Sodium Methoxide → 2,4-dihydro-5-methoxy-2-methyl-4-(2-methylphenyl)-3H-1,2,4-triazol-3-one

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Reaction Steps

8.25 g of the title compound of Step B was dissolved in 80 mL of 1:1 dimethoxyethane/methanol under N2. 14.0 mL of sodium methoxide (30% solution in methanol) was added and the solution was heated at reflux for 3 h. The mixture was allowed to cool, diluted with ethyl acetate, washed with water, and then washed with saturated aqueous NaCl. The combined organic extracts were dried (MgSO4), filtered, and concentrated under reduced pressure. The residue was purified by flash chromatography (50-70% ethyl acetate/hexanes as eluent) and triturated with 50% diethyl etherlhexanes to afford 6.7 g of the title compound of Step C (95% pure). 1H NMR (CDCl3): δ 7.35-7.27 (m,3H), 7.18 (d,1H), 3.94 (s,3H), 3.46 (s,3H), 2.2 (s,3H).

Provenance & Evidence