Hydrogen Peroxide → 1-(3,5-Dichloro-pyridin-4-ylmethyl)-6-methoxy-4-[1,2,4]triazol-1-yl-phthalazine 3-oxide

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Reaction Steps

Under N2 at 0° C. a solution of 1-(3,5-dichloro-pyridin-4-ylmethyl)-6-methoxy-4-[1,2,4]triazol-1-yl-phthalazine (5.1 g, 13.2 mmoles), prepared as described in example 51, in trifluoroacetic acid (25 ml), was dropwise added with H2O2 (1.35 ml, 13.5 mmoles). The temperature was left to rise to the room value and, after 48 hours, the pH was adjusted with NaOH. After further 24 hours under stirring, the mixture was dried, taken up in CH2Cl2. The organic phase was washed with water, anhydrified and dried to give a foam which was flash chromatographed (eluent: ethyl acetate/ethyl ether 6:4, then 8:2) to give 2.2 g of the title compound (yield: 41%). m.p.: 218-220° C. (dec.).

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