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14th February 2014 @ 22:39
START: 14/02/14 FINISH: [b][u]Scheme[/u][/b] [b][u]Hazard and Risk Assessment[/u][/b] As for KAB119-1 [data]5313[/data] [b][u]Procedure[/u][/b] [b]14/02/14.[/b] Suspended KAB8-18 (4.21 g, 11.5 mmol) in ethanol (23 mL) and HCl (1 M, 115 mL). Heated to reflux from 1500; oil bath approx. 130 °C. Yellowish heterogenous solution. [b]15/02/14.[/b] At 0930, mixture still heterogenous. At 950, additional HCl was added (32%, 1.25 mL, 11 mmol). At 1300, mixture still heterogenous. Added ethanol to homogenise (~20 mL). Clear golden yellow solution. At 1600 TLC (neat ethyl acetate) still showed presence of starting material. At 1900, reduced intensity of SM spot but still present. Allowed to reflux overnight. [b]16/02/14.[/b] At 11:30, TLC showed residual SM (100% ethyl acetate). Mostly suspected product spot on the baseline and stained strongly with KMnO4. Expected orange reaction mixture on completion. Added additional HCl (32%, 2.5 mL, 22 mmol). Suspect "1 M HCl" used at the start wasn't actually 1 M HCl. Just make up a fresh solution in future to make sure! At 13:00, still has starting material. At 15:00 added added more acid (10 mL conc. HCl). At 17:00, reaction pretty much complete. Tiny shadow of SM by TLC. Reaction was allowed to cool to rt. Cooled in an ice bath. Adjusted to pH ~13 with KOH pellets (~20 g). Extracted with dichloromethane (4 × 300 mL). Combined organic fractions were dried over sodium sulfate, concentrated under reduced pressure and dried in vacuo to give a sickly sweet smelling yellow brown solid (2.53 g, 84%). 17/02/14. The H-NMR looked "off." Suspect salt. Could also see aromatic peaks suggestive of benzoic acid. 18/02/14. Dissolved/suspended solid in water (~40 mL). Basified using NaHCO3 (to pH 10). Extracted with dichloromethane (3 × 60 mL). Combined organics, dried over Na2SO4. Conc under reduced pressure to give a fluffy/powdery yellow solid (2.1 g, 70%). --------------------------------------------
Attached Files
Scheme KAB119-2