(Z)-5H-Cyclopenta[b]pyridin-7(6H)-one O-methyl oxime

31170-78-2

593-56-6

1071727-78-0

General procedure for the synthesis of (Z)-5H-cyclopenta[b]pyridin-7(6H)-one O-methyloxime from 5,6-dihydro-7H-cyclopenta[b]pyridin-7-one and methoxylamine hydrochloride: methoxylamine hydrochloride (6.20 g, 74.23 mmol) was added to a methanol solution of 5,6-dihydro-7H-cyclopenta[b]pyridin-7-one (4.96 g. 37.25 mmol) in methanol solution followed by the addition of triethylamine (10.4 mL, 74.62 mmol). The reaction mixture was refluxed overnight, cooled to room temperature and extracted with ethyl acetate (3 x 200 mL). The organic phases were combined, washed sequentially with water (3 x 200 mL), saturated saline (1 x 200 mL), dried over anhydrous magnesium sulfate and concentrated. Purification by column chromatography using hexane:ether (4:1) as eluent afforded 4.10 g (68% yield) of the target product (Z)-5H-cyclopentadieno[b]pyridin-7(6H)-one O-methyloxime. Spectral data: 1H NMR (300 MHz, CDCl3) δ 2.90-2.96 (m, 2H), 2.99-3.07 (m, 2H), 4.08 (s, 3H), 7.21 (q, J = 4.69, 2.93 Hz, 1H), 7.63 (d, J = 7.92 Hz, 1H), 8.55 (d, J = 4.69 Hz. 1H).