Cysteamine Hydrochloride → 3-(2-Aminoethyl)-4-methyl-1,2,4-triazole dihydrobromide

Participants

Reaction Steps

The thione (44 g.) was desulphurised by slow addition to a solution prepared from nitric acid (75 ml.), water (150 ml.) and sodium nitrite (1.5 g.) at 15°-20°. Following subsequent basification with sodium carbonate and concentration, the residue was extracted with ethanol-ether 1:1 and distilled to afford 3-ethoxymethyl-4-methyl 1,2,4-triazole (30 g.), b.p. 154°-156°/0.05 mm. The above compound (15 g.) dissolved in 48% aqueous hydrobromic acid (150 ml.) was heated under reflux for 24 hours, concentrated to dryness and the residue obtained (a mixture of 4-methyl-3-bromomethyl-1,2,4-triazole and 4-methyl-3-hydroxymethyl-1,2,4-triazole) was used directly in the reaction with cysteamine hydrochloride and hydrobromic acid as described in Example 1 (i)(a) to give 3-(2-aminoethyl)-4-methyl-1,2,4-triazole dihydrobromide, m.p. 175°-177°.

Provenance & Evidence