Sulfuric Acid → 4-Dimethylamino-phenylboric acid

HRID 963380Notes

Reaction equation

HRID 963380 reaction equation
Br[C:2]1[CH:10]=[CH:9][C:5]([N:6]([CH3:8])[CH3:7])=[CH:4][CH:3]=1.[Mg].C[O:13][B:14]([O:17]C)[O:15]C.S(=O)(=O)(O)O>O1CCCC1>[CH3:7][N:6]([CH3:8])[C:5]1[CH:9]=[CH:10][C:2]([O:13][B:14]([OH:17])[OH:15])=[CH:3][CH:4]=1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 8470Trimethyl borateHCID 114654-bromo-N,N-dimethylanilineHCID 5462224Magnesium

Product 1

HCID 190817074-Dimethylamino-phenylboric acidYield 40%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

A solution of the corresponding Grignard compound is prepared from 16.8 g 4-bromo-N,N-dimethyl-aniline and 2.04 g of magnesium in 150 ml of tetrahydrofuran. This is now slowly added dropwise while stirring at -60° to a solution of 9.4 ml of trimethylborate in 50 ml of tetrahydrofuran under argon. Subsequently, the mixture is stirred at room temperature overnight. The mixture is poured on to ice-water, adjusted to pH 3-4 with dilute sulphuric acid and extracted with diethyl ether. The extract is dried, evaporated and the residue is recrystallized from water. 5.6 g (40%) of 4-dimethylamino-phenylboric acid are obtained. Mass spectrum: peaks inter alia at m/e: 164 (M±H, 100%).

Workup

  1. additionThis is now slowly added dropwise
  2. extractionextracted with diethyl ether
  3. customThe extract is dried
  4. customevaporated
  5. customthe residue is recrystallized from water

Sources & evidence

ORD record
ord-45295211147146cc965004b4e34c1268
Source dataset
uspto-grants-1998_06
Patent number
US05763450

Reaction notes

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