Sodium Iodide → 1-(2-(tert-butyldimethylsilyloxy)ethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

HRID 1472615Notes

Reaction equation

[CH3:1][C:2]1([CH3:14])[C:6]([CH3:8])([CH3:7])[O:5][B:4]([C:9]2[CH:10]=[N:11][NH:12][CH:13]=2)[O:3]1.Br[CH2:16][CH2:17][O:18][Si:19]([C:22]([CH3:25])([CH3:24])[CH3:23])([CH3:21])[CH3:20].C([O-])([O-])=O.[K+].[K+].[Na+].[I-]>CC#N>[Si:19]([O:18][CH2:17][CH2:16][N:12]1[CH:13]=[C:9]([B:4]2[O:5][C:6]([CH3:7])([CH3:8])[C:2]([CH3:14])([CH3:1])[O:3]2)[CH:10]=[N:11]1)([C:22]([CH3:25])([CH3:24])[CH3:23])([CH3:21])[CH3:20]

Participants

Conditions

Temperature: 70 °C

Procedure

A mixture of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.500 g, 2.58 mmol), (2-bromoethoxy)-t-butyldimethylsilane (2.211 mL, 10.31 mmol), K2CO3 (1.425 g, 10.31 mmol) and NaI (0.039 g, 0.258 mmol) in MeCN (8 mL) was heated to 70° C. for 2 days. The mixture was cooled to RT, the solid removed via filtration, rinsed with EtOAc and the filtrate washed with 50% satd. NaCl (1×). The organic layer was dried over MgSO4, concentrated to dryness and purified via silica gel chromatography (EtOAc/Hex) to afford 1-(2-((tert-butyldimethylsilyl)oxy)ethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (574 mg, 63%) as a colorless oil. 1H NMR (400 MHz, DMSO-d6): δ 7.79 (s, 1H), 7.51 (s, 1H), 4.12 (t, J=5.4 Hz, 2H), 3.79 (t, J=5.4 Hz, 2H), 1.17 (s, 12H), 0.71 (s, 9H), −0.17 (s, 6H); MS (ESI) m/z: 353.2 (M+H+).

Workup

temperatureThe mixture was cooled to RT
customthe solid removed via filtration
washrinsed with EtOAc
washthe filtrate washed with 50%
dry with materialThe organic layer was dried over MgSO4
concentrationconcentrated to dryness
custompurified via silica gel chromatography (EtOAc/Hex)

Sources & evidence

ORD record: ord-7a9404d4089f4f74bac7eb8b44d38310
Source dataset: uspto-grants-2015_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09012635B2

Reaction notes

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