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| | Pyrazole-3-boronic acid Basic information |
| | Pyrazole-3-boronic acid Chemical Properties |
| Melting point | 85-88°C | | Boiling point | 430.4±37.0 °C(Predicted) | | density | 1.40±0.1 g/cm3(Predicted) | | storage temp. | Inert atmosphere,Store in freezer, under -20°C | | form | solid | | pka | 8.58±0.53(Predicted) | | color | Off-white | | Water Solubility | Soluble in water. | | InChI | InChI=1S/C3H5BN2O2/c7-4(8)3-1-2-5-6-3/h1-2,7-8H,(H,5,6) | | InChIKey | NEUWPDLMDVINSN-UHFFFAOYSA-N | | SMILES | N1C=CC(B(O)O)=N1 |
| Hazard Codes | Xi | | Risk Statements | 36/37/38 | | Safety Statements | 26-36/37 | | WGK Germany | 3 | | HazardClass | IRRITANT | | HS Code | 2933199090 |
| | Pyrazole-3-boronic acid Usage And Synthesis |
| Uses | Significantly used as synthetic intermediates. They are widely used in the production of optics. | | Synthesis | General procedure for the synthesis of 1H-pyrazole-3-boronic acid from 1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole: To a solution of 1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole (7.6 g, 52 mmol) in tetrahydrofuran (THF, 50 mL) was added slowly at -78 °C n-butyllithium (n-BuLi, 33 mL, 2.5 M hexane solution, 82.5 mmol), followed by the addition of triisopropylborane (12.7 mL, 55 mmol) dropwise, keeping the reaction temperature at -70 °C. The reaction mixture was stirred at -70 °C for 1 hour and then slowly warmed to room temperature over 4 hours. After completion of the reaction, the reaction was quenched with 2M hydrochloric acid (HCl) and the solvent was removed under vacuum. The pH of the reaction mixture was adjusted to 6 with 1M sodium hydroxide (NaOH) solution, at which time a precipitate was formed. The precipitate was collected by filtration, washed sequentially with toluene and petroleum ether, and finally ground with ethyl acetate to afford 1H-pyrazole-3-boronic acid as a white solid (2.7 g, 48% yield), and the product could be used in subsequent reactions without further purification. | | References | [1] Patent: WO2007/138072, 2007, A2. Location in patent: Page/Page column 55
[2] Journal of Medicinal Chemistry, 2004, vol. 47, # 12, p. 2995 - 3008 |
| | Pyrazole-3-boronic acid Preparation Products And Raw materials |
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