Hydrochloric Acid → 9-chloro-2-methyl-7-phenyl-5H[1,2,4]triazolo-[5,1-a] [2,4]benzodiazepine

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Reaction Steps

To a stirring solution of 3.1 g (10.4 mmol) of 7-chloro-2-methyl-5-phenyl-5H-[1,2,4]triazolo[5,1-a]-isoindol-5-amine and 3.1 g (22 mmol) of hexamethylenetetramine (hexamine) in 75 ml of DME is added 1.5 ml of 4 N HCl (dioxane). A precipitate forms immediately and the two phase mixture is refluxed. After 5 hours another 1.0 g of hexamine is added and reflux is continued overnight. An additional 1.5 ml of the HCl solution is added after 12 hours and again after an additional 24 hours. After another 24 hours, thin layer chromatography (TLC) shows the disappearance of starting material. The mixture is filtered and the solvent is removed from the filtrate under vacuum. The residue is taken up in CHCl3 and applied to a 5×10 cm silica gel column (Baker 60-200 mesh). The column is eluted with CHC13 until all of the high Rf material (followed by TLC) is recovered. The solvent is removed in vacuo and the residue recrystallized from 20 ml of acetonitrile to yield 1.3 g of pure product: m.p. 150.5°-152° [concentration of the mother liquor gives an additional 0.2 g for a total yield of 1.5 g (46.6%)].

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