L 10503 → 2-(3-Methoxyphenyl)[1,2,4]triazolo[5,1-a]isoquinoline

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Reaction Steps

Thirty five grams of wet manganese dioxide, prepared as described by E. Pratt and J. Van de Castle, J. Org. Chem. 26, 2973 (1961) is suspended in 200 ml. of benzene, according to the procedure outlined by J. Goldman, J. Org. Chem. 34, 1979 (1969). The mixture is refluxed for about three hours, then a solution of 2.77 g. (0.010 mole) of 2-(m-methoxyphenyl)-5,6-dihydro-s-triazolo[5,1-a]isoquinoline in 30 ml. of anhydrous benzene is added. Refluxing is prolonged for a further six hours, then the reaction mixture is allowed to stand overnight. 20 Grams of the above manganese dioxide is added and the resulting suspension is refluxed for 8 hours. After cooling, the solid catalyst is filtered off, the benzene solution is dried under vacuum and a residue is obtained which is recrystallized from ethyl acetate. Yield 1.4 g., m.p. 159°-60° C. Alternatively, the title compound may be obtained in a 70% yield by treating at 200°-250° C with about 1.5 equimolecular proportion of sulfur.

Provenance & Evidence