Transformations of Heterocyclic Compounds

T. Zimmermann and M. Pink, Ring transformations of heterocyclic compounds. XII. Novel spiroindolines via ring transformation of 2,4,6-triarylpyrylium salts with 2-methyleneindolines, J. Prakt. Chem. Chem. Zeit., 337, 368-374 (1995). 

R] Degenerate Ring Transformations of Heterocyclic Compounds. In Advances in Heterocyclic Chemistry, Academic London, 1999, 74,9-149. 

Zimmermann, T. Schmidt, K. (1996). Ring transformations of heterocyclic compounds. 

Prostakov NS (1976) Catalytic synthesis and transformations of heterocyclic compounds. 

K. Kranjc, M. Kocevar, Microwave-assisted organic synthesis general considerations and transformations of heterocyclic compounds, Curr. Org. Chem. 14 (2010) 1050-1074. 

Chiral selenium compounds in transformations of heterocycles 99T1. 

Arylboron compounds as acid catalysts in transformations of heterocycles 99EJ0527. 

Transformations of heterocycles with participation of organozinc compounds 98T8275. 

Ring-chain transformations and their application in the synthesis of heterocyclic compounds 99MI31. 

Transformations of nitro compounds, nitrones, nitrates, hydroxylamines, and amino-A-oxides into heterocycles 98SL939. 

In this context the described methods for preparation of 2,5-dihydro-1,2-oxa-phosphole-2-oxide derivatives have to be considered as synthetic protocols for transformation of carbonyl compounds in to P-containing heterocycles. 

Polyamino acids are easy to prepare by nucleophUe-initiated polymerisation of amino acid JV-carboxyanhydrides. Polymers such as poly-(L)-leucine act as robust catalysts for the epoxi-dation of a wide range of electron-poor alkenes, such as y-substituted a,Ji-unsaturated ketones. The optically active epoxides so formed may be transformed into heterocyclic compounds, polyhydroxylated materials and biologically active compounds such as dUtiazem and taxol side chain. 

Syntheses of heterocyclic compounds that are dealt with in this review are achieved either by cyclization of open-chain substrates under the action of organohypervalent iodine reagents or by carrying out several sequential transformations of substrate heterocyclic compounds using these reagents to obtain new heterocyclic derivatives. In this section, we cover the first strategy, leaving the second one for Section III. An area that is not covered... 

Sanicanin Z, Tabakovic I (1986) Electrochemical synthetis of heterocyclic compounds. Part 16. Electrochemical transformation of 2 -hydroxychalcones into flavonoids. Tetrahedr Lett 27 407-408. 

Extensive research in the field led to the publication of several reviews and monographs in the field. The place of our book in this niche is to provide an overview of the developments in the application of palladium, nickel and copper catalyzed transformations in the preparation and functionalization of heterocyclic compounds. Although preference was given to recent results, important examples of earlier (pioneering) works are also included in this monograph. 

This section deals with transformations of heterocyclic rings and includes not only addition of carbenes and nitrenes, but also rearrangements frequently following these additions. Also included are topics such as the synthesis of Reissert compounds as well as miscellaneous oxidations and reductions. 

A useful property of hyper valent iodine reagents is their ability to react first as an electrophile and then to be transformed into an excellent leaving group. This particular aspect has been used in different rearrangements for the construction of highly functionalized molecules. Various iodine(III) reagents have been employed in Hofmann-type rearrangements [136-139]. The presence of a nucleophile in the ortho position of aromatic amides of type 72 can lead to direct cyclizations and to the formation of heterocyclic compounds 73 as shown in Scheme 33 [140]. 

This synthesis also gives a small glimpse at the chemistry of heterocyclic compounds. Most active compounds in today s pharmaceuticals or agrochemicals include heterocycles, as well as most vitamins and natural products. The chemistry of heterocycles is thus very important and lectures or textbooks should be consulted.6 Formation of amide bonds also plays a large role in this problem. It was demonstrated that the strong amide bond can be formed from an amine and a carboxylic acid only after the acid has been activated. This can be done by transformation into the carboxylic halide or imidazolide or by application of an activating agent developed for peptide synthesis. 

Khan MTH (2007) Recent Advances on the Sugar-Derived Heterocycles and Their Precursors as Inhibitors Against Glycogen Phosphorylases (GP). 9 33-52 Khan MTH (2007) Heterocyclic Compounds Against the Enzyme Tyrosinase Essential for Melanin Production Biochemical Features of Inhibition. 9 119-138 Khan MTH (2007) Molecular Modeling of the Biologically Active Alkaloids. 10 75-98 Khan MTH, Ather A (2007) Microbial Transformation of Nitrogenous Compounds. 10 99-122... 

Phthalimides. Like their aromatic ketone counterparts, TV-alkyl phthalimides participate in hydrogen atom abstraction reactions to form a large variety of heterocyclic compounds. However, despite many similarities between phthalimides and aromatic ketones, there are some important differences. In contrast to aromatic ketones, electronically excited phthalimides are not transformed quantitatively into the triplet state, and thus they may react from both the singlet and the triplet state. In addition, phtalimides are much more inclined to photoinduced single-electron-transfer (PET) reactions [24,25]. (For details see Sec. 3.3.2.1.)... 

Transformation of heterocycles on Rh(II)-mediated reactions of diazocarbonyl compounds 91T1765. 

---