Search results for "cyclic"

Chemical Carcinogenesis by Polycyclic Aromatic Hydrocarbons

1982

The realization that for a vast number of toxic effects, not the given compound itself was responsible but rather a metabolite that was produced from the compound, brought about an enormous step forward in chemical carcinogenesis and in toxicology in general (1–15). In chemical mutagenesis and in chemical carcinogenesis very often coumpounds, which by themselves are chemically inert, will produce mutagenic and carcinogenic effects. A prime example of this is the polycyclic aromatic hydrocarbons, which consisting of condensed aromatic rings are chemically inert, yet do produce mutagenic and carcinogenic effects. During the last 10 to 20 years researchers have started to realize that this is …

Neue Diels-Alder-Reaktionen von 1-Methylpyrano[3,4-b]indol-3(9H)-on mit cyclischen CC-Dienophilen: ein einfacher Zugang zu [b]anellierten Carbazol-De…

1988

1-Methylpyrano[3,4-b]indol-3(9H)-on (1) reagiert als synthetisches Aquivalent von Indolo-2,3-chinodimethan mit Arin, p-Benzochinon und p-Naphthochinon zu neuen [b]anellierten Carbazol-Derivaten. Durch das Reaktionsmedium bedingt lassen sich bei der Cycloaddition von 1 mit Arin zugleich auch mononitrierte Carbazole isolieren. New Diels-Alder Reactions of 1-Methylpyrano[3,4-b]indol-3(9H)-one with Cyclic CC-Dienophiles: A Simple Way to [b]Annulated Carbazole Derivatives. 1-Methylpyrano[3,4-b]indol-3-(9H)-one (1) reacts as synthetic equivalent of indolo-2,3-quinodimethane with benzyne, p-benzoquinone, and p-naphthoquinone to give new [b]annulated carbazole derivatives. In the Diels-Alder reacti…

Mechanismus und Reaktionswege der Xanthenylierung an ambidenten nukleophilen Arzneistoffen

1986

Am Beispiel der ambidenten nukleophilen Arzneistoffe 4-Aminobenzolsulfonamid (3), Indometacin (7) und Phenylbutazon (10) werden Aralkylierungen mit dem SN1-aktiven Reagens Xanthydrol (1) vorgestellt. Mechanism and Reaction Path of the Xanthenylation of Ambident Nucleophilic Drugs The aralkylation of ambident nucleophilic drugs, e.g. 4-aminobenzenesulfonamide (3), indometacine (7) and phenylbutazone (10), with SN1-active xanthydrol (1) is described.

A new access to 2′-amino-substituted vinylindoles as donor-activated heterocyclic dienes and their first diels-alder reactions

1992

Abstract Reactions of the 3-acylindoles 5, 10 , and 15 with α-amino-α′-diphenylphosphinoyl-substituted carbanions gave rise to the 2′-amino-substituted 3− and 2-vinylindoles 7, 12 , and 17 by way of the isolable carbinols 6 , 11 , and 16 . The heterocyclic dienes 7 , 12 , and 17 readily underwent Diels-Alder reactions with N -phenylmaleimide.

Structure elucidation of benzopyran-2-ol in solution and in solid state following the reduction of coumarin by DIBAL-H

2001

Lactols are compounds of increasing interest in the synthesis of active pharmaceutical derivatives. Nevertheless, the product obtained by the reduction of the carbonyl group of coumarin has been described only twice, and without definition of its precise chemical structure. Since these studies, doubts have been raised about the existence of a monomeric or dimeric form. Our study has led us to conclude definitely that the single dimeric form exists and to precisely define the spectral properties of the two diastereoisomers.

ChemInform Abstract: Studies on Bicyclo[3.3.1]nonanes for Synthesis of Cyclooctenes.

2010

This paper describes a full conformational and stereochemical study of bicylo[3.3.1]nonanes, obtained from the reaction between cinnamaldehyde and 1-morpholine 1-cyclohexene. NMR data and stereochemistry were unequivocally established and assigned by two-dimensional experiments and single-crystal X-ray analysis. The crystal structure of a minor compound, 4, is reported. Cyclooctenes, which are present in natural products with biological activities, were synthesized from the bicyclononanes via the Wharton fragmentation.

Mammalian Xenobiotic Epoxide Hydrolases

2002

Separation of aromatic aminophosphonic acid enantiomers by capillary electrophoresis with the application of cyclodextrins

2002

The detailed studies concerning capillary electrophoresis separation of aminophosphonic acid enantiomers with various commercially available cyclodextrins are presented. The obtained results show that the separation of these stereoisomers is dependent on pH of background electrolyte, concentration of cyclodextrin as well as on the type of applied chiral selector. The separation mechanism is based on the co-operative effect of hydrogen bond type interactions enhanced by hydrophobic forces and sterical constrains between aminophosphonate and cyclodextrin. With application of elaborated method, enantiomeric baseline or partial separation of 18 alpha-aminophosphonic acids was achieved. This sep…

Alkaloids from Rauwolfia serpentina cell cultures treated with ajmaline

1993

Abstract A group of new alkaloids, the raumaclines, and some related alkaloids were isolated from Rauwolfia serpentina cell suspensions fed with high levels of ajmaline; their structures were determined and syntheses developed providing an essential prerequisite to the further study of their biosynthesis at the enzymatic level.

Fate of Epdxides

1982

One of the most important reactions of epoxides appears to be the covalent binding to DNA which can lead to mutagenicity and is strongly suspected to be the primary lesion ultimately leading to initiation of cancer (Miller and Miller, 1974; Oesch, 1973; Jerina and Daly, 1974; Sims and Grover, 1974; Heidelberger, 1975; Gelboin et al., 1972). This review first describes structure-activity relationships for the mutagenicity of some epoxides and then outlines some findings on the metabolic control of the concentration of such epoxides by a number of enzymes.