2-Amino-6-chlorobenzothiazole

off-white to light beige crystalline powder

General procedure: A solution of substituted aniline (2 mmol) in acetonitrile (15 ml) was added to a solution of KSCN (8 mmol) in acetonitrile (15 ml). Then, 0.06 g (30 mol percent BF3) of nano-BF3/SiO2 was added to the mixture, then was placed in a freezing mixture of ice and salt and mechanically stirred for 30 min. Then, bromine (4 mmol, 0.2 ml) in acetonitrile (3 ml) as solvent was added from a dropping funnel at such a rate that the temperature never rose beyond 0°C. After all the bromine was added at 60 min, the solution was stirred for 4 h at room temperature. The progress of the reaction was monitored by TLC. Then, the mixture was poured into water with stirring and the mixture was heated to 70°C on a steam bath and filtered hot to remove the catalyst and the recovered catalyst was washed with acetone and reused in the reaction. The filtrate was neutralized with 10 percent NaOH solution and the precipitate was collected on a filter, dried and recrystallized from ethanol (10 ml) to afford the corresponding products. All of the 2-aminobenzothiazole products were identified by physical and spectroscopic data as reported below, compared and contrasted with authentic samples.#10;Spectral data for selected products#10;6-Bromo-1, 3-benzothiazol-2-amine (2e) Yellow solid; Yield = 93 percent; m.p. =202–204°C; (m.p. = 203°C), FT-IR (KBr)/t(cm-1): 3315, 3012, 2835, 1580, 1476, 1261, 920, 742, 512. 1H NMR (400 MHz, CDCl3)/d ppm: 5.44 (s, 2H, NH2) 7.4–7.5 (d, 2H, Ar–H), 7.71 (s, 1H, Ar–H); 13C NMR/(100 MHz, DMSO-d6)/d ppm: 119, 120.9, 125.15, 126.07, 133.1, 152.15, 167.75.#10;6.38 g (0.05 mol) of p-chloroaniline was placed in a 100 ml round bottom flask, dissolved in 50 ml of glacial acetic acid, and then 5.40 g (0.055 mol) of potassium thiocyanate was added.Stir at 15-20 ° C for 2 h until the solid disappears completelyThen, 1 ml of bromine acetic acid solution was added dropwise at 15-20 ° C.When the temperature is controlled, the temperature is not more than 20 ° C, and the addition is completed in about 1 h.Normal temperature reaction for 2-4 hours, TLC tracking reaction, After the raw material amine is completely reacted, dissolved in hot water, filtered after a little cold.A white filter droplet is added to add 5 ml of concentrated ammonia water to adjust the pH to neutral or weakly alkaline. During this period, a large amount of white solid precipitates, and after standing, it is filtered, the filter cake is washed with water, and dried under vacuum.7.86 g of a white to slightly yellow powdery solid product are obtained.Melting point: 199-200 ° C, yield 85percent.General procedure: A mixture of 0.1 mol of 4-substituted aniline and 0.1 mol of Potassium thiocyanate (KCNS) in 100 ml glacial acetic acid (AcOH) was cooled in an ice bath and stirred for 10-20 min, and then 0.1 mol bromine in glacial acetic acid was added dropwise at such a rate to keep the temperature below 10 °C throughout the addition. The reaction mixture was stirred at room temperature for 2-4 h, the hydrobromide (HBr) salt thus separated out was filtered, washed with acetic acid, dried, dissolved in hot water and basified to pH 11.0 with ammonia solution (NHGeneral procedure: An appropriately p-substituted aniline (0.1 mol) and potassiumthiocyanate (KCNS, 9.718 g, 0.1 mol) were dissolvedin 100 mL of glacial acetic acid (AcOH), cooled inice–salt mixture and stirred mechanically, while a solutionof bromine (15.980 g, 0.1 mol) in AcOH (20 mL)was slowly added drop by drop (Palkar et al. 2010).External cooling was applied throughout the process to keepthe temperature below 10 °C and the stirring was continuedfor 30 min. After all of the bromine had been added, thesolution was stirred for 2 h below room temperature and atroom temperature for 10 h. It was then allowed to standovernight during which the precipitate of imino-benzo[d]thiazole hydrobromide salt thus separated out was filtered, washed with acetic acid, dried, dissolved in hot water andbasified to pH 11.0 with ammonia solution (NH4OH) andthe resulting precipitate was filtered, washed with water anddried to get the desired products 2-amino-6-substitutedbenzo[d]thiazole (1a–d). The progress of the reaction wasmonitored by TLC using acetone (20percent) in toluene solvent.To a solution of 4-chloroaniline (3.0g, 23.52mmol, l .Oeq) in acetic acid (90mL) were added Potassium thiocyanate (2.28g, 23.52mmol, l .Oeq). The reaction mixture was cooled at 10°C and bromine solution (3.76g, 23.52mmol, l .Oeq) was added dropwise. Reaction mixture was further stirred at room temperature for 3h. After completion of reaction, reaction mixture was filtered and washed with acetic acid. Filtered solid was heated in water and then neutralized with aqueous ammonia to obtain solid which was filtered and dried well to obtain pure 118.1. (2.5g, 57.58percent). MS(ES): m/z 185.64 [M+H]General procedure: A solution of bromine (0.26mL, 10.0mmol) in acetic acid (5.0mL)was added over about 30 min to a mixture of aromatic amine(10.0 mmol) and potassium thiocyanate (1.07 g, 11.0 mmol) in aceticacid (20 mL), the temperature being kept between 25 and 35 °C. The slurry was then stirred for 20 h at room temperature. The precipitate was filtered, washed with a little acetic acid, slurried in water, made neutral with aqueous ammonia, and filtered again. The residue was boiled for 20 min with excess of hydrochloric acid (15percent v:v) and the hot mixture was filtered from impurities. The filtrate, cooled to 10 °C, was made alkaline with aqueous ammonia and the precipitate was filtered, washed, and dried. The crude product was recrystallized from ethanol–water to afford I–IV, respectively.The chlorothiourea (8.50 g, 45.70 mmol) was added to a 250 mL eggplant-shaped flask and dissolved in 50.00 mL of chloroform.Reflow under a 50 ° C oil bath for 20 minutes, After the reaction solution is placed in an ice water bath, Slowly add bromine (2.58 mL, 50.27 mmol), After stirring for 5 minutes, transfer back to the oil bath.Raise the temperature to 70 ° C and continue to reflux.The progress of the reaction was monitored by thin layer chromatography and the reaction was complete after 9 h.After cooling to room temperature, a solid precipitated and was filtered under reduced pressure.Slowly add ammonia water to the filtrate.Adjust the pH to neutral and a white precipitate will form.After stirring for 5 minutes, the mixture was filtered under reduced pressure, and the solid was washed twice, Vacuum drying to constant weight, Obtained white solid 3.62g, The yield was 43.10percent.General procedure: A mixture of aniline (0.05mol) and NH

Used in the synthesis of disperse dyes

Molecular Weight:184.65
XLogP3:2.9
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Exact Mass:183.9861970
Monoisotopic Mass:183.9861970
Topological Polar Surface Area:67.2
Heavy Atom Count:11
Complexity:155
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes