Sodium Bicarbonate → HCID 178433832, compound

Participants

Reaction Steps

5-(3-Amino-2-hydroxy-phenyl)-thiophene-2-carboxylic acid hydrobromide 12c (260 mg, 0.823 mmol) was dissolved in 2.7 mL of hydrochloric acid (1 N) upon cooling by an ice-water bath, followed by dropwise addition of 1.1 mL of aqueous sodium nitrite (62 mg, 0.91 mmol). After the mixture was stirred for 20 minutes, 5-methyl-2-(1,1,3,3-tetramethyl-indan-5-yl)-2,4-dihydro-pyrazol-3-one 19d (200 mg, 0.74 mmol) was added. The mixture was adjusted to pH 8 with saturated aqueous sodium bicarbonate. Then the generated bubbles were quenched with 2 mL of ethanol. The reaction mixture was warmed up to room temperature and reacted for 3 hours. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was filtered and 20 mL of water was added to the filter cake. The mixture was adjusted to pH 3˜4 with concentrated hydrochloric acid and filtered. The filter cake was dried and purified by silica gel column chromatography to obtain the title compound 5-(2-hydroxy-3-{N′-[3-methyl-5-oxo-1-(1,1,3,3-tetramethyl-indan-5-yl)-1,5-dihydro-pyrazol-4-ylidene]-hydrazino}-phenyl)-thiophene-2-carboxylic acid 49 (216 mg, yield 56.5%) as a red solid.

Provenance & Evidence