Preparation of o-nitrobenzene acetic acid_Kain Industrial Additive

Background and overview^[1][2]

O-Nitrophenylacetic acid is a widely used organic synthesis intermediate. O-Nitrophenylacetic acid can be used to synthesize benzofuran-2(3H)-one through ammonium sulfide reduction, diazotization reaction and hydrolysis. Benzofuran-2(3H)-one is an important organic synthesis intermediate and can be used for Synthetic medicines, pesticides and new antioxidants.

Preparation^[1]

A method for synthesizing intermediate o-nitrobenzene acetic acid, which is characterized in that the method includes the following steps:

Step 1. Add 100ml of absolute ethanol into a 500ml four-necked flask equipped with a thermometer, and gradually add 0.1g of catalyst Pt-MgO-CNTs and 8g of metallic sodium while stirring;

Step 2. After the reaction is completed, wait until the temperature drops to room temperature, add 35ml o-nitrotoluene and 56ml diethyl oxalate, heat to 45°C for 3 hours, then add water and raise the temperature to 60°C for hydrolysis reaction;

Step 3: After reacting for 1 hour, lower the temperature to 35°C and perform distillation under reduced pressure until the distilled component becomes a turbid liquid. Cool the reaction solution to 10°C and adjust pH=7 with sodium hydroxide solution;

Step 4. Then dropwise add hydrogen peroxide solution with a concentration of 0.3M, control the dropping speed, and keep the temperature below 20°C. While adding hydrogen peroxide dropwise, continue to add sodium hydroxide solution to the reaction solution for detection until sodium hydroxide is added. When the reaction solution no longer turns black, stop adding hydrogen peroxide and continue stirring the reaction at low temperature for 1 hour;

Step 5. At room temperature, add 100 ml of saturated sodium bicarbonate aqueous solution, then filter. The mother liquor is allowed to stand for separation, and the organic layer is removed. The aqueous layer is acidified with concentrated hydrochloric acid and adjusted to pH=2, filtered, and dried under vacuum. That is, a light yellow o-nitrobenzene acetic acid solid was obtained.

Apply^[2]

10,11-Dihydro-dibenzo[b,f]cyproheptin-10-one compound (I) is a synthetic non-steroidal anti-inflammatory drug Zaltoprofen, an antipsychotic drug An important intermediate for drugs such as Zotepine. CN200510021572.9 reports that o-nitrobenzene acetic acid is used as a starting material, coupled with a thiophenol derivative after reduction and diazotization, and then acylated and cyclized to prepare a 10,11-dihydro-dibenzo [b, f] Cyproheptine-10-one compounds.