A salt represented by formula (4) is useful for the production of an active ingredient for plant disease control agents. The salt represented by formula (4) is produced through: a first step wherein a mixture, which contains a hydrocarbon solvent and an alkali metal hydroxide represented by formula A+OH-, is dehydrated and a second step wherein the mixture dehydrated in the first step and a compound represented by formula (2) are caused to react with each other.本發明係關於一種經由如下步驟製造之式(4)所表示之鹽,其可用於製造植物病害防治劑之有效成分:對包含烴溶劑、及下述式A+OH-所表示之鹼金屬氫氧化物的混合物進行脫水處理之第1步驟;以及使於第1步驟中經脫水處理之混合物、及式(2)所表示之化合物進行反應之第2步驟。
