2-[(3-chloro-4-methyl-2-thienyl)carbonyl]-N-isobutylhydrazinecarboxamide → 5-(3-chloro-4-methyl-2-thienyl)-4-isobutyl-2,4-dihydro-3H-1,2,4-triazol-3-one

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Reaction Steps

A suspension of 1.28 g (4.42 mmol) of 2-[(3-chloro-4-methyl-2-thienyl)carbonyl]-N-isobutyl-hydrazinecarboxamide from Example 246A in 12 ml 3 N aqueous sodium hydroxide is first heated overnight under reflux. After cooling, it is filtered. The filtrate contains impure product, while the solid filtered off mainly corresponds to the educt. This solid is taken up again in ca. 15 ml of 3 N ethanolic aqueous sodium hydroxide and again heated overnight under reflux. After neutralization with 1 N hydrochloric acid and concentration, the residue together with the concentrated filtrate from the aqueous reaction is purified by preparative HPLC [Method 12]. After evaporation and drying of the product fractions, 562 mg (47% of theory) of the target compound are thus obtained.

Provenance & Evidence