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

Participants

Reaction Steps

A stirred mixture of the above 3-(3-amino-4-chlorobenzylidene)-3H-isobenzofuran-1-one (0.815 g, 3 mmol), industrial methylated spirit (10 ml) and hydrazine monohydrate (0.15 g, 3 mmol) was heated under reflux for 1 hour then cooled to ambient temperature. The resulting solid was collected by filtration, washed with industrial methylated spirit (5 ml) and water (5 ml), and dried in vacuo to give a pale grey solid. The crude material was recrystallised from acetonitrile (140 ml) and the resulting solid was collected by filtration and dried in vacuo to give 4-(3-amino-4-chlorobenzyl)-2H-phthalazin-1-one (0.607 g) as an off-white solid, m.pt. 227–228° C.; 250 MHz 1H-nmr (d6-DMSO) δ (ppm): 4.05 (s, 2H) (ArCH2—), 5.2 (s, 2H) (—NH2), 6.4–6.5 (m, 1H) (ArH), 6.6–6.7 (m, 1H) (ArH), 6.95–7.05 (m, 1H) (ArH), 7.65–7.85 (m, 3H) (3×ArH), 8.1–8.2 (m, 1H) (ArH), 12.5 (s, 1H) (CONH) ; m/z (M+H)+. 286/288, 100% purity.

Provenance & Evidence