Reaction Of Thioacetals Research Articles

A dual colorimetric and near-infrared fluorescent turn-on probe for Hg2+ detection and its applications

The increasing Hg2+ contamination in environment and ecosystem has gained wide attention and thus demands for its facile and effective detection. In this study, we constructed a new fluorescent probe (E)-2-(2-(3-(1,3-dithian-2-yl)-4-hydroxystyryl)- 4H-chromen-4-ylidene)malononitrile (DCM-Hg) for Hg2+ detection by incorporating the 1, 3-dithiane group to the dicyanomethylene-4H-pyran fluorophore for the first time. This probe can selectively detect Hg2+via the Hg2+-triggered deprotection reaction of thioacetals, which leads to a distinct color change from purple to pink and obvious fluorescence enhancement in the near-infrared (NIR) region. The NIR fluorescence intensity increased linearly with Hg2+ level within the range from 0 to 100 μM and the detection limit of DCM-Hg for Hg2+ was found to be 6.8 × 10−8 mol/L. Moreover, the probe could sense Hg2+ on paper strips and image Hg2+ in living cells with low cytotoxicity, which demonstrates its potential application in environment and biological science.

A highly selective colorimetric and ratiometric fluorescent probe for instantaneous sensing of Hg2+ in water, soil and seafood and its application on test strips

A new simple and efficient oligothiophene-based colorimetric and ratiometric fluorescent probe has been developed for highly sensitive and fast detection of Hg2+ in water, soil and seafood. The probe 5-(1,3-dithiolan-2-yl)-2,2':5′,2″-terthiophene 3 TS can selectively detect Hg2+ via the Hg2+-promoted deprotection reaction of thioacetals, which caused a remarkable color change from colorless to yellow and a strong fluorescence enhancement with emission color varying from blue to yellow, enabling naked-eye detection of Hg2+. The probe shows high sensitivity with the detection limit down to 1.03 × 10−8 M. Visual color changes of 3 TS were observed on filter paper and TLC testing strips when they were impregnated on testing strips and immersed in Hg2+ solution. Moreover, the probe 3 TS has been successfully used to rapidly detect trace amounts of hazardous Hg2+ ions in tap, distilled, river and lake water, cropland soil, fish, shrimp and kelp samples with acceptable results and good recoveries.

ChemInform Abstract: Efficient Synthesis of Highly Functionalized Vinylogous Thiol Esters.

AbstractThe title compounds can be easily prepared by thermal reaction of thioacetals with diester (II).

Green, catalyst-free thioacetalization of carbonyl compounds using glycerol as recyclable solvent

We describe herein the use of glycerol as an efficient and a recyclable solvent in the thioacetalization of aldehydes and ketones. The catalyst-free reactions proceed easily using glycerol at 90 °C and the corresponding thioacetals were obtained in good to excellent yields. Glycerol was recovered and utilized for further thioacetalization reactions.

ChemInform Abstract: Titanocene(II)-Promoted Desulfurizative Acylation of Thioacetals with Alkanenitriles.

Abstract Ketones were obtained in good yields by titanocene(II)-promoted reaction of thioacetals with alkanenitriles. The regioselective formation of α-substituted ketone was observed when the reaction was carried out in the presence of methyl iodide or benzyl bromide.

ChemInform Abstract: Titanocene(II)-Promoted Reactions of Thioacetals with Organic Molecules Having a Multiple Bond

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.

Transformation of Thioacetals to Cyclopropanes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Transformation of thioacetals to cyclopropanes

Cyclopropanes were obtained by the titanocene(II)-promoted reaction of thioacetals with vinyl pivalate. It was also found that vinycyclopropanes were produced by a similar treatment of thioacetals with the titanocene(II) species in the presence of 1,3-dienes.

Catalytic Cyclization of o-Alkynylbenzaldehyde Acetals and Thioacetals. Unprecedented Activation of the Platinum Catalyst by Olefins. Scope and Mechanism of the Reaction

A general protocol for the synthesis of functionalized indenes from o-alkynylbenzaldehyde acetals and thioacetals has been elaborated. Acetals uniformly give cyclization products having the alkyl group from the starting acetylene migrated to the alpha-position, whereas the cyclization of the corresponding thioacetals proceeds without alkyl migration. Optimization of the catalytic system for the cyclization of o-alkynylbenzaldehyde acetals revealed an unknown activation effect: PtCl(2) was found to be a better catalyst for the cyclization of acetals in the presence of olefins than without. A similar catalytic system (PtCl(2)/benzoquinone) has been found to be appropriate for the cyclization of cyclic acetals, whereas the optimal catalyst for the reaction of thioacetals is PdI(2). NMR monitoring of two reactions, acetal 3a + Pd(CH(3)CN)Cl(2) in CD(3)CN and thioacetal 5j + PdI(2) in CD(2)Cl(2), revealed that in both reactions similar cationic species are formed at the early stage of the transformation. Computational data (B3LYP/SDD level of theory) suggest that the difference in the reaction pathways for acetals and thioacetals can be rationalized by taking into account the relative stabilities of the corresponding vinylpalladium intermediates (22 vs 20 and 19 vs 21), which suggests a reversible thermodynamically controlled alkyl migration in the intermediate vinylcationic species.

Titanocene(II)-Promoted Reaction of Thioacetals with Styrenes: Stereoselective Formation of (E)-β-Substituted Styrene Derivatives

(E)-β-Substituted styrenes were obtained stereoselectively by the titanocene(II)-promoted desulfurizative coupling of thioacetals with styrenes. It is suggested that the reaction proceeds through the regioselective formation of a titanacyclobutane intermediate, followed by ?-elimination.

Titanocene(II)‐Promoted Reactions of Thioacetals with Ethylene: Selective Formation of Terminal Olefins with One‐ or Two‐Carbon Homologation.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Titanocene(II)-promoted reactions of thioacetals with ethylene: selective formation of terminal olefins with one- or two-carbon homologation

Thioacetals are selectively transformed into two types of terminal olefins, one with one-carbon homologation and the other with two-carbon homologation, by treatment with a titanocene(II) species under ethylene. The mode of the reaction is controlled by changing the ligands coordinated to titanocene(II).

ChemInform Abstract: Synthesis of Carbocycles and Heterocycles by Titanocene(II)-Promoted Reactions of Thioacetals

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.

Synthesis of carbocycles and heterocycles by the titanocene(II)-promoted reactions of thioacetals

The preparation of carbocyclic and heterocyclic compounds by the low-valent titanium species-promoted intramolecular reactions of thioacetals was studied. The cyclization of thioacetals having an olefin moiety proceeded with the loss of terminal olefin carbon to produce the corresponding five-, six-, and seven-membered cycloalkenes when they were treated with the low-valent titanium species Cp 2Ti[P(OEt) 3] 2. This method has been successfully applied to the syntheses of cyclic unsaturated amines and ethers. When S-[3,3-bis(phenylthio)propyl] thioalkanoates were treated with the low-valent titanium species, the intramolecular carbonyl olefination proceeded to produce 5-substituted 2,3-dihydrothiophenes.

Titanocene(II)-promoted desulfurizative acylation of thioacetals with alkanenitriles

Ketones were obtained in good yields by titanocene(II)-promoted reaction of thioacetals with alkanenitriles. The regioselective formation of α-substituted ketone was observed when the reaction was carried out in the presence of methyl iodide or benzyl bromide.

ChemInform Abstract: Stereoselective Formation of (Z)‐γ‐Substituted Allylsilanes by the Titanocene(II)‐Promoted Reaction of Thioacetals with Trialkyl(allyl)silanes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.

Stereoselective formation of (Z)-γ-substituted allylsilanes by the titanocene(II)-promoted reaction of thioacetals with trialkyl(allyl)silanes

The reaction of organotitanium species prepared by the desulfurizative titanation of thioacetals with (C5H5)2Ti[P(OEt)3]2 in the presence of trialkyl(allyl)silanes gives γ-substituted allylsilanes with Z stereoselectivity.

ChemInform Abstract: Titanocene(II)‐Promoted Reaction of Thioacetals with Alkynes: Highly Stereoselective Preparation of Conjugated Dienes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.

On the Mechanism of Cleavage of Thioacetals Promoted by Copper(II) Sulphate Adsorbed on Silica Gel

A probable mechanism of the cleavage reaction of thioacetals by copper(II) sulphate adsorbed on silica gel involves: formation of a chelate between sulphur atoms and copper(II), previously coordinated with hydroxyl groups on the silica surface, and the subsequent hydrolysis promoted by hydroxyl groups on the silica gel surface.

Titanocene(ii)-promoted reaction of thioacetals with alkynes: highly stereoselective preparation of conjugated dienes

The reaction of organotitanium species, prepared by the desulfurizative titanation of thioacetals using (C 5 H 5 ) 2 Ti[P(OEt) 3 ] 2 , with alkynes gives conjugated dienes in good yields with high stereoselectivity.