4-Bromobenzaldehyde diethyl acetal is an important raw material and intermediate used in organic synthesis, pharmaceuticals, agrochemicals and dyestuff.
In an absolutely anhydrous apparatus, under the protection of nitrogen, the magnesium shavings were covered with 2-methyltetrahydrofuran (10 mL), and 4-bromobenzaldehyde was added, and the reaction was initiated by heating to at 30C, followed by the dropwise addition of a solution consisting of 4-bromobenzaldehyde and anhydrous 2-methyltetrahydrofuran (40 mL), with controlled titration maintained at 35C-40C. The reaction was continued for 1.5h, then cooled down to 15C-20C for 30 min under controlled temperature conditions. After addition, the reaction was continued for 1.5h, then cooled down to 15-20, and triethyl orthoformate was added dropwise within 30 minutes under controlled temperature conditions. After the addition, continue to react at the same temperature for 6 h. After the reaction is completed, lower the temperature to 5 ~ 7 , slowly add 10% dilute cold hydrochloric acid 100mL, separate the organic layer, 10% sodium carbonate to wash the organic layer to neutral, washed with water, anhydrous sodium sulfate drying, distillation and recovery of solvents, to get a colorless liquid 4-bromobenzaldehyde diethyl acetal.
