Hydrochloric Acid → 1,4-Dihydro-1-phenyl-indeno [1,2-c]pyrazole-3-carboxylic acid

HRID 21542Notes

Reaction equation

HRID 21542 reaction equation
[C:1]1([N:7]2[C:11]3[C:12]4[C:17]([CH2:18][C:10]=3[C:9]([C:19]([O:21]CC)=[O:20])=[N:8]2)=[CH:16][CH:15]=[CH:14][CH:13]=4)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[OH-].[K+].Cl>C(O)C>[C:1]1([N:7]2[C:11]3[C:12]4[C:17]([CH2:18][C:10]=3[C:9]([C:19]([OH:21])=[O:20])=[N:8]2)=[CH:16][CH:15]=[CH:14][CH:13]=4)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 14797Potassium HydroxideHCID 12291080Ethyl 1-phenyl-1,4-dihydroindeno[1,2-c]pyrazole-3-carboxylate

Product 1

HCID 122910921,4-Dihydro-1-phenyl-indeno [1,2-c]pyrazole-3-carboxylic acidYield 91.8%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

1,4-Dihydro-1-phenyl-indeno[1,2-c]pyrazole-3-carboxylic acid, ethyl ester (3 g), prepared according to Example 1, is heated with 1% KOH solution in ethanol (100 ml) at reflux temperature for 20 minutes. The reaction mixture is diluted with ice water and acidified to pH 3 with 37% HCl. The precipitate is filtered, washed with water until neutral and dried in vacuo to give 1,4-dihydro-1-phenyl-indeno [1,2-c]pyrazole-3-carboxylic acid (2.5 g) which is reacted with thionyl chloride (1.2 ml) in dioxane (60 ml) at the reflux temperature for 2 hours. After cooling the reaction mixture is evaporated to dryness in vacuo to give 1,4-dihydro-1-phenyl-indeno[1,2-c]pyrazole-3-carbonyl chloride as crystalline residue. The crude product is dissolved in anhydrous dioxane (30 ml) and reacted for 2 hours under stirring at room temperature with the carbanion obtained by treatment of 2-cyano-acetanilide (1.6 g) with 50% sodium hydride (0.5 g) in anhydrous dimethylformamide/dioxane (1:1 (10 ml) at room temperature. The reaction mixture is then diluted with ice water and acidified to pH 2 with HCl. The precipitate is filtered and washed with water until neutral. Crystallization from dichloromethane/methanol gives 1.6 g of 2-cyano-3-(1,4-dihydro-1-phenyl-indeno [1,2-c]pyrazol-3-yl)-3-oxo-N-phenyl-propanamide, m.p. 273°-277° C.

Workup

  1. temperatureat reflux temperature for 20 minutes
  2. filtrationThe precipitate is filtered
  3. washwashed with water until neutral and
  4. customdried in vacuo

Sources & evidence

ORD record
ord-a3ca06ddc8ba4ed5a32fb7306eb6da1b
Source dataset
uspto-grants-1995_06
Patent number
US05424308

Reaction notes

Loading…