Hippuric Acid → Azlactone

HRID 466787Notes

Reaction equation

HRID 466787 reaction equation
[C:1]([OH:13])(=[O:12])[CH2:2][NH:3][C:4]([C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1)=O.C(OC(=O)C)(=O)C>C1(C)C=CC=CC=1>[C:6]1([C:4]2[O:13][C:1](=[O:12])[CH2:2][N:3]=2)[CH:7]=[CH:8][CH:9]=[CH:10][CH:11]=1

Participants

4

Reactant 2

HCID 464Hippuric AcidHCID 7918Acetic Anhydride

Product 1

HCID 65073Azlactone

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
90 °C

Procedure

This procedure is a modification of Crawford and Little (J. Chem. Soc. 1959, 729). A flask containing hippuric acid (20 g, 0.011 mol, Aldrich) and acetic anhydride (130 mL) was placed in a boiling H2O bath (90° C.) and vigorously stirred for exactly 15 min. The solution was poured onto 200 mL of toluene, 200 mL of ice water and stirred vigorously for 5 min. The phases were separated and the organic phase was stirred with 1 L of 2% aq. NaHCO3 for 10 min., separated and dried with anhydrous Na2SO4. Filtration of the solution and rotary evaporation (bath temperature 35° C., 20 mmHg) gave a yellow white solid. The formation of a red material in this procedure is due to protect degradation and condensation. Yield 11.8 g, 66%, mp 83°-86°. 1H NMR (CDCl3): δ7.95 (d, 2H; J=7 Hz); 7.55 (t, 1H, J=7 Hz), 7.45 (t, 2H, J=7 Hz), 4.38 (s, 1H). 13C NMR (CDCl3): 175.9, 163.4, 132.7, 128.8, 127.7, 125.8, 54.9.

Workup

  1. customwas placed in a boiling H2O bath
  2. stirringstirred vigorously for 5 min
  3. customThe phases were separated
  4. stirringthe organic phase was stirred with 1 L of 2% aq. NaHCO3 for 10 min.
  5. customseparated
  6. dry with materialdried with anhydrous Na2SO4
  7. filtrationFiltration of the solution and rotary evaporation (bath temperature 35° C., 20 mmHg)
  8. customgave a yellow white solid
  9. customdegradation and condensation

Sources & evidence

ORD record
ord-71c16139a9bf466babf469437de243ac
Source dataset
uspto-grants-1992_10
Patent number
US05157149

Reaction notes

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