Other Imides

Compounds 42 and 43 are based on the PBI acceptor, made soluble by a C19 swallowtail attached to one imide nitrogen The donor is attached through the other imide nitrogen. In 42, the moderate donor pyrene is separated from the PBI by a Ci ct bridge that holds the donor and acceptor close to perpendicular, with limited motion possible. Nonetheless, 42 has a persistent, small RR (Fig. 18g) [106]. In 43, the good donor ferrocene is separated from the PBI by a more flexible C2 a bridge. It has an IVT band that peaks at 595 nm and forms a rectifier with a persistent RR between 25 and 35 (Fig. 18h) [106]. 

C, A-diphenyl nitrones (p-XC6H4CHN(0)Ph, X = NO2, Cl, H, Me and MeO) with N-phenylmaleimide to form 2,3,6-triaryl derivatives of l-oxa-2,6-diazabicyclo[3.3.0]octane-5,7-dione. No enthalpy of formation data are available for A-phenylmaleimide or for maleimide itself. However, it is available for the corresponding A-methyhnaleimide along with some other imides. The gas phase enthalpy of hydrogenation of this species (derived as the difference between its enthalpy of formation and that of N-methylsucc-inimide ) is 133.7 2.2 kJmoC. This value is essentially the same as for ethylene (derived as the difference between its enthalpy of formation and that of ethane) of 136.3 0.4 kJmoH. Therefore, let us assume the reaction of the above parent nitrone with ethylene to form the diphenylated isoxazolidine, shown in equation 12, has very much the same exothermicity as with A-phenylmaleimide, namely ca 82 kJmol . If so, the enthalpy of formation of 2,3-diphenylisoxazolidine would be 233 kJmol . Now, is this value plausible ... 

Relatively few examples have been reported in which the chromophoric group was an aryl ketone (13a) - many more PET-induced cydizations with phthali-mides (13b) are known [8]. (Sometimes other imides, for example succinimides and maleimides have been used.)... 

There were relatively few examples reported, in which the chromo-phoric group was an aryl ketone (Ilia) whereas much more PET induced cyclizations with phthalimides (Illb) are known, sometimes other imides, such as succinimides and maleimides were also used. Phthalimides differ from aryl ketones in some respects despite their apparently similar photophysical properties. On one hand, their reduction potential is remarkably lower in comparison with aryl ketones [13]. On the other hand, the radical anion derived from phthalimides is clearly more stable than the corresponding species from aryl ketones [15]. Both facts increase the thermodynamic driving force of a PET and facilitates applications that are unknown from aryl ketones. In this context, one of the most successful approaches is a PET-induced decarboxylation-cyclization route, developed by Griesbeck [13]. The details of this interesting method will be discussed in Sec. 3.4.6. 

This reaction could be extended to other imide systems giving various silylated compounds such as 91 and 92 with enantioselective excess up to 98% (Scheme 64). 

Ethyl jV - cy ano met hylaceti midate (or formiraidate) reacts with primary amines to form 1-substituted 5-aminoimidazoles.75 76 Similarly, reaction between ethyl N - (carbamoylcyano methyl )for mi -midate (and other imidates) and hydrazine, phenylhydrazine, or 2-methylsemicarbazide yields l-aminoimidazole-4-carboxyamides... 

For the triimides, it is expedient to increase the scale of the preparation, and then to effect a preliminary concentration of the triimides from the other imides so that the chromatography can be done on a much smaller column. The crude imide mixture is made as just described, but uang 3 1. of dimethylfonn-amide and 420 ml. (5.2 moles) of disulfur dichloride. After grinding finely once or twice as before, it is extracted with successive portions of dry, peroxide-free ethyl ether, totaling 3 1. The combined ether extracts are left to evaporate spontaneously until 150-300 ml. of cold liquid is left. Evaporation is continued until it is judged that more than half of the solute has crystallized. The solution is decanted away from the mass of crystals of heptasulfur imide and hexasulfur diimides, and allowed to evaporate to dryness, leaving 30-40 g. of solid, which consists... 

In this section, isocyanate-based imide foams, according to model reaction (2) will be described, and other imide foams prepared by model reaction (1) will be described in a separate section. 

Other imides that mimic more closely the penicillins were synthesised [176] (Scheme 102). The good acylating power of 329 and 330 was demonstrated by their very fast reaction with hydroxylamine to give hydroxamic acids. Com-... 

Other imides, but also primsecondary amines, react with Dns-Cl in a similar way. 

N-AUcylation of l,2,4-Dithiazolidine-3,5-dione (1). The very low piifa value of 1 (p/fa = 2.85 ) compared with other imides such as phthalimide (typically ca. 9.5-10) facilitates 7V-deprotonation with a wide range of bases. These include sodium or potassium hydride, sodium acetate, sodium bicarbonate, potassium tert-butoxide, and caesium carbonate. The optimum stoichiometry of 1 to base is dependent on the base and alkyl halide in question, with acetonitrile proving to be the preferred solvent (eq 6). ... 

In analogy to the phthalimide Mitsimobu reaction above, a number of other imides also participate in the Mitsunobu reaction. For example, various imides (116 to 123) were examined by Alcarez et al. in their search for novel... 

Uronic acids esters ean be activated as imidates, bromides or t 10 phenyl glycosides among others. Imidate donors are the cornmon activating groups for the synthesis of di- and example the synthesis of the putative pnon-associate containing two D-glucuronic acid units with 1 tag The... 

Synthesis.—Alcohols can be induced to act as electrophiles in a modified Gabriel amine synthesis alkoxyphosphonium salts efficiently alkylate phthalimide and other imides (Scheme 119) with almost complete inversion... 

The data presented here were measured in our laboratory and they are in accord with those reported in the hterature for TPP [19,20] and ZnTPP [20,21] as well as PPBl [22] and PBl [23] containing other imide substituents. 

Imides (e.g. phthalimide) are ethoxycarbonylated if the potassium salt is treated with ethyl chloroformate at 5-10°C. At elevated temperatures (60-110 °C) the lithium salts are JV-ethylated in high yield. Ai-Alkylation also occurs with other imide systems... 

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