1H-Indole-2-carboxylic acid, 6-fluoro-, ethyl ester

(3-2) Ethyl 3-(4-fluoro-2-nitrophenyl)-2-oxopropanoate (5.51 g, 21.6 mmol) obtained in Reference Example (3-1) was dissolved in a mixed solvent of ethanol-acetic acid (1:1, 84 ml), and iron powder (10.9 g, 144 mmol) was added thereto, followed by heating under reflux for 3.5 hours. After the reaction mixture was diluted with tetrahydrofuran, the insolubles were filtered through Celite, and the residue obtained by concentrating the filtrate under reduced pressure was purified by silica gel column chromatography (elution solvent: methylene chloride/acetone=15/1) to obtain ethyl 6-fluoro-1H-indole-2-carboxylate (3.62 g, yield: 81percent). 6-Fluoro-1H-indole-2-carboxylic acid 12a (2.00g, 11.16mmol) was dissolved in 60mL of absolute ethanol, 10mL of 98percent concentrated sulfuric acid was added, the reaction liquid was heated to 105°C and was reacted for 2 hours. To a 500 mL flask was added toluene (200 mL)Was added thereto, and the compound(E) -ethyl-2- (2- (3-fluorophenyl) hydrazano) propanoate (22.5 g, 100.34 mmol).Then, polyphosphoric acid (120 g) was added thereto, The reflux reaction was allowed to proceed for 6 hours.After the reaction was completed, the reaction solution was cooled to 50 DEG C, and only the toluene layer was separated.The separated toluene layer was concentrated under reduced pressure.Then toluene (50 mL) was added to the solid formed, and the mixture was refluxed for 1 hour and then cooled to room temperature.The re-crystallized solid was then filtered to give ethyl-6-fluoro-lH-indole-2-carboxylate (7.2 g, 34.7 mmol, 34percent).

Molecular Weight:207.20
XLogP3:3.3
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:3
Exact Mass:207.06955672
Monoisotopic Mass:207.06955672
Topological Polar Surface Area:42.1
Heavy Atom Count:15
Complexity:247
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes