Ethyl Acetate → 2,2,4,4-Tetramethyl-chroman-6-carboxylic acid 4-(tert-butoxycarbonylmethyl)phenyl ester

HRID 844671Notes

Reaction equation

HRID 844671 reaction equation
[CH3:1][C:2]1([CH3:17])[CH2:11][C:10]([CH3:13])([CH3:12])[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([C:14]([OH:16])=[O:15])[CH:8]=2)[O:3]1.[C:18]([O:22][C:23](=[O:32])[CH2:24][C:25]1[CH:30]=[CH:29][C:28](O)=[CH:27][CH:26]=1)([CH3:21])([CH3:20])[CH3:19].C(OCC)(=O)C>S(Cl)(Cl)=O.CCCCCC>[C:18]([O:22][C:23]([CH2:24][C:25]1[CH:26]=[CH:27][C:28]([O:15][C:14]([C:7]2[CH:8]=[C:9]3[C:4](=[CH:5][CH:6]=2)[O:3][C:2]([CH3:17])([CH3:1])[CH2:11][C:10]3([CH3:12])[CH3:13])=[O:16])=[CH:29][CH:30]=1)=[O:32])([CH3:21])([CH3:19])[CH3:20]

Participants

6

Reactant 3

HCID 8857Ethyl AcetateHCID 157287092,2,4,4-Tetramethyl-3,4-dihydro-2H-1-benzopyran-6-carboxylic acidHCID 15932404Tert-butyl 2-(4-hydroxyphenyl)acetate

Product 1

HCID 695485442,2,4,4-Tetramethyl-chroman-6-carboxylic acid 4-(tert-butoxycarbonylmethyl)phenyl esterYield 55%

Reagents, catalysts & solvents 2

HCID 8058HexaneSolventHCID 24386Thionyl ChlorideSolvent

Procedure

A solution of 2,2,4,4-tetramethyl chroman-6-carboxylic acid (0.1 g, 0.43 mmol) in thionyl chloride (10 mL) was refluxed for 2 h. The thionyl chloride was evaporated under reduced pressure and the residue was dissolved in 5 mL of dichloromethane and treated with triethyl amine (5 mL) followed by tert-butyl-4-hydroxy phenyl acetate (Reagent E, 0.088 g, 0.427 mmol). After 0.5 h, the reaction mixture was subjected to flash column chromatography over silica gel (230-400 mesh) using 5-10% ethyl acetate in hexane as the eluent to afford the title compound (0.1 g, 55%).

Workup

  1. customThe thionyl chloride was evaporated under reduced pressure
  2. dissolutionthe residue was dissolved in 5 mL of dichloromethane
  3. additiontreated with triethyl amine (5 mL)

Sources & evidence

ORD record
ord-ecc44454b6c24210b9a2ad0ed34554ff
Source dataset
uspto-grants-2002_04
Patent number
US06380256B1

Reaction notes

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