6-Benzothiazolecarboxylic acid, 2-amino-, ethyl ester

yellow crystal

Ethyl 4-aminobenzoate (4.9 g, 30.0 mmol) and potassium thiocyanate (11.6 g, 120.0 mmol) are dissolved in acetic acid(180 mL), followed by dripping acetic acid solution(20 mL) with bromine (1.5 mL, 30.0 mmol) at 19 °C in 20 min, then the temperature is increased to room temperature and the mixture continues to react overnight. To methanol (800 mL) were added ethyl 4-aminobenzoate 4 (49.5 g, 0.3 mol), KSCN (291 g, 3 mol) and CuSOEthyl 4-aminobenzoate (1 eq.) and KSCN (4 eq.) were dissolved in acetic acid (4 mL/mmol) and stirred at rt for 20mins. Then the reaction mixture was cooled to 10 °C and bromine (2 eq.) dissolved in small amount of acetic acid was added dropwise. Afterwards the reaction mixture was left to warm up to rt and stirred overnight. After the reaction was completed (monitored by TLC), reaction mixture was added dropwise into the sat. aq. NHCompound 28 (2.0 g, 12 mmol) was dissolved in 16 mL of acetic acid, and to the resulting solution was suspended potassium thiocyanate (4.67 g, 48 mmol). A solution of 0.61 mL of bromine in 8 ml of acetic acid was slowly added, and the reaction mixture was stirred at room temperature overnight. Water was added and the mixture was made neutral by addition of aqueous ammonium hydroxide. The precipitation was collected by filtration and then washed with water and subsequently dried to afford compound 29 (1.80 g, 67percent) as light yellow solid. The compound was used, without structure determination, directly for the next step.Step: 1 Preparation of ethyl 2-amino-l, 3-benzothiazole-6-carboxylate.A mixture of ethyl-4-amino benzoate (1.65g, lOmmol), KCNS (9.72g, 100 mmol) and CuSO[1067] Step 1: ethyl 2-aminobenzo[d]thiazol-6-carboxylate[1068] To a solution of ethyl 4-aminobenzoate (16.5 g, 100.0 mmol) and potassium thiocyanate (10.7 g, 110.0 mmol) in acetic acid (150 mL) was added dropwise a solution of bromine (5.1 mL, 100.0 mmol) in acetic acid (50 mL) at below 10 ℃. The reaction mixture was stirred at room temperature overnight. The resulting solid was filtered and then dissolved in warm water (50 ℃). The aqueous layer was washed with chloroform and then basified to pH 11 with solid sodium carbonate. The resulting solid was filtered, washed with water, and then dried under reduced pressure to give 10.2 g of the titled compound as a white solid (Yield: 46percent).Step 1: (195-1) (195-1)

Molecular Weight:222.27
XLogP3:2.3
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:3
Exact Mass:222.04629874
Monoisotopic Mass:222.04629874
Topological Polar Surface Area:93.4
Heavy Atom Count:15
Complexity:250
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes