Propionic Acid → 1-(2,8-Dimethyl-1-thia-3,8-diaza-spiro[4.5]dec-3-yl)-propan-1-one

Participants

Reaction Steps

To a stirred solution of 2,8-dimethyl-1-thia-3,8-diaza-spiro[4.5]decane (Example 1) (0.86 g, 4.62 mmol) in dichloromethane (90 ml) at room temperature was added dicyclohexylcarbodiimide (DCC) (1.28 g, 6.2 mmol) followed by addition of propionic acid (0.41 ml, 5.5 mmol). The resulting solution was stirred at room temperature overnight. During the reaction a white solid precipitated. After filtration the solvent was evaporated and the crude product was purified by flash chromatography (silica, CH2Cl2/MeOH/NH4OH 90/10/1) to give the title compound (0.5 g) as a colorless oil. 1H NMR (CDCl3, 300 MHz) δ 5.51, 5.19 (2q, J=6.15 and J=6.22 Hz, 1H, CHCH3), 4.63, 3.74 (2d, J=11.88 and J=11.57 Hz, 1H, CHHNCO), 3.44, 3.08 (2d, J=11.55 and J=12.09 Hz, 1H, CHHNCO), 2.8-2.6 (m, 2H), 2.5-2.2 (m, 7H, CH2, CH2CH3, NCH3), 2.2-2.0 (m, 1H), 2.0-1.8 (m, 3H) 1.52, 1.48 (2d, J=630 and J=6.18 Hz, 3H, CH3—CH), 1.19-1.12 (m, 3H, CH3) ppm; 13C NMR (CDCl3, 300 MHz) δ 171.6 (C), 57.5, 57.2 (CH), 55.5 (C), 54.7, 54.3 (CH2), 53.2, 53.0 (CH2), 46.3 (CH3), 38.4, 37.7 (CH2), 37.0, 36.4 (CH2), 28.8, 26.8 (CH2), 25.6, 23.6 (CH3), 9.6, 9.4 (CH3) ppm.

Provenance & Evidence