanol, followed by chromatographic separation of the diastereomeric mixture. After saponification of the required diastereoisomeric ester (VIII), the resulting (R)-carboxylic acid was finally coupled with isopropylamine using diethylcyanophosphate as the condensing reagent.