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4th October 2012 @ 07:48

Cyclodehydration of carboxamide PMY 61-1-B to oxazoline and subsequent oxidation to the oxazole. Products at both steps to be retained. Method as previously used for PMY 58-1.


Reaction Start Time: 1540 04/10/12
PMY 61-1-B (110 mg, 0.34 mmol, 1 equiv.) in 1,2-DCE (4 mL) heated to reflux. Xtalfluor-E (158 mg, 0.69 mmol, 2 equiv.) was added (carefully) and the reaction stirred at reflux under a nitrogen atmosphere. Reaction solvent evaporated (1 hr). Redissolved in 1,2-DCE (4 mL) and left overnight.

Reaction is a brown solution. Saturated Na2CO3(aq) and water (1:1, 10 mL) were added and the mixture stirred for 20 minutes. Extracted using DCM (3 × 10 mL). The combined extracts were washed with brine and dried (MgSO4) then concentrated to a brown solid (130 mg). TLC shows consumption of starting material and more polar product(s). Expecting less polar product.

TLC (10% MeOH/DCM) visualised with UV and vanillin:
TLC crude

See also:
Scaled-up cyclodehydration of carboxamide PMY 57-2 (PMY 58-2)
Cyclodehydration of carboxamide PMY 57-1 (PMY 58-1)
Coupling of pyrrole acid chloride and L-serinamide (PMY 61-1)

Risk and Hazard Assessment:
See: Cyclodehydration of carboxamide PMY 57-1 (PMY 58-1)
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TLC crude