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8th December 2011 @ 03:29
Coupling of hippuric acid and 4-aminoantipyrine using T3P to obtain the glycine benzamide.

Reaction Scheme

Reaction start time: 16.30 08/12/11
Hippuric acid PMY 26-1 (200 mg, 1.12 mmol, 1 equiv.) and 4-aminoantipyrine (250 mg, 1.23 mmol, 1.1 equiv.) were dissolved in pyridine (1 mL) and DMF (1 mL) and cooled in ice/water. 50% T3P in EtOAc (1 mL, 1.7 mmol, 1.5 equiv.) was added after 30 minutes, the reaction was allowed to warm to room temperature and the reaction stirred for 16 hours. 0.5M HCl (10 mL) and EtOAc (10 mL) were added. After approx 10 minutes of stirring, copious white precipitate formed. Cooled in ice then filtered, white solid washed with water. Filtrate (pH 4) was separated and the organic layer washed with 5% NaOH (10 mL), water (3 × 10 mL), brine then dried (MgSO4) and concentrated to a orange solid, PMY 27-1-B (24 mg). TLC shows white solid and orange gum to be new products. White solid dried under vacuum, PMY 27-1-A (211 mg).

PMY 27-1-A solubility:
DCM (reasonably), acetone (sparingly), EtOAc (sparingly), water (insoluble), [from reaction DMF (readily)].

TLC (10% MeOH/DCM) visualised with UV and vanillin:
TLC 16 hours

TLC before quench. Left to right: PMY 26-1 in DMF, mix, reaction mixture, 4-aminoantipyrine.

After work-up

Left to right: white solid, mix, PMY 26-1 (loaded in acetone), 4-aminoantipyrine, mix, orange solid.

comparison of components

(12% MeOH/DCM) Left to right: white solid, mix, 4-aminoantipyrine, mix, orange solid, mix, PMY 26-1.

Risk and Hazard Assessment:
As for, Synthesis of TCMDC-123812 using T3P (PMY 10-4)

See also:
Synthesis of hippuric acid (PMY 26-1)
Linked Posts
Attached Files
Reaction Scheme
TLC 16 hours
After work-up
comparison of components
1H PMY 27-1-A CDCl3
1H PMY 27-1-A acetone