Hydrogen cyanide derivatives, heterocycles from

Synthesis of Heterocycles from Hydrogen Cyanide Derivatives D. S. Donald and O. W. Webster... 

Homolytic substitution of heteroaromatic compounds, 16, 123 Hydantoins, chemistry of, 38, 177 Hydrogen cyanide derivatives, synthesis of heterocycles from, 41, 1 Hydrogen exchange base-catalyzed, 16, 1 one-step (labeling) methods, 15, 137 Hydrogenated porphyrin derivatives hydroporphyrins, 43, 73 Hydroxamic acids, cyclic, 10, 199 1 -Hydroxyindoles, 1 -hydroxytryptophans, and 1-hydroxytryptamines,... 

In the first chapter, D. S. Donald and O. W. Webster summarize much fundamental heterocyclic chemistry dealing with the preparation of heterocycles from hydrogen cyanide and its derivatives, mostly previously available only in the patent literature. In the second, the account of the ringopening of five-membered heteroaromatic anions by T. L. Gilchrist brings together the numerous transformations that can succeed the removal of a proton from a carbon atom in a five-membered heterocyclic ring. 

The reaction of tnfluoromethyl-substituted N-acyl umnes toward nucleophiles in many aspects parallels that of the parent polyfluoro ketones Heteronucleophiles and carbon nucleophiles, such as enamines [37, 38], enol ethers [38, 39, 40], hydrogen cyanide [34], tnmethylsilylcarbomtnle [2,41], alkynes [42], electron-nch heterocycles [43], 1,3-dicarbonyl compounds [44], organolithium compounds [45, 46, 47, 48], and Gngnard compounds [49,50], readily undergo hydroxyalkylation with hexafluoroace-tone and amidoalkylation with acyl imines derived from hexafluoroacetone... 

Purine derivatives are considered to be prebiotic molecules. Purine as well as adenine (HCN) can be formed from hydrogen cyanide in the presence of ammonia in a prebiotic atmosphere. Similar reaction in the presence of water can lead to other purines. Purine chemistry goes back to the roots of organic chemistry. Uric acid was the first purine isolated from bladder stones by Scheelc in 1776. The correct empirical formula of uric acid was established much later by Liebig and Mitscherlich. The correct structure was suggested by L. Medicus and was shown to be correct by the syntheses ofHorbaezewski. Behrend and Roosen, and unambiguously by E. Fischer. The development of purine chemistry by E. Fischer is a milestone in heterocyclic chemistry. 

Intramolecular Diels-Alder reactions of the pyrazine derivatives 631 (X = O, S or NAc R = SiMes or HOCH2) yield mixtures of the tricyclic heterocycles 633 and 634. Both arise from the intermediate cycloadducts 632, which can lose the elements of hydrogen cyanide in two ways, as indicated. ... 

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