Sulfuric Acid → 5-Acetoxypyran-4-one-2-carbonyl chloride

HRID 2051164Notes

Reaction equation

HRID 2051164 reaction equation
[C:1]([C:4]1[O:5][CH:6]=[C:7]([OH:11])[C:8](=[O:10])[CH:9]=1)([OH:3])=O.[C:12]([O:15]C(=O)C)(=O)[CH3:13].S(=O)(=O)(O)O.C(Cl)(=O)C([Cl:27])=O>ClCCl.CN(C)C=O>[C:12]([O:11][C:7]1[C:8](=[O:10])[CH:9]=[C:4]([C:1]([Cl:27])=[O:3])[O:5][CH:6]=1)(=[O:15])[CH3:13]

Participants

7

Reactant 4

HCID 1118Sulfuric AcidHCID 7918Acetic AnhydrideHCID 65578Oxalyl chlorideHCID 68139Comenic acid

Product 1

HCID 108893295-Acetoxypyran-4-one-2-carbonyl chloride

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
0 °C

Procedure

2-Carboxy-5-hydroxypyran-4-one (20 mmole) (Chem.Abs., 1948,42,567; J. Gen. Chem., 1946,16, 2025), acetic anhydride (10 ml) and concentrated sulphuric acid (0.5 ml) were heated to reflux temperature. On cooling to 0° C., the 5-acetoxy compound crystallised (recrystallised from ethanol); δ(DMSO-d6); 2.27(s,3H); 7.05(s,1H); 8.10(s,1H). This compound (5 mmole) was treated with oxalyl chloride (10 mmole) in dichloromethane (5 ml) containing dimethylformamide (15 μl). After 30 minutes the solvent was evaporated, the residue dissolved in toluene (evaporated several times to remove oxalyl chloride) and on final evaporation crystallised to give 5-acetoxypyran-4-one-2-carbonyl chloride which was used directly.

Workup

  1. temperatureto reflux temperature
  2. customthe 5-acetoxy compound crystallised
  3. custom(recrystallised from ethanol)
  4. customAfter 30 minutes the solvent was evaporated
  5. dissolutionthe residue dissolved in toluene (evaporated several times to remove oxalyl chloride)
  6. customon final evaporation
  7. customcrystallised

Sources & evidence

ORD record
ord-e1fbcf46197543edb0e9767fbe911472
Source dataset
uspto-grants-1991_05
Patent number
US05017569

Reaction notes

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