Phthalazine → HCID 178518941, compound

Participants

Reaction Steps

The synthesis of phthalazine derivatives of general formulas 25-26 may be achieved as outlined in Scheme III. In general, a mixture of 4-bromophthalic anhydride and hydrazine may be refluxed in a suitable solvent, e.g., isopropyl alcohol, to provide 6-bromo-phthalazine-1,4-diol 21 in almost quantitative yield. Compound 21 may then be treated with phosphorus oxychloride to form 1,4-dichloro-6-bromo phthalazine 22. Treatment of compound 22 with a suitable nucleophile (where, for example, Y is NR1R2 or NaOR) affords two isomers of general formulas 23 and 24. Displacement of the bromine atom with a suitable amino or alcohol derivative A-B-X (where, for example, A is alkyl, aryl, arylalkyl, arylheteroalkyl, B is absent, CO, and X is OH, NH2), using a suitable Pd complex derivative in the presence of a base like sodium tert-butoxide in a suitable solvent, affords the desired 6-amino or 6-alkoxy phthalazine derivatives of general formula 25-26.

Provenance & Evidence