Silica-bonded S-sulfonic Acid Research Articles

Regioselective Ring Opening of Epoxides with Amines Using Silica-bonded S-sulfonic Acid under Solvent-free Conditions

Silica-bonded S-sulfonic acid (SBSSA) was used as a recyclable and reusable catalyst for the synthesis of β-amino alcohols. Several amines were reacted with epoxides to afford regioselective β-amino alcohols in high yield under solvent-free conditions at room temperature.

ChemInform Abstract: Synthesis of Naphthoxazinone Derivatives Using Silica‐Bonded S‐Sulfonic Acid as Catalyst under Solvent‐Free Conditions.

Silica-bonded S-sulfonic acid is employed as a recyclable catalyst for the synthesis of naphthoxazinone derivatives from the reaction of s-naphthol, aromatic aldehydes and urea at 150°C under solvent-free conditions. The heterogeneous catalyst was recycled for five runs after the reaction of s-naphthol, benzaldehyde and urea without losing its catalytic activity.

Synthesis of naphthoxazinone derivatives using silica-bonded S-sulfonic acid as catalyst under solvent-free conditions

Silica-bonded S-sulfonic acid is employed as a recyclable catalyst for the synthesis of naphthoxazinone derivatives from the reaction of ß-naphthol, aromatic aldehydes and urea at 150°C under solvent-free conditions. The heterogeneous catalyst was recycled for five runs after the reaction of ß-naphthol, benzaldehyde and urea without losing its catalytic activity. Silica-bonded S-sulfonic acid was employed as solid acid catalyst for the synthesis of naphthoxazinones under solvent-free conditions.

ChemInform Abstract: Efficient Synthesis of Symmetrical Bisamides from Aldehydes and Amides Catalyzed by Silica‐Bonded S‐Sulfonic Acid Nanoparticles.

Abstract Silica-bonded S-sulfonic acid nanoparticles (SBSSANPs) were easily synthesized from silica nanoparticles and showed to be an efficient catalyst in the synthesis the symmetrical N,N′-alkylidene bisamides. Reaction of aldehydes and amides in the presence of the catalyst afforded the corresponding bisamides in good to excellent yields. The extensive range of substrates suggests general applicability of the method. Reusability of the catalyst, simple workup procedure, and short reaction times are other advantages of this protocol. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications ® to view the free supplemental file.

Efficient Synthesis of Symmetrical Bisamides from Aldehydes and Amides Catalyzed by Silica-Bonded S-Sulfonic Acid Nanoparticles

Silica-bonded S-sulfonic acid nanoparticles (SBSSANPs) were easily synthesized from silica nanoparticles and showed to be an efficient catalyst in the synthesis the symmetrical N,N′-alkylidene bisamides. Reaction of aldehydes and amides in the presence of the catalyst afforded the corresponding bisamides in good to excellent yields. The extensive range of substrates suggests general applicability of the method. Reusability of the catalyst, simple workup procedure, and short reaction times are other advantages of this protocol. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications ® to view the free supplemental file.

Reusable silica-bonded S-sulfonic acid catalyst for three-component synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes and 2-amino-4H-pyrans in aqueous ethanol

Silica-bonded S-sulfonic acid (SBSSA)-catalyzed, facile, one-pot, three-component coupling of 5,5-dimethyl-1,3-cyclohexanedione (dimedone) or 5,5-dimethyl-1,3-cyclohexanedione, aromatic aldehydes, and malononitrile at reflux temperature is described for preparation of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene derivatives. 2-Amino-3-cyano-6-methyl-4-phenyl-4H-pyran-5-ethylcarboxylate derivatives can also be prepared in good yield under the same experimental conditions by use of ethyl acetoacetate, aldehydes, and malononitrile. The catalyst, silica-bonded S-sulfonic acid, was reused and recycled without any loss of activity or product yield.

A Simple and Environmentally Benign Protocol for Biginelli Reactions Catalyzed by Silica-Bonded S-Sulfonic Acid

A protocol for the synthesis of 3,4-dihydropyrimidin-2(1 H )-ones and -thiones was developed by means of a three-component condensation of an aldehyde, a β-dicarbonyl compound, and urea or thiourea in acetic acid catalyzed by silica-bonded S -sulfonic acid. Compared to the classical Biginelli reaction conditions, this new protocol has the advantages of consistently excellent yields and short reaction times. After the reaction, the catalyst could be recovered easily and reused with little change in its activity. We report a simple, efficient protocol for the synthesis of 3,4-dihydropyrimidin-2(1 H )-ones and -thiones by means of a three-component condensation of an aldehyde, a β-dicarbonyl compound, and urea or thiourea in acetic acid catalyzed by silica-bonded S -sulfonic acid (SBSSA), a green, reusable heterogeneous catalyst.

Silica-bonded S-sulfonic acid: an efficient and recyclable solid acid catalyst for the three-component synthesis of α-amino nitriles

Abstract Silica-bonded S -sulfonic acid (SBSSA) is employed as a recyclable catalyst for the synthesis of α-amino nitriles. These syntheses were performed via a one-pot three-component condensation of aldehydes, amines, and trimethylsilyl cyanide under mild reaction conditions at room temperature.

Silica‐bonded S‐Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Trisubstituted Imidazoles under Solvent‐free Conditions

AbstractTrisubstituted imidazoles have been synthesized in high yields in the presence of silica‐bonded S‐sulfonic acid as a catalyst. The reaction was carried out at 130°C under solvent‐free conditions. The reaction work‐up is simple and the catalyst is easily separated from the products by filtration.

Preparation of Silica-Bonded S-Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Bis-Indolylmethanes

Silica bonded S-sulfonic acid (SBSSA) was prepared by the reaction of 3-mercaptopropylsilica (MPS) and chlorosulfonic acid in chloroform. Silica-bonded S-sulfonic acid, as a reusable solid acid catalyst, was used for the condensation reactions of indole with carbonyl compounds at ambient temperature. Tetra-(indolyl)methanes were also obtained by the condensation reaction of indole with dialdehyde compounds. Silica bonded S-sulfonic acid was recovered and reused. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Silica-bondedS-sulfonic acid as a recyclable catalyst for the silylation of hydroxyl groups with hexamethyldisilazane (HMDS)

Silica-bonded S-sulfonic acid (SBSSA) was prepared by the reaction of 3-mercaptopropylsilica (MPS) and chlorosulfonic acid in tert-butylmethyl ether, and used as a catalyst for the silylation of hydroxyl groups. A good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane (HMDS) in the presence of catalytic amounts of SBSSA under mild conditions at room temperature with short reaction times and in good-to-excellent yields. An excellent chemoselective silylation of hydroxyl groups in the presence of other functional groups was also observed. The heterogeneous catalyst was recycled for 30 runs upon the reaction of benzyl alcohol with HMDS without lossing its catalytic activity.

Silica-bonded S-sulfonic acid: an efficient and recyclable solid acid catalyst for the synthesis of 4,4′-(arylmethylene)bis(1 H-pyrazol-5-ols)

Silica-bonded S-sulfonic acid (SBSSA) is employed as a recyclable catalyst for the condensation reaction of aromatic aldehydes with 3-methyl-l-phenyl-5-pyrazolone. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4′-alkylmethylene-bis(3-methyl-5-pyrazolones) in 75–90% yields.

Silica-bonded S-sulfonic acid a recyclable catalyst for the synthesis of coumarins

Silica-bonded S-sulfonic acid (SBSSA) was prepared by the reaction of 3-mercaptopropylsilica (MPS) and chlorosulfonic acid in chloroform. This solid acid has been employed as a recyclable catalyst for the synthesis of coumarins from phenols and β-keto-esters at 80 °C under solvent-free conditions.

Benzylidene Diacetate Formation with Silica-Bonded S-Sulfonic Acid

Benzylidene Diacetate Formation with Silica-Bonded <i>S</i>-Sulfonic Acid

Silica Bonded S-Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Quinoxalines at Room Temperature

The reaction of 3-mercaptopropylsilica (MPS) and chlorosulfonic acid in chloroform afforded silica bonded S-sulfonic acid (SBSSA), which was used as a catalyst for the room temperature synthesis of quinoxaline derivatives from 1,2-diamino compounds and 1,2-dicarbonyl compounds. The catalyst could be recycled and reused several times without any loss of efficiency.

Silica-bonded S-sulfonic acid as a recyclable catalyst for chemoselective synthesis of 1,1-diacetates

A simple and efficient procedure for the preparation of silica-bonded S-sulfonic acid ( SBSSA) by reaction of 3-mercaptopropylsilica (MPS) and chlorosulfonic acid in chloroform is described. This solid acid is employed as a recyclable catalyst for the synthesis of 1,1-diacetates from aromatic aldehydes and acetic anhydride under mild and solvent-free conditions at room temperature.