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29th June 2012 @ 07:46
Product obtained and used crude.

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Hydrogenolysis of PMY 51-1-B to provide N-methyl side-chain.

PMY53-1.png

Reaction Start Time: 16.40 29/06/12
10% Pd/C (40 mg) was stirred in ethanol (10 mL) at 0 °C. PMY 51-1-B (0.41 g, 2.30 mmol) was dissolved in EtOH (10 mL, warmed then cooled) and added to the catalyst suspension. Reaction left at room temperature over the weekend. Hydrogen balloon had deflated. TLC shows SM and new polar spot. 1H NMR confirms SM and new product consistent with expected signals (approx 2.3:3 ratio). Subjected to the same reaction conditions again (14:10 02/07/12). 05/07/12 Purged with nitrogen, celite filtered (water/ethanol) and concentrated under reduced pressure. The mixture was extracted with DCM (3 × 20 mL). The organic extracts were washed with brine then dried (MgSO4) and concentrated under reduced pressure to a white solid (114 mg, 56% of theory). 1H NMR consistent with SM, does not show product from previous NMR. Suspect product is in aqueous phase. Aqueous phase concentrated under reduced pressure. Methanol (approx 30 mL) was added to the residue, sonicated then heated and cooled. The mixture was filtered and the cake washed with further methanol (50 mL). The filtrate was concentrated under reduced pressure to a slightly pink solid. Triturated with CDCl3 (PMY 53-1-B. 1H NMR consistent with expected product and product observed on first NMR (not clean).

NMR:
1H NMR incomplete
PMY 53-1-B, aqueous layer
1H NMR further reaction


See also:
Reductive alkylation of glycinamide (PMY 51-1)

Risk and Hazard Assessment:
See: Reduction of 4-fluoro near-neighbour Micheal-acceptor (PMY 36-1)
Linked Posts
Attached Files
Scheme
scheme correction!
1H NMR incomplete
1H NMR further reaction
PMY 53-1-B, aqueous layer