Triethylamine → 3-(2,4-Dihydroxyphenyl)-2-cyclopentenone Oxime

3-[2,4-Bis(methoxymethoxy)phenyl]-2-cyclopenten-1-one (20 mg) was heated at 50° C. in MeOH (4 ml) containing acidic ion exchange resin (100 mg) for 3 hr. The reaction mixture was filtered and the resin washed with ethyl acetate (20 ml). The filtrate was concentrated in vacuo and the residue purified by flash column chromatography (SiO2, ethyl acetate/petrol, 7:3 v/v) to furnish 3-(2,4-dihydroxyphenyl)-2-cyclopenten-1-one (11 mg, 79%). 3-(2,4-Dihydroxyphenyl)-2-cyclopenten-1-one (6 mg), hydroxylamine hydrochloride (3.3 mg) and triethylamine (6.6 μl) were heated in ethanol (3 ml) under reflux for 3 hr. The reaction mixture was partitioned between ethyl acetate (20 ml) and water (20 ml). The aqueous phase was extracted with ethyl acetate (10 ml), and the combined organic phases were washed with brine (10 ml), dried over magnesium sulfate, and concentrated in vacuo. The crude residue was purified by flash column chromatography (SiO2, ethyl acetate/petrol, 1:1 v/v) to furnish the title compound as a yellow solid and as one major isomer (4 mg, 62%). Data reported for the major isomer: δH (d4-MeOH) 2.74-2.77 (2H, m), 2.96-2.99 (2H, m), 6.34 (1H, dd), 6.38 (1H, d), 6.96 (1H, t), 7.22 (1H, d); m/z (ES−) 204 (M−H)−.

1. temperatureunder reflux for 3 hr
2. customThe reaction mixture was partitioned between ethyl acetate (20 ml) and water (20 ml)
3. extractionThe aqueous phase was extracted with ethyl acetate (10 ml)
4. washthe combined organic phases were washed with brine (10 ml)
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated in vacuo
7. customThe crude residue was purified by flash column chromatography (SiO2, ethyl acetate/petrol, 1:1 v/v)

ORD record

ord-6b9e42e91e3d4755a2f1642d6c766cc3

Source dataset

uspto-grants-2005_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06933319B2