Reaction #8588

Reaction equation

1-[7-(cyclopentylamino)-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridin-3-yl]ethanone

N,N-dimethylformamide dimethyl acetal

ethylacetate

water

→

(2E)-1-[7-(cyclopentylamino)-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridin-3-yl]-3-(dimethylamino)-2-propen-1-one

Yield 99.0%

Conditions

Workup

1. 1
   Temperatureto reflux for 6 days
2. 2
   WashThe organic layer was washed with brine
3. 3
   ExtractionThe aqueous layer was extracted with ethyl acetate
4. 4
   Dryingthe combined organics were dried over magnesium sulfate
5. 5
   FiltrationFiltration and concentration

Procedure

A solution of 1-[7-(cyclopentylamino)-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridin-3-yl]ethanone (3.1 g, 9.2 mmol) in N,N-dimethylformamide dimethyl acetal (25 mL) was heated to reflux for 6 days. The mixture was cooled to room temperature, ethylacetate was added followed by water. The organic layer was washed with brine. The aqueous layer was extracted with ethyl acetate and the combined organics were dried over magnesium sulfate. Filtration and concentration followed by flash chromatography (ethyl acetate) provided (2E)-1-[7-(cyclopentylamino)-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridin-3-yl]-3-(dimethylamino)-2-propen-1-one (3.6 g, 99%) as a tinted oil. 1H NMR (CDCl3): δ 7.73–7.61 (m, 4 H), 7.32 (t, 1 H), 7.14 (t, 2 H), 6.03 (d, 1 H), 5.96 (d, 1 H), 5.05 (d, 1 H), 3.99 (m, 1 H), 5.15–2.42 (broad, 6 H), 2.19–2.08 (m, 2 H), 1.86–1.62 (m, 6 H); 19F NMR (CDCl3) δ −113.75; MS m/ 393 (M+1).

Source