Acetic Acid → 3-Acetyl-4-hydroxy-6-methyl-5,6-dihydro-pyran-2-one
Reaction equation
[OH:1][C:2]1[CH2:7][CH:6]([CH3:8])[O:5][C:4](=[O:9])[CH:3]=1.[C:10](O)(=[O:12])[CH3:11].C1(N=C=NC2CCCCC2)CCCCC1.CC1CC(OC(=O)C)=CC(=O)O1>CN(C)C1C=CN=CC=1.C1(C)C=CC=CC=1.CCCCCC.C(OCC)(=O)C.C(Cl)Cl.CC(C)=O.C(Cl)Cl>[C:10]([C:3]1[C:4](=[O:9])[O:5][CH:6]([CH3:8])[CH2:7][C:2]=1[OH:1])(=[O:12])[CH3:11]Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 4
Conditions
- Temperature
- 60 °C
Procedure
4-Hydroxy-6-methyl-5,6-dihydro-pyran-2-one (2 g, 15.6 mmol) was combined with methylene chloride (50 mL) in a 250 mL flask and then acetic acid (17.5 M, 2 eq, 31 mmol, 1.77 mL) was added to the mixture. The mixture was cooled in an ice bath and then dicyclohexylcarbodiimide (1.3 eq, 20.3 mmol, 4.19 g) was added portionwise, followed by the addition of 4-(dimethylamino)pyridine (0.05 eq, 0.78 mmol, 88 mg) to the mixture. A sufficient amount of methylene chloride was added to ensure easy stirring and the reaction was monitored by TLC (silica gel, hexane-ethyl acetate-methylene chloride-acetone (3:3:3:1 v/v)), HPLC and LCMS as the intermediate acetic acid 2-methyl-6-oxo-3,6-dihydro-2H-pyran-4-yl ester was formed. The mixture was stirred overnight at room temperature and then toluene (20 ml) was added. The mixture was heated to 60° C. and after 48 hours the mixture was filtered, concentrated and purified by flash column chromatography to provide 3-acetyl-4-hydroxy-6-methyl-5,6-dihydro-pyran-2-one (1.02 g, 38%) as a white solid, mp 96-98° C. (lit., mp 97-98° C.). LCMS: MH+ 171.0.
Workup
- temperatureThe mixture was cooled in an ice bath
- customwas formed
- stirringThe mixture was stirred overnight at room temperature
- filtrationwas filtered
- concentrationconcentrated
- custompurified by flash column chromatography
Sources & evidence
- ORD record
- ord-3e2f96d4a4ae4d96b45869b978a6a7be
- Source dataset
- uspto-grants-2005_03
- Patent number
- US06861419B2
Reaction notes
Loading…