Diisopropylethylamine → Tert-butyl 4-(5-(ethoxycarbonyl)pyridin-2-yl)piperazine-1-carboxylate

HRID 906072Notes

Reaction equation

Cl[C:2]1[CH:12]=[CH:11][C:5]([C:6]([O:8][CH2:9][CH3:10])=[O:7])=[CH:4][N:3]=1.[N:13]1([C:19]([O:21][C:22]([CH3:25])([CH3:24])[CH3:23])=[O:20])[CH2:18][CH2:17][NH:16][CH2:15][CH2:14]1.C(N(CC)C(C)C)(C)C>COCCOC>[CH2:9]([O:8][C:6]([C:5]1[CH:11]=[CH:12][C:2]([N:16]2[CH2:15][CH2:14][N:13]([C:19]([O:21][C:22]([CH3:25])([CH3:24])[CH3:23])=[O:20])[CH2:18][CH2:17]2)=[N:3][CH:4]=1)=[O:7])[CH3:10]

Participants

Conditions

Temperature: 120 °C

Procedure

A mixture of ethyl 6-chloronicotinate (2.67 g, 14.4 mmol), tert-butyl piperazine-1-carboxylate (2.5 g, 13.4 mmol) and N,N-diisopropylethylamine (3.5 mL, 20 mmol) in DME (15 mL) was heated at 120° C. for 12 hours. The mixture was then cooled to room temperature and partitioned with ethyl acetate and 10% aqueous citric acid. The organic layer was washed twice with 10% aqueous citric acid then brine and dried over anhydrous sodium sulfate. Filtration and concentration followed by silica gel flash chromatography of the residue using 3:1 hexanes:ethyl acetate to 100% ethyl acetate afforded tert-butyl 4-(5-(ethoxycarbonyl)pyridin-2-yl)piperazine-1-carboxylate (3.65 g). 1H NMR (400 MHz, CDCl3): 8.81 (s, 1H), 8.04 (d, 1H), 6.58 (d, 1H), 4.33 (q, 2H), 3.70-3.67 (m, 4H), 3.56-3.53 (m, 4H), 1.49 (s, 9H), 1.37 (tr, 3H).

Workup

temperatureThe mixture was then cooled to room temperature
custompartitioned with ethyl acetate and 10% aqueous citric acid
washThe organic layer was washed twice with 10% aqueous citric acid
dry with materialbrine and dried over anhydrous sodium sulfate
filtrationFiltration and concentration

Sources & evidence

ORD record: ord-156b697eb1e340e192a2633ed06e7b04
Source dataset: uspto-grants-2011_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08012956B2

Reaction notes

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