Methanol → (NE,S)-2-methyl-N-[[2-[4-(trifluoromethyl)phenyl]pyrimidin-5-yl]methylidene]propane-2-sulfinamide

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Reaction Steps

2-(4-trifluoromethyl-phenyl)-pyrimidine-5-carbaldehyde (35.25 g, 138.9 mmol) was suspended in anhydrous dichloromethane (470 mL) in a 3-necked 1 L flask with overhead stirrer, condenser and internal temperature. (S)-(−)-2-methyl-2-propanesulfinamide (17.13 g, 141.3 mmol) was added followed by titanium(IV) ethoxide (37.3 mL, 178 mmol). This gave a yellow solution which was heated to reflux for 3 h. The heating was discontinued and the reaction placed in an ice bath. When the internal temperature was −10° C., anhydrous methanol (246 mL) was added followed by sat. aq. NaHCO3 (71 mL). Solid crashed out which was stirred for 2 h. The solids were filtered off with a Buchner funnel using ethyl acetate to aid in transfer. Several portions of ethyl acetate were used to rinse the solid. The solid was added back into the 3-necked flask and mechanically stirred for 20 min with ethyl acetate. This was refiltered. This process was repeated to remove most of the product. The filtrate was dried over Na2SO4 and concentrated in vacuo to give (S)-2-methyl-propane-2-sulfinic acid 1-[2-(4-trifluoromethyl-phenyl)-pyrimidin-5-yl]-meth-(E)-ylideneamide (49.00 g, 99%) as a white solid. 1H NMR (400 MHz, CDCl3, δ): 9.25 (s, 2H) 8.70 (s, 1H) 8.66 (d, J=8.2 Hz, 2H) 7.79 (d, J=8.2 Hz, 2H) 1.31 (s, 9H); MS (M+1): 356.1.

Provenance & Evidence