Sulfuric Acid → 4,5-Dihydrobenzo[b]furo[3,4-d]oxepine-1,3-dione

HRID 84943

Reaction equation

HRID 84943 reaction equation
CC(C)([O-:4])C.[K+].C(OCC)(=O)C(OCC)=O.[O:17]([CH2:24][CH2:25][CH2:26][C:27]([O:29][CH2:30][CH3:31])=[O:28])[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1.OS(O)(=O)=O>O1CCCC1>[C:30]1(=[O:4])[C:31]2[C:19]3[CH:20]=[CH:21][CH:22]=[CH:23][C:18]=3[O:17][CH2:24][CH2:25][C:26]=2[C:27](=[O:28])[O:29]1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 7268Diethyl OxalateHCID 222539Ethyl 4-phenoxybutanoateHCID 23665647Potassium tert-butoxide

Product 1

HCID 538576824,5-Dihydrobenzo[b]furo[3,4-d]oxepine-1,3-dione

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To potassium tert-butoxide (1.35 g, 12 mmol) in tetrahydrofuran (30 mL) was added diethyl oxalate (2.2 g, 15 mmol) and ethyl 4-phenoxybutanoate (2.08 g, 10 mmol) in tetrahydrofuran (30 mL) at 0° C. dropwise. The mixture was allowed to stir overnight, concentrated, quenched with 1 N HCl(aq), extracted with ethyl acetate, and concentrated. A fraction of this material (308 mg, 1 mmol) was added to concentrated H2SO4 at 0° C. The mixture was stirred for 1.5 hours and was poured onto ice chips. The precipitate was collected to afford the title compound. 1H NMR (300 MHz, DMSO-d6) δ ppm 8.44 (dd, J=1.5, 8.1 Hz, 1H), 7.48 (t, J=8.1 Hz, 1H), 7.25 (t, J=7.8 Hz, 1H), 7.14 (d, J=8.4 Hz, 1H), 4.28 (t, J=5.1 Hz, 2H), and 3.02 (t, J=5.1 Hz, 2H).

Workup

  1. concentrationconcentrated
  2. customquenched with 1 N HCl(aq)
  3. extractionextracted with ethyl acetate
  4. concentrationconcentrated
  5. stirringThe mixture was stirred for 1.5 hours
  6. additionwas poured onto ice chips
  7. customThe precipitate was collected

Sources & evidence

ORD record
ord-f402ed85a97842c4a237704fccd9199b
Source dataset
uspto-grants-2014_09
Patent number
US08846951B2

Linked notes

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