* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
3-Bromo-5-iodonitrobenzene.<strong>[180624-08-2]4-bromo-2-iodo-6-nitroaniline</strong> (5 g, 0.0145 mol) was added in portions to stirred concentrated sulfuric acid (60 ml) keeping the temperature at 0-50C. After stirring in the cold for 1 h, sodium nitrite (2.3 g, 0.0326 mol) was added and the reaction mixture stirred in the cold for a further 2 h. The reaction mixture was then poured into ice (250 ml). The resultant mixture was added, in portions, to a boiling solution of copper (II) sulfate (0.36 g, 0.00145 mol) in ethanol (150 ml) and boiled for a further 2 h. The reaction mixture was cooled to ambient temperature and extracted with ethyl acetate (300 ml) which was washed with saturated sodium hydrogen carbonate solution (250 ml) and dried (MgSO4). The solvent was removed in vacuo to give 3- Bromo-5-iodonitrobenzene as a yellow solid (4.21 g, 88 %) which was used without further purification. 1H NMR (400MHz,delta,CDCI3): 8.18(1 H,s), 8.34(1 H,s), 8.50(1 H,s)
1.3
3-Bromo-5-iodoaniline.A mixture of 3-Bromo-5-iodonitrobenzene (4.21 g, 0.0128 mol) and iron powder (3.6g, 0.0642 mol) in glacial acetic acid (50 ml) was stirred at ambient temperature for 16 h. The reaction mixture was then filtered through a pad of celite and washed through with ethyl acetate. The filtrate was evaporated in vacuo to give a brown oil. This was re-dissolved in ethyl acetate, loaded onto a large pad of silica and eluted with ethyl acetate. The filtrate was evaporated in vacuo to afford 3-Bromo-5- iodoaniline as a brown solid (3.67g, 96%) which was used without further purification. 1H NMR (400MHz,δ,CDCI3): 3.72(2H,br s), 6.77(1 H,s), 6.95(1 H,s), 7.21(1 H,s).
With copper(I) oxide; potassium phosphate; bismuth (III) nitrate pentahydrate; palladium(II) trifluoroacetate; oxygen; sodium iodide; In dimethyl sulfoxide; at 170℃; for 20h;Schlenk technique;
In a Schlenk reaction tube equipped with a magnetic stirrer, 6.7 mg of palladium trifluoroacetate was added. Cuprous oxide 28.6mg,Potassium phosphorus 6.4mg,<strong>[99277-71-1]4-bromo-2-nitrobenzoic acid</strong> 49.2 mg,Sodium iodide 36mg,bismuth nitrate pentahydrate194 mg and 2 mL of dimethyl sulfoxide.The reaction was heated at 170C for 20 hours in the presence of oxygen. After the reaction is completed, distilled water is added to quench the reaction.Ethyl acetate was extracted 3 times for 10 mL each time, and the combined organic phases were concentrated to give 1-bromo-3-iodo-5-nitrobenzene.50.5 mg, yield 77%.
Multi-step reaction with 3 steps
1.1: iron; acetic acid / 16 h / 20 °C
2.1: acetone / 1 h / 20 °C
2.2: 16 h / 20 °C
3.1: sodium methylate / methanol / 4 h / 20 °C
Multi-step reaction with 2 steps
1: copper(l) iodide; (1R,2R)-N,N-dimethylcyclohexane-1,2-diamine; caesium carbonate / N,N-dimethyl-formamide / 12.08 h / 50 °C / Inert atmosphere
2: ammonium chloride; iron / ethanol; water / 88 h / 50 °C
tert-butyl 1-(3-bromo-5-nitrophenyl)hydrazine-1-carboxylate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
34%
With copper(l) iodide; caesium carbonate In dimethyl sulfoxide at 50℃; for 4h; Sealed tube;
Step 1
In a sealed tube 1-bromo-3-iodo-5-nitrobenzene (3.0 g, 9.149mmol) was dissolved in DMSO (9ml_). Te/f-butyl carbazate (1.451 g, 10.979mmol), cesium carbonate (4.471 g, 13.723mmol) and copper(l) iodide (174mg, 0.915mmol) were added and the reaction mixture was stirred at 50°C for 4h. Water was added and the mixture was extracted with ethyl acetate. The combined organic layers were dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel chromatography (eluting gradient 0- 15% Heptane/ethyl acetate) to afford te/f-butyl 1-(3-bromo-5-nitrophenyl)hydrazine-1- carboxylate (1 .045g, 34% yield) as a brown sticky solid. LCMS (MH) RT = 1 .044 min, m/z = 275.9-277.9 (M+H)+.
With copper(l) iodide; (1R,2R)-N,N-dimethylcyclohexane-1,2-diamine; caesium carbonate In N,N-dimethyl-formamide at 50℃; for 12.0833h; Inert atmosphere; Overall yield = 25 percent; Overall yield = 3.3 g;
Intermediate I4: Mixture of 1-(3-bromo-5-nitrophenyl)-1 H-pyrazole and 1-(3-iodo-5- nitrophenyl)-1 H-pyrazole
In a pressure flask, 3-bromo-5-iodonitrobenzene (7.2 g, 21.958mmol), Pyrazole (1.495 g, 21.958mmol), copper(l) iodide (836mg, 4.392mmol), trans-N,N'-dimethylcyclohexane-1 ,2- diamine (1 .249ml_, 21 .958mmol) and cesium carbonate (21 .67 g, 65.67mmol) in DMF (45ml_). The reaction mixture was bubbled with a nitrogen stream for 5 min and the mixture was stirred at 50°C for 12h. The reaction mixture was filtered over a pad of Celite and rinsing with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel chromatography (eluting gradient 0-20% Heptane/ethyl acetate) to afford to afford a mixture of the expected compound and 1-(3-iodo-5-nitrophenyl)-1 H-pyrazole (3.3 g, 25% yield) as a brown solid. LCMS (MH) RT = 0.902 min, m/z = 267.9 - 269.9 (M+H)+ and RT = 0.942 min, m/z = 315.9 (M+H)+.