Boron tribromide → 4-(4,4-Dimethyl-6-thiochromanoyloxy)-benzoic acid

HRID 330338Notes

Reaction equation

HRID 330338 reaction equation
[CH3:1][C:2]1([CH3:31])[C:11]2[C:6](=[CH:7][CH:8]=[C:9]([C:12]([O:14][C:15]3[CH:30]=[CH:29][C:18]([C:19]([O:21]CC4C=CC=CC=4)=[O:20])=[CH:17][CH:16]=3)=[O:13])[CH:10]=2)[S:5][CH2:4][CH2:3]1.B(Br)(Br)Br>C(Cl)Cl>[CH3:1][C:2]1([CH3:31])[C:11]2[C:6](=[CH:7][CH:8]=[C:9]([C:12]([O:14][C:15]3[CH:30]=[CH:29][C:18]([C:19]([OH:21])=[O:20])=[CH:17][CH:16]=3)=[O:13])[CH:10]=2)[S:5][CH2:4][CH2:3]1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 19834230Benzyl 4-(4,4-dimethyl-6-thiochromanoyloxy)benzoate

Product 1

HCID 198342194-(4,4-Dimethyl-6-thiochromanoyloxy)-benzoic acid

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a stirred solution of 580 mg (1.34) of benzyl 4-(4,4-dimethyl-6-thiochromanoyloxy)benzoate in 12 ml of methylene chloride at -10° C. under nitrogen was added slowly 1.24 ml of a 1.0 M (1.24 mmol) solution of boron tribromide in methylene chloride. The reaction mixture was stirred at -10° C. for a further 2h and then was quenched by the addition of ice. The organic layer was separated and the aqueous layer extracted with 2×25 ml methylene chloride. The organic extracts were combined and then washed with water and dried (MgSO4). The solution was then filtered and the solvent removed in-vacuo. The resultant residue was purified by flash chromatography (silica; 20% ethyl acetate in hexane followed by 100% ethyl acetate) and then recrystallization from a mixture of ethyl acetate and ethanol to give the title compound as a white solid. PMR (CDCl3): 6 1.39 (6H, s), 2.10 (2H, m), 3.10 (2H, m), 7.21 (1H, d, J~8.4 Hz), 7.28 (2H, d, J~8.7 Hz), 7.82 (1H, dd, J~8.4, 2.1 Hz), 8.14 (2H, d, J~8.7 Hz), 8.16 (1H, d, J~2.1 Hz).

Workup

  1. customwas quenched by the addition of ice
  2. customThe organic layer was separated
  3. extractionthe aqueous layer extracted with 2×25 ml methylene chloride
  4. washwashed with water
  5. dry with materialdried (MgSO4)
  6. filtrationThe solution was then filtered
  7. customthe solvent removed in-vacuo
  8. customThe resultant residue was purified by flash chromatography (silica; 20% ethyl acetate in hexane followed by 100% ethyl acetate)
  9. customrecrystallization
  10. additionfrom a mixture of ethyl acetate and ethanol

Sources & evidence

ORD record
ord-6277094fabef4308a9c2f95be3db2f2d
Source dataset
uspto-grants-1990_01
Patent number
US04895868

Reaction notes

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