Phthalimido group

The phthalimido group is susceptible to basic reagents and thus must occasionally be protected. This is accomplished by treatment with pyrrolidine to open the ring (>90%), which can be closed by treatment with HE, B(0H)3, the, H2O, 73-99% yield. ... 

This unusually high stereoselectivity is due to the high barrier to N-inversion and the presence of the electron-withdrawing phthalimido group. It can be demonstrated that the reaction is under kinetic control when the reaction mixtures described above are allowed to warm to temperatures near or above 0 °C, whereupon a partial or complete inversion of configuration at nitrogen can be seen (by NMR spectroscopy). 

Polymers with primary or secondary amine functionality cannot be prepared directly by RAFT polymerization these groups undergo facile reaction with thiocarbonylthio compounds. Such polymers can be prepared indirectly using RAFT agents with latent amine functionality, such as the phthalimido group in... 

This triiodinated synthon has an amino functional group (A) that is potentially reactive with the chloride functional groups of the acid (B). The amino functional group is protected in the form of a phthalimido group. 

The additions of ammonia equivalents, i.e. nitrogen nucleophiles like dibenzylamine (Scheme 27) which are essentially a protected primary amino group, are of special synthetic interest with respect to their possible subsequent chemical transformations. Poorly nucleophilic ammonia equivalents like acetamide or the classical phthalimide, did not add or originally gave low yields of 92a (Scheme 28) [9],but later phthalimide was found to add to 1-Me very well under mild conditions [53]. However, the a-chlorine in 92a could neither be substituted nor could the phthalimido group be cleaved without destroying the cyclopropane ring. The potassium bis(alkoxycarbonyl)amides (Boc)2NK and (Moc)(Boc)NK add to 1-Me in satisfactory yields, but the a-chlorine atom in... 

Structurally similar 5-chloro-l,2-dithiole-3-thiones 97 were obtained upon treatment of N-(2-phthalimidoethyl)-N-alkylisopropylamines with sulfur monochloride and DABCO and a final reaction with tiiethylamine (20030L929). The stability of thiones 97 is explained by the dipole-dipole interaction between the electron-rich l,2-dithiole-3-thione ring and electron-poor phthalimido groups (Scheme 48). 

Under these conditions, l-bromo-3-methylcarbazole 631 was formed via an intramolecular C-C bond formation by trapping of the diphenylnitrenium ion. In this reaction, the phthalimido group plays an important role for the generation and stabilization of a diphenylnitrenium ion. Finally, direct methoxide displacement of bromine from 631 led to murrayafoline A (7) (579) (Scheme 5.42). 

Aldehydes containing a variety of other functional groups, e.g., ether groups, the phthalimido group, keto, ester and nitrile groups. 12,13... 

Dithienylethene derivatives bearing a phthalimido group 259 have been studied (08EJO2531). The open form absorbs at 370 nm and irradiation at 313 nm resulted in a rapid appearance of the characteristic absorption band of the closed form 260 at 573 nm. 

Among them, the first compound prepared and studied was 3,5-anhydro-1,2-0-isopropylidene-a-D-xylofuranose (87)347 349 and its 1,2-O-cyclohexy-lidene analogue.350 Formation of the oxetane ring is based on the internal substitution of an conventional leaving group X at C-5, or surprisingly, also phthalimido group in 86 351 for application of the Mitsunobu reaction, see Ref. 349. 

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