Demiditraz IMpurity synthesis

Yield:-

Reaction Conditions:

with hydrogen;palladium on activated carbon in isopropyl alcohol at 60; under 2327.23 - 3102.97 Torr; for 24 h;Product distribution / selectivity;

Steps:

1

To a solution of the compound of Preparation 195 (1.0 kg, 3.25 mol) in 2-propanol (10 L) was added palladium (10 wt. % on carbon, 100.0 g) and the reaction mixture was heated at 60° C. under a hydrogen atmosphere (45-60 psi) for 24 h. The mixture was cooled and filtered through Hyflo Super Cel, washing through with 2-propanol (2×250 ml). The filtrate was concentrated in vacuo and diluted with acetonitrile (1300 ml) and stirred to get a solution. To this solution, was then added dropwise sulphuric acid (conc., 1.2 L). The reaction mixture was stirred at 55° C. for 18 h. The mixture was cooled to -5° C., quenched with water (12.5 l), and adjusted to pH 10 by addition of aqueous sodium hydroxide solution (50%). The resulting solid was collected by filtration, reslurried with water (15.0 L) filtered, washed with water (2.5 L) and dried in vacuo at 50° C. to give the title compound (0.413 kg, purity by HPLC 99.80%).

References:

US2007/167506,2007,A1 Location in patent:Page/Page column 103