Ing-Manske cleavage

N -Condensed 1,2,4-triazepine ring and o-aminobenzophenones from o-phthalimidobenzophenones Ing-Manske cleavage... 

The hydrolytic cleavage is usually slow, and requires drastic reaction conditions. A more elegant method is presented by the Ing-Manske procedure, where the A-alkylated imide is treated with hydrazine under milder conditions. In addition to the desired amine 5, the cyclic phthalic hydrazide 6 is then formed ... 

Phthalimides are relatively stable under both acidic and basic conditions but are easily cleaved by nucleophiles. Its cleavage is often accomplished using hydrazine according to the Ing-Manske procedure of the Gabriel reaction. 

Cleavage of phthaloyl protective group. The phthaloyl group is not useful for protection of the amino group of penicillins and cephalosporins because hydrazinolysis (Ing-Manske procedure, 1, 442) disrupts the azetidinone ring. Eli Lilly chemists have reported a new method of dephthaloylation that overcomes this difficulty. The phthalimido compound (1) is hydrolyzed by aqueous sodium sulfide to the corresponding phthalamic acid (2), which on dehydration... 

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