Dimethyl Sulfoxide → 2-(4'-Hexyloxyphenyl)terephthalaldehyde

Participants

Reaction Conditions

Reaction Steps

Oxalyl chloride (8.4 g, 5.7 ml, 66 mmol) were added to 70 ml of dichloromethane and the mixture was cooled to −60° C. A solution of DMSO (10.2 g, 9.3 ml, 131 mmol) in 30 ml dichloromethane was added dropwise over a period of 10 minutes. The mixture was stirred further for 5 minutes. A solution of 2,5-bis(hydroxymethyl)-4′-hexyloxybiphenyl (10 g, 32 mmol) (cf. D1) in 70 ml of dichloromethane was then added dropwise over a period of 15 minutes (the reaction solution became turbid). It was stirred further for 10 minutes and triethylamine (15.9 g, 21.8 ml, 157 mmol) was subsequently added dropwise. During this addition, the reaction solution became yellow and a precipitate formed. The acetone/dry ice bath was removed and the mixture was stirred for 2 hours at RT. This resulted in a light-colored solid floating on the yellow liquid phase. The mixture was admixed with 150 ml of water, stirred further for 10 minutes (the solid went into solution), the organic phase was separated off, the aqueous phase was extracted twice with dichloromethane, the combined organic phases were subsequently washed three times with water, dried over Na2SO4, filtered and subsequently evaporated to dryness on a rotary evaporator. The yellow oil crystallized after some time at RT; it was subsequently recrystallized from hexane. It took a relatively long time for the product to become solid: pale beige, microcrystalline powder, 5.67 g (57%), purity about 98%. Melting point: 44.5-45.5° C.

Provenance & Evidence