Ethyl Acetate → 4,5,6-Trimethoxy-4'-nitrobiphenyl-2,2'-dicarbaldehyde

Beteiligte Stoffe

Reaktionsschritte

A mixture of 2-bromo-3,4,5-trimethoxybenzaldehyde (prepared as described in Example 1, starting materials, 1.00 g, 3.64 mmol) and 2-chloro-5-nitrobenzaldehyde (obtained from Aldrich; 241.9 mg, 1.30 mmol) in dry DMF (2 mL) was added to a stirred, boiling suspension of copper bronze (0.91 g, 14.3 mmol) in dry DMF (5 mL) over a period of 30 minutes. After 8 hours TLC (petroleum ether-ethyl acetate 4:1) indicated the consumption of the starting materials. The mixture was cooled, passed through a Celite plug and diluted with toluene, which was distilled off to afford a dark oil. Column chromatography (petroleum ether 60-80°—ethyl acetate 2:1) afforded a sample of 4,5,6-trimethoxy-4′-nitrobiphenyl-2,2′-dicarbaldehyde (259 mg) containing traces of a second compound. This mixture was dissolved in ethanol (5 mL) and treated with a solution of sodium borohydride (0.2 g) in water (1.5 mL). After stirring for 40 minutes, the mixture was added to 1 M aqueous hydrochloric acid (20 mL). The precipitated product was collected on a filter, washed with water and recrystallised from ethanol, which gave the 2′-hydroxymethyl-4,5,6-trimethoxy-4′-nitrobiphenyl-2-yl)methanol as a white powder (113 mg, 25%), which was used for further reaction without further purification.

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