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The preparation of 3,5-dinitrobenzoate derivatives is utilized frequently in the qualitative organic analysis laboratory for the identification of alcohols and phenols. The recommended procedures for the preparation of these derivatives employ 3,5-dinitrobenzoyl chloride as the acylating agent under reaction conditions that include: heating the reactants without solvent (1), heating the reactants in pyridine (2), and heating the reactants under reflux in a solution of 4-methylpyridine in cyclohexane (3).
Some problems that may arise from the above procedures are described below. The facile hydrolysis of 3,5-dinitrobenzoyl chloride by atmospheric moisture limits the shelf life of this reagent. Recrystallization procedures for the purification of partially hydrolyzed samples of the reagent (3) and procedures for the preparation of "fresh" reagent (2) are available. The preparation of the 3,5-dinitrobenzoates of tertiary alcohols by the reaction of 3,5-dinitrobenzoyl chloride in the presence of a pyridine base at elevated temperatures frequently fails due...