Pyrroles, literature reviews

The literature up to the mid-1970s for pyrrole has been exhaustively reviewed in the books by Gossauer, and Jones and Bean (B-74MI30400, B-77MI30400). 

This review, which covers the literature up to mid-1968, presents the knowledge, which is available to date, concerning the molecular and electronic structure of pyrrole. It also surveys the spectroscopic and nonspectroscopic physical properties of pyrrole and its simple derivatives. During the past 25 years, as a result of developments and improvements in instrument design, the literature on the physicochemical properties of organic compounds has expanded rapidly. Mainly as a result of the instability or nonavailability of many compounds, however, the study of pyrroles has lagged somewhat behind... 

The synthesis of indoles by the Fischer method has been the subject of a review, where phosphorus trichloride and polyphosphoric acid were used as cyclizing agents [6], Although the first publication on the synthesis of phosphorus-containing indoles appeared in 1930 [7], reviews on this subject are few. The treatment of the subject in [8] was fragmentary, while the review [9] covered the literature up to 1975. It is also possible to mention [10], which was devoted to the phosphorylation of pyrrole and its carbonyl derivatives. 

The time-proven approaches for the synthesis of pyrroles and more elaborate systems have been thoroughly reviewed in the literature. Our focus is drawn to the Knorr synthesis of pyrroles as the [3 + 2] component condensation-type approach which serves as the foundation for the methodology discussed in this chapter.3 The classic reaction entails the reaction of an a-aminoketone with a P-dicarbonyl compound (Eq. 1). The likely intermediate is a P-aminoenone, which undergoes an acid-catalyzed internal cyclization reaction leading to the pyrrole ring. A variation of this process involves the condensation of a-aminoesters and... 

For the purpose of this review, the infrared spectra of the four parent azaindoles were measured and the principal bands listed in Table III those recorded in the literature are listed in Table IV. The frequencies are grouped into regions according to the scheme used by Katritzky and Ambler, and the assignments can be considered only tentative until the spectra of more compounds are examined. For correlations with the spectra of pyrroles, indoles, and pyridines consult Katritzky and Ambler,pp. 199, 211, and 274. 

Interest in aromatic chemistry continues at the same high level as in recent years. Substitution and cyclization processes are two areas which have attracted considerable attention over the past year. Pertinent here, as elsewhere in this volume, are the reviews on photochemistry with circularly polarized light by Buchardt,1 and the photochemistry of carbonium ions by Cabell-Whiting and Hogeveen.2 Current literature describing light-induced reactions of pyrroles has also been briefly reviewed.8... 

In reviewing fluorinated pyrroles, discussion will be confined to the compounds having fluorine or perfluoroaUcyl groups directly bonded to the heteroaromatic ring. The considerable literature dealing with compounds having fluorine substituted on the benzenoid portion of bicychc pyrroles (e.g., fluorinated tryptophans) will not be covered. 

Progress in Heterocyclic Chemistry (PHC) Volume 7 reviews critically the heterocyclic literature published mainly in 1994. The first two chapters are traditionally review articles. Chapter 1 surveys useful synthetic routes to "Polyfunctional Pyrroles and Pyrazoles" starting from conjugated azoalkenes. This review is based on the researches of O. A. Attanasi and his school in Urbino (Italy). As last year the second review is unconventional, comprising a compilation of the" Application of Diels-Alder Cycloaddition Chemistry for Heterocyclic Synthesis". It is written by our president A. Padwa and is in an unusual format with a pertinent list of references dating back forty years in some cases. We were encouraged to include this review because of favourable comments received from readers about this type of survey in PHC Volume 6. 

In principle, the ring system where PH replaces NH should be capable of having aromatic character because the lone electron pair on P could be delocalized into the ring as in pyrrole. The parent phosphole molecule, however, is unstable and has only been detected spectroscopically at —90°C, but the P-methyl derivative is stable and distillable, and many other substituted phospholes are known. The field is growing regularly and deserves brief consideration here. The literature has been reviewed extensively. ... 

Nitroalkenes are widely used in the eatalytie AFC alkylation of electron-rich aromatic rings such as indoles, pyrroles, electron-rich furans, and phenols. The literature up to 2009 dealing with catalytic AFC alkylation of aromatic compounds with nitroalkenes has been reviewed. In this section, only very recent progress on the development on catalytic AFC alkylation of nitroalkenes will be diseussed. 

N-Subst. pyrrolidines. A 10 M soln. of BH3-dimethyl sulfide in THF added dropwise via syringe to a soln. of startg. succinamic ester in the same solvent under N2, the mixture refluxed 7-9 h, and quenched with methanol and 2 N NaOH N-phenylpyr-rolidine. Y 82%. The method failed for highly hindered amines. F.e. incl. N-subst. piperidines s. M.C. Venuti, O. Ort, Synthesis 1988, 985-8 review of pyrrole, pyrrolidine, piperidine, pyridine and azepine alkaloids (1986-7 literature) s. A.R. Pinder, Nat. Prod. Reports 6, 67-78 (1989). 

In this review, we discuss the electrode/electrochemical properties and technological applications of -conjugated polymers. It is organized by material and the matmals are grouped in two classes, the polyaromatic polymer films such as the polymer derivatives of aniline, pyrrole, and thiophene, and the linear polyenes such as polyacetylene, polythiazyl. The report does not intend to review the preparation procedures or the physical properties of these materials since they have been summarized elsewhere It is also limited to work published in the scientific literature without attempting to include the numerous patents which have appeared in the last few years. 

Abstract Synthetic approaches towards pyrroles, bearing fluorine atoms and trifluoromethyl group, are overviewed in this chapter. Literature data are surveyed accordingly to reaction type used to obtain the fluorinated pyrrole moiety. Properties as well as some applications of fluorinated are also reviewed. 

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