Potassium Phosphate, Tribasic → 2-(1H-Indol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Into a 10-mL sealed tube, was placed methyl 2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (60 mg, 0.20 mmol, 1.00 equiv), 1H-indol-5-ylboronic acid (100 mg, 0.62 mmol, 3.05 equiv), Pd(PPh3)4 (23.6 mg, 0.02 mmol, 0.10 equiv), K3PO4 (174 mg, 0.82 mmol, 4.01 equiv), 1,4-dioxane/H2O (4/1 mL). The resulting solution was stirred for overnight at 100° C. in an oil bath. The resulting mixture was concentrated under vacuum. The residue was applied onto a silica gel column with dichloromethane/methanol (10:1). The crude product (60 mg) was purified by Prep-HPLC with the following conditions (1#-Waters 2767-2): Column, SunFire Prep C18, 19*150 mm 5 um; mobile phase, water with 0.05% TFA and CH3CN (30% CH3CN up to 55% in 8 min, hold 55% in 3 min, up to 100% in 0.1 min, hold 100% in 0.9 min); Detector, UV 220&254 nm. This resulted in 25 mg (33%) of 2-(1H-indol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic acid as a red solid.

Provenance & Evidence