2,3-Diaminopyridine

Chemical properties

Brown powder

The Uses of 2,3-Diaminopyridine

2,3-Diaminopyridine was used in the synthesis of 2,3-diaminopyridinium-4-hydroxybenzoate1. It was used as internal standard in analysis of poly(amidoamine)dendrimers having different terminal functionalities by capillary electrophoresis. It was used as reagent in synthesis of imidazopyridines and organometallic complexes.

Synthesis

2,3-Diaminopyridine can be prepared by 2,3-Diamino-5-bromopyridine under basic conditions. The specific synthesis is described below:
In an apparatus for catalytic hydrogenation 56.4 g. (0.3 mole) of 2,3-diamino-5-bromopyridine suspended in 300 ml. of 4% sodium hydroxide solution is shaken with hydrogen in the presence of 1.0 g. of 5% palladized strontium carbonate (Note 14). When absorption of hydrogen is completed, the catalyst is removed by filtration, and, after saturation with potassium carbonate (about 330 g. is required), the resulting slushy mixture is extracted continuously with ether until all the precipitate completely disappears (usually about 18 hours, but this depends on the efficiency of the extraction apparatus). The ether is removed by distillation, and the residue of crude 2,3-diaminopyridine is recrystallized from benzene (about 600 ml. is required) using 3 g. of activated charcoal and filtering rapidly through a preheated Büchner funnel. The yield of 2,3-diaminopyridine, obtained as colorless needles, m.p. 115–116°, pKa 6.84, is 25.5–28.0 g. (78–86%).

General Description

2,3-Diaminopyridine forms the bis-condensed Schiff base with salicylaldehyde. It forms charge transfer complex with tetrachloro-p-benzoquinone and tetracyanoethylene.

Purification Methods

It crystallises from *benzene and sublimes in vacuo. [Beilstein 22/11 V 241.]