Pyridine → N-(4-tert-butyl-3-hydroxy-phenyl)-3,4-dihydro-2H-1,4-benzothiazine-2-carboxamide

Participants

Reaction Steps

A solution of 3,4-dihydro-2H-1,4-benzothiazine-2-carboxylic acid (80 mg, 0.41 mmol) and 5-amino-2-tert-butyl-phenol (67 mg, 0.41 mmol) in dichloromethane (3 mL) was treated with propane phosphonic acid anhydride (610 μL of 50% w/w in ethyl acetate, 1.02 mmol) and pyridine (99 μL, 1.2 mmol) and stirred for 30 min at room temperature. The reaction was washed with water, dried over Na2SO4, and concentrated in vacuo. HPLC purification (20-99% CH3CN/0.05% TFA) provided N-(4-tert-butyl-3-hydroxy-phenyl)-3,4-dihydro-2H-1,4-benzothiazine-2-carboxamide (51 mg, 36% yield). LC/MS m/z 343.2 [M+H]+. 1H NMR (400.0 MHz, DMSO-d6) δ 10.07 (s, 1H), 9.38 (s, 1H), 7.20 (d, J=2.0 Hz, 1H), 7.03 (d, J=8.4 Hz, 1H), 6.93 (dd, J=1.1, 7.7 Hz, 1H), 6.88-6.83 (m, 2H), 6.58 (d, J=7.5 Hz, 1H), 6.51-6.47 (t, J=7.5, 1H), 3.92 (dd, J=3.0, 8.0 Hz, 1H), 3.72 (dd, J=3.0, 12.3 Hz, 1H), 3.53 (dd, J=8.1, 12.3 Hz, 1H), 1.31 (s, 9H).

Provenance & Evidence