Liu You-Cheng

A facile generation of radical cations via the action of nitroxides

Abstract Radical cations of aromatic amines and heteroaromatics were generated via the action of nitroxides in methylene chloride in the presence of trifluoroacetic acid.

CRYSTAL AND MOLECULAR STRUCTURES OF TWO ISOMERS OF DIETHYL 2, 3-DICYANO-2, 3-DIPHENYLSUCCINATE

Diethyl 2, 3-dicyano-2, 3-diphenylsuccinate was prepared through the oxidative coupling of ethyl α-cyanophenylacetate with Cu~(++)-TMEDA-O_2 system. The product gave, upon chromatography, two crystalline compounds 1 and 2. The single crystals of 1 and 2 were identified by X-ray crystallographic analysis to be meso-and racemie-diethyl 2,3-dicyano-2,3-diphenylsuccinate respectively. It is noteworthy that in the molecules of 1 and 2 there is a remarkable lengthening effect of the bond length for the central C—C bond, i. e. 1: 1.585; 2: 1.62. It is also observed that there is steric hindrance between the substituent groups attached to the two carbon atoms of the central C—C bond respectively. These data provide the structural basis for the facile dissociation into radicals and the action of polymerization initiator of the title compound. CNDO/2 calculation of charge density and Wiberg bond order for compound 1 yields the results, which are consistent with the crystallographic data.

Experimental studies on the antitumor action of free radicals: Antitumor action of galvinoxyl

SummaryGalvinoxyl is a long-lived free radical and a highly efficient scavenger of shorter-lived free radicals. In vitro studies demonstrated that galvinoxyl has an inhibitory effect on tumor cells of sarcoma 180 and ascitic form of hepatoma. The higher the concentration of galvinoxyl, the more remarkable its inhibiting effect. Growth of the hepatoma cells in vivo was also inhibited when they had been treated in vitro with galvinoxyl. Galvinoxyl showed an inhibition rate of 43.1%.6 days after implantation of tumor cells into mice an intralesional injection of galvinoxyl was given and the same was repeated 4 days later. It was found that galvinoxyl showed an inhibition rate of 51.3% on subcutaneously implanted sarcoma 180.