Water → Ethyl 5-(4-nitrophenyl)thiazole-2-carboxylate

関与物質

反応手順

A solution of Ethyl 2-(2-(4-nitrophenyl)-2-oxoethylamino)-2-oxoacetate (Intermediate 1, step C, 5 g) and Lawesson's reagent (7.22 g) in 1,4-Dioxane (100 ml) was refluxed for 2 hours. The reaction mixture was cooled, water was added and the mixture was neutralized with saturated solution of Na2CO3. This was followed by addition of EtOAc and then the layers were separated. The organic layer was dried over Na2SO4, filtered and concentrated under reduced pressure to get dark brown residue. The residue was chromatographed on silica gel in 0.5:9.5 EtOAc:CHCl3 to get dark yellow colored solid which was crystallized in CHCl3/pet ether to yield 3.65 g (73%) of the title compound. 1H NMR (CDCl3, 300 MHz): δ 8.33 (d, 2H), 8.3 (s, 1H), 7.83 (d, 2H), 4.54 (q, 2H), 1.49 (t, 3H); MS (ES+) m/z 279 (M+1).

情報源と証拠