- An ionic liquid supported on magnetite nanoparticles as an efficient heterogeneous catalyst for the synthesis of alkyl thiocyanates in water
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The present study describes a convenient method to synthesize alkyl thiocyanates from alkyl halides with the use of a novel nanomagnetic-supported organocatalyst (MNP@PEG-ImCl). The new supported ionic liquid is fully characterized by field-emission scanning electron microscopy (FESEM), Fourier-transform infrared (FT-IR), energy dispersive X-ray analysis (EDAX), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) as well as thermogravimetric analysis (TGA) techniques. It is noteworthy that we observed easy separation of the catalyst from the reaction mixture by a simple magnetic decantation and its reutilization many times without any appreciable loss of activities.
- Fallah-Mehrjardi, Mehdi,Sayyahi, Soheil
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p. 335 - 345
(2021/02/26)
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- Sulfuryl Fluoride Promoted Thiocyanation of Alcohols: A Practical Method for Preparing Thiocyanates
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A novel SO 2F 2-promoted thiocyanation method for the one-step synthesis of thiocyanates through C-O bond cleavage of readily available alcohols with ammonium thiocyanate as the thiocyanating agent was developed. The method avoids the use of additional catalyst, and a variety of (hetero)arene, alkene and aliphatic alcohols reacted with high efficiency in ethyl acetate under mild conditions to afford the corresponding thiocyanates in excellent to quantitative yields with broad functional-group compatibility.
- Zhang, Guofu,Xuan, Lidi,Zhao, Yiyong,Ding, Chengrong
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supporting information
p. 1413 - 1417
(2020/10/02)
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- PEG-DIL-based MnCl42?: A novel phase transfer catalyst for nucleophilic substitution reactions of benzyl halides
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Poly(ethylene glycol) dicationic ionic liquid-based MnCl42? was prepared by nucleophilic substitution of poly(ethylene glycol) dichloride with methylimidazole followed by reaction with MnCl2. The structural properties of the catalyst were systematically investigated using Fourier transform infrared, UV–visible and Raman spectra and thermogravimetric analysis. The application of this catalyst allows the synthesis of a variety of benzyl thiocyanates and azides in high yield under reflux conditions in water. The main advantages of this method are its easy nature, rapidity, environmental benignity and high yields.
- Goodajdar, Bijan Mombeni,Akbari, Farideh,Davarpanah, Jamal
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- Crown ether functionalized magnetic hydroxyapatite as eco-friendly microvessel inorganic-organic hybrid nanocatalyst in nucleophilic substitution reactions: an approach to benzyl thiocyanate, cyanide, azide and acetate derivatives
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In this paper, high catalytic activity of 4′,4″-diformyl dibenzo-18-crown-6 anchored onto the functionalized magnetite hydroxyapatite (γ-Fe2O3@HAp–Crown) as a new, versatile and magnetically recoverable catalyst, was prepared. It evaluated as phase-transfer catalyst and molecular host system for nucleophilic substitution reactions of benzyl halides with thiocyanate, cyanide, azide and acetate anions in water. No evidence for the formation of by-products was observed and the products obtained in pure form without further purification. The nanocomposite was easily removed from solution via application of a magnetic field, allowing straightforward recovery and reuse. The synthesized nanocomposite was characterized by several techniques such as FT-IR, TGA-DTG, EDX, XRD, BET, FE-SEM, TEM and VSM.
- Azaroon, Maedeh,Kiasat, Ali Reza
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- A simple, one-pot and phosphine-free procedure for thiocyanation of alcohols Using N-(p-toluenesulfonyl) imidazole (TsIm)
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An efficient, one-pot, phosphine-free thiocyanation of alcohols has been achieved utilising potassium thiocyanate and N-(p-toluenesulfonyl) imidazole (TsIm) as a coupling agent in the presence of triethylamine in anhydrous DMF at 70 °C. This method converts primary alcohols into the corresponding thiocyanates, without isomerisation to isothiocyanates, in good to excellent yields. A total of 17 thiocyananates were prepared, five of which are novel. Using one equivalent of KSCN, the method shows good selectivity in the thiocyanation of a primary alcohol in the presence of a secondary alcohol.
- Rad, Mohammad Navid Soltani
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p. 583 - 587
(2016/10/18)
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- Synthesis of alkyl thiocyanates from alcohols using a polymer-supported thiocyanate ion promoted by cyanuric chloride/dimethylformamide
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A convenient procedure for one-pot conversion of alcohols into the corresponding alkyl thiocyanates in the presence of cross-linked poly (N-propyl-4-vinylpyridinium) thiocyanate ion [P4-VP]Pr-SCN, promoted by cyanuric chloride/dimethylformamide, is described. Various alcohols were converted to their corresponding alkyl thiocyanates and it was observed that substituted benzyl alcohol with electron-withdrawing or electron-donating groups were transformed into the corresponding benzyl thiocyanate derivatives in high to excellent yields in a short reaction time but, sterically hindered alcohols produced the corresponding thiocyanates in very low yields.
- Karimi Zarchi, Mohammad Ali,Tabatabaei Bafghi, Asmaosadat
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p. 403 - 412
(2015/06/22)
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- Chlorodiphenylphosphine as highly selective and efficient reagent for the conversion of alcohols, tetrahydropyranyl and silyl ethers to thiocyanates and isothiocyanates
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(Equation present) A simple, highly selective and efficient method is described for the conversion of primary alcohols, tetrahydropyranyl and silyl ethers to thiocyanates by use of chlorodiphenylphosphine and ammonium thiocyanate. Secondary substrates produce both the two isomeric products, thiocyanate and isothiocyanate, while tertiary ones give isothiocyanates as the only products by this new method. In contrast to previously reported methods based on trivalent phosphorus for this transformation, the present method does not require an electrophile in the presence of trivalent phosphorus (ClPPh 2). The order of activity of these substrates is silyl ether> alcohol > tetrahydropyranyl ether. The present method not only interestingly distinguishes between primary, secondary and tertiary substrates but also converts them to the corresponding thiocyanates with excellent chemoselectivity in the presence of several other functional groups. 2014 Copyright Taylor & Francis Group, LLC.
- Aghapour, Ghasem,Asgharzadeh, Ameneh
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p. 796 - 802
(2014/07/08)
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- Nanomagnetic double-charged diazoniabicyclo[2.2.2]octane dichloride silica as a novel nanomagnetic phase-transfer catalyst for the aqueous synthesis of benzyl acetates and thiocyanates
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Abstract Nanomagnetic double-charged diazoniabicyclo[2.2.2]octane dichloride silica hybrid (Fe3O4@SiO2/DABCO) was used as an efficient and magnetically recoverable phase-transfer catalyst (PTC) for nucleophilic substitution reactions of benzyl halides for the synthesis of benzyl acetates and thiocyanates in good to excellent yields at 100 C in water. No evidence for the formation of by-products, for example, isothiocyanate or benzyl alcohol was observed and the products were obtained in pure form without further purification. The catalyst was easily separated with the assistance of an external magnetic field from the reaction mixture and reused for several consecutive runs without significant loss of its catalytic efficiency.
- Davarpanah, Jamal,Kiasat, Ali Reza
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- β-Cyclodextrin conjugated magnetic nanoparticles as a novel magnetic microvessel and phase transfer catalyst: Synthesis and applications in nucleophilic substitution reaction of benzyl halides
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This paper presents a feasible protocol for the preparation of β-cyclodextrin conjugated Fe3O4 magnetic nanoparticles as an efficient microvessel and host system for nucleophilic substitution reaction of benzyl halides in water. No evidence for the formation of by-product for example isothiocyanate or benzyl alcohol was observed and the products were obtained in pure form without further purification. The characteristics results of FT-IR, XRD, TGA and SEM shows that β-CD is grafted onto Fe3O4 nanoparticles. The nanomagnetic catalyst could be readily separated from solution via application of an external magnet, allowing straightforward recovery and reuse.
- Kiasat, Ali Reza,Nazari, Simin
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p. 363 - 368
(2013/07/26)
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- β-cyclodextrin immobilized onto dowex resin: A unique microvessel and heterogeneous catalyst in nucleophilic substitution reactions
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The catalytic activity of β-cyclodextrin immobilized on Dowex resin as an efficient solid-liquid phase transfer catalyst was developed for the synthesis of alkyl thiocyanates and phenacyl derivatives in water. The nucleophilic substitution reactions were performed under mild reaction condition and gave the products in excellent yields. Furthermore, the catalyst could be recycled by facile separation without any loss of activity.
- Kiasat, Ali Reza,Zarinderakht, Nasrollah,Sayyahi, Soheil
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experimental part
p. 699 - 702
(2012/05/05)
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- Magnetic nanoparticles grafted with β-cyclodextrin-polyurethane polymer as a novel nanomagnetic polymer brush catalyst for nucleophilic substitution reactions of benzyl halides in water
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The polymer coated magnetic nanoparticles has gained significant attention for potential applications in biomedicine, separations, and magnetic storage. In this study, β-cyclodextrin-polyurethane polymer coated Fe 3O4 magnetic nanoparticle as a novel class of hybrid organic/inorganic molecular catalyst was successfully prepared and evaluated as solid-liquid phase-transfer catalyst and molecular host system for nucleophilic substitution reactions. The nanocomposite has demonstrated the ability to catalytic the nucleophilic substitution reaction of benzyl halides with thiocyanate, azide, cyanide and acetate anions in water. No evidence for the formation of by-products for example isothiocyanate or alcohol was observed and the products obtained in pure form without further purification. The nanomagnetic polymer brush catalyst was easily removed from solution via application of a magnetic field, allowing straightforward recovery and reuse. Results obtained from scanning electron microscopy (SEM) and vibrating sample magnetometery (VSM) show that the synthesized magnetic nanocomposite are superparamagnetic with a mean diameter of 59 nm. The grafting of β-cyclodextrin-polyurethane polymer to Fe3O4 magnetic nanoparticle is confirmed by Fourier transform infrared spectroscopy (FT-IR).
- Kiasat, Ali Reza,Nazari, Simin
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- A novel and efficient synthesis of alkyl thiocyanates from alkyl halides in water using phase transfer catalysts
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1,4-Bis(triphenylphosphonium)-2-butene dichloride (BTPBDC) and 1,4-bis(triphenyl phosphonium)-2-butene dithiocyanate (BTPBDT) were prepared and used as phase-transfer catalysts. Alkyl halides were converted efficiently to the corresponding alkyl thiocyanates under mild reaction conditions in water. No evidence for the formation of isothiocyanates as by-product of the reaction was observed.
- Gorjizadeh, Maryam,Sayyahi, Soheil
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experimental part
p. 659 - 662
(2012/01/05)
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