反应详情

4-(3-Amino-2-hydroxy-phenyl)-furan-2-carboxylic acid 28e (170 mg, 0.57 mmol) was dissolved in hydrochloric acid (1.9 mL, 1 mol/L) upon cooling by an ice-water bath, followed by dropwise addition of 0.7 mL of aqueous sodium nitrite (43 mg, 0.63 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 (116 mg, 0.51 mmol) was added. The mixture was adjusted to pH 8˜9 with saturated aqueous sodium bicarbonate followed by addition of 2 mL of ethanol. 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 then 15 mL of water was added to the filter cake. Upon cooling by an ice-water bath, the mixture was adjusted to pH 2˜3 with concentrated hydrochloric acid and filtered. The filter cake was washed with ethyl acetate and dried to obtain the title compound 4-(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 28 (13 mg, yield 5.5%) as a red solid.

1. temperatureupon cooling by an ice-water bath
2. customAfter the mixture was reacted for 20 minutes
3. customThe mixture was reacted at room temperature for 24 hours
4. filtrationThe mixture was filtered
5. addition15 mL of water was added to the filter cake
6. temperatureUpon cooling by an ice-water bath
7. filtrationfiltered
8. washThe filter cake was washed with ethyl acetate
9. customdried