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15th September 2011 @ 01:44
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Synthesis of the side chain of TCMDC-123794

Reaction Scheme

Experiment start time: 9.50 EST 15/09/11
Glycolic acid (0.50 g, 6.6 mmol, 1 equiv.), 4-DMAP (0.88 g ,7.2 mmol, 1.1 equiv.), 4-aminoantipyrine (1.34 g, 6.6 mmol, 1 equiv.) were stirred in DCM (20 mL). Yellow suspension and suspension of white crystals. Diisopropylcarbodiimide (1.13 mL, 7.2 mmol, 1.1 equiv.) added. Reaction not complete at 5 hours 40 minutes. Reaction is a yellow hazy suspension. After 24 hours no change by TLC. Reaction filtered and the filtrate concentrated under reduced pressure. The residue was diluted in EtOAc (40 mL) and washed with saturated NaHCO3 (3 × 20 mL), 1M HCl (3 × 20 mL) and brine then dried (MgSO4) and concentrated to white crystalline solid with a yellow oil (214 mg). NMR not consistant with expected product. Glycolic acid looked pretty wet, it probably just killed the carbodiimide before coupling could occur. Switch solvent for better solubility and ensure dry SM next time.

TLC (10% MeOH/DCM) visualised with UV and vanillin:
TLC 5 hr 40 mins

Left to right: acid, amine, amine + reaction mixture, reaction mixture

Risk and Hazard Assessment:
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Risk Assessment
Reaction Scheme
TLC 5 hr 40 mins
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