Ethanesulfonamide → N-((5-bromopyridin-3-yl)(cyclopentyl)methyl)ethanesulfonamide

Participants

Reaction Conditions

Reaction Steps

A mixture of 5-bromonicotinaldehyde (930 mg, 5 mmol), ethanesulfonamide (546 mg, 5.00 mmol) and titanium(IV) isopropoxide (2930 μl, 10.00 mmol) in toluene (20 mL) was heated to reflux for 4 h. After concentration, the residue was dissolved in THF (25 mL) and cooled to −40° C. A solution of cyclopentylmagnesium bromide (2M in THF, 6.25 mL, 12.5 mmol) was added dropwise and the resulting mixture was slowly warmed up to 0° C. over 4 h. The reaction was quenched with a saturated NH4Cl solution. The mixture was filtered, separated, and extracted with CH2Cl2. The organic phase was dried over Na2SO4, filtered and concentrated, and the residue was purified by flash column (ethyl acetate/heptane, v/v, 10%-30%) to give a yellow oil (480 mg). ESI-MS m/z: 348.9 [M+1]+; 1H NMR (400 MHz, CDCl3): δ 1.13-1.80 (m, 7H), 1.26 (t, J=7.4 Hz, 3H), 1.97-2.05 (m, 1H), 2.20-2.29 (m, 1H), 2.67-2.92 (m, 2H), 4.27 (t, J=8.8 Hz, 1H), 5.59 (brs, 1H), 7.87 (s, 1H), 8.56 (s, 1H), 8.68 (s, 1H).

Provenance & Evidence