P-toluenesulfonyl Chloride In Pyridine Research Articles

Characterization, Hirshfeld surface analysis, DFT study and an in vitro α-glucosidase/α-amylase/radical scavenging profiling of novel 5-styryl-2-(4-tolylsulfonamido) chalcones

Sulfonylation of the 5-styryl-2-aminochalcones with p-toluenesulfonyl chloride in pyridine afforded novel 5-styryl-2-sulfonamidochalcone hybrids. XRD analysis of a representative compound helped to confirm the presence of a six-membered N–H···O intramolecularly hydrogen bonded chair-like pseudo ring. Topology was determined through Hirshfeld surface analysis and the energy of frontier molecular orbitals was used to evaluate the stability of this compound. The inhibitory effect of the test compounds against α-glucosidase and α-amylase activities was evaluated in vitro through enzymatic assays, and their antioxidant properties also in vitro through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) radical scavenging assays. An in vitro cell-based antioxidant activity assay of the most active compounds, 2f and 2h, involving lipopolysaccharide (LPS) induced reactive oxygen species (ROS) production also confirmed their capability to scavenge free radicals. Molecular modelling was used to postulate ligand–enzyme interactions and to rationalize the mechanism of antioxidant effect of these compounds.

ChemInform Abstract: A General and Simple Route to the Synthesis of Triptycenes.

A general and simple route to the synthesis of the triptycene derivatives 5,12-dihydro-5,12[1',2']-benzenonaphthacene (1), 5,14-dihydro-5,14[1',2']-benzenopentacene (2) and 5,16-dihydro-5,16[1',2']-benzenohexacene (3) is described. It involves the cycloaddition of appropriate quinone to anthracene and subsequent treatment of the resulting adduct with lithium aluminium hydride, followed by p-toluenesulfonyl chloride in pyridine

Facile conversion of alcohols to olefins by tosylation and subsequent SiO2-promoted β-elimination

A convenient and effective procedure was developed for the conversion of alcohol to olefin by tosylation and subsequent β-elimination promoted by silica gel in this study. Treatment of the alcohols with p-toluenesulfonyl chloride in pyridine at 0°C affords tosylates which undergo β-elimination with silica gel in dichloromethane or chloroform at room temperature, yielding olefins with high productivity.

Direct regioselective 2- O-( p-toluenesulfonylation) of sucrose

2- O-( p-Toluenesulfonyl)sucrose was regioselectively synthesized by direct p-toluenesulfonylation of sucrose using N-( p-toluenesulfonyl)imidazole in the presence of molecular sieves at 40 °C. The reactivities of the sucrose hydroxy groups toward this sulfonylation increased in the order as follows: OH-2≫OH-1′>OH-3′>OH-6>OH-6′. These results were diametrically opposite to the expected sulfonylation with p-toluenesulfonyl chloride in pyridine, for which the reactivity increased in the order as follows: OH-6′, OH-6≫OH-1′>OH-2. The desired 2- O-( p-toluenesulfonyl)sucrose was readily isolated by simple open reversed-phase column chromatography, followed by recrystallization, thus overcoming the main difficulties associated with regioselectivity, efficiency, and isolation techniques for the practical preparation.

Solid-phase synthesis of trisubsituted guanidines.

The solid-phase library synthesis of trisubstituted guanidines was accomplished. Amines were loaded onto the 4-formyl-3,5-dimethoxyphenoxymethyl linker via reductive amination. Subsequent acylation with Fmoc-4-aminomethylbenzoic acid followed by Fmoc deprotection gave solid-supported primary amines. Alternatively, sulfonylation of resin-bound secondary amines with 4-cyanobenzenesulfonyl chloride followed by borane reduction also gave solid-supported primary amines. Both resins were acylated with isocyanates to furnish solid-supported ureas. Dehydration of ureas with p-toluenesulfonyl chloride in pyridine gave solid-supported carbodiimides. Nucleophilic addition of amines to the carbodiimide bond followed by cleavage off the solid support gave trisubstituted guanidines.

4-Octulose Derivatives, Prepared fromL-Sorbose, as Key Intermediates in the Stereoselective Synthesis ofC-Glycoside and Polyhydroxyindolizidine Analogues

Reactions of 1 and 12 with p-toluenesulfonyl chloride in pyridine gave the corresponding 1-O-p-toluenesulfonyl derivatives 2 and 13 in yields of 91% and 60%, respectively. Compound 12 was also transformed into 14 by treatment with I2/Ph3P/imidazole in anhydrous dichloromethane. Treatment of compounds 12 and 13/14 with NaN3 in DMF furnished the respective 1-azido-1-deoxy derivatives 3 and 15, which were then deacetonated to give the free 4-octuloses 4 and 16. These were subsequently hydrogenated in the presence of 10% Pd/C to afford the expected polyhydroxylated branched-chain pyrrolidines 5 and 17. Attempted OH → OMes transformation at C-8 in the N−Cbz-protected pyrrolidines 7 and 19 was unsuccessful and an internal anhydration process took place to yield the corresponding C-glycoside-like furanoses 9 and 20. On the other hand, 23 was transformed into the D-ribo analogue 25 through reduction of the intermediate 4,6-diulose 24. Finally, deprotection of 25 in acid medium to give the free 4-ulose 26, followed by hydrogenation of the latter in the presence of 10% Pd/C in methanol, allowed the preparation of (6S,7S,8S,8aS)-6,7,8-trihydroxy-8a-methoxyindolizidin-3-one (27).

On the Sulfonylation of Diethyl Galactarate: Some Structural Corrections - Synthesis and Characterisation of Derivatives of Diethyl 2,5-Dihydroxyhexa-2,4-dienoate

Abstract The structure of one of the major products resulting from the treatment of diethyl galactarate (2) with an excess of p-toluenesulfonyl chloride in pyridine has been shown to be diethyl 2,5-ditosyloxyhexa-2,4-diendioate (5) rather than hex-3-enoate 1 proposed earlier. The corresponding dimesyloxy derivative 6 was also prepared in a similar manner. Some additional aspects of the reactions, including some mechanistic proposals, are presented.

Regioselective synthesis of 1,7-diprotected 1,4,7,10-tetraazacyclododecane and preparation of a dialcohol dicarboxylic macrocyclic ligand

The reaction of 1,4,7,10-tetraazacyclododecane with p-toluenesulfonyl chloride in pyridine or with diethyl phosphite and CCl 4 in a water/CH 2Cl 2 mixture yields selectively the 1,7-diprotected regioisomer. The 1,7-diprotected tetraaza cycles are interesting starting materials, for instance for the preparation of 4,10-bis(2′-hydroxyethyl)-1,7-bis(carboxymethyl)-1,4,7,10-tetraazacyclododecane.

Synthesis of 2,3-Dihydro-1,4-dithiins and 2-Alkylidene-1,4-dithianes by 1,2-Sulfur Migration in 2-(1-Hydroxyalkyl)-1,3-dithiolanes

2,3-Dihydro-1,4-dithiins and the isomeric 2-alkylidene-1,4-dithianes were synthesized from 1,2-diketones and alkyl pyruvates by kinetically controlled ring expansion of 2-(1-hydroxyalkyl)-1,3-dithiolanes with p-toluenesulfonyl chloride in pyridine. In addition, 2,3-dihydro-1,4-dithiins, the thermodynamic products, were formed exclusively by using p-toluenesulfonic acid in refluxing benzene. The 2-alkylidene-1,4-dithianes were readily isomerised to the corresponding 2,3-dihydro-1,4-dithiins

A General and Simple Route to the Synthesis of Triptycenes

A general and simple route to the synthesis of the triptycene derivatives 5,12-dihydro-5,12[1',2']-benzenonaphthacene (1), 5,14-dihydro-5,14[1',2']-benzenopentacene (2) and 5,16-dihydro-5,16[1',2']-benzenohexacene (3) is described. It involves the cycloaddition of appropriate quinone to anthracene and subsequent treatment of the resulting adduct with lithium aluminium hydride, followed by p-toluenesulfonyl chloride in pyridine

An Unusual Reaction Observed in Sulfonylation and Acylation of 2′,3′-O-Isopropylidenenebularine

Abstract Treatment of 2′,3′-O-isopropylidenenebularine with p-toluenesulfonyl chloride in pyridine afforded 7,8-dihydro-2′,3′-O-isopropylidene-N7-(P-toluenesulfonyl)-8(R),5′-O-cclclonebularine as the major product, the structure of which was determined by X-ray crystallography. The reactions with other sulfonyl and acyl (aroyl) chlorides were also examined.

6-O-Trisubstituted β-Cyclodextrins Whose Substituents Are Different from One Another

Abstract 6A-S-phenyl-6F-O-(β-naphthalenesulfonyl)-6X-O-(p-toluenesulfonyl)-6A-thio-β-cyclodextrins (X = B, X = C, X = D, X = E, and X = G) were prepared from the reaction of 6A-S-phenyl-6F-O-(β-naphthalenesulf onyl)-6A-thio-β-cyclodextrin with p-toluenesulfonyl chloride in pyridine. The structures were determined through their Taka amylase A-catalyzed hydrolyses.

Flameproofed polyesters prepared by direct polycondensation of aromatic dicarboxylic acids and brominated bisphenols with tosyl chloride and N,N′‐dimethylformamide in pyridine

AbstractBrominated aromatic polyesters were successfully prepared by reacting isophthalic acid and terephthalic acid with p‐toluenesulfonyl chloride in pyridine in the presence of N,N′‐dimethylformamide, followed by treating with a pyridine solution of tetrabromobisphenols. The tetrabromobisphenols were synthesized by a facile bromination of their corresponding bisphenols in aqueous acetic acid solution under mild conditions. The polycondensation was significantly affected by the reactivity of bisphenols and the solubility of the resulting polymers in the reaction media. Tetrabromobisphenols with positive linking groups between the aromatic rings and better solubility of the resulting polymers give a more favorable result. The products were nonflammable having limiting oxygen index 59–62 (ASTM D2863‐77) without much sacrifice in thermal stability.

Structure of penta-O-acetylsucroses formed by deacetylation of octa-O-acetylsucrose. Reaction of 2,3,4,6,6'-penta-O-acetylsucrose

Chromatographic separation of penta-O-acetylsucrose fraction from deacetylation of octa-O-acetylsucrose by treatment with aluminium oxide impregnated by potassium carbonate gave 1',3,4,6,6'-penta-O-acetylsucrose (XII), 1,2,3,4,6-penta-O-acetylsucrose (XIII), and the prevailing 2,3,4,6,6'-penta-O-acetylsucrose (XIV). Reaction of compound XIV with two equivalents of p-toluenesulfonyl chloride in pyridine produced besides the 1'-O-p-toluenesulfonyl derivative XXI and 1',3',4'-tri-O-tosyl derivative XXII also 1',3'-di-O-tosyl derivative XXIII and 1',4'-di-O-tosyl derivative XX. 1',2-anhydro-(3,4,6-tri-O-acetyl-α-D-glucopyranosyl 6'-O-acetyl-3',4'-anhydro-β-D-ribo-hexulofuranoside) (X) and 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-D-ribo-hexulofuranoside (VIII) were prepared from compound XXIII by two minutes boiling with 1M sodium methoxide, evaporation of the reaction mixture, and acetylation (method A). Compound XX gives under reaction conditions of method A 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-D-lyxo-hexulofuranoside (IX) only. However, upon 24h boiling with 1M sodium methoxide, neutralization, evaporation, and acetylation of the reaction mixture (method B), we obtained 3,3',4,6,6'-penta-O-acetyl-1',2-anhydro-4'-O-methylsucrose (XXIV), 1',2,3,3',4,6,6'-hepta-O-acetyl-4'-O-methylsucrose (XXV), and 1',2-anhydro-(3,4,6-tri-O-acetyl-α-D-glucopyranosyl 3',4',6'-tri-O-acetyl-β-D-xylo-hexulofuranoside) (XXVI). Compounds XXV and XXVI are also formed by reaction of epoxide IX with sodium methoxide according to method B. Compound XXVI can be prepared by hydrolysis of the dianhydro derivative X followed by acetylation. A reaction mechanism for compound XXVI formation from the epoxide IX is proposed. It assumes an intramolecular opening of the oxirane ring in compound IX under formation of α-D-glucopyranosyl 1,3-anhydro-β-D-xylo-hexulofuranoside (XLVI). The 1'-O-tosyl derivative XXI reacts with sodium methoxide according to method B to give 3,3',4,4',6,6'-hexa-O-acetyl-1',2-anhydrosucrose (XXVIII), octa-O-acetylsucrose, and 2,3,3',4,6,6'-hexa-O-acetyl-1',4'-anhydrosucrose XL.

Structures of hexa-O-acetylsucroses formed by deacetylation of sucrose octa-O-acetate

A fraction corresponding to hexa-O-acetylsucrose was isolated in 34% yield from the reaction mixture after deacetylation of sucrose octa-acetate by aluminium oxide impregnated by potassium carbonate. Its subsequent reaction with p-toluenesulfonyl chloride in pyridine provided crystalline 1',2,3,4,6,6'-hexa-O-acetyl-3',4'-di-O-p-toluenesulfonylsucrose (III). With triphenylphosphine-diethyl azodicarboxylate reagent, 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl 1,6-di-O-acetyl-3,4-anhydro-β-D-lyxo-hexulofuranoside (VI) was obtained. Treatment of ditosyl derivative III with sodium methoxide followed by acetylation gave besides the anhydro derivative VI also the anhydro derivative V with ribo configuration. The same reaction carried out with mother liquors after crystallization of ditosyl derivative III yielded in addition to anhydro derivatives V and VI the crystalline 1',2-anhydro(3,4,6-tri-O-acetyl-α-D-glucopyranosyl 6'-O-acetyl-3',4'-anhydro-β-D-ribo-hexulofuranoside) (VII). From these results and the analysis of NMR and mass spectra of the hexa-O-acetylsucrose, it follows that the deacetylation of sucrose octa-acetate is highly regioselective, providing the mixture of 1',2,3,4,6,6'-hexa-O-acetylsucrose (I) and 2,3,4,4',6,6'-hexa-O-acetylsucrose (XIII) with markedly prevailing the former component. The structure of dianhydro derivative VII (except the oxirane ring configuration) was determined by NMR spectroscopy. The configuration of this ring follows from the fact that the treatment of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl 6-O-acetyl-3,4-anhydro-1-O-methanesulfonyl-β-D-lyxo-hexulofuranoside (IX) with sodium methoxide followed by acetylation does not give the dianhydro derivative VII. However, this compound is formed from the anhydro derivative V by its partial deacetylation, mesylation, reaction with sodium methoxide, and acetylation.

ChemInform Abstract: SYNTHESES OF POLYMERIZABLE CARBODIIMIDES BEARING A TERMINAL VINYL GROUP

AbstractDie Reaktion der Vinylaniline (I) mit den Isocyanaten (II) und nachfolgende Dehydratisierung liefern die Carbodiimide (IV).

Syntheses of Polymerizable Carbodiimides Bearing a Terminal Vinyl Group

Abstract N-(p- or m-Vinylphenyl)-N′-isopropyl- and cyclohexylcarbodiimides (3) have been synthesized in reasonable yields by first synthesizing the substituted ureas by the reactions p- or m-vinylaniline with isopropyl or cyclohexyl isocyanate in THF and the subsequent dehydration with p-toluenesulfonyl chloride in pyridine. The monomers 3 were found to polymerize smoothly with AIBN to afford vinyl polymers bearing the corresponding carbodiimide units as pendants in more or less cross-linked forms. The cross-linked insoluble polymers thus obtained can act as a dehydrative coupling agent in reactions such as the formation of peptide linkages.

SYNTHESIS OF 6-AMINO-6-DEOXYCELLULOSE

Aminodeoxycellulose of a degree of substitution of 0.90 by amino group introduced mainly on C-6 position was synthesized as follows. 2, 3-Di-O-phenylcarbamoylcellulose (1) was efficiently tosylated on C-6 position with p-toluenesulfonyl chloride in pyridine. The cellulose derivative (2) with sulfonyloxy and chloro groups was converted into the corresponding 6-azido-6-deoxy derivative (3), which then was reduced with lithium aluminum hydride in tetrahydrofuran to afford 6-amino-6-deoxy-2, 3-di-O-phenylcarbamoylcellulose (4). It was treated with sodium methoxide in methanol to give 6-amino-6-deoxycellulose (5). 6-Amino-6-deoxy-D-glucose was found as a main product in the hydrolyzate of 5.

ChemInform Abstract: A STEREOSELECTIVE SYNTHETIC ROUTE TO (R)‐ZEARALANONE

Abstract(S)‐Zearalenon (I) wird in die Derivate (II) und (III) übergeführt und dann alkalisch zu (IVa) gespalten, das zu (IVb) methyliert und weiter in das Tosylat (IVc) übergeführt wird.

A stereoselective synthetic route to (R)-zearalanone.

A stereoselective synthetic route to (R)-zearalanone was studied to determine the effect of absolute configuration on uterotropic activity. Starting with the naturally occurring (S)-zearalenone the phenolic groups were converted into their respective benzyl ethers followed by ketalization of the carbon-6 carbonyl function using ethylene glycol to give 3 in high yield. The 14-membered lactone could then be opened without racemization of the carbon-10 position by treatment of 3 with sodium hydroxide in dimethyl sulfoxide to yield 4 which was converted to its methyl ester 5 with diazomethane. The reaction of hydroxy ester 5 with p-toluenesulfonyl chloride in pyridine yielded toluenesulfonic ester 6. The reaction of 6 with tetraethylammonium acetate in refluxing methyl ethyl ketone gave 7. The methyl ester in 7 was hydrolyzed to give 8 which was hydrolyzed in aqueous tetrahydrofuran to yield 9. Hydroxy acid 9 was cyclized with trifluoroacetic anhydride in benzene to yield 10 which was reduced and hydrogeneolyzed to give (R)-zearalanone. The mouse uterotropic assay revealed that (R)-zearalanone had no activity but a mixture of (R) and (S) gave approximately the same response as (S) suggesting that (R) has a synergistic effect on the uterotropic activity of (S).