Triphenylphosphine → 2-t-butyl-5-{4-[2-(t-butyldimethylsilanyloxy)ethoxymethyl]benzyloxy}-4-chloro-2H-pyridazin-3-one

Participants

Reaction Steps

To solution of the product of Example 5C (437 mg, 1.48 mmol) and 2-tert-butyl-4-chloro-5-hydroxy-2H-pyridazin-3-one (250 mg, 1.23 mmol) dissolved in anhydrous THF (12 mL) was added solid PPh3 (485 mg, 1.85 mmol) and diisopropyl azodicarboxylate (DIAD, 0.358 mL, 1.85 mmol). After completion of addition the reaction mixture continued to stir at room temperature. After 20 hours, the reaction mixture was diluted with water. The aqueous layer was separated and extracted with ethyl acetate (3×). All combined organic layers were dried over Na2SO4, filtered, and concentrated to provide an oil. The crude material was purified using silica gel chromatography (4:1 pentane:ethyl acetate) to provide the desired product 528 mg, 1.10 mmol) in 89% yield. 1H (CDCl3 7.70 (1H, s), 7.38 (4H, m), 5.30 (2H, s), 4.58, 600 MHz): δ (2H, s), 3.80 (2H, t, J=5.4 Hz), 3.57 (2H, t, J=5.4 Hz), 1.63 (9H, br s), 0.90 (9H, s), 0.07 (6H, s); 13C (CDCl3159.0, 153.7, 138.8, 134.4, 128.3, 127.3, 150 MHz): δ 125.1, 118.5, 72.8, 71.7, 71.6, 66.4, 61.9, 29.7, 27.9, 25.6, −5.1; HRMS calcd for C24H37ClN2O4Si: 481.228389, found 481.2282.

Provenance & Evidence