Potassium Carbonate → Methyl 5-chloro-2-ethynylbenzoate

HRID 1616477Notes

Reaction equation

HRID 1616477 reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([C:12]#[C:13][Si](C)(C)C)=[C:6]([CH:11]=1)[C:7]([O:9][CH3:10])=[O:8].C([O-])([O-])=O.[K+].[K+]>CO>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([C:12]#[CH:13])=[C:6]([CH:11]=1)[C:7]([O:9][CH3:10])=[O:8]

Participants

4

Reactant 2

HCID 11430Potassium CarbonateHCID 70872518Methyl 5-chloro-2-[2-(trimethylsilyl)ethynyl]benzoate

Product 1

HCID 86672667Methyl 5-chloro-2-ethynylbenzoateYield 78.8%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a solution of methyl 5-chloro-2-[2-(trimethylsilyl)ethynyl]benzoate (10 g, 37.5 mmol) in Methanol (150 ml) was added K2CO3 (10.36 g, 75 mmol) at room temperature and in air. The reaction mixture was stirred for 1 hour before being concentrated under reduced pressure. The residue was dissolved in deionized water (50 ml) and EtOAc (50 ml). The phases were separated and the aqueous layer was extracted with EtOAc (2×50 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by FCC (50 g silica, Isolute cartridge, gradient of eluents; 95:5 Heptane:EtOAc to 9:1 Heptane:EtOAc) to give 5.75 g (55.2%) of methyl 5-chloro-2-ethynylbenzoate as an orange oil that solidified upon standing. This material contained 30% of ethyl ester which was suitable for use without any further purification. LC-MS 38%, 1.98 min (3 minute LC-MS method), m/z=195.0/196.9, 1H NMR (500 MHz, Chloroform-d) δ ppm 7.93 (d, J=2.2 Hz, 1H), 7.55 (d, J=8.3 Hz, 1H), 7.45 (dd, J=8.3, 2.3 Hz, 1H), 3.94 (s, 3H), 3.43 (s, 1H).

Workup

  1. concentrationbefore being concentrated under reduced pressure
  2. dissolutionThe residue was dissolved in deionized water (50 ml)
  3. customThe phases were separated
  4. extractionthe aqueous layer was extracted with EtOAc (2×50 ml)
  5. dry with materialThe combined organic extracts were dried over MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure
  8. customThe residue was purified by FCC (50 g silica, Isolute cartridge, gradient of eluents; 95:5 Heptane:EtOAc to 9:1 Heptane:EtOAc)

Sources & evidence

ORD record
ord-6bf08ee861fd400ebb4b3eb9e45f2859
Source dataset
uspto-grants-2014_07
Patent number
US08765732B2

Reaction notes

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