5-Benzothiazolamine

A mixture OF 5-NITRO-1, 3-benzothiazole (Description 5, 1. 9 g, 11 mmol) and tin (II) chloride dihydrate (8.6 g, 38 mmol) in 2-propanol (30 ml) was heated to reflux for 24 h. The cooled reaction mixture was poured onto an ice/water mixture (85 ml) and adjusted to pH7 with sodium hydroxide (s). The mixture was extracted with ethyl acetate (3 X 50 ml) and the combined organic layers were dried over sodium sulfate, filtered and evaporated. The residue was purified by column chromatography on silica (eluant 1 : 1 hexane: ethyl acetate) to give 1, 3-benzothiazol-5-amine (820 mg, 52 percent). LHNMR (CDCL3) 6 6.85 (1H, dd, J2. 3, 8. 6), 7.40 (1H, d, J2. 1), 7.66 (1H, d, J 8.4), 8.90 (1H, s).A mixture of 5-nitrobenzo[d]thiazole (3.0 g, 16.7 mmol) and SnCl2*2H2O (19 g, 84.2 mmol) in EtOAc (150 mL) was stirred at reflux overnight. The reaction mixture was basified with Et3N until pH 8 and the precipitate was filtered. The filtrate was concentrated in vacuo and the residue was purified by column chromatography on silica gel (EtOAc/DCM = 2:1) to afford the title compound as a yellow solids (2.1 g). 1H NMR (400 MHz, CDCl3): ö 8.92 (s, 1H), 7.69 (d, 1H), 7.41 (d, 1H), 6.86 (dd, 1H), 3.82 (brs, 2H); LCMS: 151 (M+H).A stirred solution of 3 g of A solution of Br2 (2.3 g, 14.4 mmol) in CHC13 (10 mL) was added dropwise to a solution of Step 9.1: 5-Bromo-benzothiazole 4-Amino-benztothiazole (3.0 g, 0.02 mol) in 18 mL of a 35percent hydrobromic acid solution is diazotized at 0° C. by slow addition of a solution of 1.19 g (0, 0195 mmol) sodium nitrite in 11 mL of water. After stirring for 1 h at 0° C. the brown solution is added dropwise to a dark solution of 3.3 g (0.023 mol) CuBr in 45 mL of a 35percent hydrobromic acid solution at 0° C. The reaction mixture is stirred 0.5 h at 0° C., 2 h at RT and then 2 h at 90° C. The mixture is cooled to RT and pored into 20 g of crushed ice. Concentrated ammonia is added to the mixture to make it alkaline and then it is extracted with ethyl acetate. The organic layers are combined, washed with brine, dried with sodium sulfate and evaporated. The residue is purified by flash chromatography on silica gel using dichloromethane/petrol ether as eluent. The title compound is obtained as a solid: m.p. 104-106° C., HPLC tR=3.44 min; Rf (dichloromethane/petrol ether)=0.30.4-Amino-benztothiazole (3.0 g, 0.02 mol) in 18 mL of a 35 percent hydrobromic acid solution is diazotized at 0 0C by slow addition of a solution of 1.19 g (0, 0195 mmol) sodium nitrite in 11 mL of water. After stirring for 1 h at 0 0C the brown solution is added dropwise to a dark solution of 3.3 g (0.023 mol) CuBr in 45 mL of a 35 percent hydrobromic acid solution at 0 0C. The reaction mixture is stirred 0.5 h at 0 0C, 2 h at RT and then 2h at 90 0C. The mixture is cooled to RT and pored into 20 g of crushed ice. Concentrated ammonia is added to the mixture to make it alkaline and then it is extracted with ethyl acetate. The organic layers are combined, washed with brine, dried with sodium sulfate and evaporated. The residue is purified by flash chromatography on silica gel using dichloromethane/petrol ether as eluent. The title compound is obtained as a solid: m.p. 104-106 0C, HPLC tR = 3.44 min; Rf (dochloromethane/petrol ether) = 0.30.

Molecular Weight:150.20
XLogP3:1.3
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Exact Mass:150.02516937
Monoisotopic Mass:150.02516937
Topological Polar Surface Area:67.2
Heavy Atom Count:10
Complexity:129
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes