Second generation of steroid synthesis via o-quinodimethane

Nemoto, Hideo; Fukumoto, Keiichiro

doi:10.1016/s0040-4020(98)00017-9

Cited by 92 publications

(39 citation statements)

References 171 publications

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“…1). These QMs have been known to exhibit an extremely high reactivity toward various organic molecules [37], and we can expect that these species may interact with some intracellular substances even if they exit at very low level of concentration.…”

Section: Discussionmentioning

confidence: 99%

Enhancement of hyperthermia-induced apoptosis by a new synthesized class of benzocycloalkene compounds

Matsuya

Zhao

et al. 2008

Apoptosis

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The aim of this study was to examine whether, a new synthesized class of benzocycloalkene derivatives (BCs), enhances apoptosis induced by hyperthermia. The combined effects of hyperthermia (44 degrees C, 20 min) and BCs on apoptosis in human lymphoma U937 cells were investigated. Among the tested compounds (BC1 approximately 9), the combined treatment of 10 muM BC2 or BC4 and hyperthermia showed the largest potency to induce DNA fragmentation at 6 h after hyperthermia. And enhancement of hyperthermia-induced apoptosis by BC2 or BC4 in a dose-dependent manner was observed. When the cells were treated first with BC2 or BC4 at a nontoxic concentration of 20 muM, and exposed to hyperthermia afterwards, a significant enhancement of heat-induced apoptosis was evidenced by DNA fragmentation, morphological changes and phosphatidylserine externalization. Flow cytometry revealed an increase of intracellular superoxide due to BC2 or BC4, which was further increased when hyperthermia was combined. Mitochondrial membrane potential was decreased and the activation of caspase-3 and caspase-8 was enhanced in the cells treated with the combination. The activation of Bid, but no change of Bax and Bcl-2 were observed after the combined treatment. The release of cytochrome c from mitochondria to cytosol, which was induced by hyperthermia, was enhanced by BC2 or BC4. An increase in the intracellular Ca2+ concentration [Ca2+](i), externalization of Fas, and decrease in Hsp70 were observed following the combined treatment. These results indicate that the intracellular superoxide generated by BC2 or BC4 is involved in the enhancement of apoptosis through Fas-mitochondria caspase and [Ca2+](i)-dependent pathways, and a decrease in Hsp70 also contributed to the enhancement of apoptosis.

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Section: Discussionmentioning

confidence: 99%

Enhancement of hyperthermia-induced apoptosis by a new synthesized class of benzocycloalkene compounds

Matsuya

Zhao

et al. 2008

Apoptosis

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“…[45] Das Strukturgerüst wurde über eine intramolekulare [4+2]-Cycloaddition von o-Chinodimethanen synthetisiert, wobei letztere durch thermische Ringöffnung von Benzocyclobutanderivaten zugänglich sind (Schema 12). [46] Mit [42,43,47] manche hemmen außerdem auch die Cdc25B-Phosphatase. [48] Diese Grundgerüste könn-ten daher interessante Ausgangspunkte für neue Verbindungsbibliotheken zur Entwicklung von Wirkstoffkandidaten sein.…”

Section: Mehrfach Anellierte Furanderivateunclassified

Die Synthese von naturstoffinspirierten Verbindungsbibliotheken

Kumar

Waldmann

2009

Angewandte Chemie

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Der Natur abgeschaut: Die Entwicklung vielstufiger stereoselektiver Synthesen eröffnet den Zugang zu naturstoffinspirierten Verbindungsbibliotheken mit carbo‐, oxa‐ und azacyclischen Gerüststrukturen, die vielversprechende Quellen für neue Reagentien in der medizinischen Chemie und der chemischen Biologie sind. Das Bild zeigt eine Sammlung von naturstoffinspirierten Molekülen (blau) mit ihren zugrundeliegenden Naturstoffen (gelb).magnified imageNaturstoffe und ihre Derivate und Analoga gehören zu den wichtigsten Quellen neuer Wirkstoffkandidaten und Reagentien für die chemische Biologie und medizinische Chemie. Hieraus leitet sich ein großer Bedarf an effizienten Synthesemethoden ab, die einen Zugang zu naturstoffabgeleiteten oder ‐inspirierten Verbindungsbibliotheken ermöglichen. Um solche Verfahren entwickeln und anwenden zu können, ist es erforderlich, die vielstufigen stereoselektiven Synthesemethoden, wie sie für Naturstoffsynthesen charakteristisch sind, auf die Verfahrensweisen beim Aufbau von Verbindungsbibliotheken zu übertragen und entsprechend anzupassen. Neue Entwicklungen bei der Synthese naturstoffinspirierter Bibliotheken aus carbocyclischen und heterocyclischen Gerüststrukturen zeigen klar auf, dass dieses Ziel erreicht werden kann. Die bereits erzielten Fortschritte haben den Weg für die Einbeziehung naturstoffinspirierter Verbindungsbibliotheken in die medizinische Chemie und die biochemische Forschung geebnet.

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“…In the course of our continuous research on o-quinodimethane chemistry, 90,91,105) we focused our interest on the substituent effect for the thermal cleavage of benzocyclobutenes, especially on the silyl substituents 106) in conjunction with recent reports on their rate enhancement effects for that of monocyclic cyclobutenes. 107,108) The compounds 112a-c and 113a-c were conducted to thermal electrocyclic reaction involving concurrent [4ϩ2] cycloaddition with maleic anhydride.…”

Section: Novel Reaction Mode and Substituent Effectmentioning

confidence: 99%

“…The o-quinodimethanes resulting from thermolysis of benzocyclobutenes have shown important applications in the synthesis of a wide range of polycyclic compounds via intermolecular and intramolecular Diels-Alder reactions. [20][21][22][23][24] In this context, we have been studying the development of novel types of reactions including concerted ring opening reaction of chiral oxaspiropentanes to give chiral cyclobutanones, successive ring expansion-insertion reaction of olefinic vinylcyclobutanols, and pericyclic reaction of benzocyclobutenes as well as cyclohexane-fused cyclobutenes.…”

Section: Introductionmentioning

confidence: 99%