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24th January 2011 @ 06:58
Preparation of starting material for a scaled-up racemic resolution of PZQamine See: [url=]Hydrolysis of rac-PZQ (MW2-13)[/url] Following the optimized conditions for [i]rac[/i]-PZQ: see [url=]Optimizing the acid cleavage conditions II[/url] [data=size:500x160]639[/data] [b]Hazard and Risk Assessment:[/b] [data=text]641[/data] Start time: 6:30 PM 24/01/2011 End time: 8:50 AM 25/01/2011 [b]Procedure:[/b] rac-PZQ (20.0 g, 64.0 mmol) was dissolved in a mixture of EtOH (150 mL) and 1N HCl (600 mL, 53.0 mL of 11.3 N HCl solution (35%) in 547 mL water) and heated to reflux for 14 h. Reaction monitored by TLC showed a complete consumption of PZQ (TLC, EA/hexane 1:1, Rf = 0.15 for PZQ). Work-up: Solution was cooled to room temperature, washed with EtOAc (4 times 15 mL), basified with NaOH solution (5 N) to ph 12, extracted with DCM (5 x 30 mL), washed with brine, dried over NaSO4, evaporated under reduced pressure. pale yellow oil turned into a solid after freezing the oil with liquid nitrogen under high vac and warmed to room temperature. [u]Yield: [/u] 11.1 g (52.0 mmol, 86%) pale yellow solid [M.W. = 202.1 g/mol] m.p. = 116.5 - 118.5°C