Hydrochloric Acid → HCID 21268463, compound

HRID 1194709Notes

Reaction equation

HRID 1194709 reaction equation
[C:1]1([N:7]2[C:11]3[C:12]4[CH:19]=[CH:18][CH:17]=[CH:16][C:13]=4[O:14][CH2:15][C:10]=3[C:9]([C:20]([O:22]CC)=[O:21])=[N:8]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[OH-].[K+].Cl>O1CCOCC1.C(O)C>[C:1]1([N:7]2[C:11]3[C:12]4[CH:19]=[CH:18][CH:17]=[CH:16][C:13]=4[O:14][CH2:15][C:10]=3[C:9]([C:20]([OH:22])=[O:21])=[N:8]2)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 14797Potassium HydroxideHCID 86742837HCID 86742837, compound

Product 1

HCID 21268463HCID 21268463, compoundYield 91.3%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 312751,4-DioxaneSolvent

Procedure

1,4-Dihydro-1-phenyl-[1]-benzopyrano[4,3-c]pyrazole-3-carboxylic acid, ethyl ester (4.2 g) suspended in dioxane (60 ml) is heated with 1% KOH solution in ethanol (124 ml) at reflux temperature for 30 minutes. The reaction mixture is diluted with ice water and acidified to pH 3 with 37% HCl. The precipitate is filtered, washed with water and dried in vacuo at 50° C. to give 1,4-dihydro-1-phenyl-[1]-benzopyrano[4,3-c]pyrazole-3-carboxylic acid (3.5 g) which is reacted with thionyl chloride (1.34 ml) in dioxane (70 ml) at reflux temperature for 2 hours. After cooling the solution is evaporated to dryness in vacuo to give 1,4-dihydro-1-phenyl-[1]-benzopyrano[4,3-c]pyrazole-3-carbonyl chloride as crystalline residue. The crude product is dissolved in anhydrous dioxane (35 ml) and reacted for 2 hours under stirring at room temperature with ethyl cyanoacetate (1.5 g) carbanion, prepared by treatment with 50% sodium hydride (0.8 g) in anhydrous dimethylformamide (20 ml) at room temperature. The reaction mixture is then diluted with ice water and acidified to pH 1 with N HCl. The precipitate is filtered and dissolved in ethyl acetate, then the organic solution is washed with N HCl and water until neutral. Evaporation to dryness yields a residue which is purified over a SiO2 column using chloroform/methanol 80:20 as eluent. Crystallization from acetone gives 1.2 g of 2-cyano-3-(1,4-dihydro-1-phenyl-[1]-benzopyrano[4,3-c]pyrazol-3-yl)-3-oxo-propanoic acid, ethyl ester.

Workup

  1. temperatureat reflux temperature for 30 minutes
  2. filtrationThe precipitate is filtered
  3. washwashed with water
  4. customdried in vacuo at 50° C.

Sources & evidence

ORD record
ord-7ecf33bf2f7641b6adf23fe14eb4e62b
Source dataset
uspto-grants-1989_03
Patent number
US04816467

Reaction notes

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