1H-Indazole-3-carboxylic acid, ethyl ester

Yellow solid

Ethyl 1-methyl-1H-indazole-3-carboxylate and ethyl 2-methyl-2H-indazole-3-carboxylate [0521] 1a) Ethyl 1H-Indazole-3-carboxylate [0522] In a hot solution of 4.1 g (102.5 mmol) of sodium hydroxide in 65 mL of water dissolve 14.7 g (100 mmol) of isatin. Cool this solution to 0 C. and add a solution at 0 C. of 6.9 g (100 mmol) of sodium nitrite in 25 mL of water. Add this reaction medium rapidly to a solution of 19.1 g (194.7 mmol) of concentrated sulfuric acid in 200 mL of water cooled to 0 C. by ice (the temperature of the reaction medium must not exceed 4 C. during the addition). At the end of the addition, stir for 15 minutes. Add to the reaction medium a solution of 54 g (239.3 mmol) of tin chloride dihydrate in 85 mL of concentrated hydrochloric acid cooled to 0 C. Leave to stir for 1 hour. Filter off the precipitate formed. [0523] Heat to reflux for 2 hours a solution of 12 g of the recovered solid in 200 mL of ethanol in the presence of 6 g concentrated sulfuric acid. Evaporate the solvent and take up the oil obtained in dichloromethane. Wash the organic phase with a 4% solution of sodium bicarbonate then by a saturated sodium chloride solution. Dry the organic phase over anhydrous sodium sulfate, filter and evaporate to dryness. Purify the evaporation residue by successive passages through a silica gel column (dichloromethane/absolute ethanol 98/2; dichloromethane/diethyl ether: 80/20) (Int. 125). [0524] Yield: 32% [0525] Melting point: 135 C. (dichloromethane/absolute ethanol)

Molecular Weight:190.20
XLogP3:2.1
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:3
Exact Mass:190.074227566
Monoisotopic Mass:190.074227566
Topological Polar Surface Area:55
Heavy Atom Count:14
Complexity:220
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes