Polyamines cyclic

Polyamines can also be made by reaction of ethylene dichloride with amines (18). Products of this type are sometimes formed as by-products in the manufacture of amines. A third type of polyamine is polyethyleneimine [9002-98-6] which can be made by several routes the most frequently used method is the polymeriza tion of azitidine [151 -56 ] (18,26). The process can be adjusted to vary the amount of branching (see Imines, cyclic). Polyamines are considerably lower in molecular weight compared to acrylamide polymers, and therefore their solution viscosities are much lower. They are sold commercially as viscous solutions containing 1—20% polymer, and also any by-product salts from the polymerization reaction. The charge on polyamines depends on the pH of the medium. They can be quaternized to make their charge independent of pH (18). 

PBE dendrimers with a cyclic polyamine core at the focal point have been synthesized to form transition-metal complexes [27]. Tb + complexes exhibited luminescence by the excitation of the dendrons. 

The most important polyamine with cyclic amine ring on the main chain, is poly(dimethyldiallyammonium chloride) (DMDAC) (13). Due to its cationic charges, poly(dimethyldiallylammonium chloride) can... 

There are some examples of macrocyclic complexes of germanium, tin and lead reported in the recent literature. Several crown ethers73,75, tetraaza macrocycles76 [for instance dibenzotetramethyltetraaza[14]annulene (TMTAA)], cyclic polyamines (polyazacycloalkanes)77-80 or, as already mentioned above, poly(pyrazolyl)borate were... 

So far the most potent anti-HIV compounds in vitro among the macro-cyclic polyamines are dinuclear zinc(II) complex of m-xylyl-biscyclen (23) (by Kimura s group) and p-xylyl-biscyclam (30) (by De Clercq s group). They are active against various strains of HIV-1 and HIV-2, while cytotoxicity towards host MT-4 cells are minimal. Their activity against HIV is selective and they are not active against other viruses tested. Hence, the study of their mode of action is not only useful in developing... 

Suzuki et al. [14] reported the Pd-catalyzed ring-opening polymerization of a cyclic carbamate in the presence of an initiator, which also acts as a core molecule, to afford a hyperbranched polyamine. The polymerization was proposed to be an in situ multibranching process, wherein the number of propagating chain ends increase with the progress of the polymerization. 

The major components are series of homologous trimers, tetramers, and pentamers of the three acids 44-46, along with smaller quantities of dimers, hexamers, and heptamers. Furthermore, the secretion contains several isomers of each oligomer, furnishing a combinatorial library of several hundred macro-cyclic polyamines [51, 52]. Using repeated preparative HPLC fractionation, the most abundant trimeric, tetrameric and pentameric earliest-eluting compounds were isolated. One and two-dimensional H NMR spectroscopic analyses showed that these molecules were the symmetric macrocyclic lactones 48, 49, and 50 (m, n, o, p, q=7) derived from three, four or five units, respectively, of acid 46. Moreover, using preparative HPLC and NMR methods, various amide isomers, such as 53,54, and 55 (Fig. 9) were also isolated and characterized [51,52]. 

The direct A -nitration of the amino groups of the hexahydrotriazine (23) is only possible due to the inherent low basicity of the methylenediamine functionality. The methylenediamine unit is present in many cyclic and bicyclic polyamines and these are potential precursors to energetic polynitramines. Unfortunately, this route to polynitramines is rarely possible because such polyamines are usually intrinsically unstable and will readily equilibrate to a lower energy, less strained system. For the same reason, polyamines containing the methylenediamine functionality are difficult to prepare and isolate, often rapidly decomposing in both aqueous and acidic solution. A far more common route involves the preparation of iV-protected versions of the polyamine followed by nitrolysis (Section 5.6). Even so, examples of heterocyclic methylenediamine iV-nitration exist. 

Many cyclic, bicyclic and caged polyamines are synthesized via condensation reactions and these are usually isolated as their salts. The free bases are usually difficult to isolate and readily decompose in aqueous or acid solution. Since hydrochloric acid is frequently employed in these condensations the hydrochloride salt of the amine is usually used directly for the A-nitration. 

Mannich condensations involving polyamines or polynitramines are more complex, and in the case of linear dinitramines, leads to very interesting and diverse chemistry, enabling the synthesis of many cyclic nitramine products. The reaction of methylenedinitramine (168) with various primary amines in the presence of formaldehyde leads to l,5-dinitro-l,3,5,7-tetraazacyclooctanes the 3,7-dimethyl analogue (186) is isolated when methylamine is used. ... 

In addition to macrocyclic hosts discussed above, many other molecules capable of selective complexation have been synthesized. They belong to so-called macrocyclic chemistry [30] encompassing crown ethers discussed in this Chapter, cryptands 61-63 [21], spherands 70 [31], cyclic polyamines 71 [32], calixarenes 18 [5], and other cyclophane cages such as 72 [33] to name but a few. Hemicarcerand 5 [2b] discussed in Chapter 1 and Section 7.3 also belongs to this domain. Typical macrocyclic host molecules are presented in Chapter 7. 

Although the vast majority of this review has been concerned with homogeneous systems, supported catalyst and single-crystal studies of rhodium are important topics that have also been considered by some researchers. This topic extends and dovetails nicely with the discussion of the interactions of acyclic and cyclic polyamine ligands and Schiff... 

MacrocycBc lactams. Two key steps in a synthesis of the polyamine alkaloid dihydroperiphylline (4) involve ring expansion of the cyclic imino ether 1 by reaction with the /3-lactam 2 to form 3. Sodium cyanoborohydride in acetic acid reduces 3 in high yield to 4, probably by way of intermediates a and b.2... 

The subject matter of this chapter will be subdivided into sections concerning template synthesis of the complexes structural and thermodynamic properties of the complexes with synthetic cyclic polyamines complexes with mixed-donor macrocycles reactivity of the complexes cryptates and complexes with phthalocyanines and porphyrins. 

DIAMINES AND HIGHER AMINES, ALIPHATIC. The aliphatic diamine and polyaminc family encompasses a wide range of multifunctional. mullireactivc compounds. This family includes ethylenediamine I EDA) and its homologues. the polyethylene polyamines (commonly referred to as ethyleneainines). the diaminoprnpancs and several specific alkancdiamines. and analogous polyamines. The molecular structures of these compounds may be linear, branched or cyclic, or combinations of these. 

Linear component Commercial producl consists of a mixlurc of linear, hranched. and cyclic structures with the. same number of nitrogen atoms. CotiHiteicial higher polyamine prrxlucls contain up to about 40 3 PEHA. 

The rates of the formation reaction (1) in non-aqueous solvents for a variety of cyclic tetramines are comparable with those for non-cyclic polyamines.33 In aqueous solution, where protonated amine species predominate, the rates of reactions (2) are slower for the cyclic amines, the effect becoming more pronounced as the protonation number, I, increases. For different metal ions the rates parallel the water exchange rates (Cu2+ > Zn2+ > Co2+ > Ni2+), and for any particular ion the rates do not vary systematically with ring size.34... 

Multiple cyclic proton transfers occur in hydrogen bonded arrays of heterocyclic units [8.220, 8.221] or inside rings such as porphyrins [8.222]. Macrocyclic polyamines present various protonation patterns [3.13a] that could be of interest as information units. Data storage in a molecular memory by hole burning makes... 

As all cyclic polyamines presented up to now were assigned to be columnar hexagonal based on their high viscosity, the typical texture or X-ray measurements devoid of the (110) or any higher reflection, Heiney and Smith [109] reinvestigated Lehn s [5] polyamine 1. Scattering experiments were carried out using laboratory... 

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