Hydrochloric Acid → 1-(2-ethoxyethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole
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.C(OCN1C2N=CN=C(C3C=NN([CH:37]([O:39][CH2:40][CH3:41])[CH3:38])C=3)C=2C=C1)(=O)C(C)(C)C.Cl.C([O-])(O)=O.[Na+]>O1CCOCC1.C1(C)C=CC=CC=1>[CH2:37]([O:39][CH2:40][CH2:41][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)[CH3:38]Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 37.5 °C
Procedure
A 22 L 4-neck flask equipped with a mechanical stirrer, thermowell, addition funnel, condenser and N2 inlet was charged with 4-(4,4,5,5-tetra-methyl[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (17, 1.42 kg, 7.32 mol), toluene (9.5 L) and ethyl vinyl ether (18, 790.5 g, 1050 mL, 10.98 mol, 1.50 equiv). A 4 M HCl in dioxane (50 mL) was added via an addition funnel over 10 minutes and the resulting reaction mixture was heated at 35-40° C. for 7 hr to give a clear homogeneous solution. When the reaction was shown to be complete by GC, solid NaHCO3 (130 g) was added and the mixture was stirred for 1 hr before being filtered. The filtrate was concentrated under reduced pressure. Heptane (200 mL) was added to the residue to affect crystallization. The solid was collected by filtration and dried in a vacuum oven to afford 1-(ethoxyethyl)-4-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (19, 1.896 Kg, 1.948 Kg theoretical, 97.3%) as a white to off-white solid. For 19: 1H NMR (DMSO-d6, 400 MHz) δ ppm 8.09 (s, 1H), 8.58 (s,1H), 7.62 (s,1H), 5.55 (q, 1H, J=6.1 Hz), 3.37 (dq, 1H, J=7.1, 9.6 Hz), 3.12 (dq, 1H, J=7.0, 9.7 Hz), 1.56 (d, 3H, J=6.0 Hz), 1.24 (s, 12H), 1.00 (t, 3H, J=7.0 Hz); C13H23BN2O3 (MW, 266.14), LCMS (EI) m/e 267 (M++H).
Workup
- customA 22 L 4-neck flask equipped with a mechanical stirrer
- additionthermowell, addition funnel, condenser and N2 inlet
- customthe resulting reaction mixture
- customto give a clear homogeneous solution
- additionwas added
- filtrationbefore being filtered
- concentrationThe filtrate was concentrated under reduced pressure
- additionHeptane (200 mL) was added to the residue
- customcrystallization
- filtrationThe solid was collected by filtration
- customdried in a vacuum oven
Sources & evidence
- ORD record
- ord-f7f8822d44374a989b9dc88bc57c47d2
- Source dataset
- uspto-grants-2013_04
- Patent number
- US08410265B2
Reaction notes
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