Phthalimides, reductive coupling with

The reductive coupling of phthalimides with ketones and aldehydes in THF by low-valent titanium generated from Zn-TiC gave 3-hydroxy-3-(l-hydroxyaIkyl)-isoindolin-l-ones as two-electron reduced products and alkyhdene-isoindolin-l-ones as four-electron reduced products. These could be obtained selectively by controlling the reaction conditions. The geometric ratios of the alkylideneisoindolin-l-ones obtained from phthalimides and aldehydes could be increased by reflux in PPTS/ toluene (catalyst). In particular, the Z-isomers of A-unsubstituted alkylideneisoindolin-l-ones could be obtained exclusively. 

Phthalimide protection is stable towards acids and bases, but can be cleaved with strong nucleophiles, such as hydrazines or sulfides, or by reduction with sodium boro-hydride [230]. More sensitive towards nucleophilic attack than unsubstituted phthalimide is tetrachlorophthalimide [33]. This group has been successfully used as N(a) protection of amino acids in the solid-phase synthesis of peptides (deprotection N2H4/DMF (15 85), 40 °C, 1 h coupling DIC/HOAt/amino acid (1 1 1), 3 equiv. of each, DMF, 25 °C, 4 h [294]). Typical conditions for the removal of phthaloyl protection on cross-linked polystyrene include treatment of the resin with hydrazine hydrate [295,296], with methyl hydrazine [297], or with primary aliphatic amines [298] in DMF, EtOH, or solvent mixtures for several hours at room temperature or above [296,299,300]. Illustrative examples are sketched in Figure 10.15. It has been claimed that the hydrazinolysis of polystyrene-bound phthalimides proceeds more readily in DCM or DCE than in DMF [301]. 

N-Substituted phthalimides are easily synthesized via solvent-free condensation of phthalic anhydrides with amines or via coupling methods [3]. The phthalimide moiety has a reversible reduction potential in dimethylformamide (DMF) which is... 

Photo-addition of alkenes to A methylnaphthalene dicarboxamides in benzene has been studied. The structure of the arene moiety in the imide was important in determining the reaction path. Mainly cyclobutane and oxetan formation occurred. The dicarboximide (342) undergoes photochemical cyclization with incorporation of methanol to yield the two products (343) and (344) in 55 and 16% respectively. This type of cyclization appears to be quite general for such systems and is also reported for the imides (345) and (346). A variety of products resulting from aminolysis, reduction, and radical coupling is produced on irradiation of the phthalimide (347) in diethylamine. ... 

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