4,7-Dibromo-2,1,3-benzothiadiazole

10 g (73.4 mmol) of the intermediate and 100 ml of 48percent hydrobromic acid were mixed, 35 g (22.3 mmol) of bromine was added dropwise at room temperature and the reaction was heated under reflux for 6 hours, Cooled to room temperature, add 100ml of saturated aqueous sodium bisulfite solution, filter, filter cake and then washed with water, ethanol recrystallization, 20.7g yellow solid, the yield of 96percent.Compound 4 (3g, 22.03mmol) and 100 mL of HBr (48percent) were added toa 500 mL flask. A solution containing Br2, 1, 3-Benzothiadiazole (3g, 22.0mmol) was dissolved in 65mL of HBr (47percent). On the other hand, BrBenzothiadiazole (25 g, 184 mmol) was reacted overnight with 20.8 mL bromine (2.2 eq) in 400 mL of 48percent HBr (in water) at 125-130 °C. After cooling the reaction mixture (heavy suspension of reddish-brown solid) was poured into 1 liter of crushed ice and left to stir for 30 minutes. Filtration, washing with water, followed by washing with sodium sulfite solution and water gave 4, 7-dibromobenzothiadiazole as brick colored needles, (50.1 g, 92percent, after drying in vacuum oven). This material was used for nitration with fuming nitric acid in trifluoromethanesulfonic acid (TFMSA) as follows: nitric acid (10.0 mL) was added dropwise to TFMSA (150 g) which was cooled below 5 °C. with intensive stirring (white solid formed). 4, 7-Dibromobenzothiadiazole (as solid) was added portionwise to the above reaction mixture and, after it became homogenous, the flask was placed in an oil bath and left to stir at 50 °C. for 16-24 hours. The reaction was monitored bySynthesis of dibromobenzo[c][1, 2, 5]thiadiazole (M1):Bromine was added drop wise over a period of 5 min to avigorously stirred suspension of benzo[c][1, 2, 5]thiadizole inhydrobromic acid (30 mL) at 120 °C. The reaction was left tostir for 36 h during which a canary yellow precipitate formed.Water (100 mL) was added, the suspension left to stir for 10min, then filtered and washed with a little water. The yellow solid was dried in vacuo for 24 h to give the pure product. (25g, 91.3 percent) 1H NMR (400 MHz, CDCl3, ppm): δ-aromatic H, 7.73 (s, 2H)A mixture of 2, 1, 3-benzothiadiazole (13.6 g, 0.1 mol) in 45percent hydrobromicacid (30 mL) was heated under reflux with stirring while48 g (0.3 mol, 15.3 mL) of bromine was added slowly. The reactionmixture became a suspension of solid in hydrobromic acid and 15 mL ofhydrobromic acid was added, then the mixture was refluxed for another2.5 h. After cooling to room temperature, the precipitate formed andcollected, washed with water, then recrystallized from chloroform togive yellow needle crystals (26.8 g, 91percent). mp 186–188 °C. 1H NMR(400 MHz, CDCl3) δ (ppm): 7.73 (s, 2H). 13C NMR (100 MHz, CDCl3) δ(ppm): 153.34, 132.67, 114.31. Anal. Calcd for C6H2Br2N2S: C, 24.51;H, 0.69; N, 9.53. Found: C, 24.12; H, 0.72; N, 9.66.1.1Compound 1c (1.360 g, 9.988 mmol) was dissolved in the solution of HBr (35 mL, 40percent), then a solution of BrBenzo-1, 2, 5-thiadiazole (5.0 g, 36.7 mmol) was dissolved in 40 mL HBr (47percent) in room temperature. Later, a solution of BrTo a stirredsuspension of benzo[c][1, 2, 5]thiadiazole (14; 10 g, 73.4 mmol) in30 mL of hydrobromic acid (48percent), bromine (11.4 mL, 222.5 mmol, 3 eq.) was added slowly, while the temperature raised to 60°C.The resulting reaction mixture was heated to reflux for additional 3 h andwas then allowed to cool to room temperature, while a white precipitate wasformed. The mixture was diluted with saturated Na13.6 g of benzothiadiazole (100 mmol) (compound 1) and 300 mL of HBr aqueous solution (48percent) were added to a 1, 000 mL round-bottom flask and heated to reflux. 15.4 mL of bromine (300 mmol) was then slowly dropped and reacted overnight. After adding sodium thiosulfate aqueous solution to quench the reaction, the resulting solution was filtered. The filtered solid was then washed with acetone. Thus, 25.3 g of light ashen solid product (compound 2) was obtained, with a yield of 86percent.In a two-neck bottle (1000mL), Product 2 (5.00 g, 36.72 mmol), Hydrogen bromide (47percent, 80 mL) was added and stirred until dissolved.A mixed solution of liquid bromine (17.60 g, 110.16 mmol) and hydrogen bromide (47percent, 50 mL) was slowly added dropwise.Stir under reflux for 6 hours.Cooling and suction filtration, concentration, Purification to obtain a yellow powder of 4, 7-dibromobenzo[c][1, 2, 5]thiadiazole, That is, product 3 (9.10 g, 85percent).Compound 8 was obtained based on a procedure reported in the literature [51]. A total of 10.0 g (73.43 mmol) of 2, 1, 3-benzothiadiazole (7) and 150 mL of hydrobromic acid (48percent) were transferred to a 500 mL, two-neck, round-bottom flask. A reflux condenser was coupled to one input, and an additional funnel containing a solution of 35.2 g (220.3 mmol) of bromine in 100 mL of hydrobromic acid (48percent) was coupled to the other. Br4, 7-Dibromo-2, 1, 3-benzothiadiazole (2) As analogous to [1], 2, 1, 3-benzothiadiazole (1, 2 g, 14.69 mol) and 5 mL of HBr (48percent) wereplaced in a 100 mL two-necked round-bottomed flask. A solution of Br2 (1.5 mL, 29.4 mol)in HBr was added slowly through a dropping funnel at 0 °C. After completion of the addition, the mixture was stirred for 4 h at rt followed by reflux for 6 h. The formation of an orangesolid precipitate was observed. The mixture cooled to rt and a sufficient amount of saturatedsolution of NaHSO3 was added to remove excess bromine. The solid product was filtered offand thoroughly washed with DI water followed by diethyl ether. The product was purified byrecrystallization from ethanol. Yield 83percentThen put the 2, 1, 3-benzothiadiazole (10g) To a round flask equipped with a condenser injecting hydrobromic acid (200mL), heated to 110 °C makes it. After the temperature of 110 °C slowly inject bromine (20mL), and reacted for 6 hours. If fy species when the reaction via the reaction H2O and then there is produced a solid, which after filtering through the semi-H2O, filtered the solid and re-crystallized through the MC and methanol, the 4, 7-dibromobenzo [c] [1-white solid product, 2, 5] thiadiazole to afford the (compound a-1). (Yield: 81percent).The mixture of compound 1 (13.6g, 0.1mol) and HBr (40percent, 30mL) are heated to reflux under stirring. When BrBenzo [2, 1, 3] thiadiazole (8.16g, 60mmol), 40ml hydrobromic acid was added 500ml three-neck flask, was slowly added dropwise bromine (30.72g, 10ml, 192mmol) solution of hydrobromic acid is heated reflux for about 2.5h end.The reaction was cooled to room temperature, the reaction mixture was poured into ice water solution of sodium hydroxide, filtration to give a yellow solid (17.62g, yield 79.6percent).General Procedure I-DYA mixture of compound I-XVa (10.0 g, 73.4 mmol) in aq. HBr (48percent, 150 mL) was heated to reflux with stirring, while a solution containing Br2, 1, 3-Benzothiadiazole (1 g, 73.7 mmol) was dissolved in 47percent hydrobromic acid (10 mL) in a 50 mL three-necked round bottomed flask. A solution of bromine (1.14 mL, 22.02 mmol) in 47percent hydrobromic acid (10 mL) was added dropwise into the solution. The mixture was refluxed and stirred for 4 h. Precipitates were isolated by filtration washed with water. The product was dried invacuo. Yield 1.57 g (72.56percent). First, 20.0 g (146 mmol) of benzo [2, 1, 3] thiadiazole and 160 mL of hydrobromic acid (48percent aqueous solution) were placed in a 500 mL three-necked flask.The reaction solution was refluxed at 110 DEG C while dropwise adding 3 mL (446 mmol) of bromine.After completion of the dropwise addition, the mixture was further refluxed at 110 DEG C for 1 hour.After refluxing, The mixture was washed with water, The precipitate was collected by suction filtration. The obtained solid was recrystallized from methanol, and as a result, 31.0 g of a light brown powdery solid of 4, 7-dibromobenzo [2, 1, 3] thiadiazole was obtained (yield: 72percent).(2) Step 1:

Molecular Weight:293.97
XLogP3:3.2
Hydrogen Bond Acceptor Count:3
Exact Mass:293.82850
Monoisotopic Mass:291.83054
Topological Polar Surface Area:54
Heavy Atom Count:11
Complexity:142
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes