Preparing 5-chloromethyl salicylic acid (I) by reacting salicylic acid with paraformaldehyde and hydrogen chloride in glacial acetic acid comprises performing the reaction at room temperature in the presence of a catalyst, e.g. phosphoric acid, calcium hydroxide, zinc chloride, sodium (bi)sulfate or hydrogen bromide, where the product is recovered by filtration or centrifugation and the resulting filtrate is used directly for a new synthesis. An independent claim is also included for preparing 5-(2-hydroxy-1-naphthylmethyl) salicylic acid (II) by reacting (I) with 1-naphthol in a mixture of glacial acetic acid and methylene chloride at 40[deg]C, where the product is recovered by filtration or centrifugation, the product is then decolorized by washing with methylene chloride, the product is then washed with benzene or toluene to remove unreacted 1-naphthol, the product is recovered by vacuum drying at 40[deg]C in the dark and is then recrystallized from ethanol/water to give a 97% pure product, and the product is optionally converted to its zinc, magnesium or calcium salt.
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