7-Nitro-1H-indole-2-carboxylic acid

brown powder

Preparation of Compound 3 (7-Nitro-1H-indole-2-carboxylic acid); The compound 2 (13.79 g, 58.88 mmol) was added into a flask (250 mL), ethanol (72.7 mL, 40 °C) was added into the flask, and the solution was stirred for 5 min. Then, a solution of KOH formulated with KOH (7.25 g, 189.59 mmol) and water (17.40 g) was added into the solution, and the solution was stirred for 5 min to obtain a clear solution with red oxide color. When the solution was cooled down, a yellow-brown solid was started to precipitate. After the solution was stirred for 3 hr, hot water (295 mL) was added to dissolve the yellow-brown solids to obtain a clear solution with red oxide color. Then, 3 N of HCl was added into the solution, and a breast-yellow solid was precipitated. The solution was kept stirring unitl the precipitation of the yellow solids was stopped, and filtered. The yellow solids were washed by water, dried, and re-crystallized in ethanol to obtain a fiber-shaped light-yellow solid, compound 3 (11.57 g, 96percent). mp 269-271 °C (lit. 269-272 °C); 7-Nitro-lH-indole-2-carboxylic acid methyl ester (13 g, 59 mmol) prepared inPreparation 17 was dissolved in a solvent mixture of tetrahydrofuran and water (1:1, 300 mL), to which was added IN aqueous sodium hydroxide solution (180 mL, 177 mmol). The mixture was stirred for 3 h at room temperature, and excess 6N hydrochloric acid solution was added thereto. The reaction mixture was extracted with ethyl acetate. The extract was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and filtered. The solvent was removed by distillation under reduced pressure, and the residue was dried to give the title compound (12 g, Yield 99percent).Preparation 19: Synthesis of 2, 2-dimethyl-propionic acid (R)-2-(7-amino-1 H-indol-2-yl)-4, 5-dihydro-thiazol-4-ylmethyl ester; (Step 1); Methyl 7-nitroindole-2-carboxylate (13g, 59 mmol) prepared in Preparation 8 was dissolved in a solvent mixture of tetrahydrofuran and water (1 :1, 300ml), and IN aqueous sodium hydroxide solution (180ml, 177 mmol) was added thereto. The mixture was stirred for 3 h at room temperature, excess 6N hydrochloric acid solution was added, and the mixture was extracted with ethyl acetate. The extract was washed with saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and filtered. The filtrate was distilled under reduced pressure to give 7-nitro-lH-indole-2- carboxylic acid (12g, Yield 99percent).7-Nitro-1H-indole-2-carboxylic acid methyl ester (13 g, 59 mmol) prepared in Preparation 17 was dissolved in a solvent mixture of tetrahydrofuran and water (1:1, 300 mL), to which was added 1N aqueous sodium hydroxide solution (180 mL, 177 mmol). The mixture was stirred for 3 h at room temperature, and excess 6N hydrochloric acid solution was added thereto. The reaction mixture was extracted with ethyl acetate. The extract was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and filtered. The solvent was removed by distillation under reduced pressure, and the residue was dried to give the title compound (12 g, Yield 99percent).Methyl 7-nitroindole-2-carboxylate (13 g, 59 mmol) prepared in Preparation 8 was dissolved in a solvent mixture of tetrahydrofuran and water (1:1, 300 ml), and 1N aqueous sodium hydroxide solution (180 ml, 177 mmol) was added thereto. The mixture was stirred for 3 h at room temperature, excess 6N hydrochloric acid solution was added, and the mixture was extracted with ethyl acetate. The extract was washed with saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and filtered. The filtrate was distilled under reduced pressure to give 7-nitro-1H-indole-2-carboxylic acid (12 g, Yield 99percent).

Molecular Weight:206.15
XLogP3:1.7
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:1
Exact Mass:206.03275668
Monoisotopic Mass:206.03275668
Topological Polar Surface Area:98.9
Heavy Atom Count:15
Complexity:288
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes