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

Of the compound from Example 167A, 4.85 g (17.46 mmol) were dissolved in 17 ml (52.39 mmol) of 3M aqueous sodium hydroxide solution and heated under reflux for 168 h. During this, after 16, 40, 64 and 88 h, 1.05 g portions (26.19 mmol, in total 104.76 mmol) of solid sodium hydroxide were added. The batch was acidified to pH 10 using 1M hydrochloric acid, and the mixture was extracted with twice 30 ml of ethyl acetate. The combined organic phases were dried over sodium sulphate, filtered, freed from the solvent on a rotary evaporator and dried in an HV. This gave 2.44 g (54% of theory) of the title compound.

Provenance & Evidence