2-amino-5-chlorophenol

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Amino-5-chlorophenol (5.7 g, 40 mmol) is dissolved in DMSO/water/H2SO4 (200/60/140 mL) and cooled to 0° C. To this solution is added sodium nitrite (4.1 g, 60 mmol) in water (20 mL) and the mixture is stirred for 1 h at 0° C. To the mixture is added potassium iodide (19.9 g, 120 mmol) in water (20 mL) and the mixture is stirred at room temperature for 1 h. Another batch of potassium iodide (19.9 g, 120 mmol) in water (20 mL) is added and the mixture is stirred at room temperature for 1 h. The mixture is diluted with ethyl acetate, washed with water, saturated aqueous sodium sulfate, and brine. The organic portion is dried over MgSO4, filtered, and concentrated under reduced pressure. The resulting residue is purified by flash chromatography (Biotage™ Si65M, 20% ethyl acetate/hexane) to yield 8.09 g (79%) of the title compound as a pink solid. GCMS m/e 254 [M]−. the mixture is stirred at room temperature for 1 h the mixture is stirred at room temperature for 1 h washed with water, saturated aqueous sodium sulfate, and brine The organic portion is dried over MgSO4 filtered concentrated under reduced pressure The resulting residue is purified by flash chromatography (Biotage™ Si65M, 20% ethyl acetate/hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 500 mg 2-amino-5-chlorophenol and 800 mg mono-tert-butyl piperidine-1,4-dicarboxylate are heated to 200° C. in 4 ml polyphosphoric acid for 4 h. After cooling the reaction mixture is combined with ice water and stirred for 30 min. The precipitate is suction filtered, washed with water and dried. 850 mg product are obtained as the phosphate. After cooling the reaction mixture filtered washed with water dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 143.6 g (1 mol) of 5-chloro-2-aminophenol, 164 g (1.02 mols) of sodium methyl xanthate (90% strength) and 500 ml of water were introduced into a 1 liter flask equipped with stirrer, thermometer and reflux condenser. The reaction mixture (the chloro-aminophenol remained undissolved) was warmed with stirring, from 80° C. on vigorous hydrogen sulfide development occured. After about 1 hour the reaction was essentially complete, but stirring with reflux was continued for a further 2 hours. The resulting black reaction solution was cooled, and acidified with 70 g of 85% phosphoric acid. The precipitate was suction-filtered, washed thoroughly with water and subsequently dried at about 80° C. under reduced pressure. After drying, 180.5 g (97.3% of th.) of 6-chloro-2-mercaptobenzoxazole having a melting point of 221°-223° C. were obtained. (The literature gives a m.p. of 224°-225° C. after recrystallization from water/isopropanol, J. org. Chem. 19, 758). According to gas chromatography, the purity degree of the product was higher than 98%. equipped with stirrer thermometer and reflux condenser with reflux was continued for a further 2 hours The resulting black reaction solution was cooled The precipitate was suction-filtered washed thoroughly with water subsequently dried at about 80° C. under reduced pressure After drying

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 2-amino-5-chlorophenol (1.01 g, 7.0 mmol) in methanol (10 mL) was added acetic anhydride (1.08 g, 10.55 mmol) and the reaction mixture was stirred at room temperature for 30 min. The volatiles were removed in vacuo and the residue was purified by silica gel flash chromatography (hexane:ethyl acetate 5:2) to give the subtitled compound (1.19 g). The volatiles were removed in vacuo the residue was purified by silica gel flash chromatography (hexane:ethyl acetate 5:2)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 2-amino-5-chlorophenol (1.01 g, 7.0 mmol) in methanol (10 mL) was added acetic anhydride (1.08 g, 10.55 mmol) and the reaction mixture was stirred at room temperature for 30 min. The volatiles were removed in vacuo and the residue was purified by silica gel flash chromatography (hexane:ethyl acetate 5:2) to give the subtitled compound (1.19 g). The volatiles were removed in vacuo the residue was purified by silica gel flash chromatography (hexane:ethyl acetate 5:2)