Dimethyl Sulfoxide → 4-Hydroxyphenylacetaldehyde

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of oxalyl chloride (2.0 ml) and dichloromethane (20 ml), previously cooled to -78° in a dry ice/acetone bath, is added dropwise over 5 min a solution of DMSO (3.4 ml) and methylene chloride (5 ml). The mixture is stirred at -78° for 5 min and then allowed to warm to 0° in an ice bath. To the mixture is added dropwise a solution of 4-(2-hydroxyethoxy)-phenol (1.54 g) in methylene chloride (15 ml) over 10-15 min. The mixture is stirred at 0° for 30 min. triethyl amine (7 ml) is added dropwise and the mixture allowed to warm to 20°-25°. The mixture is diluted with methylene chloride (25 ml) and washed with hydrochloric acid (5%, 50 ml), twice with water (50 ml), dried over sodium sulfate and the solvent removed at reduced pressure to leave an oil that is flash chromatographed on silica gel (25 g) eluting with ethyl acetate/hexane (33/67) to give 4-hydoxyphenylacetaldehyde which is carried on immediately by the addition of 2,6-bis(1-pyrrolidinyl)-4-(1-piperazinyl)pyrimidine (PREPARATION A-22, 0.79 g) and methanol (10 ml). To the mixture is added sodium cyanoborohydride (0.16 g) and the mixture is stirred at 20°-25° for 18 hr. The mixture is treated with aqueous hydrochloric acid (10%, 10 ml) HCl at 0° and the methanol removed at reduced pressure. The residue is distributed between ethyl acetate (50 ml) and water (40 ml). The aqueous phase is brought to pH 8 with aqueous potassium hydroxide (45%) at 0° and then extracted methylene chloride (2×50 ml). The combined extracts are dried over sodium sulfate and the solvent removed at reduced pressure to give a foam that is flash chromatographed on silica gel (35 g) eluting with hexane/ethyl acetate (33/67) to give the title compound.

Herkunft & Nachweise