Hydrochloric Acid → 4-Cyanophenylboronic acid

HRID 1979160Notes

Reaction equation

HRID 1979160 reaction equation
Br[C:2]1[CH:9]=[CH:8][C:5]([C:6]#[N:7])=[CH:4][CH:3]=1.C([Li])CCC.C[O:16][B:17](OC)[O:18]C.Cl>O1CCCC1>[C:6]([C:5]1[CH:8]=[CH:9][C:2]([B:17]([OH:18])[OH:16])=[CH:3][CH:4]=1)#[N:7]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 12162Benzonitrile, 4-bromo-HCID 178418339Butyllithium

Product 1

HCID 27343264-Cyanophenylboronic acidYield 71%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a stirred solution of 4-bromobenzonitrile (1.807 g, 0.009929 mol) in anhydrous tetrahydrofuran (30 mL) at −85° C. under nitrogen was added dropwise over 15 minutes a 2.1 M solution of n-butyl lithium in hexanes (4.7 mL, 0.0099 mol), and the mixture was stirred. After 20 minutes, trimethylborate (1.0 mL, 0.0088 mol) was added in one portion, and the mixture was allowed to slowly warm. After 40 minutes, the reaction was quenched with 1 M aqueous hydrochloric acid (2.2 mL, 0.0022 mol) and stirred. Solids began crystallizing after 1 hour. The solids were filtered, washed with diethyl ether, and dried under house vacuum (air bleed, T=40° C.) to give 0.918 g of crude (4-cyano-phenyl)boronic acid. This material was used in the next reaction without further purification.

Workup

  1. temperatureto slowly warm
  2. waitAfter 40 minutes
  3. stirringstirred
  4. customSolids began crystallizing after 1 hour
  5. filtrationThe solids were filtered
  6. washwashed with diethyl ether
  7. customdried under house vacuum (air bleed, T=40° C.)

Sources & evidence

ORD record
ord-432859fbb0b14343a7966934bcc94581
Source dataset
uspto-grants-2001_05
Patent number
US06239288B1

Reaction notes

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