Showing papers on "Xanthene published in 1982"

Spectrophotometric study of several rhodamines commonly used in microscopy (1)

Abstract: Rhodamines, commonly used in microscopic studies, are basic dyes derived from xanthene. They have recently been used for the quantitative analysis of important cations, as well as in the vital staining of mitochondria of normal or pathological cells and also in the routine staining procedures. These applications may require a knowledge of the spectral behaviour of rhodamines. Here we report the visible and ultraviolet absorption spectra, together with the excitation and fluorescence spectra of the chromatographically pure samples of rhodamine B, rhodamine 6G and violamine R.

Polymerization of vinyl or diene monomer

Abstract: PURPOSE: To prevent deposition of solid polymer on the inner surface of a polymerization apparatus used, by closely attaching a specified pigment to the inner surface of the apparatus with the help of an aqueous or organic medium, and polymerizing therein a vinyl or diene monomer. CONSTITUTION: A mixture is prepared by using at least one member selected from pigments having a maximum absorption wavelength in the range of 545W 740mμ, such as azo, triarylmethane, xanthene, amine or thiazole type with an aqueous medium or a mixture or reaction product between an aliphatic dialdehyde of formula I , wherein R is 0W6C saturated aliphatic hydrocarbon, and an aliphatic polyamine of formula II, wherein x is 0W5 and y is 1W6. Then, this mixture is applied to the inner surface of a polymerization apparatus so as to form a wet film of 0.01W0.1g/m 2 , and a vinyl or diene monomer alone or together with another copolymerizable monomer is fed to the apparatus and (co)polymerized in an aqueous medium contained therein. COPYRIGHT: (C)1983,JPO&Japio

Mercaptan prodn. from olefinic cpd. and hydrogen sulphide - using xanthene deriv. as photoinitiator catalyst

Abstract: Mercaptans are synthesised by the photochemical reaction of an olefinic cpd. with H2S in the presence of an initiator of formula (I). (Y is O or S; X is O, S , Se, -CH2, -CH2CH2-, SO2, CO, CS, NR' (R' is a hydrocarbon gp.), -P(R)-, P(OR)-, -P(OR)3- or -P(R)3-(R is alkyl, aryl, H or halogen) and R1-R8 are H, halogen, alkoxy, alkyl and/or aryl). Process gives improved yield of mercaptans and can be effected either with or without an organic solvent such as an organic sulphide, a hydrocarbon or an ether. When using an organic sulphide, the advantage is enhanced in that the latter may be that which is obtd. as by-prod. of the reaction itself.

Structure of the Cornubert ketone

Abstract: The self-condensation of cyclohexanone in diethyl ether catalyzed by sodium amide has been found to provide a one-step route to pyran 3. Evidence is presented that the Cornubert ketone formed by this reaction corresponds to ketol 2 which readily rearranges under dehydrating conditions to afford pyran 3. Structural elucidation of pyran 3 was achieved by a combination of degradative (3 → 5b), synthetic (8 → 5b), and spectral methods. Xanthene 7, a key dehydrogenation product of ketol 2, was converted by selective reduction to dihydropyran 5b. The five-step synthesis of dihydroxypyran 5b from 1-carbomethoxycyclopentanol (8) provided unequivocal evidence for the structure assigned pyran 3 and xanthene 7.