Phthalazine → HCID 178507327, compound

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Reaction Steps

The synthesis of phthalazine derivatives of general formulas 13-20 may be achieved as outlined in Scheme II. In general, a mixture of 4-nitrophthalic anhydride 9 and hydrazine may be refluxed in a suitable solvent, e.g., isopropyl alcohol, to provide 6-amino-phthalazine-1,4-diol 10 in almost quantitative yield. Compound 10 may then be treated with phosphorus oxychloride and N,N-diisopropylethylamine to form 1,4-dichloro-phthalazin-6-ylamine 11. Reduction of compound 11 with a suitable reducing agent, e.g., iron, may be used to produce the amino derivative 12. Alkylation or acylation of the amino group of compound 12 using A-B-X (where, for example, A is alkyl, aryl, arylalkyl, arylheteroalkyl, B is absent, CO, SO2, and X is a suitable leaving group, such as, Cl, Br, I, OTosyl, etc.) may be used to provide the dichloro derivative of general formula 13. Treatment of compound 13 with a nucleophile of general formula R1R2NH affords two isomers of general formulas 17 and 18. Alternatively, compound 13 may be treated with NaI and HI in, e.g., acetone to obtain the di-iodo derivative 14. Compound 14 may then be reacted with an appropriate nucleophile (e.g., of general formula R1R2NH) to produce compounds 15 and 16. Compounds 15 and 16 may then be treated with CuCN to produce the corresponding cyano derivatives 19 and 20.

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