Phthalic Anhydride → 2,3-Dihydro-1,4-phthalazinedione

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Reaction Steps

Compounds of this invention with Formulae I-VIII could be prepared as illustrated by the exemplary reaction in Scheme 20. Reaction of phthalic anhydride with hydrazine hydrate in acetic acid produces 2,3-dihydro-phthalazine-1,4-dione. Chlorination of 2,3-dihydro-phthalazine-1,4-dione and subsequent reaction with an amine, such as N-methyl-p-anisidine, produces the substituted 4-chlorophthalazine, such as (4-chlorophthalazin-1-yl)(4-methoxyphenyl)-amine. The chloro group can then be removed via hydrogenation to produce the substituted phthalazine, such as (4-methoxyphenyl)-methylphthalazin-1-yl-amine.

Provenance & Evidence