Diethyl butylmalonate → 4-(1-Butyl)-1-(4-methoxyphenyl)-2-phenyl-3,5-pyrazolidinedione

Participants

Reaction Conditions

Reaction Steps

Diethyl butylmalonate (4.33 g; 20.0 mmol) was added to a stirred solution of sodium (0.46 g; 20.0 mmol) in absolute ethanol (20 ml), followed by crude 1-(4-methoxyphenyl)-2-phenylhydrazine (4.3 g; 20 mmol max.) in absolute ethanol (5 ml). About ⅔ of the ethanol was distilled off and xylene (20 ml) was added to the residue. The reaction mixture was heated to 140-145° C. (bath temperature) for 15 h to distill off the rest of the ethanol. The reaction mixture was cooled to 0° C. (bath temperature) and poured into ice water (ca. 100 ml). The aqueous layer was extracted with CH2Cl2 (2×15 ml); the extracts were discarded. The cold aqueous layer was acidified with 6 H HCl (5 ml) and extracted with CH2Cl2 (3×10 ml). The combined extracts were washed with water (2×10 ml) and dried (MgSO4). Filtration and evaporation gave 3.84 g amber oil. Purified by flash chromatography on a 130×65 mm silica gel 60 column eluted with ethyl acetate-heptane (1:3) to give 1.45 g (21%) colourless oil.

Provenance & Evidence