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12th October 2011 @ 07:19
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Reduction of pyrrole-3-ester PMY 6-1 using LiAlH4.

Reaction Scheme

Reaction start time: 10.15 13/10/11
LiAlH4 (36 mg, 0.96 mmol, 0.5 equiv, 2 hydride equiv.) was stirred in Et2O (5 mL) at room temperature. PMY 6-1 (500 mg, 1.91 mmol, 1 equiv.) in Et2O (10 mL) was added dropwise over 5 minutes. After 1.5 hours, TLC shows partial conversion of SM. Further LiAlH4 (36 mg, 0.96 mmol, 0.5 equiv, 2 hydride equiv.) was added and the reaction heated to reflux. After 2 further hours, reaction still not complete. Addition of further LiAlH4 (36 mg, 0.96 mmol, 0.5 equiv, 2 hydride equiv.) does not result in visible reaction. After a further 30 minutes, reaction cooled in ice. Water (0.5 mL) added and the reaction stirred. After 10 minutes the reaction was diluted with EtOAc (20 mL) and a saturated solution of Rochelle's salt (approx 10 mL) was added, shaken and left over night to separate. Organic washed with more Rochelles salt (2 × 10 mL), water (3 × 10 mL), brine and dried (MgSO4) then concentrated to a brown oil (465 mg). Purified by chromatography (2-30% EtOAc/hexane) to obtain, according to TLC, SM brown solid (86 mg) and product brown oil (81 mg).

NMR:
1H NMR


Risk and Hazard Assessment:
Risk Assessment


See also:
Synthesis of Ethyl 1-(4-fluorophenyl)-2,5-dimethyl-1H-pyrrole-3-carboxylate (PMY 6-1)
Linked Posts
Attached Files
Reaction Scheme
Reaction Scheme
Risk Assessment
TLC 1.5 hours
1H NMR