Hydrochloric Acid → N-[(5,6-Dihydro-2H-pyran-3-yl)methylidene]hydroxylamine

To a cooled (0° C.) solution of 5,6-dihydro-2H-pyran-3-carbaldehyde (10 g, 89 mmol) and hydrochloric acid salt of hydroxylamine (12.0 g, 178 mmol) in water (80 mL) was added a solution of sodium hydroxide (6.4 g, 160 mmol) in water (20 mL) dropwise. The cooling bath was removed and the mixture was allowed to stir at ambient temperature for 1 hour, the resulting solution was acidified with 2 N aqueous hydrochloric acid to pH 3-4, and then extracted with ethyl acetate (3×100 mL). All the organic solutions were washed with saturated NaHCO3 aqueous solution (2×50 mL), brine (2×50 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to afford the title compound as a white solid, which was used in next step without further purification. 1H NMR (300 MHz, CD3OD) δ 7.76 (s, 1H), 6.15 (br, 1H), 4.35 (d, J=1.8 Hz, 2H), 3.86 (t, J=5.7 Hz, 2H), 2.32-2.31 (m, 2H).

1. customThe cooling bath was removed
2. extractionextracted with ethyl acetate (3×100 mL)
3. washAll the organic solutions were washed with saturated NaHCO3 aqueous solution (2×50 mL), brine (2×50 mL)
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated in vacuo

ORD record

ord-ad3091b0ff1143fcb45c75095281ba18

Source dataset

uspto-grants-2016_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09394282B2