Diethyl squarate → 3-Ethoxy-4-[(2-hydroxy-6-methylphenyl)amino]-3-cyclobutene-1,2-dione

HRID 357296

Reaction equation

HRID 357296 reaction equation
[NH2:1][C:2]1[C:7]([CH3:8])=[CH:6][CH:5]=[CH:4][C:3]=1[OH:9].[CH3:10][CH2:11][O:12][C:13]1[C:17](=O)[C:15](=[O:16])[C:14]=1[O:19]CC>C(O)C>[CH2:11]([O:12][C:13]1[C:14](=[O:19])[C:15](=[O:16])[C:17]=1[NH:1][C:2]1[C:7]([CH3:8])=[CH:6][CH:5]=[CH:4][C:3]=1[OH:9])[CH3:10]

Participants

4

Reactant 2

HCID 123228Diethyl squarateHCID 30141382-Amino-m-cresol

Product 1

HCID 189374263-Ethoxy-4-[(2-hydroxy-6-methylphenyl)amino]-3-cyclobutene-1,2-dione

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A solution of 2-amino-3-methylphenol (3.6 g, 29.2 mmol) and diethyl squarate (5 g, 29.4 mmol) in dry ethanol (80 mL) was heated to reflux for two days, then allowed to stand at room temperature for 48 hours. The reaction mixture was concentrated under reduced pressure and the resulting residue was suspended in ethyl acetate (50 mL). Hexane (50 mL) was added to produce a slurry, which was filtered, and rinsed with three portions of hexane:ethyl acetate (1:1). The resulting solid was suspended in dichloromethane (200 mL) and methanol (20 mL), stirred at room temperature for 30 minutes, and filtered. The precipitate was suspended in hot dichloromethane, filtered hot, and dried to give 3-ethoxy-4-(2-hydroxy-6-methylphenylamino)-cyclobut-3-ene-1,2-dione, 1.56 g (6.3 mmol, 22%).

Workup

  1. temperatureto reflux for two days
  2. concentrationThe reaction mixture was concentrated under reduced pressure
  3. additionHexane (50 mL) was added
  4. customto produce a slurry, which
  5. filtrationwas filtered
  6. washrinsed with three portions of hexane:ethyl acetate (1:1)
  7. filtrationfiltered
  8. filtrationfiltered hot
  9. customdried

Sources & evidence

ORD record
ord-ca6c9425068e44fb973eae46052db046
Source dataset
uspto-grants-1998_11
Patent number
US05840764

Linked notes

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