Hydrochloric Acid → (1-Hydroxy-6-methoxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl ester

HRID 1798091Notes

Reaction equation

HRID 1798091 reaction equation
[CH2:1]([O:3][C:4](=[O:18])[CH2:5][CH:6]1[O:10][B:9]([OH:11])[C:8]2[CH:12]=[C:13]([OH:17])[CH:14]=[C:15]([CH3:16])[C:7]1=2)[CH3:2].[C:19]([O-])([O-])=O.[Cs+].[Cs+].CI.Cl>CN(C=O)C>[CH2:1]([O:3][C:4](=[O:18])[CH2:5][CH:6]1[O:10][B:9]([OH:11])[C:8]2[CH:12]=[C:13]([O:17][CH3:19])[CH:14]=[C:15]([CH3:16])[C:7]1=2)[CH3:2]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 6328Methyl iodideHCID 10796Cesium carbonateHCID 58292549Ethyl 2-(1,6-dihydroxy-4-methyl-1,3-dihydrobenzo[c][1,2]oxaborol-3-yl)acetate

Product 1

HCID 58292700(1-Hydroxy-6-methoxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl esterYield 39.1%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of (1,6-dihydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl ester (3.0 g, 12.0 mmol) in anhydrous DMF (20 mL) were added Cs2CO3 (23.45 g, 72 mmol) and methyl iodide (17.03 g, 120 mmol) at 0° C. After stirring at room temperature for 3 hours the reaction mixture was cooled to 0° C. and acidified to pH 2 with dilute hydrochloric acid. The mixture was extracted with ethyl acetate and the organic extracts were dried over sodium sulfate and concentrated in vacuo. The residue was purified by silica gel flash column chromatography (EtOAc/hexane/AcOH=1:1:1) to give the product (1.24 g, 39.1%). 1HNMR (400 MHz, DMSO-d6) δ9.12 (s, 1H), 7.02 (d, J=2.34 Hz, 1H), 6.83 (d, J=2.34 Hz, 1H), 5.44 (dd, J=9.23, 2.49 Hz, 1H), 3.93-4.08 (m, 2H), 3.73 (s, 3H), 3.08 (dd, J=15.24, 2.64 Hz, 1H), 2.10-2.31 (m, 4H), 1.05-1.19 (m, 3H).

Workup

  1. temperaturewas cooled to 0° C.
  2. extractionThe mixture was extracted with ethyl acetate
  3. dry with materialthe organic extracts were dried over sodium sulfate
  4. concentrationconcentrated in vacuo
  5. customThe residue was purified by silica gel flash column chromatography (EtOAc/hexane/AcOH=1:1:1)

Sources & evidence

ORD record
ord-caf0d55b6a0f4bf6928272359ce3d2d6
Source dataset
uspto-grants-2013_01
Patent number
US08343944B2

Reaction notes

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