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17th July 2012 @ 04:25
Product obtained. === Reductive amination of pyrrole aldehyde with crude PMY 53-2 (PMY 56-1). [b]Reaction Start Time: 1400 17/07/12[/b] PMY 2-5 (200 mg, 0.92 mmol, 1 equiv.) and crude PMY 53-2 (150 mg) were dissolved in MeOH (10 mL) and acetic acid (0.25 mL). 1505: Sodium cyanoborohydride (64 mg, 1.01 mmol, 1.1 equiv.) was added in 3 portions over 3 minutes. TLC at 18 hours shows new product and SM (+ 2 less polar spots). Further sodium cyanoborohydride (30 mg, 0.50 mmol, 0.5 equiv) added. After a further 8.5 hours, TLC shows no change. After a further 16 hours, no change by TLC. Reaction was concentrated under reduced pressure. 1M NaOH (10 mL) and DCM (20 mL) was added and the reaction stirred for 10 minutes. Extracted with further DCM (2 × 15 mL). The organic extracts were washed with brine then dried (MgSO4) and concentrated to a slightly yellow gum. Purification by chromatography on silica (1-10% MeOH/DCM) gave PMY 56-1 (148 mg), consistent with expected product and impurity carried over in starting material. Impurity and product have very similar Rf on TLC. [b]TLC (5% MeOH/DCM) visualised with UV and vanillin:[/b] [data]2753[/data] [b]NMR:[/b] [data]2831[/data] [b]Mass Spec:[/b] HRMS (ESI+) found 312.14899 [M+Na], C16H20N3OFNa requires 312.14826. [b]See also:[/b] [blog]3679[/blog] [blog]3587[/blog] [b]Risk and Hazard Assessment:[/b] See: [blog]2606[/blog]
Attached Files
TLC 18 hours