3-Amino-4-bromopyrazole

Grey Crystalline Solid

At 0-5Experimental steps: 0.5565mmol, 4eq) in the reaction solution, After 4h reaction at room temperature, the amine (0.3mmol, 2eq) was condensed and refluxed at 80 C for 12h. The reaction was followed by TLC.After completion of the reaction, the solvent was removed by condensing at room temperature under reduced pressure, and the solvent was removed. The organic phase was extracted by extraction with 0.5 M HCl and EA (V: V = 1: 1), The obtained organic phase was transferred to a 125 ml separatory funnel, and saturated brine (2 × 20 ml), 5% sodium bicarbonate solution (2 × 20 ml) were sequentially added.Add saturated saline (3 × 20ml), and measure the pH of the saturated saline at the time of extraction. The pH is neutral.Anhydrous sodium sulfate was added to dry the organic phase, and the crude product was distilled under reduced pressure at 45 C. The ethyl acetate petroleum ether system was used for column chromatography to obtain the pure compound.To a solution of compound B1 (6.0 g, 37.04 mmol) in DMF (200 mL) was added trimethyl orthoacetate (14.2 g, 118.53 mmol) , stirred for 16 hours at 110. The reaction mixture was cooled to room temperature and added into water (150 mL) , extracted with EtOAc (100 mL × 3) . The organic layers were washed with brine (50 mL) , dried over anhydrous Na 2SO 4 and concentrated under vacuum to afford crude product, which was purified by silica gel chromatography (elution gradient: petroleum ether/ethyl acetate, 3/1, v/v) , pure fractions were evaporated to dryness to afford compound B2 (4.3 g) as a yellow oil, yield: 53.7%. [0643] 1H NMR (400 MHz, DMSO-d 6) : delta ppm 1.93 (s, 3H) , 3.74 (s, 3H) , 7.87 (s, 1H) , 12.68 (s, 1H) . [0644] LCMS: Rt = 1.29 min, MS Calcd.: 217.0, 219.0, MS Found: 217.9, 219.9 [M+H] +.General procedure: A soln. of amine BB-34 (1 eq) and aldehyde or ketone BB-12 (1.05 to 1.1 eq) in MeOH (2 to 4 mL/mmol) was stirred for 1 h at RT. NaBI-U (1.6 to 2 eq) was added portionwise at 0C and the rxn mixture was stirred at a given temperature for a given time (see Table 52). It was quenched with H2O at 0C and extracted with EtOAc. The combined org. phases were washed with brine, dried over MgSCh and concentrated in vacuo. When necessary, the crude was purified by CC using EtOAc/MeOHGeneral procedure: A soln. of amine BB-34 (1 eq) and aldehyde or ketone BB-12 (1.05 to 1.1 eq) in MeOH (2 to 4 mL/mmol) was stirred for 1 h at RT. NaBI-U (1.6 to 2 eq) was added portionwise at 0C and the rxn mixture was stirred at a given temperature for a given time (see Table 52). It was quenched with H2O at 0C and extracted with EtOAc. The combined org. phases were washed with brine, dried over MgSCh and concentrated in vacuo. When necessary, the crude was purified by CC using EtOAc/MeOHExperimental steps: Weigh AsB-COOH (67.4 mg, 0.142 mmol, 1 eq) in a 50 ml round bottom flask.The compound was dissolved in 2 ml of anhydrous 1, 2-dichloroethane, and then EDC (57.2 mg, 0.298 mmol, 2 eq) was weighed.HoBt (75.2 mg, 0.5565 mmol, 4 eq) was reacted in the reaction mixture for 4 h at room temperature.The reamine (0.3 mmol, 2 eq) was refluxed at 80 C for 12 h, and the reaction was followed by TLC.After the completion of the reaction, the solvent was evaporated under reduced pressure at room temperature, and extracted with 0.5 M HCl and EA (V: V = 1:1) to obtain an organic phase (50 ml of a separating funnel).The obtained organic phase was transferred to a 125 ml separatory funnel, followed by saturated brine (2×20 ml), 5% sodium hydrogen carbonate solution (2×20 ml).Saturated saline solution (3 × 20 ml) was added, and the pH of the saturated saline solution extracted at the end was measured, and the pH was neutral.The organic phase was dried over anhydrous sodium sulfate, and the crude product was evaporated under reduced pressure at 45 C. White soldi, yiled 60.5%A stirred solution of

Molecular Weight:161.99
XLogP3:0.6
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:2
Exact Mass:160.95886
Monoisotopic Mass:160.95886
Topological Polar Surface Area:54.7
Heavy Atom Count:7
Complexity:67.2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes