Hydrochloric Acid → 5-(5-Chloro-2-thienyl)-4-(2-methoxyethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one

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Reaction Steps

4.85 g (17.46 mmol) of the compound of Example 49A were dissolved in 17 ml (52.39 mmol) of 3 M aqueous sodium hydroxide solution and heated under reflux for 168 h. After 16, 40, 64 and 88 h, in each case a further 1.05 g (26.19 mmol, 104.76 mmol in total) of solid sodium hydroxide were added. Using 1M hydrochloric acid, the reaction was adjusted to pH 10, and the mixture was extracted twice with in each case 30 ml of ethyl acetate. The combined organic phases were dried over sodium sulphate, filtered and freed from the solvent on a rotary evaporator. The residue was dried under high vacuum. This gave 2.44 g (54% of theory) of the title compound.

Provenance & Evidence