Water → 3-cyclopentyl-2-(4-methoxy-6-oxo-6H-pyridazin-1-yl)-propionic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 5-methoxy-2H-pyridazin-3-one (500 mg, 3.96 mmol) in tetrahydrofuran (19.8 mL, 0.2M) cooled to 0° C. was treated with a 60% dispersion of sodium hydride in mineral oil (190 mg, 4.75 mmol). The reaction was stirred at 25° C. for 30 min. After this time, the reaction was treated with 2-bromo-3-cyclopentyl-propionic acid methyl ester (Intermediate 10, 1.02 g, 4.36 mmol). The reaction was then warmed to 50° C. where it stirred overnight. After this time, the reaction was cooled to 25° C., was poured into water (100 mL) and was extracted into ethyl acetate (3×75 mL). The organics were dried over sodium sulfate, filtered and concentrated in vacuo. Silica gel column chromatography (ISCO 80 g, 40% ethyl acetate/hexanes) afforded 3-cyclopentyl-2-(4-methoxy-6-oxo-6H-pyridazin-1-yl)-propionic acid methyl ester (488 mg, 43%) as a clear oil; ES+-HRMS m/e calcd for C14H20N2O4 [M+H+] 281.1496 found 289.1495. 1H NMR (300 MHz, DMSO-d6) δ ppm 0.92-1.16 (m, 2H), 1.33-1.64 (m, 6H), 1.63-1.78 (m, 1H), 1.89-2.03 (m, 1H), 2.16 (ddd, J=13.9, 10.9, 5.4 Hz, 1H), 3.61 (s, 3H), 3.82 (s, 3H), 5.39 (dd, J=10.7, 4.4 Hz, 1H), 6.32 (d, J=2.7 Hz, 1H), 7.84 (d, J=2.7 Hz, 1H).

Provenance & Evidence