Reaktion #471576

Reaktionsgleichung

sodium bicarbonate

sodium nitrite

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

5-(3-amino-2-hydroxy-5-methyl-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-5-methyl-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 34.9%

Lösungsmittel

ethanol

hydrochloric acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturupon cooling by an ice-water bath
2. 2
   SonstigeAfter the mixture was reacted for 20 minutes
3. 3
   SonstigeThe reaction mixture was reacted at room temperature overnight
4. 4
   FiltrationThe mixture was filtered
5. 5
   workup.ADDITIONthe filter cake was added to 20 mL of water
6. 6
   FiltrationThe mixture was filtered
7. 7
   Sonstigethe filter cake was dried
8. 8
   Sonstigepurified by silica gel column chromatography

Vorschrift

5-(3-Amino-2-hydroxy-5-methyl-phenyl)-furan-2-carboxylic acid hydrobromide 46c (120 mg, 0.38 mmol) was dissolved in 1.3 mL of 1 N hydrochloric acid upon cooling by an ice-water bath, followed by dropwise addition of 0.5 mL of aqueous sodium nitrite (29 mg, 0.42 mmol). After the mixture was reacted for 20 minutes, 5-methyl-2-(5,6,7,8-tetrahydro-naphthalen-2-yl)-2,4-dihydro-pyrazol-3-one 3i (78 mg, 0.34 mmol) was added. The mixture was adjusted to pH 8 with saturated aqueous sodium bicarbonate followed by addition of 2 mL of ethanol. The reaction mixture was reacted at room temperature overnight. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was filtered and the filter cake was added to 20 mL of water. The mixture was adjusted to pH 3˜4 with concentrated hydrochloric acid. The mixture was filtered and the filter cake was dried and purified by silica gel column chromatography to obtain the title compound 5-(2-hydroxy-5-methyl-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 50 (56 mg, yield 34.8%) as a red solid.

Quelle