Ethyl 3-oxo-3-(pyridin-2-yl)propanoate → HCID 178422350, Verbindung

Beteiligte Stoffe

Reaktionsschritte

(prepared according to an analogous procedure described in Polish J. Chem., 56 (1982) p 963) 3-Oxo-3-(pyridin-2-yl)propionic acid ethyl ester (2 g, 0.01035 mol) and 5-methyl-2H-pyrazol-3-ylamine (1 g, 1 eq) were heated together at 140° C. for 2 h; after cooling to rt, the solid residue was stirred with EtOAc and the solid collected by filtration to give 1.84 g of 2-methyl-5-pyridin-2-yl-4H-pyrazolo[1,5-a]pyrimidin-7-one. Step B: The product of step A (1.84 g) was dissolved in POCl3 (24 ml) and cooled to 0° C. N,N-dimethylaniline (3.1 ml, 3 eq) was added and the mixture heated at 60° C. for 16 h. The mixture was cooled to rt and the volatiles removed. The resulting residue was dissolved in CH2Cl2, poured onto ice, and taken to pH 8 with NaHCO3 (s). The CH2Cl2 layer was removed, washed with water, and dried (MgSO4). The mixture was concentrated under reduced pressure and the residue chromatographed (SiO2, hexane-EtOAc/hexane 1:1) to give 1.2 g of the title compound. 1H NMR (CDCl3) δ 8.71 (m, 1H), 8.49 (d, J=8.4 Hz, 1H), 8.14 (s, 1H), 7.87 (t, J=9.6 Hz, 1H), 7.41 (m, 1H), 6.64 (s, 1H), 2.60 (s, 3H).

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