Xanthene

About: Xanthene is a research topic. Over the lifetime, 2132 publications have been published within this topic receiving 34803 citations. The topic is also known as: Xanthene & dibenzo[a,e]pyran.

Hair dyeing method and hair dyeing agent composition used therefor

Abstract: PURPOSE: To provide a hair dyeing method for dyeing black hair in clear color free from blackish color by treatment once and to obtain a hair dyeing agent used for the method. CONSTITUTION: This hair dyeing agent comprises an agent A containing 2-50-wt.%, especially 5-2wt.% of xanthene-based dye, an agent B containing 2-6wt.%, especially 5-6wt.% calculated as H2 O2 of hydrogen peroxide and/or a hydrogen peroxide generating part and an agent C containing a persulfate. The agents A, B and C are mixed in the ratio of 0.1-5 pts.wt. of H2 O2 . contained in the agent B based on 1 pt.wt. of the xanthene-based dye in the agent A and 0.5-8 pts.wt. of the persulfate contained in the agent C based on 1 pt.wt. of H2 O2 contained in the agent B and the mixed solution is used to dye hair. The pH of the mixed solution is >=7 and preferably 8-10 and is controlled by the amount of an alkali substance to be mixed with the agent A and/or the agent B.

Film forming polymeric compositions of 7,7-dimethyl-7h-dibenzo (c,h)xanthene compounds

Abstract: Novel monomers of 7,7-dimethyl-7H-dibenzo(c,h)xanthene-5,9disulfonyl halide and novel high molecular weight polymers containing 7,7-dimethyl-7H-dibenzo-(c,h)xanthene residues are useful in the preparation of photographic film bases.

Experimental and Computational Studies on the Ruthenium-Catalyzed Dehydrative C-H Coupling of Phenols with Aldehydes for the Synthesis of 2-Alkylphenol, Benzofuran, and Xanthene Derivatives.

Abstract: The cationic Ru-H complex [(C6H6)(PCy3)(CO)RuH]+BF4- (1) was found to be an effective catalyst for the dehydrative C-H coupling reaction of phenols and aldehydes to form 2-alkylphenol products. The coupling reaction of phenols with branched aldehydes selectively formed 1,1-disubstituted benzofurans, while the coupling reaction with salicylaldehydes yielded xanthene derivatives. A normal deuterium isotope effect was observed from the coupling reaction of 3-methoxyphenol with benzaldehyde and 2-propanol/2-propanol-d8 (kH/kD = 2.3 ± 0.3). The carbon isotope effect was observed on the benzylic carbon of the alkylation product from the coupling reaction of 3-methoxyphenol with 4-methoxybenzaldehyde (C(3) 1.021(3)) and on both benzylic and ortho-arene carbons from the coupling reaction with 4-trifluorobenzaldehdye (C(2) 1.017(3), C(3) 1.011(2)). The Hammett plot from the coupling reaction of 3-methoxyphenol with para-substituted benzaldehydes p-X-C6H4CHO (X = OMe, Me, H, F, Cl, CF3) displayed a V-shaped linear slope. Catalytically relevant Ru-H complexes were observed by NMR from a stoichiometric reaction mixture of 1, 3-methoxyphenol, benzaldehyde, and 2-propanol in CD2Cl2. The DFT calculations provided a detailed catalysis mechanism featuring an electrophilic aromatic substitution of the aldehyde followed by the hydrogenolysis of the hydroxy group. The calculations also revealed a mechanistic rationale for the strong electronic effect of the benzaldehdye substrates p-X-C6H4CHO (X = OMe, CF3) in controlling the turnover-limiting step. The catalytic C-H coupling method provides an efficient synthetic protocol for 2-alkylphenols, 1,1-disubstituted benzofurans, and xanthene derivatives without employing any reactive reagents or forming wasteful byproducts.

1 benzopyrano 2*33b xanthene derivative and its preparation

Abstract: NEW MATERIAL:A compound of formula I (R1, R2, R3, R4 and R5 are H or lower alkyl groups; X is lowr alkyl, halogen, lower alkyenyl, lower alkoxy group, etc; n is 0, 1 or 2) EXAMPLE:5a,12a-Etheno-6H,6aH,7H,13H,13aH,14H-[ 1 ]benzopyrano[ 2,3-b ] xanthene USE:A medicine having an analgesic and an anti-inflammatory actions or an intermediate for the synthesis of other medicines or agricultural chemicals PROCESS:A 3,6-bis(2-alkenylphenoxy)pyridazine derivative of formula II is heated with preferably an inert solvent, eg N,N-dimethylaniline, or an inert solid carrier, eg anhydrous sodium carbonate, at 150 degC or above to give the compound of formula I The starting novel compound of formula II is obtained by heating one mole of 3,6-dichloropyridazine with 2 moles or more of the corresponding 2-alkenyl substituted phenol in the presence of a base