43.20 g (0.081 Mol) of 6-[((2E)-{4[(ethoxycarbonyl)oxy]phenyl}prop-2-enoyl)oxy]hexyl 3,5-dinitrobenzoate are dissolved in 66 ml (0.815 Mol) of pyridine and 400 ml of acetone at room temperature. 61 ml (0.815 Mol) of ammonium hydroxide solution 25% are added dropwise to the solution at room temperature. After 12 h reaction, the mixture is thrown on water and acidified by the addition of HCl 25% (up to pH=3-4). A paste is obtained which is filtrated and dissolved in ethyl acetate and extracted with water. The organic phase is dried with sodium sulfate, filtrated, concentrated by rotary evaporation. Filtration of the residue over silica gel with tert-Butyl methyl ether as eluant and crystallization of the residue in 200 ml of ethyl acetate and 1200 ml of hexane at 0° C. give 15.84 g of 6-[((2E)-{4-hydroxyphenyl}prop-2-enoyl)oxy]hexyl 3,5-dinitrobenzoate as yellow crystals.
