Rhodanine → 5-[4-(2,2-Diethoxy-ethoxy)-benzylidene]-2-thioxo-thiazolidin-4-one

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Reaction Steps

Under nitrogen, a mixture of 4-hydroxybenzaldehyde (1.71 g, 14 mmol), bromoacetaldehyde diethyl acetate (37.4 g, 190 mmol), tetrabutylammonium bromide (0.61 g, 1.9 mmol) and potassium carbonate (26.1 g, 190 mmol) in 100 mL of toluene was refluxed for 2.5 days. After cooling the mixture was dissolved in water and extracted with dichloromethane. The organic layers were dried over magnesium sulfate and concentrated. The residue was purified by column chromatography (eluent: hexanes/ethyl acetate) to give 4-(2,2-diethoxyethoxy) benzaldehyde as a colorless oil (2.60 g, 79%). The title compound was prepared from 4-(2,2-diethoxyethoxy) benzaldehyde and rhodanine according to the procedure of Intermediate 15 as a yellowish solid; 1H NMR (300 MHz, DMSO-d6) δ 1.14(t, J=7.1 Hz, 6 H), 3.50-3.80 (m, 4 H), 4.04(d, J=5.0 Hz, 2 H), 4.05-4.30(m, 2 H), 6.06 (t, J=5.0 Hz, 1 H), 7.14 (d, J=9.0 Hz, 2 H), 7.60 (d, J=9.0 Hz, 2 H), 7.63(s, 1 H); MS (ES) m/z:351.7 ((M−H)−, 100%); HRMS Calcd. for C16H20NO4S2 (MH+): 353.0775. Found: 353.0757.

Provenance & Evidence