Carbon Dioxide → 4-(N-ethylpiperazino)-2-butynoic acid

HRID 1068980Notes

Reaction equation

C([Li])CCC.[CH2:6]([N:8]1[CH2:13][CH2:12][N:11]([CH2:14][C:15]#[CH:16])[CH2:10][CH2:9]1)[CH3:7].[C:17](=[O:19])=[O:18].O>CCCCCC.O1CCCC1.CO>[CH2:6]([N:8]1[CH2:13][CH2:12][N:11]([CH2:14][C:15]#[C:16][C:17]([OH:19])=[O:18])[CH2:10][CH2:9]1)[CH3:7]

Participants

Conditions

Temperature: -78 °C

Procedure

n-Butyl lithium in hexane (42 mL, 2.5M in n-hexane) was slowly added to 1-ethyl-4-prop-2-ynyl-piperazine (16 g, 105 mmol) in 80 mL of tetrahydrofuran under nitrogen. The mixture was stirred for 1 hr at −78° C., then dry carbon dioxide was passed through overnight. The resulting solution was poured into water and washed with ethyl acetate. The aqueous layer was evaporated under reduced pressure to give the crude acid. The dry acid was dissolved in methanol, and the insoluble salt was removed via filtration. The filtrate was collected and dried in vacuo to give 18 g of 4-(4-ethyl-piperazin-1-yl)-but-2-ynoic acid: mass spectrum (m/e):M−H 195.

Workup

washwashed with ethyl acetate
customThe aqueous layer was evaporated under reduced pressure
customto give the crude acid
customthe insoluble salt was removed via filtration
customThe filtrate was collected
customdried in vacuo

Sources & evidence

ORD record: ord-8e9c9e47f10741cd9e265c02c38fc5fa
Source dataset: uspto-grants-2001_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06251912B1

Reaction notes

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