Hydrochloric Acid → 6-bromo-3,4-dihydro-1H-2-benzopyran-1-one

HRID 1466109Notes

Reaction equation

HRID 1466109 reaction equation
[Li+].[CH3:2]C([N-]C(C)C)C.[Br:9][C:10]1[CH:18]=[CH:17][C:13]([C:14]([OH:16])=[O:15])=[C:12]([CH3:19])[CH:11]=1.C=O.Cl>C1COCC1>[Br:9][C:10]1[CH:11]=[C:12]2[C:13](=[CH:17][CH:18]=1)[C:14](=[O:16])[O:15][CH2:2][CH2:19]2

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 712FormaldehydeHCID 995704-Bromo-2-methylbenzoic acidHCID 2724682Lithium diisopropylamide

Product 1

HCID 441308436-bromo-3,4-dihydro-1H-2-benzopyran-1-one

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

LDA (12 ml, 17 mmol) was dissolved in THF (50 ml) at −78° C. then 4-Bromo-2-methylbenzoic acid (1.0 g, 4.6 mmol) in 10 ml THF was added. The mixture was stirred for 10 minutes then paraformaldehyde (0.56 g, 18.6 mmol) was added. The reaction was stirred at RT for 4 hours. When LC-MS showed the product M+1=229, the reaction was poured into 1N HCl and extracted with ether. The organic layer was washed with brine, dried and evaporated to dryness. The residue was flashed through an Analogix 115 g column and eluted with 0-100% ethyl acetate/hexane to yield 6-bromo-3,4-dihydro-1H-isochromen-1-one.

Workup

  1. stirringThe reaction was stirred at RT for 4 hours
  2. extractionextracted with ether
  3. washThe organic layer was washed with brine
  4. customdried
  5. customevaporated to dryness
  6. washeluted with 0-100% ethyl acetate/hexane

Sources & evidence

ORD record
ord-4e270d9f43d841be9c8d4fda82d60d22
Source dataset
uspto-grants-2015_04
Patent number
US08999990B2

Reaction notes

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