Phosphorus sulfide (P2S5) → 3-(3,4-Dimethoxy-phenyl)-thiopropanamide

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Reaction Steps

To a 25 ml eggplant-shaped bottle were added 0.15 g (0.717 mmol) 3-(3,4-dimethoxy-phenyl)-propanamide prepared in step 2, 0.16 g (0.717 mmol) P2S5 and 10 ml THF. A reflux condensing tube carrying a calcium chloride drying tube was mounted. The mixture was refluxed for 1 hour under magnetic agitation, concentrated under a reduced pressure, partitioned between ethyl acetate and saturated NaHCO3 solution each of 15 ml. The aqueous layer was extracted with ethyl acetate twice ×10 ml. The organic phase was combined, washed with saturated brine twice ×15 ml, dried over Na2SO4, filtered and concentrated to obtain a solid crude product which was purified under a reduced pressure by silica gel column chromatography eluted with petroleum ether and ethyl acetate at a ratio of 10:1 (V:V) to obtain a 0.11 g product as a white solid in a yield of 68.8%, mp: 140-141 └. 1H-NMR (CDCl3, 600 MHz) δ: 2.93 (2H, t, J=7.20 Hz, CH2), 3.07 (2H, t, J=7.84 Hz, CH2), 3.86 (3H, s, CH3O), 3.87 (3H, s, CH3O), 6.62 (1H, br), 6.75˜6.82 (3H, m, ArH), 7.35 (1H, br); ESI-MS (m/e, %): 248.3 (M+Na, 100), 226.3 (M+H, 64).

Provenance & Evidence