Polyaza compounds

The special cases 2-Le-3-aza, 4-Le-8-aza, and 4-Le-5-aza are apparent from a glance at the names of the polyaza compounds given to them by the activation-numbering system. 

In the same manner we succeeded in the formation of multicyclic nonskid-chain-like polyaza compounds with an increasing number of macrocyclic chains per iteration step [17] (Fig. 5). 

Reaction of 6-halopurines with Michael acceptors under Heck conditions gives N- -substituted hypoxanthine derivatives <00CCC797>. Reactions of a series of 1-aminobenzimidazoles and l-amino-3-methylbenzimidazolium chlorides with 2,4-pentanediones afford pyridazino[l,6-a]benzimidazoles and 2-pyrazolylanilines, the product ratio depending on conditions and on the electronic character of the substituents at the benzene moiety <00BMC37>. Cyclization reactions of adenine derivative 75 with different amines or hydrazine afford tricyclic polyaza compounds 76 <00CCC1109>. 

In their quest for large molecular cavities capable of binding molecules or ionic guests, Vogtle and coworkers 1 synthesized non-cyclic polyaza compounds via a repetitive stepwise process (one-directional case Scheme 4.2). The use of two-directional cores (Scheme 4.5), e.g., ethylenediamine, 2,6-di(aminomethyl)pyridine (8) or l,3-di(amino-methyl)benzene, with acrylonitrile afforded the tetranitrile 9, which was reduced with Co(n)-catalyzed borohydride to produce hexaamine 10. This terminal tetraamine was subsequently treated with excess acrylonitrile to generate the octanitrile 11 although the process was terminated at this stage, a foundation of dendrimer construction was established. 

Although comparison in polyaza. compounds is facilitated most by this method of numbering, reactivity relations in monoazanaphtha-lenes are also clarified, e.g., between 4-chloroquinolineand 1-chloroiso-quinoline (1-aza- and 3-aza-4-chloro analogs) and among the 14 possible monoaza derivatives of 373 and 374. The difference between... 

In 1978, we reported the repetitive synthesis of noncyclic and cyclic (so called nonskid chainlike ) polyaza compounds, which were the first examples of cascade molecules (Scheme 1). Since that time, dendrimers have gained widespread attention in organic, as well as in inorganic2,3 and physical chemistry.4 In 1992, De Gennes received the Nobel prize in physics for his studies on chaos and fractals. His results are relevant for the molecular design of cascade polymers especially in their three-dimensional growth. 

Polyaza six-membered ring systems, 3, 1039-1086 Poly-e-caprolactone production, 7, 589 Polycyclic compounds nomenclature, 1, 14-28 Polyfuroxans, 6, 426 Polygermacyclopentanes, 1, 609... 

Proceeding from a precursor polyaza-caged structure, which may be different from the desired product, but includes the final structure within the cage. Although not a caged compound the synthesis of RDX from the nitrolysis of hexamine would fit this category. 

Other polyaza derivatives of aromatic systems, such as the blue tria-zaphentalene derivative (478), are also adequately described as meso-meric betaines or inner salts. Ohta and Kato, in a section entitled Bridged Heterocyclic Compounds (ref. 9b, page 241), have referred to seven types of compounds and the stereochemically unacceptable structures (479-485) which had been allocated to them. The possibility was considered by Ohta and Kato that some of these structures might have to be replaced by their meso-ionic equivalents. However, we have now established that this is not the case, and the relation between the original structures (479-485) and the correct structures (486-492) is given in Fig. 10. ... 

The alternative regiochemical disposition of the diazo and tether of indole 260 failed to deliver any product upon addition of catalyst. Friedrichsen and co-workers (136) also applied this method to amine substituted tethers to generate polyaza-cyclic compounds (Scheme 4.70). The presence of the amino substituted furan subsequent to diazo-decomposition made it possible to cleave the ether bridge through the facility of the amino group formed to produce adduct 263. 

Aza and polyaza heteroaromatic compounds generally undergo C-attachment of the amide ion in KNH2-NH3. The structure of the resulting a-adducts has been firmly established in a large number of instances. 

In going to polyaza derivatives, the tendency to form adducts decidedly increases. Very reactive compounds, such as 1,2,4-triazines and pteridines, undergo covalent addition in liquid ammonia alone, i.e., without any added amide salts, presumably by a two-stage process via anionic ff-adduct formation. 

Polyaza rings suffer complete hydrolytic ring cleavage. Monocyclic 1,2,3-triazines are hydrolyzed by acid to yield 1,3-dicarbonyl compounds (Scheme 15). 1,2,3-Benzotriazines are easily converted into derivatives of 2-aminobenzaldehyde. 1,2,4,5-Tetrazines (180) are hydrolyzed with a base to give aldehyde hydrazones, RCH = NNHCOR. 

The polyaza[3.3.3]cyclazines have become of increasing interest. Ceder, Shaw and their coworkers have been predominant in this area. It is not possible to discuss the available syntheses in any detail but the three examples of Schemes 117-119 illustrate the strategies in the preparation of these compounds (77JHC679,72ACS596,74JHC627). 

A recently reported preparation of a pooled library used an unsymmetrical polyaza-cyclophane scaffold to prepare pools of 100 compounds resulting from N-alkylation using sets of 10 benzyl halides at two different sites on the molecule [9],... 

A general synthetic approach consists of the reaction of 1,2-diaminopyrazines or A,A -dimethyl-ethane-1,2-diamines with glyoxal. This method has already been described in CHEC-I. Additionally, some new approaches have been developed. Nucleophilic exchange of the chlorine atoms of 5,6-dichloropyrazine-2,3-dicarbonitrile (118) by 1,2-diamino compounds affords the pyrazino[2,3-6]py-razines (119) and (120) (Scheme 20) <88LA1197>. Variation of the amines and treatment with hydrazine hydrate forms several polyaza derivatives <88LA1197>. 

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