Sulfuric Acid → (3S)-3-amino-1-methyl-3-[3-[4-methyl-6-[4-(trifluoromethyl)phenyl]-pyrimidin-2-yl]prop-2-ynyl]pyrrolidin-2-one

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Reaction Steps

To a solution of tert-butyl N-[(3S)-1-methyl-3-[3-[4-methyl-6-[4-(trifluoromethyl)-phenyl]pyrimidin-2-yl]prop-2-ynyl]-2-oxo-pyrrolidin-3-yl]carbamate (which may be prepared as described in Description 7) (99.5 g, 203.68 mmol) in 1,4-dioxane (750 mL) cooled with an ice/water bath to an internal temperature of 15° C. was added conc. sulphuric acid (75 mL, 1407 mmol) dropwise maintaining internal temperature below 20° C. over approximately 35 minutes. After complete addition, the reaction mixture was stirred at room temperature over 30 minutes. The reaction was poured into a beaker and washed in with ethyl acetate (400 mL) and a little water. The mixture was cooled to 15° C. and a solution of sodium carbonate (160 g in 1200 mL water) was added over 5 minutes. The mixture was filtered over a pad of celite and the remaining solids washed with ethyl acetate (400 mL). The filtrate phases were separated and the aqueous phase was extracted with ethyl acetate (2×400 mL). The combined organics were washed with brine (500 mL), dried over magnesium sulphate, filtered and evaporated to yield a foaming amber oil. This was twice dissolved in acetonitrile (100 mL) and evaporated and the resulting yellow foam dried under vacuum to give the title material (D8) in good purity by NMR, consistent spectroscopically with that produced by Method 1.

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