Chloroacetaldehyde → 2-(3-Nitrophenyl)-1,3-thiazole

Participants

Reaction Steps

A yellow suspension of 3-nitrobenzothioamide (2.0 g, 10.98 mmol), 2-chloroacetaldehyde (45% in H2O) (2.01 g, 11.53 mmol), and acetic acid (7.32 mL) was heated to reflux for 1 hour. The mixture was cooled to room temperature, poured into ice water, and rendered alkaline using 30 mL of 12 N NaOH solution. Ethyl acetate was then added, and the resulting emulsion was filtered through CELITE®. The aqueous layer was extracted twice with ethyl acetate, and the combined organic layers were dried over magnesium sulfate. Filtration and concentration under reduced pressure afforded Intermediate 57A (2.107 g, 91% yield) as a brown solid. HPLC: Rt=3.331 min. (YMC S5 ODS 4.6×50 mm, 10-90% aqueous methanol containing 0.2% H3PO4, 4 min. gradient, monitored at 220 nm). MS (ES): m/z=207.0 [M+H]+. 1H NMR (400 MHz, DMSO-d6) δ ppm 8.68 (1H, t, J=1.89 Hz), 8.34-8.41 (1H, m), 8.28-8.34 (1H, m), 8.00-8.05 (1H, m), 7.94 (1H, d, J=3.27 Hz), 7.80 (1H, t, J=8.06 Hz).

Provenance & Evidence