Azabenzene

Aspirin, a56 Azabenzene, p257 Azacyclopentane, p280 Azacyclopropane, el46 1-Azanaphthalene, q3 Azelaic acid, n93... 

Heterocyclic aromatic compounds a. Pyridine and other azabenzenes. The azabenzenes, compounds in which — N= groups replace —CH= groups, often bear remarkable chemical spectroscopic similarities to the parent homooyclic hydrocarbons. This is associated with their being 7r-isoelectronic with them. 

Synonyms AI3-01240 Azabenzene Azine BRN 0103233 C-00747 Caswell No. 717 CCRIS 2926 CP 32 EINECS 203-809-9 EPA pesticide chemical code 069202 FEMA No. 2966 NCI-C55301 NSC 406123 RCRA waste number U196 UN 1282. 

Synonyms Azabenzene azine Physical Form. Colorless liquid... 

Fig. 18 Unimolecular pathways for 2-picolinylperoxy radical, a representative peroxy radical for alkylated azabenzenes.

Since trivial names are so well established, it is now very difficult to abandon them in favour of a logical nomenclature system that provides structural information. Nevertheless, a predictive method of this type is very desirable, especially for molecules where there may be two or more heteroatoms present in the ring. One approach is to use a prefix, which is indicative of the heteroatom [aza (N), oxa (O), thia (S), bora (B), phos-pha (P), sila (Si), etc.], to the name of the corresponding carbocycle. Thus, pyridine becomes azabenzene and piperidine is azacyclohexane. 

Many fully unsaturated heterocyclic compounds are described as aromatic, and some have a close similarity to benzene and its derivatives. For example, pyridine (azabenzene) is formally derived from benzene through the replacement of one CH unit by N. As a result, the consti-... 

The most important example of this category is pyridine (azabenzene),. ... 

LB films prepared from an azabenzene-containing surfactant donor-TCNQ acceptor and transferred to solid substrates Absorption spectra, polarized microscopy, and conductivity measurements... 

Introduction of an azabenzene unit into the surfactant backbone permitted light-induced cis-trans rearrangements. A change in conductivity accompanied the cis-to-trans transition. Thus, these LB films offer a basis for the construction of molecular switching devices (Fig. 120) [743-745],... 

Dinitra-2,2,-dimethy azabenzene red-bm lfts (from toluene), mp 258° readily sol in boiling glacial acetic acid or nitrobenzene and in benz, diffc sol in ale prepd by treating 5-nitro-l-methyIbenzene-2-diazonium sulfate with a cuprous chloride soln in HC1 (Ref 1)... 

With this limitation in mind, one should consider the possibility of applying -ium and -ylium suffixes to ordinary replacement names (instead of using -onia- prefixes) this sort of treatment could be very useful in certain cases (see, for example, Section iii), and may prove to be the method of choice for naming cations if the use of replacement nomenclature becomes more widely accepted. By this method, 100 could be named 4aA5-4a-azanaphthalen-4a-ylium 99, 8ai/-4a-azanaphthalen-4a-ium and 103, azabenzen-1 (4f/)-ylium or azacyclo-hexa-2,5-dien-1 -ylium. 

Best with primary ROH pyridine (azabenzene, a weak nitrogen base) acts to keep the acidity low, which may reduce side reactions such as rearrangement. 

Chlorides can be prepared in this way from primary and secondary, but not tertiary, alcohols. In practice, an equivalent of a weak base, such as pyridine (azabenzene), is added to neutralize the hydrogen chloride that is formed. If the acid is not removed, undesirable degradation, elimination, and rearrangement reactions may occur. 

Substantial differences in base strength are found between alkanamines and unsaturated amines that have the group C=N —. An example is azabenzene (pyridine, C3H5N), which is a nitrogen analog of benzene ... 

Azabenzene is quite a weak base—in fact, it is 1/100,000 as strong a base as typical alkanamines. This low basicity can be ascribed to the hybridiza-... 

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