Imides macrocyclic

Because of spatial limitations, only meso- and macrocycles possessing heteroatoms and/or subheterocycik rings ate reviewed in general, lactones, lactams, and cyclic imides have been excluded. In view of the delayed availability of some articles appearing in previous years, several have been incorporated. 

A useful method to synthesize ten and fourteen-membered ring imides 346 involved an initial condensation of macrocyclic -ketoestes 343 with alkyl or aryl isocyanates and carbodiimides, respectively, in the presence of a base [68]. After a nucleophilic attack of the enolate on the isocyanate C, the resultant amide N anion 344 induced a ring closure by addition to the keto group. Then, the intermediately formed four-membered ring 345 underwent a fragmentation... 

Electron transfer from a macrocycle (82), based on cyclen, complex to coordinated riboflavin proceeds via an inner sphere electron transfer pathway. The riboflavin coordinates through the imide and the relevance to the interception of biological electron transfer pathways is discussed.709... 

The condensation reactions described above are unique in yet another sense. The conversion of an amine, a basic residue, to a neutral imide occurs with the simultaneous creation of a carboxylic acid nearby. In one synthetic event, an amine acts as the template and is converted into a structure that is the complement of an amine in size, shape and functionality. In this manner the triacid 15 shows high selectivity toward the parent triamine in binding experiments. Complementarity in binding is self-evident. Cyclodextrins for example, provide a hydrophobic inner surface complementary to structures such as benzenes, adamantanes and ferrocenes having appropriate shapes and sizes 12) (cf. 1). Complementary functionality has been harder to arrange in macrocycles the lone pairs of the oxygens of crown ethers and the 7t-surfaces of the cyclo-phanes are relatively inert13). Catalytically useful functionality such as carboxylic acids and their derivatives are available for the first time within these new molecular clefts. 

Cyclic amines (including local anesthetic drugs) and amides were among the first classes of chiral compounds investigated in the early stages of the application of macrocyclic antibiotics as chiral selectors therefore, they were screened on vancomycin [7], teicoplanin [30], and ristocetin A [33] CSPs, under RPmode systems. Cyclic imides (including barbiturates, piperidine-2,6-diones, and mephenytoin) have been separated on a vancomycin CSP [157], under NP and RP mobile phase conditions. 

Aboul-Enein, H.Y. and Serignese, V., Enantiomeric separation of several cyclic imides on a macrocyclic antibiotic (vancomycin) chiral stationary phase under normal and reversed phase conditions, Chirality, 10, 358, 1998. 

Similar results have been obtained upon irradiation of naphthylimides [92,93] (Scheme 35). However, 12- and 14-membered macrocyclic imides give rise to photoproducts diacylated at the aromatic ring [94],... 

Initial cyclizadons were effected by the addition of an enamine to an imidate ester, both groups being suitably located by ligand coordination.263 An analogous process can be carried out on a thioimidate but a sulfide is formed and removal of sulfur with consequent ring contraction yields the corrin (100).264 These two complementary routes can be effected with different metal ions, nickel(II), palladium(II) and cobalt(III) in the first route, zinc(II) in the second. Removal of zinc ions easily provides the free corrin macrocycle. These two routes are summarized in Scheme 64. The sulfide contraction route was used in the Eschenmoser-Woodward total synthesis of vitamin Bn-265... 

Analytical Properties Substrate has 38 chiral centers and 7 aromatic rings surrounding 4 cavities (A, B, C, D), making this the most structurally complex of the macrocyclic glycopeptides substrate has a relative molecular mass of 2066 this phase can be used in normal, reverse, and polar organic phase separations selective for anionic chiral species with polar organic mobile phases, it can be used for a-hydroxy acids, profens, and N-blocked amino acids in normal phase mode, it can be used for imides, hydantoins, and N-blocked amino acids in reverse phase, it can be used for a-hydroxy and halogenated acids, substituted aliphatic acids, profens, N-blocked amino acids, hydantoins, and peptides Reference 47, 48... 

A reactive macrocyclic ether-urethane carbodiimide (MC-CDI), which is the key intermediate for synthesizing poly(amide-urethane) and poly(amide-imide-urethane), was prepared by the sequential self-repetitive reaction. A se-... 

Macrocycle 177 in which the 2,6-pyridino and the 1,4-piperazino moieties were incorporated into the macrocyclic framework has been reported. The synthesis of 177 (10%) was accomplished by treatment of 2,6-dichloropyridine with the dianion of Ar,Ar -W. (2-hydroxyethyl)piperazine in refluxing xylene. Attempts to prepare the cobalt(II) complex of 177 resulted in diprotonation of the macrocycle. The X-ray crystal structure determination analysis has been performed for both 177 and 178. According to the crystal structure analysis of 178, the piperazine rings are in the chair conformation in the solid state and the molecule is fairly rigid due to the imposed steric constraints of the imidate moieties l39). 

---