Showing papers on "Xanthene published in 1970"

Alkyl or halo substituted tetrahalofluorans

Abstract: 6''-((C2H5-)2-N-)SPIRO(PHTHALAN-1,9''-XANTHENE) WHEREIN EACH R1, R2, R3 OR R4 IS HYDROGEN, AN ALKYL RADICAL HAVING 1 TO 4 CARBON ATOMS OR CHLORINE AND AT LEAST ONE OF SAID R GROUPS IS AN ALKYL RADICAL OR CHLORINE. 3-(O=),4,5,6,7-TETRA(CL-),1''-R1,2''-R2,3''-R3,4''-R4, A CHROMOGENIC MATERIAL OF NORMALLY COLORLESS FORM IS DISCLOSED HAVING THE STRUCTURAL FORMULA:

Studies of the Chemiluminescence of Several Xanthene Dyes. V. Blue Emission from an Excited State of a Reaction Product

Abstract: We have found that the chemiluminescence emission of several xanthene dyes with hydrogen peroxide is comprised of two emission components; one is a greenish-yellow emission whose spectral distribution is similar to that of the fluorescence of the dye, and the other is a blue emission similar to the fluorescence band which appears during the course of the reaction. Summarizing the results, we can conclude that the chemical formation of an excited species from the oxidation of a dye, and an energy-transfer process from the species to an unoxidized dye, are likely to be the mechanism for the luminescent reaction. Certain dyes, uranin, eosin Y, eosin R, erythrosin B, 2′,7′-dichlorofluorescein, mercurochrome, rhodamine B, rhodamine 6G, and rhodamine S, showed similar characteristic chemiluminescence emissions, whereas phloxine, rose bengale, 4-nitrofluorescein, 4,5,6,7-tetrachlorofluorescein, sulfonfluorescein, and pyronine G did not chemiluminesce under comparable conditions.

Reactions of enamines with benzaldehyde and benzylidenecyclohexanone

Abstract: Benzaldehyde reacts with 1-pyrrolidin-1-ylcyclohexene and 1-piperidin-1-ylcyclohexene to give xanthene derivatives identical to the products of reaction of dibenzylidenecyclohexanone with the enamines : 1-morpholinocyclohexene behaves differently. Benzylidenecyclohexanone with 1-pyrrolidin-1-ylcyclohexene gives an analogous adduct the hydrolysis of which has been investigated.

Bis-basic ketones of xanthene and xanthen-9-one

Abstract: D R A W I N G WHEREIN X is oxygen or NR4, and R4 is hydrogen or lower alkyl of from 1 to about 4 carbon atoms; or a pharmaceutically acceptable acid addition salt thereof. These compounds can be prepared by several different methods. WHEREIN N IS A WHOLE INTEGER FROM 4 TO 6, AND R3 is hydrogen, lower alkyl of from 1 to about 4 carbon atoms and can be linked to any one of the carbon atoms of the heterocyclic group; or C. the group WHEREIN R1 and R2 are individually hydrogen, lower alkyl having from 1 to about 6 carbon atoms, cycloalkyl having from 3 to 6 carbon atoms, alkenyl of from 3 to 6 carbon atoms and having the vinyl unsaturation in other than the 1-position of the alkenyl group; or B. the group Novel bis-basic ketones of xanthene and xanthen-9-one have antiviral activity when administered orally and parenterally. The compounds are represented by the following formula: WHEREIN Z is oxygen or H2; each A is a straight or branched alkylene chain having from 1 to about 6 carbon atoms; and each Y is A. the group

Photocolorable vacuum sublimed xanthene dye

Abstract: AN OPTICAL RECORDING AND STORAGE MEDIA COMPRISES A SUBSTRATE HAVING AN ESSENTIALLY COLORLESS VACCUM SUBLIMED XANTHENE DYE TYPE FILM THEREON. THE XANTHENE DYE IS OF THE TYPE HAVING A PENDANT PHENYL RING AT THE 9TH CARBON OF THE XANTHENE STRUCTURE. A COOH GROUP IS PRESENT ON THE CARBON ATOM OF THE PHENYL RING IMMEDIATELY ADJACENT THE LINKING CARBON OF THE RING. ELECTRON WITHDRAWING GROUPS ARE PRESENT ON THE XANTHENE STRUCTURE. AN EXAMPLE OF SUCH A MATERIAL IS RHODAMINE B.

Reaction paths to pure 5- and 6-aminofluorescein. Pitfalls encountered in conventional synthesis procedures

Abstract: Previously unrecognized pitfalls in the published procedure for the preparation of 5- and 6-isothiocyanatofluoresceins were examined. Hydrolysis of 5-nitrofluorescein diacetate with hot ethanol saturated with sodium hydroxide gave varying amounts of 5,5″-azoxydifluorescein in addition to 5-nitrofluorescein. The use of methanol and sodium hydroxide was found to give pure 5- and 6-nitrofluorescein from the corresponding diacetate. Further, reduction of 5-nitrofluorescein with hydrogen and W-2 Raney nickel gave a mixture of 5-aminofluorescein and 9-(4-amino-2-carboxyphenyl)-3,6-dihydroxyxanthene. A sodium sulphide–sodium hydrosulphide reduction system reduced 5-nitrofluorescein cleanly to the amine without reductive lactone cleavage. Synthesis and characterization of 5,5″-azoxydifluorescein, 9-(4-amino-2-carboxyphenyl)-3,6-dihydroxyxanthene, and related fluorescein and xanthene derivatives are described.

On the Relation between Photodynamic Activities and Photochemical Oxidation in Xanthene Dyes

Abstract: Xanthene dyes such as erythrosine, eosine, phloxine, rose bengale when exposed to visible light have lethal effects on bacteria at concentrations at which the bacteria can still duplicate in the absence of light.Y. Kurayuki et al. have reported on the formation of resorcinol, phthalic acid and other decomposed products in the fading solution of xanthene dye exposed to daylight. But in our experiments the lethal activities of those decomposed products on bacteria were negligible. And as the photodynamic activities in xanthene dyes as well as methylene blue and proflavine can be found only in aerobic condition, the photodynamic effects on bacteria presumably are due to the oxidation of some component of bacterial cell. This mechanism is simillar to that of photochemical oxidation reported by G. Oster et al.