Sodium Hydroxide → 5-Ethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylic acid

HRID 1842594Notes

Reaction equation

HRID 1842594 reaction equation
C[O:2][C:3]([C:5]1[S:6][C:7]([CH2:19][CH3:20])=[C:8]([B:10]2[O:14][C:13]([CH3:16])([CH3:15])[C:12]([CH3:18])([CH3:17])[O:11]2)[CH:9]=1)=[O:4].[OH-].[Na+]>CO>[CH2:19]([C:7]1[S:6][C:5]([C:3]([OH:4])=[O:2])=[CH:9][C:8]=1[B:10]1[O:14][C:13]([CH3:16])([CH3:15])[C:12]([CH3:17])([CH3:18])[O:11]1)[CH3:20]

Participants

4

Reactant 2

HCID 14798Sodium HydroxideHCID 58046399Methyl 5-ethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylate

Product 1

HCID 683041955-Ethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylic acid

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Methyl-5-ethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylate (2.07 g, 5.05 mmol) was dissolved in methanol (17.7 mL) and 2N NaOH (aq) (17.7 mL, 35.3 mmol). The mixture was stirred at room temperature for 48 h. After hydrolysis was complete, the reaction mixture was concentrated to half volume (to take the methanol off) and then extracted once with diethyl ether (removes excess bis(pinacolato)diboron from previous reaction). The aqueous layer was then acidified with 1N HCl (aq) and extracted 3× with ethyl acetate. The ethyl acetate layers were combined, washed with brine 2×, dried with magnesium sulfate, filtered, and concentrated under reduced pressure. The material was left to dry to give the title compound (quantitative yield). 1H NMR (CDCl3, 500 MHz) δ 8.04 (s, 1H), 3.14 (q, J=7.5, 2H), 1.33 (t, J=7.5, 3H), 1.32 (m, 12H).

Workup

  1. customAfter hydrolysis
  2. concentrationthe reaction mixture was concentrated to half volume (
  3. extractionthen extracted once with diethyl ether (removes excess bis(pinacolato)diboron from previous reaction)
  4. extractionextracted 3× with ethyl acetate
  5. washwashed with brine 2×
  6. dry with materialdried with magnesium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated under reduced pressure
  9. waitThe material was left
  10. customto dry

Sources & evidence

ORD record
ord-4407363b2dd04fb29c1e0b905c490c4c
Source dataset
uspto-grants-2015_02
Patent number
US08946237B2

Reaction notes

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