Preparation of 2-ethoxybenzamide_Kain Industrial Additive

Background and overview^[1][2]

2-Ethoxybenzamide is an alkoxybenzamide, a new type of pigment image stabilizer in photosensitive materials. This type of alkoxybenzamide compound is evenly distributed in the form of fine particles. The gelatin of the photosensitive dye coupler can be mixed well with the photosensitive dye coupler. It has low turbidity and high transparency. It is an excellent new type of photosensitive material pigment image stabilizer. In addition, 2-ethoxybenzamide has antipyretic and analgesic effects. Its analgesic effect is equivalent to that of aspirin, and it has no obvious gastrointestinal irritation. Therefore, this drug is also suitable for patients with headache and fever who are not suitable for using aspirin.

Preparation^[2]

Under nitrogen protection, mix 200mL ethanol, copper iodide (3.8g, 0.02mol) and potassium hydroxide (16.8g, 0.3mol) evenly, add o-chlorobenzonitrile (27.5g, 0.2mol), Then heat to 80°C and keep the reaction, monitor the reaction with TLC or liquid phase. After the reaction is complete, recover the ethanol, bring it down to room temperature, add 100 mL of water and 150 ml of toluene for washing, then recover the toluene, and purify the intermediate o-ethoxy by distillation under reduced pressure. Benzonitrile 23.5g (154℃/20Torr).

Dissolve 20.6g (0.14mol) o-ethoxybenzonitrile in 150mL toluene, add potassium tert-butoxide (47.1g, 0.42mol), heat to 60°C for reaction, and monitor the reaction with TLC or liquid phase. After the reaction is complete, 150 mL of water is added for washing, and the solvent is recovered from the organic phase. The residual liquid is recrystallized with ethanol and dried to obtain 19.7 g of 2-ethoxybenzamide, a white solid product.

Apply^[2]

CN201910496696.4 discloses a method for separating succinic acid and glutaric acid. Dissolve the mixture of succinic acid and glutaric acid in an organic solvent, add 2-ethoxybenzamide in an equal molar amount to glutaric acid, raise the temperature to 60-80°C, and keep it for 2-4 hours. When it becomes clear, slowly cool it to room temperature and keep it for 2-8 hours. Glutaric acid and 2-ethoxybenzamide form a eutectic, and succinic acid dissolves in the organic solvent. Filter to obtain an organic solution of glutaric acid and 2-ethoxybenzamide eutectic solid and succinic acid. Dissolve the obtained eutectic solid of glutaric acid and 2-ethoxybenzamide in pure water, dissociate at 20-30°C for 2-4 hours, and extract the 2-ethoxy group with n-hexane, cyclohexane or toluene. Benzamide, glutaric acid dissolve in water. The organic solution of succinic acid is rotary evaporated to obtain succinic acid, and the aqueous solution of glutaric acid is rotary evaporated to obtain glutaric acid. The preparation process of this method is simple and mild, and is suitable for large-scale separation of succinic acid and glutaric acid.

Main reference materials

[1]CN201910496696.4 A method for separating succinic acid and glutaric acid

[2][Chinese invention] CN201611123650.0 Preparation method of alkoxybenzamide