Heterocyclic systems nomenclature

Table 1.4 Suffixes for Specialist Nomenclature of Heterocyclic Systems 1.12...

TABLE 1.3 Specialist Nomenclature for Heterocyclic Systems Heterocyclic atoms are listed in decreasing order of priority. 

Organic ring systems are named by replacement nomenclature. Three- to ten-membered mono-cyclic ring systems containing uncharged boron atoms may be named by the specialist nomenclature for heterocyclic systems. Organic derivatives are named as outlined for substitutive nomenclature. The complexity of boron nomenclature precludes additional details the text by Rigaudy and Klesney should be consulted. 

Heterocyclic systems, which can be regarded as formed by replacement of carbon atoms in the parents described above by heteroatoms, are named by replacement nomenclature. 

The principal advances in the systematization of organic nomenclature have come from the International Union of Pure and Applied Chemistry (IUPAC) Commission on the Nomenclature of Organic Chemistry, and from the Chemical Abstracts Service. The IUPAC Definitive Rules for Hydrocarbons and Heterocyclic Systems (1957)4 and for Characteristic Groups (1965)5 have been widely accepted by the chemical community, and, in their latest revised form,6 constitute the standard reference work. These rules are closely related to those developed in parallel by Chemical Abstracts for indexing purposes, and it is fortunate that, as a result of close cooperation between the two bodies, there are few areas of disagreement. 

IUPAC Nomenclature of Organic Chemistry, Definitive Rules for Section A. Hydrocarbons, Section B. Fundamental Heterocyclic Systems. Butterworths, London, 1958. 

Heterocyclic systems can be named by various methods, depending on ring size, the presence or absence of metal atoms, the availability of trivial names, etc. For this index the naming of the heterocyclic parents has generally followed the practices of IUPAC and Chemical Abstracts. Thus Hantzsch-Widman names have been employed for all monocyclic systems and for the other systems when the smallest ring size is five atoms or more, but replacement nomenclature has usually been followed for bicyclic and higher systems when they contain three- and four-membered rings. 

Nitrogen heterocyclic systems, Claisen rearrangements in, 8, 143 Nomenclature of heterocycles, 20, 175 Nuclear magnetic resonance spectroscopy, application to indoles, 15, 277 Nucleophiles, reactivity of azine derivatives with, 4, 145... 

The nomenclature of peri-naphthalene heterocycles does not follow a common principle. In many original papers, the names of heterocyclic systems are derived from the corresponding peri-annelated hydrocarbon derivatives (1,2-diazaacenaphthylene, 1-oxaphenalene, etc.), from monoheterocycles with an indication of linked positions (naphtho[l,8-6c]furan, naphtho[l,8-de]azepine, etc.), and from benzoannelated heterocycles (benzo[o/]indole, benzo[heterocyclic systems and some compounds have trivial names, for instance, perimidine, naph-thostyryl, and naphtholactone. Moreover, it is necessary to remember some peculiarities in the electronic structure of peri-annelated heterocycles, namely the absence of independent existance of the 7r-closed-loop monoheterocycles which could be a fragment of peri-annelated heterocyclic systems. Therefore, the separation of a heterocycle from the united 7r-system is impossible. In this case, the simplest structure and the tt-electron unit is the whole peri-heterocyclic nucleus. 

If the corresponding carbocyclic system is partially or completely hydrogenated, the additional hydrogen is cited using the appropriate H- or hydro- prefixes. A trivial name from Tables 1.5 and 1.6, if available, along with the state of hydrogenation may be used. In the specialist nomenclature for heterocyclic systems, the prefix or prefixes from... 

Abstract This chapter is devoted to recent progress in the chemistry of the 5 5 fused heterocyclic systems. There are four possible modes of 5 5 fusions of the simple five-membered heterocycles leading to four structures containing one heteroatom in each ring. The heteroatoms may be the same or different and may be O, NH, S, Se, Te, P, As, or Sb. The fully conjugated hetero analogs of pentalene dianion have a central C-C bond and are isoelectronic with the 10-7t-electron pentalene dianion. The scope of the chapter is outlined with a survey of various structural types and nomenclature of the parent compounds and their derivatives. New synthetic procedures and synthetic applications of title compounds are presented. This review has concentrated on the new developments achieved from 1997 to September 2007. 

---