Acetic Acid → Carvedilol

Participants

Reaction Steps

To 450 ml ethylacetate, 70 g (0.27 moles) of anhydrous N-2-[2-(methoxy)-phenoxy]-ethyl]-benzylamine, 3.65 g (0.06 moles) of acetic acid and 25 g (0.105 moles) of 4-(oxiranylmethoxy)-9H-carbazole are added and the reaction mixture is heated to reflux for 24 hrs ( TLC control for checking conversion to N-benzyl carvedilol). To the above reaction mixture, a second lot of 3.65 g (0.06 moles) of acetic acid and 25 g (0.105 moles) of 4-(oxiranylmethoxy)-9H-carbazole are added and the reaction mixture is further heated to reflux for 24 hrs (TLC control for checking conversion to N-benzyl carvedilol). The reaction mixture is cooled to ambient temperature and subjected to hydrogenation reaction. To this solution of N-benzyl carvedilol in ethylacetate, (7 g) of wet Pd/C catalyst (5% Pd content and 50% moisture content) is added. The reaction mixture is hydrogenated at 3.5-4.5 Kg/cm2 at temperature of 60-70° C. for a period of about 8 hours. The reaction mixture is filtered and the filtrate is washed with 12-15% v/v aqueous ammonia (1 volume w. r .t. to the carbazole). The product enriched organic layer is separated and concentrated to remove ethylacetate. To the resultant syrupy mass n-butanol (100 ml) is added and the solution is stirred for about 10 hours, the crystals separated by filtration, washed successively with n-butanol (50 ml) and toluene (50 ml) to obtain carvedilol (45 g). The product is recrystallized from 3 volumes of ethyl acetate to obtain carvedilol (41 g).

Provenance & Evidence