Potassium Phosphate, Tribasic → (R)-2'-(2-fluoropyridin-3-yl)-7'-(2-fluoropyridin-4-yl)-2,6-dihydrospiro[[1,4]oxazine-3,9'-xanthen]-5-amine

Participants

Reaction Conditions

Reaction Steps

In a microwave vial, sodium carbonate (0.094 g, 0.885 mmol), 2-fluoropyridin-4-ylboronic acid (0.048 g, 0.339 mmol), Pd(PPh3)4 (0.034 g, 0.030 mmol), and (S)-2′-bromo-7′-iodo-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (0.139 g, 0.295 mmol) were suspended in DME (2.5 mL) and water (0.5 mL). Argon gas was blown through the vessel which was sealed and heated in an 80° C. oil bath. After 6 h, the reaction mixture was diluted with brine (10 mL) and the aqueous phase was extracted with 7.5% MeOH-dcm (3×25 mL). The organics were combined, washed with dilute brine (5 mL), dried over sodium sulfate and concentrated. The material was purified through silica gel (33 mL) using 3.5 to 4.5 to 7% MeOH-DCM to afford (R)-2′-bromo-7′-(2-fluoropyridin-4-yl)-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine Step 2: In a microwave vial, the potassium phosphate (0.071 g, 0.334 mmol), PdCl2(AmPhos)2 (7.88 mg, 0.011 mmol), 2-fluoropyridin-3-ylboronic acid (0.020 g, 0.139 mmol), and (R)-2′-bromo-7′-(2-fluoropyridin-4-yl)-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (0.049 g, 0.111 mmol) were suspended in dioxane (2 mL) and water (0.5 mL). Argon gas was blown through the vessel, which was sealed and heated by microwave at 120° C. for 30 min. The mixture was concentrated, and the residue was diluted with brine (15 mL), and the aqueous phase was extracted with 5% MeOH-dcm (3×25 mL). The organics were combined, dried over sodium sulfate and concentrated. The residue was purified by chromatography (3.5%-4.5% MeOH/DCM) to afford (R)-2′-(2-fluoropyridin-3-yl)-7′-(2-fluoropyridin-4-yl)-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (35 mg, 0.076 mmol). MS (m/z) 457 (M+H)+.

Provenance & Evidence