Chemical Properties
light beige to yellow powder
Uses
Indole-5-carboxylic acid is the suitable reagent used to study the intramolecular excited state proton transfer in indole-2-carboxylic acid and indole-5-carboxylic acid in various solvents in acidic, basic, and neutral media by steady state and time resolved fluorescence spectroscopy. It may be used in the electrochemical synthesis of poly(indole-5-carboxylic acid) (PICA) films.
Uses
Reactant for preparation of tryptophan dioxygenase inhibitors pyridyl-ethenyl-indoles, as potential anticancer immunomodulators 1 Reactant for preparation of indolyl-quinolines via metal- and solvent-free autoxidative coupling reaction 2 Reactant for preparation of anthranilic acids using bromamine-B oxidant and palladium chloride catalyst 3 Reactant for synthesis of indirubin derivatives 4 Reactant for preparation of amide conjugates with ketoprofen, as inhibitors of Gli1-mediated transcription in Hedgehog pathway 5 Reactant for preparation of piperazine-bisamide analogs as human growth hormone secretagogue receptor antagonists for treatment of obesity.
Uses
Indole-5-carboxylic acid is the suitable reagent used to study the intermolecular excited state proton transfer in indole-2-carboxylic acid and indole-5-carboxylic acid in various solvents in acidic, basic, and neutral media by steady state and time resolved fluorescence spectroscopy. It may be used in the electrochemical synthesis of poly(indole-5-carboxylic acid) (PICA) films. Also used as reactant for preparation of tryptophan dioxygenase inhibitors pyridyl-ethenyl-indoles, as potential anticancer immunomodulators, synthesis of indirubin derivatives and amide conjugates with ketoprofen, as inhibitors of Gli1-mediated transcription in Hedgehog pathway.
Definition
ChEBI: Indole-5-carboxylic acid is an indolecarboxylic acid in which the carboxy group is the only substituent and is located at position 5. It has a role as a plant metabolite.
General Description
Indole-5-carboxylic acid is an indole derivative. On electropolymerization, it affords electroactive polymer film of poly(indole-5-carboxylic-acid). Different concentrations of indole-5-carboxylic acid in sulfuric acid solution has been investigated for the preventive action against mild steel corrosion. On electropolymerization it affords a trimeric product. Characterization studies of the trimeric product by
1H NMR and various one- and two-dimensional NMR techniques have been reported.
Synthesis
To a solution of 5-bromo-1H-indole (0.86 g, 4.4 mmol, 1.0 eq.) in anhydrous THF (20 mL) was slowly added 2 M isopropylmagnesium chloride (i-PrMgCl) in a solution of THF (2.2 mL, 4.4 mmol, 1.0 eq.) at 0 °C, keeping the reaction temperature at 0 °C. After addition, the clarified solution was continued to be stirred at the same temperature for 5 minutes. Subsequently, a hexane solution (3.5 mL, 8.8 mmol, 2.0 eq.) of 2.5 M n-butyllithium (n-BuLi) was added dropwise over 5 min, controlling the reaction temperature to not exceed 20 °C. After addition, the reaction mixture was stirred at 0 °C for 30 min. Then, dry carbon dioxide gas (0.2 g, 4.4 mmol, 1.0 eq.) was passed into the reaction system and the reaction mixture was slowly warmed up to 20°C over 0.5 hr. Upon completion of the reaction, the reaction was quenched with deionized water (6 mL) and stirring was continued for 10 min. The organic and aqueous phases were separated and the aqueous phase was extracted once with ethyl acetate (10 mL). The organic phases were combined, and after the suspension was returned to room temperature, it was filtered through a silica gel pad (0.51 cm, eluting with 10 mL of ethyl acetate). The filtrate was concentrated and the residue was purified by rapid column chromatography on silica gel (eluent: petroleum ether/ethyl acetate = 3:1) to afford indole-5-carboxylic acid (3das) as an off-white solid (0.46 g, yield: 65%), melting point: 210 °C. 1H NMR (600 MHz, DMSO) δ 12.39 (s, 1H), 11.46 (s, 1H), 8.25 (s, 1H), 7.72 (dd, J = 8.5, 1.5 Hz, 1H), 7.45 (dd, J = 8.4, 5.7 Hz, 2H), 6.57 (s, 1H). 13C NMR (151 MHz, DMSO) δ 168.90, 138.80, 127.64, 127.35, 123.28, 122.67, 121.87, 111.57, 102.93.
References
[1] Molecules, 2017, vol. 22, # 11,
[2] Journal of the American Chemical Society, 2017, vol. 139, # 28, p. 9467 - 9470
