Selenium heterocycles, literature

Selenium heterocycles receive far less mention in the literature than do such homologs as oxazole, thiazole, or imidazole. In fact, preparative methods of selenium heterocycles are much more limited than for the other series, mainly because of manipulatory difficulties arising from the toxicity of selenium (hydrogen selenide is even more toxic) that can produce severe damage to the skin, lungs, kidneys, and eyes. Another source of difficulty is the reactivity of the heterocycle itself, which can easily undergo fission, depending on the reaction medium and the nature of the substituents. 

Larger chalcogen-phosphorus heterocycles, although less common in the literature, are accessible via a variety of synthetic routes.2,83,84 For example, the cyclic trimer (SPR)3 (R = 2,4,6-tri-tert-butylphenyl) contains a puckered six-membered P3S3 ring and is produced in the reaction of a phosphinic chloride with lithium sulfide (Equation 73).98 Additionally (R P)3Se5 (R = 2,4-di-tert-butyl-6-wopropoxyphenyl), synthesised from the oxidation of a primary phosphine with three equivalents of elemental selenium (Equation 74), has... 

There are very few examples in the literature of fully saturated bicyclic selenonium ions with selenium as the bridgehead atom. The selenonium salts (33) and (34) are used as precursors for the syntheses of medium sized heterocycles containing a selenium atom. 

This new Specialist Periodical report combines the material previously reviewed in "Saturated Heterocyclic Chemistry", "Aromatic and Hetei oaromatic Chemistry", both of which are now discontinued, and "Organic Compounds of Sulphur, Selenium and Tellurium", which although still thriving has surrendered its heterocyclic parts but will continue to report on S-lactam antibiotic chemistry. The literature reviewed in this volume covers the period July 1978to July 1979. Brief Contents ... 

The major changes in the format and contents of this volume have been necessitated by economic considerations. Sulphur-containing heteroaromatic compounds which previously were included in these Reports and in the Reports on Aromatic and Heteroaromatic Chemistry are now covered in detail only in the new Reports, Heterocyclic Chemistry . The literature on these compounds has been reviewed up to March 1978 in Volume 5 of this series and thereafter in Volume 1 of the new series. Highlights of the literature of these compounds are given as Chapter 6 of this volume. The organization of the remainder of this volume is essentially the same as that of Volume 5 except that the section on the ylides and carbanionic compounds of selenium and tellurium has been considerably extended and the coverage of Chapter 3, Part III has been extended to include dithiocarbamates, xanthates, and trithiocarbonates. 

Heterocyclic Chemistry is an annual publication which combines material previously reviewed in three separate SPR titles Saturated Heterocyclic Chemistry, Aromatic and Heteroaromatic Chemistry, and the heterocyclic sections of Organic Compounds of Sulphur, Selenium, and Tellurium. Heterocyclic Chemistry has now reached its fourth volume, which reviews the literature published on the subject during the period July 1981 to July 1982. 

A review of saturated, heterocyclic, three-membered rings has been published, and the literature for 1972 concerned with heterocyclic chemistry has been surveyed. The chemistry of three-membered, sulphur-containing rings has been reviewed. " The n.m.r. spectra of small-ring sulphur heterocyclic compounds and other heterocycles have been discussed. Selenium-containing cyclic compounds, including three- and four-membered rings, have been reviewed/... 

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