Reaktion #471503

Reaktionsgleichung

sodium nitrite

5-(3-Amino-2-hydroxy-phenyl)-furan-2-carboxylic acid hydrobromide

5-(3-amino-2-hydroxy-phenyl)-furan-2-carboxylic acid hydrobromide

2-indan-5-yl-5-methyl-2,4-dihydro-pyrazol-3-one

sodium bicarbonate

→

5-{2-hydroxy-3-[N′-(1-indan-5-yl-3-methyl-5-oxo-1,5-dihydro-pyrazol-4-ylidene)-hydrazino]-phenyl}-furan-2-carboxylic acid

Ausbeute 71.8%

Lösungsmittel

hydrochloric acid

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturupon cooling by an ice-water bath
2. 2
   SonstigeAfter the mixture was reacted for 10 minutes
3. 3
   SonstigeThe mixture was reacted at room temperature for 24 hours
4. 4
   FiltrationThe mixture was filtered
5. 5
   Waschenthe filter cake was washed with 20 mL of water
6. 6
   workup.DISSOLUTIONdissolved in 20 mL of water
7. 7
   TemperaturUpon cooling by an ice-water bath
8. 8
   Filtrationfiltered
9. 9
   Sonstigedried

Vorschrift

5-(3-Amino-2-hydroxy-phenyl)-furan-2-carboxylic acid hydrobromide 9c (300 mg, 1.0 mmol) was dissolved in hydrochloric acid (3.4 mL, 1 mol/L) followed by dropwise addition of 1.2 mL of aqueous sodium nitrite (73 mg, 1.05 mmol) upon cooling by an ice-water bath. After the mixture was reacted for 10 minutes, 2-indan-5-yl-5-methyl-2,4-dihydro-pyrazol-3-one 1i (193 mg, 0.9 mmol), sodium bicarbonate (1.26 g, 15 mmol) and 4.4 mL of ethanol were added successively. The mixture was reacted at room temperature for 24 hours. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was filtered and the filter cake was washed with 20 mL of water and then dissolved in 20 mL of water. Upon cooling by an ice-water bath, the mixture was adjusted to pH<5 with concentrated hydrochloric acid, filtered and dried to obtain the title compound 5-{2-hydroxy-3-[N′-(1-indan-5-yl-3-methyl-5-oxo-1,5-dihydro-pyrazol-4-ylidene)-hydrazino]-phenyl}-furan-2-carboxylic acid 9 (287 mg, yield 71.8%) as a yellow solid.

Quelle