Phthalimides special

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... 

Arylene ether/imide copolymers were prepared by the reaction of various amounts 4,4 -carbonylbis[Ar-(4 -hydroxyphenyl)phthalimide] and 4,4 -biphenoi with a stoichiometric portion of 4,4 -dichlorodiphenyl sulfone in the presence of potassium carbonate in NMP/CHP [55]. To obtain high molecular weight polymer, the temperature of the reaction was kept below 155 °C for several hours before heating to >155°C in an attempt to avoid undesirable side reactions such as opening of the imide ring. The imide ring is not stable to conditions of normal aromatic nucleophilic polymerizations unless extreme care is exercised to remove water. Special conditions must be used to avoid hydrolysis of the imide as previously mentioned in the section on Other PAE Containing Heterocyclic Units and as practiced in the synthesis of Ultem mentioned in the Historical Perspective section. 

A. Potassium Phthalimide.—In a 2-1. round-bottom flask fitted with a reflux condenser are placed 80 g. (0.54 mole) of phthalimide (Note 1) and 1600 cc. of absolute alcohol. (Org. Syn. 5, 56.) The mixture is gently boiled for about fifteen minutes or until no more of the phthalimide dissolves (Note 2). The hot solution is decanted from any solid into a specially prepared solution of 30.5 g. (0.54 mole) of potassium hydroxide (Note 3). A precipitate of potassium phthalimide separates at once. The mixture is stirred and cooled quickly to room temperature, and the precipitate is filtered with suction. To the alcoholic mother liquors a second 80-g. portion of phthalimide is added, and the entire process is repeated. The two crops of crystals are united (Note 4) and washed with 200 cc. of acetone... 

History. Braun and Tschemak [23] obtained phthalocyanine for the first time in 1907 as a byproduct of the preparation of o-cyanobenzamide from phthalimide and acetic anhydride. However, this discovery was of no special interest at the time. In 1927, de Diesbach and von der Weid prepared CuPc in 23 % yield by treating o-dibromobenzene with copper cyanide in pyridine [24], Instead of the colorless dinitriles, they obtained deep blue CuPc and observed the exceptional stability of their product to sulfuric acid, alkalis, and heat. The third observation of a phthalocyanine was made at Scottish Dyes, in 1929 [25], During the preparation of phthalimide from phthalic anhydride and ammonia in an enamel vessel, a greenish blue impurity appeared. Dunsworth and Drescher carried out a preliminary examination of the compound, which was analyzed as an iron complex. It was formed in a chipped region of the enamel with iron from the vessel. Further experiments yielded FePc, CuPc, and NiPc. It was soon realized that these products could be used as pigments or textile colorants. Linstead et al. at the University of London discovered the structure of phthalocyanines and developed improved synthetic methods for several metal phthalocyanines from 1929 to 1934 [1-11]. The important CuPc could not be protected by a patent, because it had been described earlier in the literature [23], Based on Linstead s work the structure of phthalocyanines was confirmed by several physicochemical measurements [26-32], Methods such as X-ray diffraction or electron microscopy verified the planarity of this macrocyclic system. Properties such as polymorphism, absorption spectra, magnetic and catalytic characteristics, oxidation and reduc-... 

In this section it will be shown, how special molecular constitution and conformation may force the formation of macrocycles. Furthermore, examples will be discussed in which the photoinduced electron transfer (PET) from electron rich functional groups to the excited keto carbonyl group initiates a macrocyclization. The exceptionally successful PET assisted macrocyclizations of phthalimides will be treated separately in Sec. 3.4.6. 

Table 17.1. Experimental glass transition temperatures Tg in degrees Kelvin, the quantities (8, N and NTg) used in the specialized correlation equation for Tg, and the fitted values of Tg, for 14 polymers containing phthalimide groups, and completely built from C, N, O, S and H atoms. 

The last example presented in this section also involved a specialized hydrazone intermediate, a N-phlhalimide hydrazone. Once the amine group in 1,114 (prepared by literature methods) was blocked as the phthalimide, the acid moiety in 1.114 was subjected to the Amdt-Eistert sequence shown. This reaction sequence extended the carbon chain by one and this new acid was converted to its t-butyl ester (7.775).65 The N-phthalimido protecting group was removed, with reduction of the imine moiety, to give 5-methyl-7-aminooctanoic acid, 1.116. When another... 

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