Hydrochloric Acid → 4,4'-Bidibenzothiophene-6-boronic acid

HRID 628241Notes

Reaction equation

HRID 628241 reaction equation
[C:1]1([C:14]2[C:22]3[C:21]4[CH:23]=[CH:24][CH:25]=[CH:26][C:20]=4[S:19][C:18]=3[CH:17]=[CH:16][CH:15]=2)[C:9]2[C:8]3[CH:10]=[CH:11][CH:12]=[CH:13][C:7]=3[S:6][C:5]=2[CH:4]=[CH:3][CH:2]=1.C([Li])CCC.[B:32](OC)([O:35]C)[O:33]C.Cl>CCCCCC.O1CCCC1>[C:1]1([C:14]2[C:22]3[C:21]4[CH:23]=[CH:24][CH:25]=[CH:26][C:20]=4[S:19][C:18]=3[CH:17]=[CH:16][CH:15]=2)[C:9]2[C:8]3[CH:10]=[CH:11][CH:12]=[C:13]([B:32]([OH:35])[OH:33])[C:7]=3[S:6][C:5]=2[CH:4]=[CH:3][CH:2]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 85728735Bidibenzo[b,d]thiopheneHCID 178418339Butyllithium

Product 1

HCID 1317353434,4'-Bidibenzothiophene-6-boronic acidYield 50%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8058HexaneSolvent

Conditions

Temperature
-80 °C

Procedure

Into a 500-mL three-neck flask was put 5.0 g (13 mmol) of 4,4′-bidibenzothiophene, and the air in the flask was replaced with nitrogen. Into this flask was put 100 mL of tetrahydrofuran (THF), and this solution was cooled down to −80° C. To this solution, 8.7 mL (14 mmol) of n-butyllithium (a 1.6 mol/L hexane solution) was dripped with a syringe. After the dripping, this solution was stirred for 2 hours while its temperature was returned to room temperature. After the stirring, this solution was cooled down to −80° C. To this solution, 1.9 mL (17 mmol) of trimethyl borate was added, and the mixture was stirred for 18 hours while its temperature was returned to room temperature. After the stirring, approximately 50 mL of dilute hydrochloric acid (1.0 mol/L) was added to this solution, followed by stirring for 1 hour. After the stirring, the aqueous layer of this mixture was extracted with ethyl acetate, and the extracted solution and the organic layer were combined and washed with a saturated aqueous solution of sodium hydrogen carbonate and saturated brine. The organic layer was dried with magnesium sulfate, and then this mixture was gravity-filtered. The resulting filtrate was concentrated to give a white solid. This solid was washed with 100 mL of hot toluene to give 2.6 g of white powder, which was an objective substance, in 50% yield. Synthesis Scheme (a-2) of Step 2 is shown below.

Workup

  1. customInto a 500-mL three-neck flask was put
  2. customInto this flask was put
  3. customwas returned to room temperature
  4. stirringthe mixture was stirred for 18 hours while its temperature
  5. customwas returned to room temperature
  6. stirringby stirring for 1 hour
  7. extractionAfter the stirring, the aqueous layer of this mixture was extracted with ethyl acetate
  8. washwashed with a saturated aqueous solution of sodium hydrogen carbonate and saturated brine
  9. dry with materialThe organic layer was dried with magnesium sulfate
  10. filtrationthis mixture was gravity-filtered
  11. concentrationThe resulting filtrate was concentrated
  12. customto give a white solid
  13. washThis solid was washed with 100 mL of hot toluene

Sources & evidence

ORD record
ord-3b79dcd5d2eb4596bd12166ccf159b56
Source dataset
uspto-grants-2016_04
Patent number
US09312498B2

Reaction notes

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