2-Amino-5-chloropyridine

Based on the structural analysis of 2-amino-5-chloropyridine, a synthetic route was designed. 2-amino-5-chloropyridine was prepared from 2-aminopyridine as a starting material. The target compound was obtained through nitration, amidation, and reduction reactions. The synthetic reaction formula for 2-amino-5-chloropyridine is shown in the figure below:

beige to beige-brown crystalline powder

5-Chloro-2-pyridinamine is a useful synthetic intermediate. It can be used to synthesize zopiclone (Z700500) which is a cyclopyrrolone member of a family of non-benzodiazepine GABAA receptor agonists.

2-Amino-5-chloropyridine can be used to electro-organically synthesize 6-aminonicotinic acid. 6-aminonicotinic acid is the main component of vitamin B3 and can be used to treat pellagra. The specific method is as follows:
In the presence of sulfuric acid and carbon dioxide, in dimethylformamide (DMF) solution, 5-chloro-2-nitropyridine 1 is electrochemically converted to 2-amino-5-chloropyridine 2 on a nickel cathode and a copper anode at an apparent current density of 10 mA/cm2 using a diaphragmless electrolytic cell, with a yield of up to 84%. Then 2 is reductively carboxylated to synthesize 6-aminonicotinic acid 3 on the cathode surface with a yield of 78%.

The Journal of Organic Chemistry, 41, p. 93, 1976 DOI: 10.1021/jo00863a020

2-Amino-5-chloropyridine is an irritant, causing severe eye irritation, possibly skin and respiratory irritation, and harmful if ingested. The substance is non-mutagenic, but has a relatively high toxicity to zebrafish embryonic development, with embryonic malformation and mortality rates being concentration-dependent.

Recrystallise this base from pet ether. It sublimes at 50o/0.5mm. [Beilstein 22 II 332, 22/8 V 541.]