Water → tert-Butyl 4-(1H-indazol-5-yl)piperazine-1-carboxylate

HRID 1192319Notes

Reaction equation

[N:1]1([C:7]2[CH:8]=[C:9]3[C:13](=[CH:14][CH:15]=2)[NH:12][N:11]=[CH:10]3)[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.[OH-].[Na+].[C:18]([O:22][C:23](=O)[O-:24])([CH3:21])([CH3:20])[CH3:19].O>O1CCOCC1>[C:18]([O:22][C:23]([N:4]1[CH2:5][CH2:6][N:1]([C:7]2[CH:8]=[C:9]3[C:13](=[CH:14][CH:15]=2)[NH:12][N:11]=[CH:10]3)[CH2:2][CH2:3]1)=[O:24])([CH3:21])([CH3:20])[CH3:19]

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 5-Piperazin-1-yl-1H-indazole (0.34 g, 1.3 mmol) in 1,4-dioxane (5 mL) was added 3N NaOH (0.42 mL, 1.3 mmol). After cooling to 0° C., a solution of tert-butylcarbonate (0.25 g, 1.3 mmol) in 1,4-dioxane (1 mL) was added dropwise. The reaction mixture was stirred at room temperature overnight and then poured into water and extracted with EtOAc. The combined organic layers were washed with saturated aqueous NaHCO3, water, brine, dried and concentrated. The residue was purified by column chromatography (EtOAc:hexanes, 1:1) to give 4-(1H-Indazol-5-yl)-piperazine-1-carboxylic acid tert-butyl ester (0.31 g, 82%) as a white solid. 1H NMR (CDCl3, 400 MHz) δ 10.01 (s, 1H), 7.80 (s, 1H), 7.42 (d, J=9.2 Hz, 1H), 7.21 (dd, J=9.2 Hz, J=2.0 Hz, 1H), 7.16 (d, J=2.0 Hz, 1H), 3.62 (m, 4H), 3.09 (m, 4H), 1.50 (s, 9H). LCMS (APCI+) m/z 303 [M+H]+; Rt=2.50 minutes.

Workup

extractionextracted with EtOAc
washThe combined organic layers were washed with saturated aqueous NaHCO3, water, brine
customdried
concentrationconcentrated
customThe residue was purified by column chromatography (EtOAc:hexanes, 1:1)

Sources & evidence

ORD record: ord-8114f7303ccd4baca77d182d7c151228
Source dataset: uspto-grants-2014_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08680114B2

Reaction notes

Loading…