Ethyl chloroformate → Ethyl 3-(pyridin-2-yl)prop-2-ynoate

HRID 402372Notes

Reaction equation

HRID 402372 reaction equation
[C:1]([C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][N:4]=1)#[CH:2].[Li]CCCC.Cl[C:15]([O:17][CH2:18][CH3:19])=[O:16]>C1COCC1>[CH2:18]([O:17][C:15](=[O:16])[C:2]#[C:1][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][N:4]=1)[CH3:19]

Participants

5

Reactant 3

HCID 10928Ethyl chloroformateHCID 137268EthynylpyridineHCID 178418339Butyllithium

Product 1

HCID 12426870Ethyl 3-(pyridin-2-yl)prop-2-ynoateYield 66.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-75 °C

Procedure

To a solution of 2-ethynyl-pyridine (309 mg, 3 mmol) in THF (6 mL) was added BuLi (1.6 M in hexane, 1.88 mL, 3 mmol) dropwise at −75° C. and the reaction mixture was stirred at −75° C. for 30 min, then ethyl chloroformate (286 μL, 3 mmol) was added dropwise at −75° C. and the reaction mixture was stirred at −75° C. for 1 h. The mixture was then poured into ice water and extracted with ethyl acetate and the combined organic extracts washed with brine, dried over sodium sulphate, filtered and evaporated. Purification by chromatography (silica, 0 to 50% ethyl acetate in heptane) afforded the title compound (349 mg, 66%) as a brown solid. MS: m/e=176.2 [M+H]+.

Workup

  1. stirringthe reaction mixture was stirred at −75° C. for 1 h
  2. extractionextracted with ethyl acetate
  3. washthe combined organic extracts washed with brine
  4. dry with materialdried over sodium sulphate
  5. filtrationfiltered
  6. customevaporated
  7. customPurification by chromatography (silica, 0 to 50% ethyl acetate in heptane)

Sources & evidence

ORD record
ord-ff321238326340f5b3f34bbffc913929
Source dataset
uspto-grants-2014_06
Patent number
US08742097B2

Reaction notes

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