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

Participants

Reaction Conditions

Reaction Steps

A solution of 2H-pyridazin-3-one (2.0 g, 20.81 mmol) in tetrahydrofuran (104 mL, 0.2M) cooled to 0° C. was treated with a 60% dispersion of sodium hydride in mineral oil (839 mg, 24.97 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, 5.38 g, 22.89 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 (150 mL) and was extracted into ethyl acetate (3×100 mL). The organics were dried over sodium sulfate, filtered and concentrated in vacuo. Silica gel column chromatography (ISCO 80 g, 30% ethyl acetate/hexanes) afforded 3-cyclopentyl-2-(6-oxo-6H-pyridazin-1-yl)-propionic acid methyl ester (3.0 g, 57%) as a tan oil; ES+-HRMS m/e calcd for C13H18N2O3 [M+H+] 251.1390 found 251.1389.

Provenance & Evidence