Hydrazine hydrate (1:1) → 4-(3-amino-4-methoxybenzyl)-2H-phthalazin-1-one

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Reaction Steps

A stirred mixture of the above 3-(3-amino-4-methoxybenzylidene)-3H-isobenzofuran-1-one (1.336 g, 0.005 mol), industrial methylated spirit (20 ml) and hydrazine monohydrate (0.25 g, 0.005 mol) was heated under reflux for 1.5 hours then cooled to ambient temperature. The resulting solid was collected by filtration, washed with water (5 ml), and dried in vacuo to give 4-(3-amino-4-methoxybenzyl)-2H-phthalazin-1-one (1.15 g) as a beige solid, m.pt. 211.5–214.5° C.; 250 MHz 1H-nmr (d6-DMSO) δ (ppm): 3.75 (s, 3H) (—OCH3), 4.15 (s, 2H) (ArCH2—), 4.75 (s, 2H) (—NH2) 6.5–6.6 (m, 2H) (2×ArH), 6.7–6.75 (m, 1H) (ArH) 7.8–8.0 (m, 3H)(3×ArH), 8.3 (d, 1H) (ArH), 12.65 (s, 1H) (CONH); m/z (M+H)+. 282, 100% purity.

Provenance & Evidence