Dimethylformamide → 3,5-Pyridinedicarboxylic acid, 4-(2,3-dichlorophenyl)-1,4-dihydro-2,6-dimethyl-, 3-methyl 5-((1-oxobutoxy)methyl) ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a stirred mixture of 1,4-dihydro-2,6-dimethyl-4-(2',3'-dichorophenyl)-5-carboxymethyl-3-pyridinecarboxylic acid (2.62 g, 7.35 mmol) and sodium bicarbonate (1.26 g, 15 mmol) in DMF (130 ml) under nitrogen atmosphere was added chloromethyl butyrate (1.53 g, 11.21 mmol). The reaction mixture was heated at 80° C. for 24 h. Workup by filtration followed by evaporation of solvent. The crude residue was chromatographed on silica gel with 45% ethyl acetate in isooctane. Recrystallization from diisopropylether gave colorless crystals (2.20 g, 66%), mp. 136.2°-138.5° C. 1H-NMR (CDCl3): 7.30-7.03 (m, 3H); 5.89 (s, 1H); 5.74 (d, J=5.5 Hz, 1H); 5.70 (d, J=5.5 Hz, 1H); 5.46 (s, 1H); 3.60 (s, 3H); 2.33 (m, 8H); 1.65-1.55 (m, 2H); 0.90 (t, J=7.4 Hz, 3H). 13C-NMR (CDCl3): 172.25; 167.61; 165.80; 147.43; 146.59; 143.82; 132.89; 131.11; 129.82; 128.30; 126.95; 103.97; 101.99; 78.63; 50.92; 38.49; 35.79; 19.91; 19.30; 18.01; 13.50.

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