5-Hydroxy-2-nitrobenzaldehyde

100-83-4

42454-06-8

The general procedure for the synthesis of 5-hydroxy-2-nitrobenzaldehyde (formula VI) using m-hydroxybenzaldehyde (formula V, R5=H) as starting material was as follows: 3 g of m-hydroxybenzaldehyde was slowly added to 30 ml of nitric acid (density = 1.17, 28% solution), and the temperature of the solution was maintained at a temperature between 35°C and 45°C during the reaction. After the addition was completed, hydrolysis was carried out and the reaction mixture was subsequently left to stand at room temperature. The reaction produced a yellow precipitate which was filtered and the precipitate was refluxed in 20 ml of benzene for 15 to 20 minutes. The insoluble material was separated and purified by recrystallization in water. 5-Hydroxy-2-nitrobenzaldehyde (formula VI) was finally obtained in 25% yield with a melting point of 167°C (molecular formula: C7H5NO4, molecular weight = 167).