Acid Surfactant-combined Catalyst Research Articles

Surfactant-mediated thioglycosylation of 1-hydroxy sugars in water.

Thioglycosides are an important class of sugars, since they can be used as non-ionic biosurfactants, biomimetic glycosides, and building blocks for carbohydrate synthesis. Previously, Brønsted- or Lewis-acid-catalyzed dehydrative glycosylations between a 1-hydroxy sugar and a thiol have been reported to yield open-chain dithioacetal sugars as the major products instead of the desired thioglycosides. These dithioacetal sugars are by-products derived from the endocyclic bond cleavage of the thioglycosides. Herein, we report dehydrative glycosylation in water mediated by a Brønsted acid-surfactant combined catalyst (BASC). Glycosylations between 1-hydroxy furanosyl/pyranosyl sugars and primary, secondary, and tertiary aliphatic/aromatic thiols in the presence of dodecyl benzenesulfonic acid (DBSA) provided the thioglycoside products in moderate to good yields. Microwave irradiation led to improvements in the yields and a shortening of the reaction time. Remarkably, open-chain dithioacetal sugars were not detected in the DBSA-mediated glycosylations in water. This method is a simple, convenient, and rapid approach to produce a library of thioglycosides without the requirement of anhydrous conditions. Moreover, this work also provides an excellent example of complementary reactivity profiles of glycosylation in organic solvents and water.

Expeditious synthesis of functionalized tricyclic 4-spiro pyrano[2,3-c]pyrazoles in aqueous medium using dodecylbenzenesulphonic acid as a Brønsted acid–surfactant-combined catalyst

An eco-friendly multicomponent strategy has been developed to access a single tricyclic molecular scaffold possessing pyran, pyrazole and spiro functionalities.

Efficient, stable, and reusable Lewis acid–surfactant-combined catalyst: One-pot Biginelli and solvent-free esterification reactions

Cerium(III) trislaurylsulfonate (Ce(LS)3), a Lewis acid and surfactant combined catalyst, was prepared and characterized by SEM, SEM-EDX, XRD, NMR, FT-IR, TG, and elemental analysis. Ce(LS)3 was found to be stable and efficient to catalyze one-pot Biginelli and solvent-free esterification reactions. Furthermore, Ce(LS)3 is easy to recycle after reaction by pouring into cold water and filtration. Present work will shed deep insight into the understanding of the catalytic nature of LASCs, and extend its application in important organic transformations.

Facile synthesis of ninhydrin and isatin based hydrazones in water using PEG-OSO3H as a highly efficient and homogeneous polymeric acid-surfactant combined catalyst

Abstract The synthesis of a series of biologically important ninhydrin and isatin based hydrazones has been carried out by refluxing easily synthesized novel N ′-(chloro-aryl-methylene)- tert -butylcarbazates with ninhydrin and isatins in the presence of PEG-OSO 3 H as catalyst in water medium. The dual characteristic of PEG-OSO 3 H as a Bronsted acid as well as a phase-transfer catalyst is successfully exploited in this synthesis. Reduced reaction time, operational simplicity, excellent yields of the products with high purity, and more importantly, easy recoverability, and reusability of the homogeneous polymeric catalyst make the reaction an attractive, economic, and sustainable green synthetic methodology.

Nano-TiO2 on Dodecyl-Sulfated Silica: As an Efficient Heterogeneous Lewis Acid–Surfactant-Combined Catalyst (HLASC) for Reaction in Aqueous Media

A reusable Lewis acid–surfactant-combined catalyst (LASC), using immobilization of nano-TiO2 on dodecyl-sulfated silica support (NTDSS), has been developed. To obtain this catalyst system, sodium dodecyl sulfate (SDS) was reacted with silica chloride (SC) to generate a dodecyl-sulfated silica (DSS) substrate. Subsequently, the addition of TiCl4 to a water solution of DSS resulted in the immobilization of nano-TiO2 on the surface of a DSS substrate. The NTDSS catalyst was characterized using different techniques such as TEM, SEM, XRD, ICP, and FT-IR. The catalyst was successfully used for the synthesis of coumarin derivatives via Pechmann condensation in water as a green solvent. High catalytic activity of the catalyst in water media can be a result of colloidal particle formation on the surface of the NTDSS catalyst due to the grafted DS moieties on the surface of silica, which act as a surfactant. It seems that the generation of emulsion droplets containing nano-TiO2 on the surface of the catalyst would function as an effective reaction reactor to accelerate the rate of the reaction in water media.

Lewis acid–surfactant-combined catalyzed synthesis of 4-aminocyclopentenones from glycals in water

4-Aminocyclopentenones were synthesized from readily available glycals and secondary anilines, with the aid of a Lewis acid–surfactant-combined catalyst. The reactions proceeded via a 4π conrotatory electrocyclization, affording the corresponding 4-aminocyclopentenones in good yields with excellent diastereoselectivities.

DBSA catalyzed, one-pot three-component “on water” green protocol for the synthesis of 2,3-disubstituted 4-thiazolidinones

A simple and environmentally benign one-pot three-component tandem synthesis of a series of novel 4-thiazolidinones has been accomplished “on water” by reacting aliphatic or aromatic primary amines with thioglycolic acid and a wide range of aromatic aldehydes at ambient temperature using p-dodecylbenzenesulfonic acid (DBSA) as a Bronsted acid-surfactant combined catalyst. The unique ability of the catalyst has been utilised to form emulsion droplets with organic substrates in aqueous medium whose interior core is hydrophobic enough to exclude the water molecules generated during the rate limiting dehydration step of the reaction. This protocol worked well with a variety of substrates and the desired products were obtained in fairly good yields.

Eco‐friendly synthesis of 1,8‐dioxo‐octahydroxanthenes catalyzed by ionic liquid in aqueous media

Abstract A biodegradable functionalized ionic liquid 3‐(N,N‐dimethyldodecylammonium)propanesulfonic acid hydrogen sulfate ([DDPA][HSO4]) was prepared and used as a Brønsted acid–surfactant‐combined catalyst for the eco‐friendly one‐pot synthesis of 1,8‐dioxo‐octahydroxanthenes at 100°C in water. Under these conditions, the reaction of various aromatic aldehydes with dimedone generated 1,8‐dioxo‐octahydroxanthenes in good yields with a simple postreaction procedure. The products could simply be separated from the catalyst/water system, and the catalyst could be reused at least six times without noticeably decreasing the catalytic activity. J. Heterocyclic Chem., (2011).

Functionalized ionic liquid as the recyclable catalyst for Mannich-type reaction in aqueous media

Abstract A novel functionalized ionic liquid 3-(N,N-dimethyldodecylammonium)propanesulfonic acid hydrogen sulfate ([DDPA][HSO4]) was prepared. The ionic liquid could be used as a Bronsted acid–surfactant-combined catalyst for one-pot three-component Mannich-type reaction at room temperature in water. The heterogeneous catalytic procedure was simple and the catalyst could be reused at least six times without noticeably decreasing the catalytic activity.

ChemInform Abstract: Three‐Component Reaction of 2‐Alkynylbenzaldehyde, Amine, and Nucleophile Using Lewis Acid Surfactant Combined Catalyst in Water.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Three-component reaction of 2-alkynylbenzaldehyde, amine, and nucleophile using Lewis acid-surfactant combined catalyst in water

Lewis acid-surfactant combined catalyst (LASC) catalyzed three-component reactions of 2-alkynylbenzaldehyde, amines, and nucleophiles (alkyne, nitromethane, or diethyl phosphate) in water under ultrasonic conditions afforded the corresponding 1,2-dihydroisoquinoline derivatives in good yields.

Aluminum tris (dodecyl sulfate) trihydrate Al(DS) 3·3H 2O as an efficient Lewis acid–surfactant-combined catalyst for organic reactions in water : Efficient conversion of epoxides to thiiranes and to amino alcohols at room temperature

High yielding preparation of structurally different thiiranes, β-amino alcohols and bis(β-amino) alcohols from the reaction of epoxides with thiourea and amines in the presence of catalytic amounts of aluminum tris (dodecyl sulfate) trihydrate Al(DS) 3·3H 2O as a Lewis acid–surfactant-combined catalyst at room temperature in water has been described. Ring opening of epoxides with amines in the presence of this catalyst proceeded with high chemo- and regioselectivity.

Synthesis of tetrahydroisoquinolines and isochromans via Pictet–Spengler reactions catalyzed by Brønsted acid–surfactant-combined catalyst in aqueous media

Perfluorooctanesulfonic acid (PFOSA), Brønsted acid–surfactant-combined catalyst, efficiently catalyzes the Pictet–Spengler reactions of β-arylethyl carbamate derivatives with aldehydes in water. The present reaction is accelerated by the addition of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). PFOSA in HFIP–water (10 v/v %) is also successfully applied to the oxa-Pictet–Spengler reactions of β-arylethyl alcohol compounds.

Dehydrative Glycosylation in Water Using a Brønsted Acid–Surfactant-Combined Catalyst

Abstract Brønsted acid–surfactant-combined catalyst, dodecylbenzenesulfonic acid (DBSA), was used in catalytic dehydrative glycosylation reactions in water. 1-Hydroxy sugars, such as O-benzyl-protected furanose and pyranose, reacted with alcohols and a nitrogen nucleophile in the presence of a catalytic amount of DBSA to afford the desired adducts in good yields. Detailed study of the glycosylation of 2-deoxy-d-ribofuranose showed that hydrophobicity of the substrates was important to attain higher yields. Regarding the α/β selectivities, d-ribose and d-mannose derivatives gave the products in high β- and α-selectivities, respectively.

Three-component carbon–carbon bond-forming reactions catalyzed by a Brønsted acid–surfactant-combined catalyst in water

Reactions of aldehydes, amines, and various nucleophiles such as silyl enolates, ketones, Danishefsky's diene, and allyltribuyltin in water were successfully carried out in the presence of p-dodecylbenzenesulfonic acid (DBSA) as a Brønsted acid–surfactant-combined catalyst.

Facile synthesis of α-amino phosphonates in water using a Lewis acid–surfactant-combined catalyst

Three-component reactions of aldehydes, amines and triethyl phosphite were efficiently catalyzed by scandium tris(dodecyl sulfate) at ambient temperature in water to give various α-amino phosphonates in high yields.

Synthetic reactions using organometallics in water. Aldol and allylation reactions catalyzed by Lewis acid–surfactant-combined catalysts/Brønsted acids systems

Aldol reactions of aldehydes with silyl enolates and allylation reactions with tetraallyltin have been successfully carried out using Lewis acid–surfactant-combined catalysts/Brønsted acids systems. Remarkable enhancement of reactivity by a Brønsted acid such as HCl was observed in these reactions in the presence of a Lewis acid–surfactant-combined catalyst such as scandium tris(dodecyl sulfate) or scandium trisdodecanesulfonate in water. The addition of Brønsted acids was also effective for catalytic asymmetric aldol reactions in water using copper bis(dodecyl sulfate) and a chiral bis(oxazoline) ligand.

Catalytic Asymmetric Synthesis of Antimalarial Alkaloids Febrifugine and Isofebrifugine and Their Biological Activity.

Antimalarial alkaloids febrifugine (1) and isofebrifugine (2) were efficiently synthesized from simple achiral starting materials on the basis of the catalytic asymmetric synthesis. The first key reaction was performed using the tin(II)-mediated catalytic asymmetric aldol protocol to afford chiral aldehyde 3 in high yield with high diastereo- and enantioselectivities. The second key step, a Mannich-type reaction, did not give satisfactory results according to the conventional methods. We then developed a novel aqueous Mannich-type three-component reaction of an aldehyde, an amine, and a vinyl ether using a Lewis acid-surfactant combined catalyst (LASC), and the key intermediates 16 and 17 were obtained in high yields. The final coupling reactions of bromoacetone 14 with 4-hydroxyquinazoline were carried out using basic conditions, and successive deprotection gave 1 and 2, respectively, without any isomerization. These unambiguous total asymmetric syntheses revealed that the absolute configurations of febrifugine and isofebrifugine were not (2'S,3'R) and (2'R,3'R) as reported previously but (2'R,3'S) and (2'S,3'S), respectively (1' and 2'). Finally, antimalarial activities of the synthesized febrifugine and isofebrifugine, and their antipodes, were examined. It was revealed that the activities and selectivities of natural febrifugine and isofebrifugine were much higher than those of the antipodes.