Potassium Carbonate → tert-butyl 6-(6-(methoxycarbonyl)-5-(3-phenoxypropoxy)pyridin-2-yl)-2H-benzo[b][1,4]oxazine-4(3H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of tert-butyl 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2H-benzo[b][1,4]oxazine-4(3H)-carboxylate (53B) (72 mg, 0.20 mmol), methyl 6-bromo-3-(3-phenoxypropoxy)picolinate (26C) (72 mg, 0.20 mmol), K2CO3 (30 mg, 0.22 mmol in 0.5 mL of water), tetrabutyl ammonium bromide (64 mg, 0.20 mmol) and dichlorobis(triphenylphosphine)palladium (1) (10 mg, catalytic amount) in 1,4-dioxane (5 mL) was heated to 90° C. for 6 hours. The reaction mixture was cooled to rt, diluted with EtOAc, filtered through Celite, and concentrated under reduced pressure. The crude material was purified by column chromatography on silica gel eluting with 20% EtOAc in hexanes to provide the desired product tert-butyl 6-(6-(methoxycarbonyl)-5-(3-phenoxypropoxy)pyridin-2-yl)-2H-benzo[b][1,4]oxazine-4(3H)-carboxylate (53C). 1H NMR (300 MHz, CDCl3): 8.49 (1H, s), 7.74 (1H, d), 7.60 (1H, d), 7.38 (1H, d), 7.24 (2H, m), 6.90 (4H, m), 4.31 (2H, t), 4.18 (2H, t), 4.25 (2H, t), 3.95 (3H, s), 3.85 (2H, t), 2.3 (2H, m), 1.58 (9H, s). LCMS (APCI): m/z 521.1 (M+H).

Provenance & Evidence