Water → 3-Nitrophthalic anhydride

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Reaction Steps

where M is Li, Na, K wherein 5-nitro-2,3-dihydrophthalazine-1,4-dione is solved in water solution of MOH, where M has the above mentioned meaning, with forming solution of 5-nitro-2,3-dihydrophthalazine-1,4-dione alkaline salt which is catalytically transformed in 5-amino-2,3-dihydrophthalazine-1,4-dione salt at the temperature of 40-90° C. by means of hydrogen under the pressure of 1-4 MPa at the presence of a transition metal catalyst (Pt, Pd) on active carbon, and separation of 5-amino-2,3-dihydrophthalazine-1,4-dione crystalline salt is performed by dilution of the water solution with lower alcohol or cyclic lower ether while cooling to the temperature −5° C. to −15° C., providing that there is used 5-nitro-2,3-dihydrophthalazine-1,4-dione obtained in the reaction of 3-nitrophthalic acid anhydride with hydrazine hydrate in anhydrous acetic acid at the temperature 100-110° C. with distilling the mixture of acetic acid and water off.

Provenance & Evidence