3-(4-chloro-6,7-dihydro-5H-cyclopenta[b]pyridin-2-yl)cyclopent-2-enone → 3-(4-chloro-6,7-dihydro-5H-cyclopenta[b]pyridin-2-yl)cyclopent-2-enol

HRID 1508801Notes

Reaction equation

[Cl:1][C:2]1[CH:7]=[C:6]([C:8]2[CH2:12][CH2:11][C:10](=[O:13])[CH:9]=2)[N:5]=[C:4]2[CH2:14][CH2:15][CH2:16][C:3]=12>C1COCC1>[Cl:1][C:2]1[CH:7]=[C:6]([C:8]2[CH2:12][CH2:11][CH:10]([OH:13])[CH:9]=2)[N:5]=[C:4]2[CH2:14][CH2:15][CH2:16][C:3]=12

Participants

Conditions

Temperature: 55 °C

Procedure

A 25-mL round bottom flask was charged with 3-(4-chloro-6,7-dihydro-5H-cyclopenta[b]pyridin-2-yl)cyclopent-2-enone (0.434 g, 1.85 mmol) and THF (8 mL) at rt. Borane-dimethylsulfide complex (0.22 mL, 2.32 mmol) was added and the resulting solution was stirred at 55° C. for 4 h. After this time, the reaction was quenched with methanol, treated with 2N aqueous HCl (5 drops), and concentrated under reduced pressure. The residue was diluted with methanol and then concentrated under reduced pressure. The residue was then purified by chromatography on silica using hexanes/ethyl acetate (10:0 to 0:10) as the eluent to afford the title compound (0.123 g, 28%) as an off-white solid. MW=235.71. 1H NMR (CDCl3, 500 MHz) δ 7.15 (s, 1H), 6.58 (q, J=2.0 Hz, 1H), 5.06-4.99 (m, 1H), 3.08 (t, J=7.5 Hz, 2H), 2.99 (t, J=7.5 Hz, 2H), 2.97-2.90 (m, 1H), 2.72-2.64 (m, 1H), 2.52-2.44 (m, 1H), 2.15 (quin, J=7.5 Hz, 2H), 1.93-1.85 (m, 1H).

Workup

additionBorane-dimethylsulfide complex (0.22 mL, 2.32 mmol) was added
customAfter this time, the reaction was quenched with methanol
additiontreated with 2N aqueous HCl (5 drops)
concentrationconcentrated under reduced pressure
additionThe residue was diluted with methanol
concentrationconcentrated under reduced pressure
customThe residue was then purified by chromatography on silica

Sources & evidence

ORD record: ord-6bdc9f7ee6584a1a9273ff13d4d30092
Source dataset: uspto-grants-2015_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09221843B2

Reaction notes

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