Reaction field pyrimidine

Table 1-2. Nonzero components of the reaction field at the nitrogen nuclei in pyrimidine calculated using either DPM or PCM. All calculations are at B3LYP/6-311++G(2d,2p) level. Results are in 103 au...

A. R. Katritzky and M. Karelson,/. Am. Chem. Soc., 113, 1561 (1991). AMI Calculations of Reaction Field Effects on the Tautomeric Equilibria of Nucleic Acid Pyrimidine and Purine Bases and Their 1-Methyl Analogues. 

The same amino compounds also underwent reactions with a series of 3-cyano-4-imino- and 3-cyano-4-oxo-piperidines to yield 4-amino-5,0,7,8-tetrahydropyrido[4,3-d]pyrimidines. . A tetra-hydropyTido[4,3-prepared from 4-amino-l-henzyl-3-cyano-d -piperidine (134) hy a simple one-step preparation. This method is of general application for the preparation of fused pyrimidines and previous papers in this field are listed by Taylor. ... 

Recent developments in palladium-catalyzed coupling reactions have arisen in the pyrimidine field as well. The Sonogashira coupling of bromopyrimidine 85 with alkynes 86 produced pyrimidines 87, important intermediates reported by Hart and co-workers in their approach to the cylindrospermopsin substructure . 

The Chemistry of Heterocyclic Compounds has been pubhshed since 1950 under the initial editorship of Arnold Weissberger, and later, until his death in 1984, under the joint editorship of Arnold Weissberger and Edward C. Taylor. In 1997, Peter Wipf joined Prof. Taylor as editor. This series attempts to make the extraordinarily complex and diverse field of heterocyclic chemistry as organized and readily accessible as possible. Each volume has traditionally dealt with syntheses, reactions, properties, structure, physical chemistry, and utihty of compounds belonging to a specific ring system or class (e.g., pyiidines, thiophenes, pyrimidines, three-membered ring systems). This series has become the basic reference collection for information on heterocyclic compounds. 

It is a major challenge to keep our coverage of this immense field up to date. One strategy is to publish Supplements or new Parts when merited by the amount of new material, as has been done, inter alia, with pyridines, purines, pyrimidines, quinazolines, isoxazoles, pyridazines and pyrazines. The chemistry and applications to synthesis of 1,3-dipolar cycloaddition reactions in the broad context of organic chemistry were first covered in a widely cited two-volume treatise edited by Prof. Albert Padwa that appeared in 1984. Since so much has been published on this fascinating and broadly useful subject in the intervening years, we felt that a Supplement would be welcomed by the international chemistry community, and we... 

The recent popularity of palladium-catalyzed cross coupling reactions has been extended into the field of pyrimidines as well. For example, the palladium-catalyzed couplings of arylthiols and 2-bromopyrimidine (47) to produce 48 were reported by Thorarensen and coworkers <99SL1579>. 

Clearly, the most widespread nucleophilic reaction by heteroatoms is alkylation at ring nitrogen atoms. It is unsurprising that the very great interest in nucleosides of pyrrolo[2,3-d]pyrimidines, as deaza analogues of purine nucleosides, dominates this field. Selected examples of this chemistry... 

Although A-acyl enamines and their cationoid derivatives are not the intermediates in all the above-mentioned syntheses of pyrimidines, these reactions are listed here for demonstration of the synthetic applicability of the reaction between nitriles and carbonyl compounds and their derivatives. During the course of investigation of these processes interesting theoretical results were obtained which allow one to evaluate from a new viewpoint some concepts regarding this field. 

The synthesis of cytidine9 by the Hilberb-Johnson procedure (which may be formulated as a reaction of 2,4-dialkoxypyrimidines with halogenoses) initiated further investigations in the field of the pyrimidine nucleoside synthesis. Thus, for example, the treatment of... 

The effect of micro-waves in resonance with ZF transitions or 1 T static magnetic field on the rate of photochemical reaction of the triplet state of solid pyrimidine in benzene at 1.6 K, Here, the vertical axis represent the relative phosphorescence intensity of this system. (Reproduced from Ref. [1] by permission from The American Chemical Society)... 

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