Reaktion #471515

Reaktionsgleichung

sodium bicarbonate

sodium nitrite

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

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

5-methyl-2-(5,6,7,8-tetrahydro-naphthalen-2-yl)-2,4-dihydro-pyrazol-3-one

→

5-(2-hydroxy-3-{N′-[3-methyl-5-oxo-1-(5,6,7,8-tetrahydro-naphthalen-2-yl)-1,5-dihydro-pyrazol-4-ylidene]-hydrazino}-phenyl)-furan-2-carboxylic acid

Ausbeute 39.8%

Lösungsmittel

hydrochloric acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturupon cooling by an ice-water bath
2. 2
   SonstigeThe generated bubbles were quenched with 2 mL of ethanol
3. 3
   Sonstigereacted overnight
4. 4
   FiltrationThe mixture was filtered
5. 5
   workup.DISSOLUTIONthe filter cake was dissolved in 20 mL of water
6. 6
   workup.ADDITIONAfter mixing well
7. 7
   Filtrationfiltered
8. 8
   Sonstigedried
9. 9
   SonstigeThe crude product was purified by HPLC

Vorschrift

5-(3-Amino-2-hydroxy-phenyl)-furan-2-carboxylic acid hydrobromide 9c (292 mg, 0.975 mmol) was dissolved in 3.3 mL of hydrochloric acid (1 N) upon cooling by an ice-water bath, followed by dropwise addition of 1.3 mL of aqueous sodium nitrite (74 mg, 1.07 mmol). After the mixture was stirred for 20 minutes, 5-methyl-2-(5,6,7,8-tetrahydro-naphthalen-2-yl)-2,4-dihydro-pyrazol-3-one 3i (200 mg, 0.88 mmol) was added. The mixture was adjusted to pH 8-9 by batch addition of aqueous sodium bicarbonate (1.226 g, 14.6 mmol). The generated bubbles were quenched with 2 mL of ethanol. The reaction mixture was warmed up to room temperature and reacted overnight. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was filtered and the filter cake was dissolved in 20 mL of water. After mixing well, the mixture was adjusted to pH 3˜4 with concentrated hydrochloric acid, filtered and dried. The crude product was purified by HPLC to obtain the title compound 5-(2-hydroxy-3-{N′-[3-methyl-5-oxo-1-(5,6,7,8-tetrahydro-naphthalen-2-yl)-1,5-dihydro-pyrazol-4-ylidene]-hydrazino}-phenyl)-furan-2-carboxylic acid 15 (160 mg, yield 39.8%) as a red solid.

Quelle