Water → 2-Octylcoumaran-5-boronic acid

HRID 3064

Reaction equation

HRID 3064 reaction equation
Br[CH:2]([CH2:13][CH2:14][CH2:15][CH2:16][CH2:17][CH3:18])[CH2:3][CH:4]1[CH2:12][C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[O:5]1.C([Li])CCC.C([O:27][B:28](OC(C)C)[O:29]C(C)C)(C)C.O>CCCCCC.C1COCC1>[CH2:3]([CH:4]1[CH2:12][C:11]2[C:6](=[CH:7][CH:8]=[C:9]([B:28]([OH:29])[OH:27])[CH:10]=2)[O:5]1)[CH2:2][CH2:13][CH2:14][CH2:15][CH2:16][CH2:17][CH3:18]

Participants

7

Reactant 4

HCID 962WaterHCID 21531Triisopropyl borateHCID 18934310b-Bromo-2-octylcoumaranHCID 178418339Butyllithium

Product 1

HCID 189343232-Octylcoumaran-5-boronic acidYield 67.1%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolvent2×

Procedure

Then, 2.00 g (6.43 mM) of b-bromo-2-octylcoumaran and 28 ml of dry THF were placed in a 100 ml-three-necked flask. To the mixture, 4.5 ml (7.20 mM) of a 1.6M solution of butyllithium in hexane was added dropwise under stirring and nitrogen atmosphere on a dry ice-acetone bath at an inner temperature of -70° to -68° C., followed by stirring for 50 minutes at the same temperature. To the resultant mixture a solution of 3.2 ml (13.9 mM) of triisopropylborate in 5.7 ml of dry THF was added dropwise in 10 minutes at an inner temperature of -73° to -68° C., followed by stirring for minutes at the same temperature. Thereafter, the cooling bath was removed and the inner temperature was increased to room temperature, followed by gradual addition of 9.5 ml of 10%-hydrochloric acid. After the reaction, the reaction mixture was poured into water and subjected to extraction with isopropyl ether, followed by washing with water, drying with mirabilite and distilling-off of the solvent to obtain a residue. To the residue, hexane was added and the mixture was left standing in a freezer to precipitate a crystal. The crystal was recovered by filtration to obtain 1.19 g of 2-octylcoumaran-5-boronic acid (Yield: 67.1%).

Workup

  1. customnitrogen atmosphere on a dry ice-acetone bath at an inner temperature of -70° to -68° C., followed
  2. stirringby stirring for 50 minutes at the same temperature
  3. stirringby stirring for minutes at the same temperature
  4. customThereafter, the cooling bath was removed
  5. additionfollowed by gradual addition of 9.5 ml of 10%-hydrochloric acid
  6. customAfter the reaction
  7. extractionsubjected to extraction with isopropyl ether
  8. washby washing with water
  9. dry with materialdrying with mirabilite and distilling-off of the solvent
  10. customto obtain a residue
  11. waitthe mixture was left
  12. customto precipitate a crystal
  13. filtrationThe crystal was recovered by filtration

Sources & evidence

ORD record
ord-bcf47efb084b407da3df0c21bd581e1b
Source dataset
uspto-grants-1998_03
Patent number
US05733476

Linked notes

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