Hydrochloric Acid → Methyl {3-(4-chlorophenyl)-5-oxo-4-[(1E)-3,3,3-trifluoroprop-1-en-1-yl]-4,5-dihydro-1H-1,2,4-triazol-1-yl}acetate

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Reaction Steps

At RT, 5.0 g (13.12 mmol) of the compound from Example 8A together with 1.93 g (15.8 mmol) of 4-N,N-dimethylaminopyridine were initially charged in 70 ml of pyridine, 5.54 ml (32.92 mmol) of trifluoromethanesulfonic anhydride were added a little at a time and the mixture was stirred for 18 h. For work-up, 5 ml of 1 N hydrochloric acid were added and the pyridine was removed on a rotary evaporator. The residue was taken up in 50 ml of ethyl acetate and washed with 25 ml of water. The aqueous phase was re-extracted twice with in each case 25 ml of ethyl acetate. The combined organic phases were dried over sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by chromatography on silica gel (mobile phase: cyclohexane/ethyl acetate 10:1, then 4:1). This gave 3.50 g (73% of theory) of the title compound.

Provenance & Evidence