Methyl atropate → 6-Phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrimidin-7-on

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Reaction Steps

A solution of 9.01 g (55.6 mmol) 2-phenyl acrylic acid methyl ester and 4.24 g (50.4 mmol) 3-amino-1,2,4-triazole in 41 ml n-butanol was refluxed for 24 hours. The solvent was removed under reduced pressure. The residue was treated with a small amount of ethanol and diethyl ether and cyclohexane were added. The diethyl ether is slowly removed under reduced pressure. The crude 6-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrimidin-7-on precipitated during evaporation, was isolated by filtration and washed with diethyl ether. 6-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrimidin-7-on was recrystallized from a small amount of ethanol. 2.04 g (19%) 6-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrimidin-7-on was isolated (m.p. 184-186° C.).

Provenance & Evidence