Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 3994-50-1, name is 1-Methyl-4-nitro-1H-pyrazole, A new synthetic method of this compound is introduced below., HPLC of Formula: C4H5N3O2
A solution of l-methyl-4-nitro-lH-pyrazole (9.7 g, 76.7 mmol) and 4-pentenal (10 g, 84.4 mmol) in dry THF (250 mL) was cooled to -78 C and stirred under nitrogen. A solution of LiHMDS (1 M in THF, 192 mL, 191.7 mmol) was added dropwise over a period of 3 hr. The reaction mixture was allowed to warm and to -40 C and stirred for 2 hr, quenched by dropwise addition of saturated ammonium chloride solution (100 mL), warmed to room temperature and diluted with EtOAc (200 mL). The organic layer was washed with saturated ammonium chloride solution (50 mL), separated, dried over MgS04 and the solvent removed under reduced pressure. Purification via silica gel chromatography (0-100% EtOAc/DCM) followed by silica gel chromatography (0-100% EtOAc/isohexane) to gave l-(l-methyl-4- nitro-lH-pyrazol-5-yl)pent-4-en-l-ol as a pale yellow oil (5.75 g, 36%). NMR (400 MHz, CDC13) delta 8.06 (s, 1H), 5.85-5.78 (m, 1H), 5.32-5.26 (m, 1H), 5.12-5.04 (m, 2H), 3.98 (s, 3H), 3.45 (d, / = 8.7 Hz, 1H), 2.92-2.09 (m, 3H), 1.90-1.86 (m, 1H).
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.
Reference:
Patent; F. HOFFMANN-LA ROCHE AG; GENENTECH, INC.; BURCH, Jason; CHEN, Huifen; WANG, Xiaojing; WO2015/140189; (2015); A1;,
Pyrazole – Wikipedia,
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