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8th January 2012 @ 22:44
Product obtained in good yield. === Coupling of Boc-protected glycine and 4-aminoantipyrine using T3P. [b]Reaction start time: 15.00 04/01/12 [/b] Boc-Gly-OH (200 mg, 1.14 mmol, 1 equiv.) and 4-aminoantipyrine (255 mg, 1.26 mmol, 1.1 equiv.) were dissolved in EtOAc (5 mL) and pyridine (0.55 mL, 6.85 mmol, 6 equiv.). T3P (50 wt.% in EtOAc, 1.4 mL, 2.20 mmol, 1.9 equiv.) was added at room temperature and the mixture stirred overnight. A white precipitate formed. 0.5 M HCl (20 mL) was added and the mixture diluted with EtOAc (20 mL). The layers were separated and the aqueous extracted with further EtOAc (2 × 10 mL). The aqueuous was then basified with 10% NaHCO3 and extracted with EtOAc (3 × 10 mL). The organic layers were washes separately with brine and dried (MgSO4) and concentrated to orange oils; extracted at pH 1 PMY 29-1-A (140mg), and extracted at pH 9 PMY 29-1-B (280 mg). 1H NMR consistent with expected product. Shift in signals observed between A and B. Total yield 420 mg, 102%. [b]NMR:[/b] [data]1192[/data][data]1190[/data] [b]Risk and Hazard Assessment:[/b] See also: [blog]1346[/blog] [blog]1296[/blog] [blog]1270[/blog] InChI=1S/C18H24N4O4/c1-12-15(20-14(23)11-19-17(25)26-18(2,3)4)16(24)22(21(12)5)13-9-7-6-8-10-13/h6-10H,11H2,1-5H3,(H,19,25)(H,20,23)
Attached Files
Scheme
1H NMR basic extraction
1H NMR acidic extraction
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