Bromine → 6-Bromo-3,4-dihydro-4,4,5,8-tetramethyl-2H-1-benzothiopyran

HRID 1871213

Reaction equation

HRID 1871213 reaction equation
[CH3:1][C:2]1([CH3:14])[C:11]2[C:6](=[C:7]([CH3:13])[CH:8]=[CH:9][C:10]=2[CH3:12])[S:5][CH2:4][CH2:3]1.[Br:15]Br.S([O-])(O)=O.[Na+]>C(Cl)Cl>[CH3:1][C:2]1([CH3:14])[C:11]2[C:6](=[C:7]([CH3:13])[CH:8]=[C:9]([Br:15])[C:10]=2[CH3:12])[S:5][CH2:4][CH2:3]1

Participants

5

Reactant 3

HCID 24408BromineHCID 129936844,4,5,8-TetramethylthiochromanHCID 23665763Sodium Bisulfite

Product 1

HCID 129936856-Bromo-3,4-dihydro-4,4,5,8-tetramethyl-2H-1-benzothiopyranYield 87.1%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

100 ml of methylene chloride was added to 13.2 g (0.064 mol) of 4,4,5,8-tetramethylthiochroman, 10.2 g (0.064 mol) of bromine was dropwise added at room temperature, and then the mixture was allowed to react for 2 hours. After the completion of the reaction, 70 ml of a 2% sodium hydrogensulfite aqueous solution was added, excessive bromine was removed, and the reaction mixture was liquid-separated. An organic layer was washed with a saturated sodium hydrogencarbonate aqueous solution and with a saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate. The methylene chloride was distilled off under reduced pressure, and the resultant oily substance was purified by silica gel column chromatography to give 15.9 g (yield 87%) of 4,4,5,8-tetramethyl-6-bromothiochroman.

Workup

  1. additionwas dropwise added at room temperature
  2. customto react for 2 hours
  3. additionwas added
  4. customexcessive bromine was removed
  5. customthe reaction mixture was liquid-separated
  6. washAn organic layer was washed with a saturated sodium hydrogencarbonate aqueous solution and with a saturated sodium chloride aqueous solution
  7. dry with materialdried over anhydrous sodium sulfate
  8. distillationThe methylene chloride was distilled off under reduced pressure
  9. customthe resultant oily substance was purified by silica gel column chromatography

Sources & evidence

ORD record
ord-ee664f1fd4704d80b217e11afca7539b
Source dataset
uspto-grants-2000_08
Patent number
US06103668

Linked notes

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