Condensation of phthalic anhydride (I) with 4-methylpyridine (II) and heating with NH2-NH2 hydrate yields phthalazine (III) which is converted into chloro derivative (IV) by directly heating in presence of POCl3 or alternatively by heating a solution of (IV) in CH3CN with HCl/dioxane and POCl3. Phthalazine (III) is added to a melt formed by 4-chloroaniline (V), P2O5 and Et3N.HCl to afford the desired product. Alternatively the final product is obtained by heating (V) with (IV) in EtOH or 1-butanol.
The reaction of phthalide (I) with pyridine-4-carbaldehyde (II) by means of NaOMe in methanol gives the nonisolated intermediate (III), which rearranges in the reaction medium to yield indenone (IV). The reaction of (IV) with hydrazine hydrate affords the phthalazinone (V), which was activated as the imidoyl chloride (VI) by means of POCl3 and then reacted with 3-bromo-4-methylaniline (VII) in ethanol to afford the 1-anilino-phthalazine.
The reaction of phthalide (I) with pyridine-4-carbaldehyde (II) by means of NaOMe in methanol gives the nonisolated intermediate (III), which rearranges in the reaction medium to yield indenone (IV). The reaction of (IV) with hydrazine hydrate affords the phthalazinone (V), which was activated as the imidoyl chloride (VI) by means of POCl3 and then reacted with 3,4-bis(trifluoromethyl)aniline (VII) in ethanol to afford the 1-anilino-phthalazine.
The reaction of phthalide (I) with pyridine-4-carbaldehyde (II) by means of NaOMe in methanol gives the nonisolated intermediate (III), which rearranges in the reaction medium to yield indenone (IV). The reaction of (IV) with hydrazine hydrate affords the phthalazinone (V), which was activated as the imidoyl chloride (VI) by means of POCl3 and then reacted with 3-bromo-5-trifluoromethylaniline (VII) in ethanol to afford the 1-anilino-phthalazine.
The reaction of phthalide (I) with pyridine-4-carbaldehyde (II) by means of NaOMe in methanol gives the nonisolated intermediate (III), which rearranges in the reaction medium to yield indenone (IV). The reaction of (IV) with hydrazine hydrate affords the phthalazinone (V), which was activated as the imidoyl chloride (VI) by means of POCl3 and then reacted with 3-chloro-5-trifluoromethylaniline (VII) in ethanol to afford the 1-anilino-phthalazine.
The reaction of phthalide (I) with pyridine-4-carbaldehyde (II) by means of NaOMe in methanol gives the nonisolated intermediate (III), which rearranges in the reaction medium to yield indenone (IV). The reaction of (IV) with hydrazine hydrate affords the phthalazinone (V), which was activated as the imidoyl chloride (VI) by means of POCl3 and then reacted with 4-chloro-3-trifluoromethylaniline (VII) in ethanol to afford the 1-anilino-phthalazine.
The reaction of phthalide (I) with pyridine-4-carbaldehyde (II) by means of NaOMe in methanol gives the nonisolated intermediate (III), which rearranges in the reaction medium to yield indenone (IV). The reaction of (IV) with hydrazine affords the phthalazinone (V), which is finally condensed with 4-chloroaniline (VI) by means of P2O5 and TEA at 170 C to provide the target phthalazine.