Tetrabutylammonium Fluoride → HCID 67383703, Verbindung

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A sealable tube was charged with (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (3.00 g, 8.62 mmol), tetrakis(triphenylphosphine)palladium (0.996 g, 0.862 mmol), copper(i) iodide (0.164 g, 0.862 mmol). To this was added trimethyl((3-methyloxetan-3-yl)ethynyl)silane (2.90 g, 17.23 mmol) followed by tetra-n-butylammonium fluoride (1 M in THF) (25.9 mL, 25.9 mmol). The resulting brown solution was flushed with argon and heated at 70° C. for 5 hours. The reaction was cooled to rt and diluted with 250 mL of water. The slurry was poured into a separatory funnel containing EtOAc (500 mL). The layers were separated and the aqueous layer was extracted with EtOAc (3×250 mL). In the first extraction a slight emulsion formed, this was cleared upon the addition of 50 mL of brine. The aqueous layer was then extracted with CH2Cl2 (3×200 mL). The organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown foam that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (330 g), 0-100% CH2Cl2 to 10:1 methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-2′-amino-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as a brown foam.

Herkunft & Nachweise