Properties | 2-chloro-5-nitronicotinic acid, its molecular formula is C6H3ClN2O4, molecular weight is 202.55,CAS number is 42959-38-6, melting point 140-143°C, white or yellow solid. |
Application | 2-chloro-5-nitronicotinic acid is a chemical intermediate used in the synthesis of pesticides and medicines. For example, French Rhone-Planck Agricultural Co., Ltd. uses it to synthesize new herbicides. |
Synthesis method | France Rhone-Planck Agricultural Co., Ltd. proposed a two-step preparation of 2-chloro-5-nitronicotinic acid from 2-hydroxynicotinic acid The solution: 1) Add fuming nitric acid (26ml) to a concentrated H2SO4(100ml) solution of stirred 2-hydroxynicotinic acid (34.8g) at 35-40°C. The resulting mixture was stirred at 50°C for 4 hours. Cool the mixture to room temperature and pour on ice. The precipitate was filtered and collected, air-dried on a filter, and recrystallized from ethanol to obtain 2-hydroxy-5-nitronicotinic acid, which is a light yellow solid (39.6g);2) Dimethylformamide (4 drops) was added to 2-hydroxy-5-nitronicotinic acid (5g) in phosphoryl chloride (10ml). The mixture was stirred at reflux temperature for 3 hours. The excess solvent is evaporated and removed, and the residue is carefully poured into the water to maintain the temperature below 40 ℃. The mixture was stirred for a further 30 minutes at room temperature and then extracted with ethyl acetate. The extract was washed with water, dried (MgSO4), and evaporated to dry. The obtained residue was co-researched with ether/hexane to obtain 2-chloro-5-nitronicotinic acid, which was a light yellow oil (3.6g). |