Boron tribromide → HCID 23050232, compound

HRID 1651630Notes

Reaction equation

HRID 1651630 reaction equation
C[O:2][C:3]1[C:13]([O:14]C)=[CH:12][C:6]2[S:7][C:8]([C:10]#[N:11])=[CH:9][C:5]=2[CH:4]=1.B(Br)(Br)Br>ClCCl>[OH:2][C:3]1[C:13]([OH:14])=[CH:12][C:6]2[S:7][C:8]([C:10]#[N:11])=[CH:9][C:5]=2[CH:4]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 23050245HCID 23050245, compound

Product 1

HCID 23050232HCID 23050232, compoundYield 95.6%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Conditions

Temperature
-70 °C

Procedure

5,6-Dimethoxy-benzo[b]thiophene-2-carbonitrile (9.0 g) was dissolved in dichloromethane (135 ml) and the solution was stirred and cooled to -70° C. and treated at a rapid dropwise rate with a cold solution of boron tribromide (19.5 ml) in dichloromethane (60 ml). The resultant suspension was stirred at room temperature for 1 h. then poured into ice-cold water (1000 ml). The light coloured solid was filtered, dried, dissolved in acetone:hexane (1:1) then eluted through coarse silica (0.2-0.5 mm, Merck, 50 g) in acetone:hexane (1:1). The appropriate fractions were combined, evaporated to dryness and crystallised from acetone/n-hexane to give 5,6-dihydroxy-benzo[b]thiophene-2-carbonitrile (7.5 g), m.p. 229°-230° C.

Workup

  1. filtrationwas filtered
  2. customdried
  3. dissolutiondissolved in acetone:hexane (1:1)
  4. washthen eluted through coarse silica (0.2-0.5 mm, Merck, 50 g) in acetone:hexane (1:1)
  5. customevaporated to dryness
  6. customcrystallised from acetone/n-hexane

Sources & evidence

ORD record
ord-a6019feac5e044bf8586f20432a18a16
Source dataset
uspto-grants-1990_05
Patent number
US04929636

Reaction notes

Loading…