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Journal ArticleDOI

Ground states of conjugated molecules. XIX. Tautomerism of heteroaromatic hydroxy and amino derivatives and nucleotide bases

01 May 1970-Journal of the American Chemical Society (American Chemical Society)-Vol. 92, Iss: 10, pp 2929-2936
About: This article is published in Journal of the American Chemical Society.The article was published on 1970-05-01. It has received 125 citations till now. The article focuses on the topics: Tautomer.
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Journal ArticleDOI
TL;DR: A facile route toward the synthesis of isoquinolin-3-ones through a cooperative B(C6 F5 )3 - and Cp*Co(III) -catalyzed C-H bond activation of imines with diazo compounds is presented.
Abstract: A facile route toward the synthesis of isoquinolin-3-ones through a cooperative B(C6 F5 )3 - and Cp*Co(III) -catalyzed C-H bond activation of imines with diazo compounds is presented. The inclusion of a catalytic amount of B(C6 F5 )3 results in a highly efficient reaction, thus enabling unstable NH imines to serve as substrates.

166 citations

Book ChapterDOI
TL;DR: The chapter discusses tautomerism of cytosine and presents the essential physicochemical properties of cytOSine and some of its derivatives and to the theoretical interpretation of these properties.
Abstract: Publisher Summary The chapter focuses tautomerism and electronic Structure of biological pyrimidines. The understanding of the tautomeric properties of the purine and pyrimidine bases of the nucleic acids and the determination of the electronic properties of the principal tautomers are of fundamental importance in molecular biology, in particular, in connection with the theory of mutations. The principal tautomeric properties of the fundamental biological pyrimidines-cytosine, uracil, and thymine-are due to the presence in these N-heteroaromatic compounds of electron-donor substituents, such as NH and OH, and of SH in some important analogs. The chapter discusses tautomerism of cytosine and presents the essential physicochemical properties of cytosine and some of its derivatives and to the theoretical interpretation of these properties. The chapter also discusses tautomerism and physicochemical properties of uracil and thymines and to give a theoretical interpretation of these properties. The study of the optical properties of naturally occurring pyrimidines and purines is a problem of great interest in molecular biology. The knowledge of these properties provide information important for understanding energy transfer, hypochromism, photochemistry, optical rotatory dispersion, circular dichroism, magnetic optical rotator dispersion, and magnetic circular dichroism of DNA, RNA, and related model systems. Tautomerism, electronic structures, and spectra of rare pyrimidine bases of the nucleic acids have also been discussed.

131 citations

Journal ArticleDOI
TL;DR: 2,6-pyridinediol and 6-benzyl-2-thiouracil have been identified as being potent inhibitors of UrdPase and dThdPase respectively.

109 citations

Book ChapterDOI
TL;DR: In this paper, the authors review various definitions of aromaticity in common use and to survey their applications in heterocyclic chemistry, concluding that the characteristics of an aromatic compound are easy to define from a qualitative viewpoint.
Abstract: Publisher Summary This chapter discusses aromaticity of heterocycles. At a time when the validity of the concept of aromaticity is questioned, increasingly, it seems appropriate to review various definitions in common use and to survey their applications in heterocyclic chemistry. From a qualitative viewpoint the characteristics of an aromatic compound are easy to define. A compound is said to be aromatic if it is cyclic and unsaturated with an enhanced stability over simple olefinic compounds. The characteristic aromatic reactivity of the type described is clearly a matter of degree and is difficult to assess quantitatively. From a simple consideration of pyridine, which reacts less readily with electrophiles but more readily with nucleophiles at the ring carbon atoms than does benzene, it soon becomes apparent that attempts to discuss even relative aromatic character using kinetic criteria is fraught with difficulties; this is apart from the fundamental objection that chemical reactivity is not solely a function of ground-state stability.

104 citations

Book ChapterDOI
TL;DR: In this article, a review of the developments in imidazole chemistry is presented, including the properties of the 1-acylimidazoles (imidazolides), which are extremely reactive in such nucleophilic reactions as hydrolysis and alcoholysis.
Abstract: Publisher Summary This chapter reviews the developments in imidazole chemistry and discusses condensed imidazoles (such as benzimidazole, purines, etc), and compounds containing reduced imidazole rings The methods for the syntheses of the imidazole ring system are also presented Physical properties of imidazole and its derivatives such as dipole moments; melting points, boiling points, and solubilities; acid and basic strength; crystal structure; UV spectra; IR and Raman spectra; NMR spectra; mass spectrometry; electron spin resonance; optical rotatory dispersion and polarography; chromatography; thermodynamic data; and quantum mechanical calculations are described In addition, the chemical properties such as structure; aromatic character and reactivity; electrophilic substitution reactions; nucleophilic attack; reactions involving radicals; reactions of substituents on ring carbon atoms; reactions of substituents on ring nitrogen atoms; and miscellaneous properties of imidazole and its derivatives are illustrated Most of the reactions and properties of 1-substituted imidazoles have been discussed Apart from the utilization of the readily removable benzyl substituent in synthetic procedures leading to 2-substituted imidazoles, perhaps the most exciting advances have stemmed from the reactions of the 1 -acylimidazoles (imidazolides), which are extremely reactive in such nucleophilic reactions as hydrolysis and alcoholysis

100 citations