Pyridine → 4-[3-(8,8-Dimethyl-5-p-tolyl-7,8-dihydro-naphthalen-2-yl)-3-hydroximino-propenyl]-benzoic Acid

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Reaction Steps

To a solution of 2-trimethylsilanyl-ethyl 4-[3-(8,8-dimethyl-5-p-tolyl-7,8-dihydro-naphthalen-2-yl)-3-oxo-propenyl]-benzoate (Compound 6, 240 mg, 0.46 mmol) in 5 mL of EtOH was added hydroxylamine hydrochloride (64 mg, 0.92 mmol) and pyridine (77 mg, 0.97 mmol). The reaction mixture was then heated at reflux for 6 h. After cooling to room temperature, the solvent was removed in vacuo and the residue was taken up in water. The aqueous layer was adjusted to pH=4–5 with 1 N HCl and extracted with ethyl acetate (3×10 mL). The organic layers were combined and washed with water (2×10 mL) and brine (1×10 mL), dried (MgSO4) and concentrated at reduced pressure to obtain a yellow crude oil. This crude product was then dissolved in 2 mL of dimethylsulfoxide (DMSO) and tetraethylammomium fluoride (TEAF) (137 g, 0.92 mmol) was added. After stirring at room temperature for 0.5 h, the mixture was diluted with water (10 mL), extracted with ethyl acetate (3×5 mL), washed with brine (1×5 mL), dried (MgSO4) and concentrated at reduced pressure. Purification by recrystallization with acetonitrile yielded Substance 7c, (a mixture of E/Z isomers, 84 mg, 42% yield).

Provenance & Evidence