Dichloromethane → 2-Chloro-5-methyl-7-phenyl-1,2,4-triazolo[1,5-a]pyrimidine

Beteiligte Stoffe

Reaktionsschritte

To 2.0 g (8.9 mmol) of 5-methyl-7-phenyl-1,2,4triazolo[1,5-a]pyrimidin-2-amine stirring in 25 ml of concentrated hydrochloric acid, 1.2 g (17.4 mmol) of sodium nitrite dissolved in 4.0 ml of water was added dropwise at ambient temperature. After the addition, the reaction suspension was warmed at about 60° for 15 minutes followed by stirring another 10 minutes without heat. Ethyl acetate (150 ml) and excess water were added. The ethyl acetate layer was separated whereby a certain amount of insoluble material present was ignored and the extract washed with water (2X), saturated sodium bicarbonate, brine, dried over magnesium sulfate, and evaporated in vacuo to give a solid residue. Silica gel column chromatography (methylene chloride followed by 10:1 methylene chloride/ethyl acetate) afforded the title compound, m.p. 179°-181° C.

Herkunft & Nachweise