1,1-Dibromoethane → 8-(2-Bromoethoxy)-3,4-dihydro-2H-1-benzothiopyran

HRID 581068Notes

Reaction equation

HRID 581068 reaction equation
[OH:1][C:2]1[C:11]2[S:10][CH2:9][CH2:8][CH2:7][C:6]=2[CH:5]=[CH:4][CH:3]=1.[OH-].[Na+].[Br:14][CH:15](Br)[CH3:16]>[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.C(#N)C>[Br:14][CH2:15][CH2:16][O:1][C:2]1[C:11]2[S:10][CH2:9][CH2:8][CH2:7][C:6]=2[CH:5]=[CH:4][CH:3]=1

Participants

6

Reactant 3

HCID 112011,1-DibromoethaneHCID 14798Sodium HydroxideHCID 1216173,4-dihydro-2H-1-benzothiopyran-8-ol

Product 1

HCID 152958328-(2-Bromoethoxy)-3,4-dihydro-2H-1-benzothiopyran

Reagents, catalysts & solvents 2

HCID 74236Tetrabutylammonium BromideCatalystHCID 6342AcetonitrileSolvent

Procedure

Tetrabutylammonium bromide (1.94 g 6 mmol; 0.2 eq.), phase-transfer agent, is added to a heterogeneous mixture composed of 8-hydroxy-3,4-dihydro-2H-1-benzothiopyran (5 g; 30 mmol), acetonitrile (30 ml) and a 1.6N sodium hydroxide solution (28.3 ml; 45 mmol; 1.5 eq.). Dibromoethane (10 ml; 60 mmol; 1.5 eq.) is added after 30 minutes' stirring, the stirring being continued for 24 hours at 30° C. Concentration of the various phases under reduced pressure at 25° C. is followed by extraction of the products with dichloromethane. Washing with a 5% sodium hydroxide solution allows a first purification, which is followed by purification over a silica column eluted with a 3:7 AcOEt/PE mixture, yielding the brominated title compound.

Workup

  1. extractionConcentration of the various phases under reduced pressure at 25° C. is followed by extraction of the products with dichloromethane
  2. washWashing with a 5% sodium hydroxide solution
  3. customa first purification, which
  4. customis followed by purification over a silica column
  5. washeluted with a 3:7 AcOEt/PE mixture

Sources & evidence

ORD record
ord-a78f46b20ff94f0681878b90bac417de
Source dataset
uspto-grants-1999_07
Patent number
US05919814

Reaction notes

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