Triphenylphosphine → 6-[2-(Morpholin-4-yl)ethoxy]-1,3-benzothiazol-2-amine

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Reaction Steps

To a solution of benzothiazole 225 (3.62 g, 21.8 mmol) in THF at room temperature under nitrogen, were successively added 4-(2-hydroxyethyl)morpholine (3.17 mL, 26.1 mmol), triphenylphosphine (7.43 g, 28.3 mmol) followed by a dropwise addition of diethyl azodicarboxylate (4.46 mL, 28.3 mmol). The solution was stirred for 3.5 h and THF was partially removed in vacuo. The mixture was partitioned between ethyl acetate and H2O. The combined organic layers were extracted with 1N HCl. The combined acidic extracts were neutralized using a saturated aqueous solution of NaHCO3 and the precipitate was dissolved with ethyl acetate. These combined organic layers were washed with brine, dried over MgSO4, and concentrated. The filtrate was concentrated to afford the title compound 226 (5.83 g, 96% yield) as a light yellow oil. 1H NMR: (Acetone-d6) δ (ppm): 7.37 (d, J=8.8 Hz, 1H), 7.34 (d, J=2.6 Hz, 1H), 6.94 (dd, J=8.8, 2.6 Hz, 1H), 6.60 (bs, 2H), 4.19 (t, J=6.2 Hz, 2H), 3.70-3.67 (m, 4H), 2.90 (s, 2H), 2.81 (t, J=6.2 Hz, 2H), 2.62-2.58 (m, 4H).

Provenance & Evidence