Hydrochloric Acid → 5-(But-2-ynyloxy)pyrazine-2-carboxylic acid

HRID 1965048Notes

Reaction equation

Cl[C:2]1[N:3]=[CH:4][C:5]([C:8]([OH:10])=[O:9])=[N:6][CH:7]=1.[CH2:11]([OH:15])[C:12]#[C:13][CH3:14].CC(C)([O-])C.[K+].Cl>CN(C=O)C>[CH2:11]([O:15][C:2]1[N:3]=[CH:4][C:5]([C:8]([OH:10])=[O:9])=[N:6][CH:7]=1)[C:12]#[C:13][CH3:14]

Participants

Conditions

Temperature: 65 °C

Procedure

To a slurry of 5-chloro-pyrazine-2-carboxylic acid (0.79 g, 5.00 mmol) in DMF (35 mL) were added 2-butyn-1-ol (3.74 mL, 50.0 mmol) and potassium tert-butoxide (2.24 g, 20.0 mmol). The resulting mixture was heated at 65° C. overnight. The reaction mixture was neutralized with 2 M HCl and then concentrated in vacuo. A part (400 mg) of the crude material was partitioned between 0.5 M NaOH and a 1:1 mixture of heptane and EtOAc. The aqueous phase was made slightly acidic (pH-3-4) by addition of 1 M HCl. To the obtained suspension was added NaCl (s) and the mixture was extracted twice with EtOAc. The combined organic phases were dried (Na2SO4) and evaporated to give 0.11 g of the title compound. 1H NMR (400 MHz, DMSO-d6) δ ppm 1.84 (t, 3 H), 5.06 (q, 2 H), 8.42 (d, 1 H), 8.82 (d, 1 H), 13.38 (br. s., 1 H); MS (ES+) m/z 193 [M+H]+.

Workup

concentrationconcentrated in vacuo
customA part (400 mg) of the crude material was partitioned between 0.5 M NaOH
additiona 1:1 mixture of heptane and EtOAc
additionby addition of 1 M HCl
additionTo the obtained suspension was added NaCl (s)
extractionthe mixture was extracted twice with EtOAc
dry with materialThe combined organic phases were dried (Na2SO4)
customevaporated

Sources & evidence

ORD record: ord-267a6ceb18c84425a6743f78ba348d52
Source dataset: uspto-grants-2013_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08415483B2

Reaction notes

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