6-CHLORO-8-HYDROXYQUINOLINE

Step 4: In a 500 ml 3-necked flask equipped with a mechanical stirrer, a reflux condenser, were added in order ferrous sulfate (2.0 g), 4-amino-3-chlorophenol hydrochloride (6.4 g, commercially available), nitrobenzene (2.9 mL) and a solution of boric acid (3.0 g) in glycerol (16 g). Example 10 In a 500 ml 3-necked flask equipped with a mechanical stirrer and a reflux condenser, added in order were 2.0 g ferrous sulfate, 6.4 g 4-amino, 3-chloro-phenol (generated from 9.0 g of the corresponding commercially available HC1 salt), 2.9 m nitrobenzene and a cold solution of 3.0 g boric acid in 16 g of glycerol. Then, 9 ml of concentrated sulfuric acid was added drop by drop with cooling. The ice bath was removed and replaced by an oil bath and the mixture was heated cautiously to 120°C for 2 hrs, then at 150°C and kept stirring under this temperature for 20 hrs. The mixture was then cooled and poured on crushed ice and the resulting solution was neutralized to with K2C03 (saturated solution in water) till exactly pH 5. The product separated as a light brown solid which was filtered off, washed with water and hexane and dried in a vacuum oven (35°C) overnight. The product was purified by dissolving it in a minimal amount OF THF, and the solution poured in 20X volume of hexane, giving 7 g (77 percent) of the desired product.Step 4: 8-Chloro-6-hydroxyquinoline In a 500 mL 3-necked flask equipped with a mechanical stirrer, a reflux condenser, were added in order ferrous sulfate (2.0 g), 4-amino-3-chlorophenol hydrochloride (6.4 g, commercially available), nitrobenzene (2.9 mL) and a solution of boric acid (3.0 g) in glycerol (16 g). Then concentrated sulfuric acid (9 mL) was added drop by drop with cooling. The ice bath was removed and replaced by an oil bath and the mixture was heated cautiously to 120Step 4: 8-Chloro-6-hydroxyquinoline In a 500 mL 3-necked flask equipped with a mechanical stirrer, a reflux condenser, were added in order ferrous sulfate (2.0 g), 4-amino-3-chlorophenol hydrochloride (6.4 g, commercially available), nitrobenzene (2.9 mL) and a solution of boric acid (3.0 g) in glycerol (16 g). Then concentrated sulfuric acid (9 mL) was added drop by drop with cooling. The ice bath was removed and replaced by an oil bath and the mixture was heated cautiously to 120° C. for 2 hours, then at 150° C. and kept stirring under this temperature for 20 hours. After cooling, the reaction was poured on crushed ice and the resulting solution was neutralized with K2CO3. The product separated as a light brown solid that was filtered off, washed with water and hexanes and dried in a vacuum oven (35° C.) overnight giving 7 g (77percent) of the desired product. MS (ES) m/z (relative intensity): 180 (M++-H, 100).In a 500 ml 3-necked flask equipped with a mechanical stirrer, a reflux condenser, were added in order ferrous sulfate (2.0 g), 4-amino-3-chlorophenol hydrochloride (6.4 g, commercially available), nitrobenzene (2.9 mL) and a solution of boric acid (3.0 g) in glycerol (16 g). Then concentrated sulfuric acid (9 mL) was added drop by drop with cooling. The ice bath was removed and replaced by an oil bath and the mixture was heated cautiously to 120° C. for 2 hours, then at 150° C. and kept stirring under this temperature for 20 hours. After cooling, the reaction was poured on crushed ice and the resulting solution was neutralized with K2CO3. The product separated as a light brown solid that was filtered off, washed with water and hexanes and dried in a vacuum oven (35° C.) overnight giving 7 g (77percent) of the desired product. MS (ES) m/z (relative intensity): 180 (M++-H, 100).Example 10 Intermediate 10-In a 500 ml 3-necked flask equipped with a mechanical stirrer and a reflux condenser, added in order were 2.0 g ferrous sulfate, 6.4 g 4-amino, 3-chloro-phenol (generated from 9.0 g of the corresponding commercially available HC1 salt), 2.9 m nitrobenzene and a cold solution of 3.0 g boric acid in 16 g of glycerol. Then, 9 ml of concentrated sulfuric acid was added drop by drop with cooling. The ice bath was removed and replaced by an oil bath and the mixture was heated cautiously to 120C for 2 hrs, then at 150C and kept stirring under this temperature for 20 hrs. The mixture was then cooled and poured on crushed ice and the resulting solution was neutralized to with K2C03 (saturated solution in water) till exactly pH 5. The product separated as a light brown solid which was filtered off, washed with water and hexane and dried in a vacuum oven (35C) overnight. The product was purified by dissolving it in a minimal amount OF THF, and the solution poured in 20X volume of hexane, giving 7 g (77 %) of the desired product.Step 5: 8-Chloro-6-methoxyquinoline To a solution of 3.3 g of Intermediate 11-8-chloro-6-methoxy-quinoline To a solution of 15 g of To a solution of 15 g of To a solution of 3.3 g of Step 5: 8-Chloro-6-methoxyquinolineTo a solution of 3.3 g of Step 4: 8-Chloro-6-hydroxyquinoline In a 500 mL 3-necked flask equipped with a mechanical stirrer, a reflux condenser, were added in order ferrous sulfate (2.0 g), 4-amino-3-chlorophenol hydrochloride (6.4 g, commercially available), nitrobenzene (2.9 mL) and a solution of boric acid (3.0 g) in glycerol (16 g). Then concentrated sulfuric acid (9 mL) was added drop by drop with cooling. The ice bath was removed and replaced by an oil bath and the mixture was heated cautiously to 1200C for 2 hours, then at 1500C and kept stirring under this temperature for 20 hours. After cooling, the reaction was poured on crushed ice and the resulting solution was neutralized with K2CO3. The product separated as a light brown solid that was filtered off, washed with water and hexanes and dried in a vacuum oven (35°C) overnight giving 7 g (77 percent) of the desired product. MS (ES) m/z (relative intensity): 180 (M++-H, 100).