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10th July 2012 @ 04:39
Product obtained, contaminated with impurity. === Hydrogenolysis of PMY 51-2 at 100 psi hydrogen pressure using Pd/C catalyst. Hydrogenolysis at 1 atm did not go to completion, see PMY 51-2. Note: PMY 51-2 is not pure. [b]Reaction Start Time: 13.30 10/07/12[/b] 10% Palladium on charcoal catalyst (195 mg, 15 % wt.) was suspended in ethanol (50 mL). PMY 51-2 (1.30 g, "7.29 mmol", 1 equiv.) in ethanol (40 mL) was added to the catalyst suspension and the mixture hydrogenated in a Parr hydrogenator (stirred not shaken) at 118 psi (initial). 16.43 111 psi. Reaction left overnight. After overnightl; 110 psi. Reaction vented. TLC shows SM remains along with some baseline product. Further catalyst (195 mg) was added and the reaction placed under 200 psi hydrogen pressure. After 4 hours, 187 psi. After 6 hours, 187 psi. TLC shows a faint SM spot. Reaction vented, filtered (celite) and concentrated under reduced pressure to a clear oil (0.65 g, 101% of theory yield).1H NMR consistent with the hydrogenation product observed in PMY 53-1, however the impurities carried over from SM are still present. SM or impurity peaks close to it are still present. [b]TLC (5% MeOH/DCM) visualised with UV and vanillin:[/b] [data]2717[/data] [b]NMR:[/b] [data]2819[/data] [b]Mass Spec:[/b] (ESI+) 88.9 [M+H] [b]See also:[/b] [blog]3435[/blog] [blog]3481[/blog] [b]Risk and Hazard Assessment:[/b] [data]2687[/data] Class 3: paper copy signed.
Attached Files
RA
TLC
1H NMR