1,2-Dibromoethane → 2-(2-Bromoethyl)-4-methylphthalazin-1(2H)-one

Participants

Reaction Steps

4-Methyl-(2H)-phthalazin-1-one (6 g) and sodium hydride (1.5 g, 60% in oil) in dimethylformamide (DMF) were stirred at room temperature until hydrogen evolution ceased. To this suspension was added a five fold excess of 1,2-dibromoethane (25 ml) and stirring was continued for a further 2 hours. The solvent was removed and the residue taken up in ethyl acetate, washed twice with brine, dried (MgSO4) and evaporated. Chromatography on silica [Merck `Kieselgel 60` (Trade Mark)] eluting with methylene chloride containing methanol (0% up to 5%) gave, after collection and evaporation of appropriate fractions, a solid which was recrystallised from ethanol to give the title compound, yield 6.25 g, m.p. 102°-103°, used in the next stage.

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