Nitrogen nomenclature

Phosphorus compounds, of nitrogen, nomenclature of, 2 285 Phosphorus (I II) cyanide, 6 84... 

The nomenclature (qv) of polyamides is fraught with a variety of systematic, semisystematic, and common naming systems used variously by different sources. In North America the common practice is to call type AB or type AABB polyamides nylon-x or nylon-respectively, where x refers to the number of carbon atoms between the amide nitrogens. For type AABB polyamides, the number of carbon atoms in the diamine is indicated first, followed by the number of carbon atoms in the diacid. For example, the polyamide formed from 6-aminohexanoic acid [60-32-2] is named nylon-6 [25038-54-4], that formed from 1,6-hexanediamine [124-09-4] or hexamethylenediamine and dodecanedioic acid [693-23-2] is called nylon-6,12 [24936-74-1]. In Europe, the common practice is to use the designation "polyamide," often abbreviated PA, instead of "nylon" in the name. Thus, the two examples above become PA-6 and PA-6,12, respectively. PA is the International Union of Pure and AppHed Chemistry (lUPAC) accepted abbreviation for polyamides. 

Because the rules for organic nomenclature determine the priority of naming different carbon chains from their relative lengths, the systematic names for type AABB polyamides depend on the relative length of the carbon chains between the amide nitrogens and the two carbonyl functions of the polymer for aUphatic nylon-Ayy, when x < the lUPAC name is poly[imino-R imino(l2y-dioxo-R )]. When x > then the name is... 

Heteroeyeles structurally based on the phenalene ring system form an interesting elass, frequently possessing distinetive eolours. With nitrogen as the central atom we have the unstable 9b-azaphenalene (24), whieh has only fairly reeently been prepared and is still comparatively little studied (76JCS(Pl)34l). The cyclazine nomenclature is commonly applied to this and related compounds thus, (24) is (3.3.3)cyclazine. With further aza substitution, in positions alternant to the central atom, their stability increases the heptaazaphenalene (25) is (thermally) a very inert compound, derivatives of which, e.g. the triamine, have been known since the early days of organic chemistry (see Chapter 2.20). 

Conidine — see 1-A2abicyclo[4.2.0]octane Conjugation reactions nitrogen heterocycles at carbon, 1, 239 at nitrogen, 1, 234-238 Conjunction nomenclature, 1, 37 Contagious bovine pleuropneumonia heterocyclic compounds as, 1, 205 A Convention... 

For the purposes of nomenclature, the simple cryptands are assumed to be macro-bicyclic and nitrogen is assumed to be the bridgehead atom. The different cryptands are designated by assigning numbers according to the number of heteroatoms in each ethylenoxy chain. The three cryptands shown below are designated [ 1.1.1 ]-cryptand (9), [2.2.1 ]-cryptand (10) and [3.2.2]-cryptand (11), respectively. 

An even more complicated nomenclature problem arises with the closely related all-oxygen cryptands. These compounds do not utilize nitrogen as the three-chain junction. Most examples of this class of compounds have utilized pentaerythritol or glycerol as the junction. This naturally imparts a somewhat lower flexibility to the molecule than would be present in the nitrogen-containing cases. Structures of two such molecules are illustrated below. 

In the 1,3-dipolar cycloaddition reactions of especially allyl anion type 1,3-dipoles with alkenes the formation of diastereomers has to be considered. In reactions of nitrones with a terminal alkene the nitrone can approach the alkene in an endo or an exo fashion giving rise to two different diastereomers. The nomenclature endo and exo is well known from the Diels-Alder reaction [3]. The endo isomer arises from the reaction in which the nitrogen atom of the dipole points in the same direction as the substituent of the alkene as outlined in Scheme 6.7. However, compared with the Diels-Alder reaction in which the endo transition state is stabilized by secondary 7t-orbital interactions, the actual interaction of the N-nitrone p -orbital with a vicinal p -orbital on the alkene, and thus the stabilization, is small [25]. The endojexo selectivity in the 1,3-dipolar cycloaddition reaction is therefore primarily controlled by the structure of the substrates or by a catalyst. 

---