Dibutyltin dichloride → 4-{[6-(2-Morpholin-4-yl-ethoxy)-benzothiazol-2-ylamino]-methyl}-benzoic Acid Methyl Ester

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Reaction Steps

To a round-bottom flask containing benzothiazole 226 (5.80 g, 20.8 mmol) was added methyl 4-formylbenzoate (5.11 g, 31.1 mmol), followed by THF (8 mL), dibutyltin dichloride (315 mg, 1.04 mmol) and dropwise addition of phenylsilane (3.24 mL, 31.1 mmol). The resulting mixture was stirred overnight at room temperature under nitrogen. The mixture was diluted in ethyl acetate and filtered. The filtrate was partitioned between ethyl acetate and water and the combined organic layers were washed with 1N HCl. The combined acidic layers were neutralized using a saturated aqueous solution of NaHCO3 and the precipitate was extracted with ethyl aceate. The combined organic layers were washed with brine, dried over MgSO4, and concentrated. The resulting crude was purified by flash chromatography using MeOH/CHCl3 (10:90) to afford 227 (3.69 g, 42% yield). 1H NMR: (Acetone-d6) δ (ppm): 8.04 (d, J=8.5 Hz, 2H), 7.65 (d, J=8.8 Hz, 2H), 7.41 (d, J=8.8 Hz, 1H), 7.34 (d, J=2.5 Hz, 1H), 6.94 (dd, J=8.5, 2.7 Hz, 1H), 4.50 (t, J=5.5 Hz, 2H), 3.86 (s, 3H).

Provenance & Evidence