Water → 5-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylic acid

HRID 1364485Notes

Reaction equation

HRID 1364485 reaction equation
[OH:1][B:2]([OH:11])[C:3]1[S:7][C:6]([C:8]([OH:10])=[O:9])=[CH:5][CH:4]=1.O[C:13]([C:16](O)([CH3:18])[CH3:17])([CH3:15])[CH3:14].O>CCOCC.CO>[CH3:14][C:13]1([CH3:15])[C:16]([CH3:18])([CH3:17])[O:1][B:2]([C:3]2[S:7][C:6]([C:8]([OH:10])=[O:9])=[CH:5][CH:4]=2)[O:11]1

Participants

6

Reactant 3

HCID 962WaterHCID 6425Pinacol2×HCID 27798075-Boronothiophene-2-carboxylic acid

Product 1

HCID 532171185-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylic acid

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 3283Diethyl EtherSolvent

Procedure

5-(Dihydroxyboryl)-2-thiophenecarboxylic acid (1 g; 5.82 mmol; 1 eq.) is dissolved in a mixture of Et2O (100 ml) and MeOH (5 ml). Pinacol (687.2 mg; 5.82 mmol; 1 eq.) is added. The reaction mixture is stirred at rt for 24 hours. To complete the reaction, some pinacol is added (200 mg; 1.7 mmol; 0.3 eq.) and the mixture is stirred for 12 additional hours. Water (50 ml) is added and the two phases are separated. Aqueous phase is extracted with ether (50 ml). Combined organic phases is dried over MgSO4, filtrated and evaporated, affording 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylic acid as white-off solid (1.33 g; 90%). 1H NMR (DMSO-d6, 300 MHz) δ 1.13 (s, 12H), 7.37 (d, J=3.8 Hz, 1H), 7.58 (d, J=3.8 Hz, 1H), 13.12 (s, 1H). M−(ESI): 253. HPLC, Rt: 0.98 min (purity: 100%).

Workup

  1. customthe reaction
  2. stirringthe mixture is stirred for 12 additional hours
  3. customthe two phases are separated
  4. extractionAqueous phase is extracted with ether (50 ml)
  5. dry with materialCombined organic phases is dried over MgSO4
  6. filtrationfiltrated
  7. customevaporated

Sources & evidence

ORD record
ord-4f077f0f50b2479ba3999b23f7bc9a7c
Source dataset
uspto-grants-2011_02
Patent number
US07888379B2

Reaction notes

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