Sodium Bicarbonate → HCID 178433796, compound

Participants

Reaction Steps

5-(3-Amino-2-hydroxy-phenyl)-thiophene-2-carboxylic acid hydrobromide 12c (380 mg, 1.2 mmol) was dissolved in 3.9 mL of hydrochloric acid (1 N) upon cooling by an ice-water bath, followed by dropwise addition of 1.5 mL of aqueous sodium nitrite (90 mg, 1.32 mmol). After the mixture was stirred for 20 minutes, 2-indan-5-yl-5-methyl-2,4-dihydro-pyrazol-3-one 1i (210 mg, 1 mmol) was added. The mixture was adjusted to pH 8˜9 by batch addition of aqueous sodium bicarbonate (1.51 g, 18 mmol). The generated bubbles were quenched with 2 mL of ethanol and 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 5% aqueous sodium hydroxide. The layers were separated and then the aqueous layer was extracted with dichloromethane (50 mL×3). The aqueous layer 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′-(1-indan-5-yl-3-methyl-5-oxo-1,5-dihydro-pyrazol-4-ylidene)-hydrazino]-phenyl}-thiophene-2-carboxylic acid 18 (15 mg, yield 3.3%) as an orange solid.

Provenance & Evidence