Synthesis of 1,8-dioxooctahydroxanthenes utilizing PMA-SiO_2 as an efficient reusable catalyst

PMA-SiO2 has been utilized as an efficient catalyst system in preparation of 1,8-dioxooctahydroxanthenes.

A rapid and efficient method for the synthesis of 14H-dibenzo[α.j]xanthenes,aryl-5H-dibenzo[b.i]xanthene-5,7,12,14-(13H)-tetraone and 1,8-dioxooctahydroxanthenes by acidic ionic liquid

Various xanthenes have been synthesized by the condensation ofβ-naphthol,2-hydroxynaphthalene-1,4-dione or dimedone with various aldehydes in the presence of trifluoroacetic acid as catalyst in 1,1,3,3-N,N,N′,N′-tetramethylguanidinium trifluoroacetate （TMGT） ionic liquid within 1 h at 75℃.

Silica supported ammonium dihydrogen phosphate(NH_4H_2PO_4/SiO_2):A mild,reusable and highly efficient heterogeneous catalyst for the synthesis of 14-aryl-14-H-dibenzo[a,j]xanthenes

catalyst for the synthesis of 14-aryl- 14-H-dibenzo[aj]xanthenes Silica supported ammonium dihydrogen phosphate （NH4H2PO4/SiO2） is found to be a recyclable heterogeneous catalyst for a rapid and efficient synthesis of various aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times and milder conditions. 2009 Shahnaz Rostamizadeh. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Fe(HSO_4)_3:An efficient,heterogeneous and reusable catalyst for the synthesis of 14-aryl- or alkyl-14H-dibenzo[a,j]xanthenes

Fe（HSO4）3 has been used as an efficient and recyclable catalyst for the one-pot synthesis of 14-aryl- or alkyl-14Hdibenzo[aj]xanthene derivatives by the reaction of 2-naphtol and aldehydes. Different types of aromatic and aliphatic aldehydes are used in the reaction and in all cases the products were obtained in good to excellent yields.

Oxalic acid as a catalyst for efficient synthesis of bis-(indolyl)methanes,and 14-aryl-14H-dibenzo[a,j]xanthenes in water

A simple, efficient, and environment benign route was developed for the preparation of bis-（indolyl）methanes and 14-aryl-14H- dibenzo[aj]xanthenes from condensation of various aromatic aldehydes or ketones with indole, and 2-naphthol, respectively, using oxalic acid catalyst in aqueous medium. Use of cheap and easily available catalyst, better yields and simple reaction protocol are the advantages of the present method.

L-Pyrrolidine-2-Carboxylic Acid Sulfate (LPCAS): A New Ionic Liquid for the Synthesis of 14-Aryl-14H-Dibenzo[a,j] Xanthenes under Solvent Free Condition

A new Bronsted acidic ionic liquid, L-Pyrrolidine-2-carboxylic acid sulfate (LPCAS) was employed to promote one-pot synthesis of 14-aryl-14H-dibenzo [a,j] xanthenes via condensation reaction of aldehydes and 2-naphthol under solvent free condition. Distinguishing features of the methodology are excellent yield of products in shorter reaction time, cleaner reaction profile, eco-friendly nature and the use of inexpensive catalyst.

Silica supported sodium hydrogen sulfate(NaHSO_4/SiO_2):A mild and efficient reusable catalyst for the synthesis of aryl-14-H-dibenzo[a,j]xanthenes under solvent-free conditions

A simple and efficient procedure for the preparation of aryl- 14-H-dibenzo [aj]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes, in the presence of silica supported sodium hydrogen sulfate （NaHSO4/SiO2） as a catalyst and in the absence of solvent has been developed. The present method offers several advantages such as excellent yields, short reaction time （10-30min）, mild condition, simple work-up, and the use of a cheap and environmentally friendly catalyst with remarkable reusability.

Silica Gel-Supported Polyphosphoric Acid （PPA/SiO2）： An Efficient and Reusable Heterogeneous Catalyst for Facile Synthesis of 14-Aryl-14H-dibenzo[aj]xanthenes under Solvent-free Conditions

A simple, efficient and green method for the synthesis of 14-aryl-14H-dibenzo[aj]xanthenes by a one-pot condensation reaction of β-naphthol and aryl aldehydes using silica gel-supported polyphosphoric acid （PPA/SiO2）, an effective and reusable catalyst, under solvent-free conditions is described. The present methodology offers several advantages, such as a simple procedure with an easy work-up, short reaction times, high yields, and the absence of any volatile and hazardous organic solvents.

An efficient and eco-friendly synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes using H_4[SiW_(12)O_(40)]as a heterogeneous and reusable catalyst under solvent-free conditions

A simple and efficient catalytic protocol for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes via the one-pot condensation ofβ-naphthol and aryl aldehydes using silicotungstic acid（H_4[SiW_（12）O_（40）]） is reported.The present method offers several advantages such as high to excellent yields,short reaction times,recovery and reusability of catalyst,mild reaction conditions and easy workup procedures.

Synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes promoted by Mg(HSO_4)_2

14-Aryl or alkyl-14H-dibenzo[a,j]xanthenes were prepared by condensation of 2-naphthol and aldehydes in the presence of Mg（HSO4）2 as an efficient, cheap, readily available and eco-friendly catalyst. This procedure has the advantages of high yields, easy work-up, short reaction times, and green conditions.

1,3-Dibromo 5,5-dimethylhydantoin (DBH):A novel and efficient catalyst for the synthesis of 14-aryl-14H-dibenzo[a,j] xanthenes under solvent-free conditions

An atom-efficient and environment-friendly approach for the synthesis of aryl-14H-dibenzo[a,j]xanthenes (3a–o) via the one-pot reaction of β-naphthol and aryl aldehydes (1) catalyzed by DBH has been developed. The present approach offers several advantages such as reduced reaction times, moderate temperature, higher yields, solvent free, eco-friendly reaction condition, easy purification and economic availability of the catalyst.

The efficient synthesis of 14-alkyl or aryl 14H-dibenzo[a,j] xanthenes catalyzed by bismuth(Ⅲ)chloride under solvent-free conditions

An efficient method for the synthesis of 14-alkyl or aryl 14H-dibenzo[a,j]xanthene derivatives by the reaction of β-naphthol,and aldehydes in the presence of a catalytic amount of bismuth（Ⅲ） chloride（BiCl_3） under solvent-free conditions at 110℃is described.Aliphatic and aromatic aldehydes were used in the reaction and in all cases the desired products were synthesized successfully.This reaction was studied under different temperatures;the maximum yield was obtained in a short reaction period at 110℃.The method offers the advantages of high yields,short reaction times,simplicity and easy workup compared to the conventional method of syntheses.

Zinc oxide nanoparticles:A highly efficient and readily recyclable catalyst for the synthesis of xanthenes

A novel and efficient route for the synthesis of 1,8-dioxooctahydroxanthenes and 14-aryl-14H-dibenzo[a,j]xanthenes is described through one-pot multi-component reaction of dimedone and 2-naphthol with various aryl aldehydes using ZnO nanoparticles under solvent-free conditions. This method provides a novel and improved pathway for the synthesis of xanthenes in the terms of excellent yields, short reaction times, reusability and low catalyst loading.

Synthesis of 14-Fluorophenyl-14H-Dibenzo[a,j]xanthenes and Their Derivatives under Microwave Irradiation and Solvent-free Conditions

A facile and efficient synthesis of 14-fluorophenyl-14H-dibenzo[a,j]xanthenes has been developed by one-pot condensation of fluorinated benzaldehydes with β-naphthol in the presence of p-TSA·H2O under microwave irradiation and solvent-free conditions. These products are conveniently oxidized to 14-fluorophenyl-14-hydroxydibenzo[a,j]xanthenes by PbO2 in acetic acid in good yields.

1,3-Dibromo-5,5-dimethylhydantoin(DBH)/kaolin:An efficient reagent system for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes under solvent-free conditions

1,3-Dibromo-5,5-dimethylhydantoin, has been used as an efficient catalyst for the synthesis of 14-aryl-14H-dibenzo[a,j]- xanthenes in the presence of kaolin. All reactions are performed in the absence of solvent in relatively short reaction times in good to high yields.

Synthesis of 9-phenol-substituted xanthenes by cascade O-insertion/1,6-conjugate addition of benzyne with ortho-hydroxyphenyl substituted para-quinone methides

The cascade O-insertion/1,6 conjugate addition between benzynes and ortho-hydroxyphenyl substituted para-quinone methides has been reported, affording 9-phenol substituted xanthenes in 49%-84% yields.

Iodine Catalyzed Microwave-Assisted Synthesis of 14-Aryl（Alkyl）-14H-dibenzo[a,j]xanthenes

A straightforward and effective procedure for the synthesis of 14-aryl（alkyl）-14H-dibenzo[aj]xanthenes was described using a catalytic amount of molecular iodine under microwave irradiation to afford the corresponding xanthenes in good yields.

Synthesis and Biological Activities of 10-Substituted 9-Aryl-3,4,6,7,9,10-hexahydroacridine-1,8(2H,5H)-diones

A series of 10-substituted 9-aryl-3,4,6,7,9,10-hexahydroacridine-1,8（2H,5H）-dione derivatives 2 were synthesized by a two-step reaction.All the compounds were characterized by IR,MS,and ^1H NMR.Crystals of 1a and 2c were obtained and determined by X-ray single-crystal diffraction.Crystal data of 1a：C_（20）H_（22）O_5,orthorhombic system,space group Pbcn,a = 15.8888（19）,b = 18.228（2）,c = 11.6926（13） A,V = 3386.4（7） A^3,Z = 8,F（000） = 1456,Dc = 1.343 g/cm^3,R = 0.0456 and w R = 0.1600.Crystal data of 2c：C_（26）H_（24） Cl NO_3,monoclinic system,space group P2_1/n,a = 8.628（2）,b = 10.912（3）,c = 22.425（7） A,β = 90.786（4）°,V = 2111.1（10） A^3,Z = 4,F（000） = 912,D_c = 1.365 g/cm^3,R = 0.0613,and w R = 0.1196.The results of biological experiments show that compounds 2b and 2c could inhibit the proliferation of Hep G2 cells.

Effect of Solvents on Oxidation of 1,1′-Bi-2-naphthol

A novel biomimetic catalyst of complex Cu(p-OTs) 2/ethanolamine(1∶1) was used to oxidize 1,1′-bi-2-naphthol into xanthene derivatives with a relative high yield in a mixed solvents of dimethyl sulfoxide(DMSO) and CH 3OH. The studies on the effect of some solvents on the yield of xanthene derivatives indicates that the yield reduces dramatically with the increase of the content of H 2O in the mixed solvents of H 2O and DMSO. No product can be obtained when the content of H 2O is up to 70%. The cyclic voltammetric study demonstrated that the copper ion in complex Cu(p-OTs) 2/ethanolamine(1∶1) is reduced via a two-step one-electron reduction process from Cu(Ⅱ) to Cu in the mixture of DMSO and H 2O. Water as a poor solvent in respect to the reactants probably hampered the coordination of 1,1′-bi-2-naphthol to copper/amine complex and led to the insufficient catalytic efficiency of complex Cu(p-OTs) 2/ethanolamine(1∶1).

A novel soluble polyamide containing xanthene structure and trifluoromethylphenoxy pendent

A novel polyamide containing xanthene structure and trifluoromethylphenoxy pendent was prepared from 9,9-bis[4-(4- aminophenoxy)phenyl]xanthene,a novel diamine with 2-(4-trifluoromethylphenoxy)terephthaloyl chloride,by the low temperature polycondensation.This new polyamide with the inherent viscosity of 0.95 dL/g was amorphous and readily soluble in polar solvents such as DMAc,m-cresol,etc.This polyamide showed the glass transition temperature(T_g) of 236℃,decomposition temperature (Td) at 5%weight loss of...