Hydrochloric Acid → 9-Phenyl-9H-carbazole-3-boronic acid

HRID 2041685Notes

Reaction equation

HRID 2041685 reaction equation
Br[C:2]1[CH:3]=[CH:4][C:5]2[N:6]([C:15]3[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=3)[C:7]3[C:12]([C:13]=2[CH:14]=1)=[CH:11][CH:10]=[CH:9][CH:8]=3.C([Li])CCC.[B:26](OC)([O:29]C)[O:27]C.Cl>CCCCCC.O1CCCC1>[C:7]1([N:6]2[C:5]3[CH:13]=[CH:14][C:2]([B:26]([OH:29])[OH:27])=[CH:3][C:4]=3[C:20]3[C:15]2=[CH:16][CH:17]=[CH:18][CH:19]=3)[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 189426243-Bromo-9-phenylcarbazole2×HCID 178418339Butyllithium

Product 1

HCID 513584509-Phenyl-9H-carbazole-3-boronic acidYield 86%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8058HexaneSolvent

Conditions

Temperature
-80 °C

Procedure

Into a 500 mL three-neck flask was put 10 g (31 mmol) of 3-bromo-9-phenyl-9H-carbazole. The atmosphere in the flask was substituted by nitrogen. Into the flask was put 150 mL of tetrahydrofuran (THF), and 3-bromo-9-phenyl-9H-carbazole was dissolved therein. This solution was cooled to −80° C. Into this solution were dripped 20 mL (32 mmol) of n-butyllithium (a 1.58 mol/L hexane solution) with the use of a syringe. After the dripping was completed, this solution was stirred at the same temperature for 1 hour. After the stirring, 3.8 mL (34 mmol) of trimethyl borate was added to the solution, and the solution was stirred for about 15 hours while the temperature of the solution was being brought back to room temperature. After that, about 150 mL (1.0 mol/L) of dilute hydrochloric acid were added to the solution, and then the solution was stirred for 1 hour. After the stirring, an aqueous layer of the mixture was extracted with ethyl acetate. The extract was combined with an organic layer and then washed with a saturated sodium hydrogen carbonate solution. The organic layer was dried with magnesium sulfate. After the drying, the mixture was subjected to gravity filtration. The obtained filtrate was condensed to give an oily light brown substance. The obtained oily substance was dried under reduced pressure to give 7.5 g of a light brown solid, which was the object of the synthesis, at a yield of 86%. A synthesis scheme of Step 1 is shown in (A-1) given below.

Workup

  1. customInto a 500 mL three-neck flask was put
  2. dissolutionwas dissolved
  3. stirringthe solution was stirred for about 15 hours while the temperature of the solution
  4. customwas being brought back to room temperature
  5. stirringthe solution was stirred for 1 hour
  6. extractionAfter the stirring, an aqueous layer of the mixture was extracted with ethyl acetate
  7. washwashed with a saturated sodium hydrogen carbonate solution
  8. dry with materialThe organic layer was dried with magnesium sulfate
  9. filtrationAfter the drying, the mixture was subjected to gravity filtration
  10. customcondensed
  11. customto give an oily light brown substance
  12. customThe obtained oily substance was dried under reduced pressure

Sources & evidence

ORD record
ord-0aa6c44cebda4b9c87acb8064528cb8d
Source dataset
uspto-grants-2013_11
Patent number
US08581237B2

Reaction notes

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