3,6-Dibromocarbazole

tan to light green powder

The detailed steps of the present invention are as follows:among them, The amount of charge is as follows:Carbazole: 167.2 g, Dibromohydantoin:300. lg, Anhydrous B.Alcohol: 1800 ml.167. 2 g of carbazole (lmol) and 1000 ml of absolute ethanol were added to a 2000 ml reaction flask and stirred for 20 minutes.So as to disperse uniformly.Dibromohydantoin was then added in batches''285 g (1. 05 mol) was added and the reaction temperature was controlled at 20-25 ° C, about 2 hoursWhen added, after adding a large number of white solid precipitation. And reacted at this temperature for 1 hour. The reaction was monitored by HPLC. When the monobrominated product was less than 1percent, the reaction was stopped and the reaction was stopped at 20-25 ° CThe filter cake was added to a 1000 ml three-necked flask, and 800 ml of absolute ethanol was added. The mixture was heated to reflux (80 ° C) for 1 hour, cooled slowly to 20-25 ° C, Dried at 100 ° C under normal pressure to obtain 312 g of a white powdery solid. Figure 3 shows the 3, 6-dibromo carbazole HPLC spectrum andTable 3 shows that the 3, 6-dibromocarbazole content was 99.00percent, and the GC spectrum of 3, 6-dibromo carbazole as shown in Figure 4 and the results shown in Table 4The yield of 3, 6-dibromocarbazole was 99.66percent, and the yield of 3, 6-dibromocarbazole was 96.0percent.A solution of NBS (42.72g, 0.24mol) in 200mL DMF was added slowly to a suspension of carbazole (20g, 0.12mol) in dichloromethane (1.2L). The reaction mixture was stirred at room temperature and the progress of the reaction was controlled by GCMS analysis. Then the solution was washed with water (3×200mL), the organic layer was dried under magnesium sulfate and filtered. The solvent was evaporated and the residue was dissolved in acetone (100mL) and precipitated with hexane (600mL). 3, 6-dibromocarbazole was filtered and dried under vacuum to afford 35g (yield 90percent) of product.9.7 g (58 mmol) of the carbazole was dissolved in 600 ml of dichloromethane, and 21.7 g (121.8 mmol) of N-bromosuccinimide was added dropwise over 10 minutes. After 4 hours, the solvent was removed in vacuo, The residue was subjected to ethanol and water, Filtered, washed with ethanol and dried to give 17.0 g (90percent) of a colorless powder.A mixture of carbazole (1.00 g, 6.00 mmol) and silica gel(8.00 g, 133.33 mmol) was added to CH2Cl2(60 mL) at roomtemperature, N-bromosuccinimide (1.07 g, 12.00 mmol), added to the above system, the mixture was reacted for 24 hat room temperature, then filtering and evaporating off thesolvent, and the residue was extracted with n-hexane/ethylacetate (10:1, v/v) to generate a white solid. 1.71 g, yield:88percent.Mp: 204–206 °C. 1H NMR (400 MHz, DMSO-d6, δ, ppm): 11.60 (s, 1H, –NH), 8.44 (d, J = 8.8 Hz, 2H), 7.54(d, J = 8.9 Hz, 2H), 7.48 (d, J = 8.7 Hz, 2H). 13C NMR(101 MHz, DMSO-d6, δ, ppm): 139.3, 129.2, 123.9, 123.8, 113.8, 111.5. Anal. calcd for C12H7Br2N:C, 44.35; H, 2.17;Br, 49.17; N, 4.31. Found: C, 44.28; H, 2.15; Br, 49.14; N, 4.29.To a 500 mL three-necked flask was added carbazole (24.7 g, 0.1 mol)Dimethylformamide 200 mL, Stir to dissolve, NBS (49.84 g, 0.28 mol) was dissolved in 120 mL of DMF, Ice bath to 0 , Slowly drop the NBS solution, Reaction to light, After the dropwise addition, the temperature was allowed to rise to room temperature and the reaction was continued for 6 hours.The reaction solution was added dropwise to the water to precipitate, and the crude product was collected by suction filtration. The filtrate was recrystallized from absolute ethanol and dried to give white needles. Yield: 85percent4-3: Synthesis of 3, 6-dibromo-9H-carbazole: Carbazole (5.0 g, 29.9 mmol) was dissolved in THF (50 mL), and then N-bromosuccinimide (11.18 g, 62.80mmol) was added thereto to prepare a mixed solution. Then, the mixed solution was reacted at room temperature for 4hours. After the reaction of the mixed solution, a solvent was removed, and the reacted mixed solution was extractedwith water and ethyl acetate to obtain an extract. The extract was dried by magnesium sulfate (MgSO4), and then areaction product was separated by column chromatography (n-hexane/EtOAc = 4/1). The yield ofthe reaction productwas 83percent (8.1 g).1HNMR(300 MHz, CDCl3) 8.13-(s, -Ar, 2H), 7.53(d, -Ar, 2H), 7.32-7.3(d, -Ar, 2H)In the 100mL single-mouth bottle, 1.00 g (5.99 mmol) of carbazole was added, dissolved in tetrahydrofuran, and the jar was placed in an ice bath and protected from light.Then 2.67g (15mmol) of NBS was dissolved in tetrahydrofuran and slowly poured into a constant pressure dropping funnel. Into a 100ml single-mouth bottle, An ice bath was stirred under nitrogen for 4 h.The reaction was poured into 100 mL of water.Extract three times with ethyl acetate, The resulting liquid spins dry, With ethyl acetate:Column chromatography of petroleum ether = 1:200 gave 1.56 g (4.8 mmol) of a white solid, Compound 2, yield 80percent.Synthesis of Compound 2:; Compound 2 was obtained by dibromination of compound 1.This dibromination was carried out by making this compound (2.01 g, 12.0 mmol) react with N-succinimide (4.20 g, 23.8 mmol), in the presence of silica preactivated at 120° C. (40.50 g, 0.063-0.2 nm) in order to protonate the nitrogen atom of compound 1, and in dichloromethane (350 ml), as described by Smith et al. in Tetrahedron, 1992, 48, 36, 7479-7488, [4].The yield of the reaction was 76percent.Carbazole (16.72g, 100mmol), NBS (59.4g, 210mmol), BPO (2.42g, 10mmol), followed by stirring at room temperature, insert the methylenechloride (300mL). When the reaction is complete, methylene chloride and water, and extracted using an aqueous solution of NaHCO3 was obtained organic layer was dried with Na2SO4, and the product was recrystallized 23.73g (73percent) and was concentrated.3, 6-Dibromo-9H-carbazole (1), a solution of N-bromosuccinimide (0.21 mol) in DMF (80 mL) was slowly added to a solution of carbazole (0.1 mol) in DMF (20 mL) in an ice bath. After reaction for 30 min, the mixture was poured into ice water (1 L), and the crude product was collected by filtration to give a blue powder. Recrystallization from EtOH/H9H- carbazole (1) (2.00g, 12.0mmol) in dichloromethane (100ml)To, N- bromosuccinimide (4.30g, 24.0mmol) and silica gel(SiO2) was added (20.0g).The dark, was stirred at room temperature for 12 hours, filtered, washed twice with water, dried over anhydrous sodium sulfate, filtered, using a rotary evaporator, the solvent was distilled off under reduced pressure at room temperature from the filtrate, the crude product I got things. The resulting crude product was recrystallized from dichloromethane, 3, 6-dibromo-9H-carbazole and (2b) 2.50 g (yield: 64percent) was obtained.Step 1: In a 1000 mL three-necked flask equipped with a mechanical stirrer, 4 g (0.024 mol)Carbazole and 240 mL of dichloromethane, under an argon atmosphere at 5 mL / minAt a rate of dropwise addition of N-bromosuccinimideN, N '-dimethylformamide solution, Wherein N-bromosuccinimide is8.54 g (0.048 mol), N, N'-dimethylformamide solution was 40 mL; stirred for 3 hours, The solution was washed four times with 280 mL of distilled water, The organic phase was dried over anhydrous magnesium sulfate; the solvent in the organic phase was distilled off under reduced pressure at room temperature, To give a pale gray crude product; mixed with acetone and n-hexane(In which acetone is 30 mL and n-hexane is 400 mL) to recrystallize the light gray crude product;The final product was vacuum dried at 70 ° C for 10 hours to give a gray bulk crystal, I.e., 3, 6-dibromocarbazole; the resulting product was 4.9 g in a yield of 61.5percentSynthesis of 3, 6-dibromocarbazole. Carbazole (1 .0 g, 6 mmol) was added to anhydrous DMF (15 mL) at room temperature while stirring. The resulting mixture was stirred at room temperature for another 15 minutes. N- bromosuccinimide (2.3 g, 13 mmol) in anhydrous DMF (10 mL) was added drop wise to carbazole-DMF mixture at 0°C in inert atmosphere. The resulting solution was allowed to reach to the room temperature and continued stirring for another 2 hours. This solution was poured to Dl water. The milky white precipitate formed was filtered and dissolved in DCM . DCM layer was washed with water several times. Then DCM layer was dried with anhydrous sodium sulfate and solvent was removed under high vacuum. Resultant white solid was recrystallized using ethanol to get light brown silvery flake-like 3, 6-dibromocarbazole crystals (1 .1 g, 55percent yield) . MS, ESI - m/z 323 (M+); N-N-dimethylformamide (DMF) (20 ml) dissolved with carbazole (10 g, 59.8 mmol) was stirred under ice-The solution was added dropwise to a solution of N-bromosuccinimide (21.28 g, 120 mmol) in DMF (30 mL) with a constant pressure dropping funnelin. After completion of the drop, the ice bath was removed and the reaction was conducted overnight at room temperature. The reaction solution was then washed with deionized water and analyzedThe solid was filtered off and the product was recrystallized from ethanol. Yield: 47percent.

Pharmaceutical intermediates are also important intermediates for the synthesis of optoelectronic materials

Molecular Weight:325.00
XLogP3:4.8
Hydrogen Bond Donor Count:1
Exact Mass:324.89247
Monoisotopic Mass:322.89452
Topological Polar Surface Area:15.8
Heavy Atom Count:15
Complexity:222
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes