- Phosphorus pentoxide as an efficient catalyst for the tetrahydropyranylation of alcohols under solvent-free conditions
-
A facile and efficient method for the preparation of tetrahydropyranyl ethers from alcohols is improved in solvent-free media. These reactions are catalyzed by P2O5 and afford various tetrahydropyranyl ethers in shorter reaction time, with good to excellent yields (75-95%) at room temperature. This method is also compatible with substrates containing acid-sensitive functional groups.
- Eshghi, Hossein,Shafieyoon, Parvaneh
-
-
Read Online
- Efficient role of ionic liquid (bmim)HSO4 as novel catalyst for monotetrahydropyranylation of diols and tetrahydropyranylation of alcohols
-
A simple procedure for the monotetrahydropyranylation of diols and alcohols, in excellent to moderate yields, has been reported using a catalytic amount of the acidic ionic liquid, 1-butyl-3-methylimidazolium hydrogensulphate (bmim)HSO4 under microwave and ultrasonic irradiation. Results have been compared with those obtained by reactions in the absence of these energies, and effectiveness of the recycled ionic liquid has also been studied. Copyright Taylor & Francis Group, LLC.
- Singh, Jasvinder,Gupta, Neeraj,Kad, Goverdhan L.,Kaur, Jasamrit
-
-
Read Online
- 2,3-Dichloro-5,6-dicyano-p-benzoquinone as a Mild and Efficient Catalyst for the Tetrahydropyranylation of Alcohols
-
Hydroxy compounds readily add to 3,4-dihydro-2H-pyran under neutral conditions in the presence of a catalytic amount of 2,3-dichloro-5,6-dicyano-p-benzoquinone, to give high yields of the corresponding tetrahydropyranyl ethers.
- Tanemura, Kiyoshi,Horaguchi, Takaaki,Suzuki, Tsuneo
-
-
Read Online
- Bis [trinitratocerium (IV)] chromate [ce(NO3)2 Cro4] and tris [trinitratocerium (IV)] paraperiodate [(No3)3Ce]3 H2IO6. Two mild and efficient catalysts for tetrahydrop
-
The tetrahydropyranyl derivatives of variety of alcohols are efficiently prepared in the presence of catalytic amounts of [Ce(NO3)2CrO4] and [(NO3)3 Ce]3 H21O6 in mild
- Oskooie,Abaszadeh,Zamani,Heravi
-
-
Read Online
- Mild and efficient tetrahydropyranylation of alcohols and dehydropyranylation of THP ethers catalyzed by ferric perchlorate
-
A simple, mild and efficient method for tetrahydropyranylation and dehydropyranylation of alcohols in the presence of ferric perchlorate are described.
- Heravi, Majid M.,Behbahani, Farahnaz K.,Oskooie, Hossien A.,Shoar, Rahim Hekmat
-
-
Read Online
- Envirocat EPZG as a new heterogenous catalyst for the solvent-free tetrahydropyranylation of alcohols and phenols
-
Envirocat EPZG was used as a solid supported acid catalyst for tetrahydropyranylation of alcohols and phenols in the absence of a solvent. This new method is rapid, efficient and convenient giving the corresponding products in high yields and purity.
- Bandgar,Jagtap,Aghade,Wadgaonkar
-
-
Read Online
- Comparison of the efficiency of two dicationic ionic liquids catalysts based on perchloric acid for the protection of alcohols
-
In this article, two aliphatic and aromatic types of dicationic acidic ionic liquids formulated as [H2-DABCO][ClO4], [H2-Bisim][ClO4]2 were used for the acceleration of the protection of alcohols as t
- Rahmanzadeh, Akram,Daneshvar, Nader,Shirini, Farhad,Tajik, Hassan
-
p. 3295 - 3302
(2021/05/13)
-
- Fully recyclable Br?nsted acid catalyst systems
-
Homogeneous and heterogeneous sulfonic acid catalysts are some of the most common catalysts used in organic chemistry. This work explores an alternative scheme using a fully recyclable polymeric solvent (a poly-α-olefin (PAO)) and soluble PAO-anchored polyisobutylene (PIB)-bound sulfonic acid catalysts. This PAO solvent is nonvolatile and helps to exclude water by its nonpolar nature which in turn drives reactions without the need for distillation of water, avoiding the need for excess reagents. This highly nonpolar solvent system uses polyisobutylene (PIB) bound sulfonic acid catalysts that are phase-anchored in solvents like PAO. The effectivenes of these catalysts was demonstrated by their use in esterifications, acetalizations, and multicomponent condensations. These catalysts and the PAO solvent phase show excellent recyclability in schemes where products are efficiently separated. For example, this non-volatile polymeric solvent and the PIB-bound catalyst can be recycled quantitatively when volatile products are separated and purified by distillation. In other cases, product purification can be effected by product self-separation or by extraction.
- Watson, Christopher B.,Kuechle, Adrianna,Bergbreiter, David E.
-
p. 1266 - 1273
(2021/02/26)
-
- A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
-
A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
- Huang, Binbin,Guo, Lin,Xia, Wujiong
-
supporting information
p. 2095 - 2103
(2021/03/26)
-
- Highly selective tetrahydropyranylation/dehydropyranylation of alcohols and phenols using porous phenolsulfonic acid-formaldehyde resin catalyst under solvent-free condition
-
An efficient protocol for solvent-free chemoselective tetrahydropyranylation/depyranylation of alcohols and phenols is reported herein using mesoporous Phenolsulfonic Acid Formaldehyde Resins as a heterogeneous acid catalyst. The catalyst successfully performed chemoselective protection and deprotection reactions of a wide range of substrates ranging from primary to secondary and tertiary alcohols and also phenols. The reactions were carried out at ambient temperature under solvent-free condition (SolFC) which resulted in high yields within a very short time. FT-IR, TEM, SEM, EDS and TG-DSC analysis techniques were employed to characterize the synthesized polymeric catalyst. The chemoselective nature of our method was confirmed using 13C DEPT-135 NMR studies. The polymer catalyst was found to be recoverable even after 10th catalytic cycle without much depreciation in its activity. The heterogeneity of the catalyst was verified by hot filtration method. Good yield, energy and cost- effective method, solvent-free protocol, mild reaction conditions, no inert atmosphere, metal-free heterogeneous polymer catalyst and excellent recoverability of the catalyst are notable milestones of the reported protocol.
- Rajkumari, Kalyani,Laskar, Ikbal Bahar,Kumari, Anupama,Kalita, Bandita,Rokhum, Lalthazuala
-
-
- Cyclopropenium Enhanced Thiourea Catalysis
-
An integral part of modern organocatalysis is the development and application of thiourea catalysts. Here, as part of our program aimed at developing cyclopropenium catalysts, the synthesis of a thiourea-cyclopropenium organocatalyst with both cationic hydrogen-bond donor and electrostatic character is reported. The utility of the this thiourea organocatalyst is showcased in pyranylation reactions employing phenols, primary, secondary, and tertiary alcohols under operationally simple and mild reaction conditions for a broad substrate scope. The addition of benzoic acid as a co-catalyst facilitating cooperative Br?nsted acid catalysis was found to be valuable for reactions involving phenols and higher substituted alcohols. Mechanistic investigations, including kinetic and 1H NMR binding studies in conjunction with density function theory calculations, are described that collectively support a Br?nsted acid mode of catalysis.
- Smajlagic, Ivor,Durán, Rocio,Pilkington, Melanie,Dudding, Travis
-
supporting information
p. 13973 - 13980
(2018/11/21)
-
- A mild and efficient THP protection of indazoles and benzyl alcohols in water
-
A mild and efficient method for THP protection of indazoles and benzyl alcohols has been developed in water, the most environmentally friendly solvent, in which Tween 20 (2% w/w) was added to form aqueous micelles to increase the solubility of starting materials. This aqueous protocol allowed the reaction to proceed smoothly at room temperature and with only 1.2 equiv of DHP, providing moderate to good yields of THP protected products for a wide scope of substrates. In addition, the methodology was highly practical in the large-scale synthesis (1 g synthesis of 2c as an example), wherein the convenient work-up and purification procedure (simple filtration) made the protocol even more attractive.
- Zhan, Yang,Ding, Xiao,Wang, Hailong,Yu, Haihua,Ren, Feng
-
supporting information
p. 2150 - 2153
(2018/05/08)
-
- Secondary amine salt catalyzed controlled activation of 2-deoxy sugar lactols towards alpha-selective dehydrative glycosylation
-
A new organocatalytic glycosylation method exploiting the lactol functionality has been disclosed. The catalytic generation of glycosyl oxacarbenium ions from lactols under forcible conditions via weakly Br?nsted-acidic, readily available secondary amine salts affects the diastereoselective glycosylation of 2-deoxypyranoses and furanoses. This operationally simple iminium catalyzed activation of 2-deoxy hemi-acetals is a potential alternative to the existing cumbersome methods that need specialized handling. The mechanisms for this unique transformation and kinetic/thermodynamic effects have been discussed based on both experimental evidence and theoretical studies.
- Ghosh, Titli,Mukherji, Ananya,Srivastava, Hemant Kumar,Kancharla, Pavan K.
-
p. 2870 - 2875
(2018/05/03)
-
- Magnetic Fe3O4@silica sulfuric acid nanoparticles promoted regioselective protection/deprotection of alcohols with dihydropyran under solvent-free conditions
-
Protection (and deprotection) of hydroxyl groups via tetrahydropyranylation was carried out effectively using a catalytic amount of Fe3O4 supported silica sulphuric acid nanoparticles (Fe3O4@SiO2@SO3H) under solvent-free conditions. The synthesized nanocatalyst was characterized by XRD, TEM, FT-IR etc. A wide range of tetrahydropyranylated alcohol derivatives were synthesized using this heterogeneous magnetic nanocatalyst within 10-20 min with high yields. In addition, tetrahydropyranyl ethers could also be deprotected to the parent alcoholic compounds in the presence of MeOH using the same catalyst. After completion of the reactions, the catalyst was easily separated from the reaction medium using an external magnet, which ameliorated the overall synthetic process. The catalyst was recovered and reused for five successive reactions without any appreciable loss in its activity. Mild reactions conditions, operational simplicity, solvent free conditions, high selectivity, easy recyclability of the magnetic nanocatalyst, and high yields can be considered as the advantageous features of our procedure.
- Rajkumari, Kalyani,Kalita, Juri,Das, Diparjun,Rokhum, Lalthazuala
-
p. 56559 - 56565
(2017/12/27)
-
- Magnetic nanoparticle-supported DABCO tribromide: A versatile nanocatalyst for the synthesis of quinazolinones and benzimidazoles and protection/deprotection of hydroxyl groups
-
1,4-Diazabicyclo[2.2.2]octane tribromide supported on magnetic Fe3O4 nanoparticles (MNPs-DABCO tribromide) as a novel heterogeneous tribromide type compound was found to be an efficient and reusable nanocatalyst for the one-pot synthesis of 2-arylquinazolin-4(3H)-ones and 2-aryl-1H-benzo[d]imidazoles through oxidative cyclization of aldehydes with 2-aminobenzamides and 1,2-phenylenediamine, respectively. Also, MNPs-DABCO tribromide catalyzed trimethylsilylation/tetrahydropyranylation and desilylation/depyranylation of a wide variety of alcohols and phenols through changing the solvent medium at room temperature.
- Rostami, Amin,Pourshiani, Omid,Navasi, Yahya,Darvishi, Neda,Saadati, Shaghayegh
-
p. 9033 - 9040
(2017/08/29)
-
- Zwitterionic imidazolium salt: An efficient organocatalyst for tetrahydropyranylation of alcohols
-
An aprotic imidazole based zwitterionic-salt, 4-(3-methylimidazolium)-butane sulfonate has been found to be an efficient organocatalyst for tetrahydropyranylation by the reaction of 3,4-dihydro-2H-pyran (DHP) and different aliphatic alcohols as well as various phenolic compounds. The notable advantages of the present method are general applicability to various alcohols, clean reaction, production of no hazardous waste, open air reaction conditions and high yields. The catalyst can be reused without the loss of significant catalytic activity.
- Mahato, Sachinta,Chatterjee, Rana,Chakraborty Ghosal, Nirnita,Majee, Adinath
-
supporting information
p. 1905 - 1915
(2017/10/07)
-
- Light-promoted metal-free cross dehydrogenative couplings on ethers mediated by NFSI: Reactivity and mechanistic studies
-
Cross dehydrogenative couplings on ethers occur very effectively using N-fluorobis(phenyl)sulfonimide (NFSI) as oxidizing agent under UVA irradiation in the presence of 2 mol% benzophenone. The reaction was shown to proceed first by fast radical fluorination of the α-C-H bond of ethers, followed by HF elimination to yield the highly electrophilic oxocarbenium ion as a key intermediate.
- Beniazza, Redouane,Abadie, Baptiste,Remisse, Lionel,Jardel, Damien,Lastécouères, Dominique,Vincent, Jean-Marc
-
supporting information
p. 12708 - 12711
(2017/12/02)
-
- Supported N-propylsulfamic acid onto Fe3O4 magnetic nanoparticles as a reusable and efficient nanocatalyst for the protection/deprotection of hydroxyl groups and protection of aldehydes
-
N-propylsulfamic acid supported onto Fe3O4 magnetic nanoparticles (MNPs-PSA) as an efficient and magnetically reusable nanocatalyst has been reported for the tetrahydropyranylation/depyranylation of a wide variety of alcohols and phenols by changing the solvent medium. Also, the protection of aldehydes as acylals using Ac2O in the presence of catalytic amount MNPs-PSA in good to high yields at room temperature under solvent-free conditions is described. After completing the reaction, the catalyst was easily separated from the reaction mixture with the assistance of an external magnetic field and reused for several consecutive runs without significant loss of their catalytic efficiency.
- Rostami, Amin,Tahmasbi, Bahman,Abedi, Fatemeh
-
p. 3689 - 3701
(2016/04/05)
-
- An efficient Br?nsted–Lewis acidic ionic liquid catalyzed tetrahydropyranylation of alcohols
-
An imidazolium based Br?nsted–Lewis acidic ionic liquid has been shown to be an excellent catalyst and reaction medium for the tetrahydropyranylation of various alcohols in good to excellent yields with short reaction times. Selective protection of benzyl
- Azizi, Najmedin,Abdoli-Senejani, Masumeh,Abbasi, Faezeh
-
p. 5009 - 5011
(2016/10/24)
-
- Facile O-glycosylation of glycals using Glu-Fe3O4-SO3H, a magnetic solid acid catalyst
-
A new glucose derived magnetic solid acid catalyst (Glu-Fe3O4-SO3H) was synthesized in a convenient and ecofriendly manner and well characterized using FTIR, PXRD, EDAX, SEM, and XPS which showed the presence of Fe3/
- Thombal, Raju S.,Jadhav, Vrushali H.
-
p. 30846 - 30851
(2016/04/09)
-
- P4VPy–CuO nanoparticles as a novel and reusable catalyst: application at the protection of alcohols, phenols and amines
-
P4VPy–CuO nanoparticles were synthesized using ultrasound irradiations. Relevant properties of the synthesized nanoparticles were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. After identification, the prepared reagent was used for the promotion of different types of protection reactions of alcohols, phenols and amines. Easy workup, short reaction times, excellent yields, relatively low cost and reusability of the catalyst are the striking features of the reported methods.
- Shirini, Farhad,Fallah-Shojaei, Abdollah,Abedini, Masoumeh,Samavi, Laleh
-
p. 1699 - 1712
(2016/07/27)
-
- Selective tetrahydropyranylation of alcohols and phenols using titanium(IV) salophen trifluoromethanesulfonate as an efficient catalyst
-
Titanium(IV) salophen trifluoromethanesulfonate, [TiIV(salophen)(OSO2CF3)2], as a catalyst enables selective tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran. Using this catalytic system, primary, secondary and tertiary alcohols, as well as phenols, were converted to their corresponding tetrahydropyranyl ethers in high yields and short reaction times at room temperature. Investigation of the chemoselectivity of this method showed discrimination between the activity of primary alcohols in the presence of secondary and tertiary alcohols and phenols. This heterogenized catalyst could be reused several times without loss of its catalytic activity. Copyright
- Yadegari, Maryam,Moghadam, Majid
-
p. 872 - 875
(2016/09/20)
-
- Tetrahydropyranylation of alcohols in the presence of a slightly basic, heterogeneous titanium catalyst
-
4 ? molecular sieve modified with titanium (IV) is an efficient heterogeneous catalyst for the tetrahydropyranylation of alcohols under mild, slightly basic reaction conditions. The catalyst can be reused with good yield after a simple treatment with dichloromethane.
- Magyar, ágnes,Nagy, Balázs,Hell, Zoltán
-
p. 1876 - 1879
(2019/11/28)
-
- Introduction of a New Ionic Liquid Catalyst for the Trimethylsilyl and Tetrahydropyranyl Protection of Alcohols
-
1,1'-Disulfo-[2,2'-bipyridine]-1,1'-hydrogen sulfate, BiPy(SO3H)2(HSO4)2, is prepared and identified as a new ionic liquid. This reagent was used for the promotion of the chemoselective trimethylsilyl and tetrahydropyranyl protection of alcohols. All reactions were performed under mild reaction conditions in high to excellent yields. Ease of the preparation of the heterogeneous catalyst, simplicity and easy work-up procedure, high reaction rates, and recyclability and reusability of the catalyst are the main advantages of this method.
- Shirini, Farhad,Abedini, Masoumeh,Mahmoodi, Nosratollah,Biglari, Mohammad,Safarpoor Nikoo Langrudi, Mohaddeseh
-
p. 1912 - 1921
(2015/12/12)
-
- Unexpected Mild Protection of Alcohols as 2-O-THF and 2-O-THP Ethers Catalysed by Cp2TiCl Reveal an Intriguing Role of the Solvent in the Single-Electron Transfer Reaction
-
A method for the conversion of primary, secondary and tertiary alcohols into the corresponding THF ethers at room temperature and primary and secondary alcohols into the corresponding THP ethers, has been developed using titanium(III) species generated from a catalytic amount of titanocene dichloride or (4R,5R)-(-)-2,2-dimethyl-α,α,α′,α′-tetra(1-naphthyl)-1,3-dioxolane-4,5-dimethanolatotitanium(IV) dichloride:acetonitrile adduct together with manganese(0) as a reductant and bromoform in THF or THP as the solvent. A radical mechanism is proposed for this transformation revealing an intriguing role of the solvent in the single-electron transfer reactions catalysed by the low valent TiIII system. A set of primary, secondary and benzylic alcohols have been converted into the corresponding THF and THP ethers and tertiary alcohols into the corresponding THF ethers using a catalytic amount of titanium dichloride in good yields and mild reaction conditions.
- Durán-Pe?a, María Jesús,Botubol-Ares, José Manuel,Hanson, James R.,Hernández-Galán, Rosario,Collado, Isidro G.
-
p. 6333 - 6340
(2015/10/06)
-
- 3,5-Dinitrobenzoic acid catalyzed synthesis of 2,3-unsaturated O- and S-glycosides and tetrahydropyranylation of alcohols and phenols
-
A simple procedure for the synthesis of 2,3-unsaturated glycosides in acetonitrile and tetrahydropyranylation of alcohols and phenols in dichloromethane in the presence of 3,5-dinitrobenzoic acid is described. A variety of alcohols and thiols are reacted with glycals to give the desired products in high yields with high α-selectivity.
- Bodipati, Naganjaneyulu,Palla, Srinivasa Rao,Komera, Venkateshwarlu,Peddinti, Rama Krishna
-
supporting information
p. 6878 - 6881
(2015/02/02)
-
- Aniline-terephthalaldehyde resin p-toluenesulfonic acid (ATRT) salt as efficient mild polymeric solid acid catalyst
-
Aniline-terephthalaldehyde resin p-toluenesulfonic acid (ATRT) salt was easily prepared by the reaction of aniline with 1.25 equiv of terephthalaldehyde in the presence of 1.0 equiv of p-toluenesulfonic acid at 75 C for 24 h in EtOH. ATRT efficiently catalyzed the tetrahydropyranylation of alcohols and deprotection of tetrahydropyranyl (THP), triethylsilyl (TES), and tert-butyldimethylsilyl (TBDMS) ethers. Deprotection of dodecyl THP ether and dodecyl TBDMS ether catalyzed by ATRT proceeded faster than those by pyridinium p-toluenesulfonate (PPTS). ATRT was reused without significant loss of activities.
- Tanemura, Kiyoshi,Suzuki, Tsuneo
-
supporting information
p. 6740 - 6743
(2013/11/19)
-
- {[[K.18-Crown-6]Br3}n: A tribromide catalyst for the catalytic protection of amines and alcohols
-
{[K.18-Crown-6]Br3}n, a unique tribromide-type catalyst, was utilized for the N-boc protection of amines and trimethylsilylation (TMS) and tetrahydropyranylation (THP) of alcohols. The method is general for the preparation of N-boc derivatives of aliphatic (acyclic and cyclic) and aromatic, and primary and secondary amines and also various TMS-ethers and THP-ethers. The simple separation of the catalyst from the product is one of the many advantages of this method.
- Chehardoli, Gholamabbas,Zolfigol, Mohammad Ali,Derakhshanpanah, Fateme
-
p. 1730 - 1733
(2013/10/21)
-
- Solvent-free NaHSO4-SiO2-catalyzed efficient tetrahydropyranylation of alcohols and phenols
-
A simple and efficient tetrahydropyranylation of alcohols and phenols has been developed using NaHSO4-SiO2 (0.5 mol%) as a catalyst under solvent-free conditions to yield corresponding tetrahydropyranyl ethers in excellent yields.
- Kinfe, Henok H.,Mebrahtu, Fanuel M.,Moshapo, Paseka T.
-
p. 1237 - 1242
(2013/04/10)
-
- CuBr2-promoted tetrahydrofuranylation of alcohols and 1,3-dione
-
A method for the CuBr2-promoted tetrahydrofuranylation of alcohols and 1,3-dione has been developed. A variety of different alcohols were efficiently converted into the corresponding 2-tetrahydrofuran ethers in the presence of CuBr2. It is noteworthy that this protocol also successfully converted 1,3-diphenyl-1,3-dione into the corresponding 2-tetrahydrofuran derivative in good yield. Georg Thieme Verlag Stuttgart - New York.
- Wang, Meng-Ke,Zhou, Zeng-Le,Tang, Ri-Yuan,Zhang, Xing-Guo,Deng, Chen-Liang
-
supporting information
p. 737 - 740
(2013/05/08)
-
- Short communication: Catalytic tetrahydropyranylation of phenols and alcohols using vanadium(V)-substituted polyoxomolybdates
-
Alcohols and phenols were tetrahydropyranylated in the presence of H 7[PMo8V4O40] in good to excellent yields in acetonitrile and under solventfree reaction conditions. A mild and convenient method for the formation and deprotection of ethers (THP ethers) is described. The formation of THP ethers from the corresponding alcohols was accomplished in the presence of acid-sensitive functional groups.
- Gharib, Ali,Jahangir, Manouchehr
-
experimental part
p. 287 - 296
(2012/05/20)
-
- Polystyrene-supported GaCl3: A new, highly efficient and recyclable heterogeneous Lewis acid catalyst for tetrahydropyranylation of alcohols and phenols
-
A new, simple and highly chemoselective method for tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) in the presence of polystyrene-supported gallium trichloride (PS/GaCl3) as a highly active and reusable heterogeneous Lewis acid catalyst at room temperature is presented.
- Rahmatpour, Ali
-
p. 66 - 71,6
(2012/12/11)
-
- Simple and efficient method for tetrahydropyranylation of alcohols and phenols by using silica supported sodium hydrogen sulphate as a catalyst
-
A Simple and efficient process for tetrahydropyranylation of alcohols and phenols has been developed by reacting with dihydropyran at room temperature in presence of catalytic amount of silica supported sodium hydrogen sulphate.
- Ravi Kumar,Satyanarayana,Srinivasa Reddy
-
experimental part
p. 3876 - 3878
(2012/09/21)
-
- Tetrahydropyranylation of alcohols and phenols using polystyrene supported lewis acids as catalysts
-
Polystyrene supported TiCl4 (Ps-TiCl4) and polystyrene supported FeCl3(Ps-FeCl3) were prepared by coordinating Lewis acids with polystyrene. The catalysts were characterized by TGA, BET, SEM, IR and pyridine-adsorbed IR. The loading of Ps-TiCl4 and Ps-FeCl3 were 0.35 and 0.3 mmol·g-1 respectively. Both catalysts were found to be efficient for the tetrahydropyranylation and detetrahydropyranylation of various alcohols and phenols in different solvents. Two catalysts can be recovered and reused for five times with good activity. Polystyrene supported TiCl4 (Ps-TiCl4) and polystyrene supported FeCl3(Ps-FeCl 3) were prepared by coordinating Lewis acids with polystyrene. The catalysts were characterized by TGA, BET, SEM, IR and pyridine-adsorbed IR. The loading of Ps-TiCl4 and Ps-FeCl3 were 0.35 and 0.3 mmol·g-1 respectively. Both catalysts were found to be efficient for the tetrahydropyranylation and detetrahydropyranylation of various alcohols and phenols in different solvents. Two catalysts can be recovered and reused for five times with good activity. Copyright
- Zhang, Yi,Dou, Qianqian,Liu, Yuan,Dai, Liyan,Wang, Xiaozhong,Chen, Yingqi
-
p. 2567 - 2572
(2013/01/15)
-
- Mild and efficient chemoselective tetrahydropyranylation of alcohols using bronsted acidic ionic liquid as catalyst under solvent-free conditions
-
A straightforward and efficient method for preparation of morpholinium bisulfate ([mroH]HSO4) as a novel acidic ionic liquid is reported. The application of this efficient and inexpensive acidic ionic liquid catalyst for tetrahydropyranylation of alcohols under mild and solvent-free conditions at room was investigated.
- Hajipour, Abdol R.,Nasresfahani, Zahra
-
experimental part
p. 1995 - 2006
(2012/06/04)
-
- Tetrahydropyranylation of alcohols and phenols catalyzed by a new polystyrene-bound tin(IV) porphyrin
-
In the present work, tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) catalyzed by tetrakis(p-aminophenyl) porphyrinatotin(IV) trifluoromethanesulfonate, [SnIV(TNH 2PP)(OTf)2], supported on chloromethylated polystyrene is reported. The prepared catalyst was characterized by elemental analysis, FT-IR and diffuses reflectance UV-Vis spectroscopic methods. This new heterogenized catalyst was found as efficient and reusable catalyst for tetrahydropyranylation of primary, secondary and tertiary alcohols as well as phenols at room temperature.
- Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Gharaati, Shadab
-
experimental part
p. 95 - 101
(2011/04/22)
-
- Synthesis of sulfonic acid functionalized carbon catalyst from glycerol pitch and its application for tetrahydropyranyl protection/deprotection of alcohols and phenols
-
A novel carbon catalyst with -SO3H, -OH and -COOH functional groups was prepared from glycerol pitch by in situ partial carbonization and sulfonation with sulfuric acid. The activity of the catalyst was investigated through tetrahydropyranylation and dehydropyranylation of a wide variety of alcohols and phenols at room temperature by changing the solvent medium from dichloromethane to methanol. Excellent yields, short reaction times, easy and quick isolation of the products and reusability of the catalyst are the main attractions of this method. The novel carbon catalyst holds great potential in the green chemical processes.
- Prabhavathi Devi,Gangadhar,Siva Kumar,Shiva Shanker,Prasad,Sai Prasad
-
experimental part
p. 96 - 100
(2011/10/05)
-
- Solvent-free tetrahydropyranylation of alcohols catalyzed by amine methanesulfonates
-
A comparative study of tetrahydropyranylation of alcohols under various solvents or solvent-free conditions using different amine methanesulfonates as catalysts shows that tetrahydropyranyl ethers of alcohols are obtained under solvent-free conditions in good yields using catalytic amounts of triethylenediamine methanesulfonate, 1,6-hexanediamine methanesulfonate, diethylenetriamine methanesulfonate and pyridine methanesulfonate, respectively. The reaction occurs readily in short times at room temperature catalyzed by these catalysts, especially triethylenediamine methanesulfonate. Some of the major advantages of this procedure are that the catalysts are environmentally friendly, highly effective, and easy to prepare and handle. The reaction is also clean and needs no solvent, and the work-up is very simple.
- Wang, Rui,Sun, Mingzhu,Jiang, Heng
-
experimental part
p. 61 - 67
(2012/02/16)
-
- Metal benzenesulfonates/acetic acid mixtures as novel catalytic systems: Application to the protection of a hydroxyl group
-
A surprising synergistic effect has been discovered in mixtures of metal benzenesulfonates (Co, Al, Ni, Zn, Cd, Pr, La, Cu, Mn) and acetic acid, leading to active catalytic systems for the tetrahydropyranylation of alcohols and phenols to produce tetrahydropyranyl ethers. All reactions proceed mildly and efficiently with moderate to high yields at room temperature without solvent. After the reaction, the metal benzenesulfonate can be easily recovered and reused many times. The efficiency of these systems might result from the "double activation" by Bronsted and Lewis acid catalysis.
- Wang, Min,Gao, Jingjing,Song, Zhiguo
-
experimental part
p. 1349 - 1352
(2011/01/11)
-
- High-valent tin(IV) porphyrin: An efficient and reusable catalyst for tetrahydropyranylation of alcohols and phenols under mild conditions
-
In this paper, rapid and highly efficient tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) in the presence of catalytic amounts of high-valent tin (IV) tetraphenylporphyrinato trifluoromethanesufonate, [SnIV(TPP)(OTf)2] is reported. In this catalytic system, primary, secondary and tertiary alcohols as well as phenols were converted to their corresponding tetrahydropyranyl ethers (THP-ethers) in excellent yields and short reaction times at room temperature. It is noteworthy that this method can be used for chemoselective tetrahydropyranylation of primary alcohols in the presence of secondary and tertiary alcohols and phenols. The catalyst was reused several times in the protection reactions without loss of its catalytic activity.
- Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Gharaati, Shadab
-
experimental part
p. 1523 - 1528
(2010/08/04)
-
- Poly(N-bromo-N-ethyl-benzene-1,3-disulfonamide), N,N,N′,N′- tetrabromobenzene-1, 3-disulfonamide as new efficient reagents for conversion of alcohols to THP ethers and aldehydes to oxazoline compounds
-
This paper is concerned with an easy preparation of THP ethers from primary, secondary and tertiary alcohols and oxazoline compounds from various aldehydes using poly(N-bromo-N-ethyl-benzene-1,3-disulfonamide), N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide [TBBDA] as new and efficient reagents under ambient conditions without over-oxidation.
- Ghorbani-Vaghei,Akbari-Dadamahaleh,Amiri
-
experimental part
p. 301 - 307
(2010/09/03)
-
- 1,6-Hexanediamine methanesulfonate: A mild and efficient catalyst for the tetrahydropyranylation of alcohols under solvent-free conditions
-
Various alcohols react with 3,4-dihydro-2 H-pyran under mild conditions using a catalytic amount of 1,6-hexanediamine methanesulfonate. It affords the corresponding tetrahydropyranyl ethers in good yields at a faster rate in the absence of solvent. Taylor & Francis Group, LLC.
- Wang, Rui,Jiang, Heng
-
experimental part
p. 171 - 176
(2012/01/05)
-
- Dowex 50WX4-100: An efficient catalyst for the tetrahydropyranylation of alcohols
-
The ion-exchange resin Dowex 50WX4-100 has been found to catalyze efficiently the protection reaction of a variety of alcohols with 2,3-dihydro-4H pyran (DHP) and dichloromethane at ambient conditions. Copyright Taylor & Francis Group, LLC.
- Poon,Banerjee, Ajoy K.,Bedoya, Liadis,Laya, Manuel S.,Cabrera, Elvia V.,Albornoz, Karla M.
-
experimental part
p. 3369 - 3377
(2011/03/19)
-
- A highly efficient and ecofriendly procedure for tetrahydropyranylation of alcohols and phenols in the presence of in-situ generated I2 under heterogeneous and neutral conditions
-
Molecular iodine generated in situ from Fe(NO3) 3?9H2O/NaI acts as a highly efficient catalyst for tetrahydropyranylation of various alcohols and phenols with 3,4-dihydro-2H-pyran in almost quantitative yields. The reaction occurs rapidly in dichloromethane at room temperature, and use of toxic molecular iodine is avoided.
- Rostami, Amin,Rahmati, Sadegh,Khazaei, Ardeshir
-
experimental part
p. 663 - 667
(2010/05/18)
-
- Copper nitrate/acetic acid as an efficient synergistic catalytic system for the chemoselective tetrahydropyranylation of alcohols and phenols
-
Tetrahydropyranylation of alcohols and phenols was accomplished successfully using copper nitrate and acetic acid as a synergistic catalyst at room temperature under solvent-free condition. Compared with other synergistic catalytic systems, copper nitrate/acetic acid proved to be the most efficient. Both alcohols (primary, secondary, tertiary, benzylic, cyclic, allyl, cinnamyl, and furyl) and phenols reacted smoothly in high yields. Graphical abstract: [Figure not available: see fulltext.]
- Wang, Min,Song, Zhi-Guo,Gong, Hong,Jiang, Heng
-
experimental part
p. 177 - 179
(2010/04/02)
-
- Allyl tetrahydropyranyl ether: a versatile alcohol/thiol protecting reagent
-
Allyl tetrahydropyranyl ether (ATHPE) can be used as a versatile protecting reagent. In combination with NBS/I2, O-allyl group can easily be replaced by hydroxyls (including tertiary-OH) or thiols, in the molecules comprising other reactive fun
- Kumar, Brijesh,Aga, Mushtaq A.,Mukherjee, Debaraj,Chimni, Swapandeep S.,Taneja, Subhash C.
-
supporting information; experimental part
p. 6236 - 6240
(2010/01/18)
-
- NON-STEROIDAL PROGESTERONE RECEPTOR MODULATORS
-
The present invention relates to non-steroidal progesterone receptor modulators of the general formula 1, the use of the progesterone receptor modulators for the manufacture of medicaments, and pharmaceutical compositions which comprise these compounds. The compounds according to the invention are suitable for the therapy and prophylaxis of gynaecological disorders such as endometriosis, leiomyomas of the uterus, dysfunctional bleeding and dysmenorrhoea, and for the therapy and prophylaxis of hormone-dependent tumours and for use for female fertility control and for hormone replacement therapy.
- -
-
Page/Page column 75
(2009/04/24)
-
- Photosensitized tetrahydropyran transfer
-
(Chemical Equation Presented) THP ethers were formed cleanly during photolysis of 3,4-dihydro-2H-pyran, an alcohol, and catalytic 1,5-dichloro9,10-anthraquinone with use of visible light. The reaction could be conducted under ambient fluorescent lighting or with sunlight as well as in a Rayonet reactor. The scope and mechanism are discussed.
- Oates,Jones, Paul B.
-
p. 4743 - 4745
(2008/09/21)
-
- Copper p-toluenesulfonate/acetic acid: A recyclable synergistic catalytic system for the tetrahydropyranylation of alcohols and phenols
-
Copper p-toluenesulfonate/acetic acid was found to be an efficient, chemoselective synergistic catalytic system, with catalyst loading as low as 0.3 mol% leading to clean, high-yielding tetrahydropyranylation of a variety of alcohols and phenols. By simple phase-separation, copper p-toluenesulfonate can be easily recovered and reused for several times without deterioration in catalytic activity.
- Wang, Min,Song, Zhi-Guo,Jiang, Heng,Gong, Hong
-
experimental part
p. 601 - 604
(2009/08/07)
-
- AI(OTf)3 - A highly efficient catalyst for the tetrahydropyranylation of alcohols under solvent-free conditions
-
A simple and highly efficient method has been developed for the tetrahydropyranylation of alcohols by their reaction with 3,4-dihydro-2H-pyran (DHP) using a catalytic amount (0.01-1 mol%) of aluminium triflate under solvent-free conditions. The effect of various factors like temperature, amount of the catalyst, and molar ratio of substrates on the reaction conditions has also been studied. The comparative study of tetrahydropyranylation of benzyl alcohol using various catalysts including some reported ones shows the efficiency of this catalyst.
- Kamal, Ahmed,Naseer A Khan,Srikanth,Srinivasa Reddy
-
scheme or table
p. 1099 - 1104
(2009/03/11)
-
- Fe3+-Catalyzed transacetalization of 2-alkoxytetrahydrofurans with alcohols
-
The transacetalization of 2-alkoxy-4-benzylidenetetrahydrofurans with alcohols proceeds smoothly with the aid of Fe(ClO4)3 catalyst. The catalyst reactivity is ordered as Fe(ClO4)3 > Zn(ClO4)2/s
- Yamanaka, Daisetsu,Matsunaga, Sei,Kawamura, Yasufumi,Hosokawa, Takahiro
-
-
- Parallel synthesis in an EOF-based micro reactor
-
We present herein a micro reactor set-up that enables parallel syntheses to be performed under electroosmotic flow conditions. The Royal Society of Chemistry.
- Wiles, Charlotte,Watts, Paul
-
p. 4928 - 4930
(2008/09/17)
-
- Generally applicable organocatalytic tetrahydropyranylation of hydroxy functionalities with very low catalyst loading
-
This paper presents the first acid-free, organocatalytic tetrahydropyran and 2-methoxypropene protection of alcohols, phenols, and other ROH derivatives utilizing privileged N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea and a polystyrene-bound analogue. The reactions are broadly applicably (also on preparative scale), in particular, to acid-sensitive substrates such as aldol products, hydroxy esters, acetals, silyl-protected alcohols, and cyanohydrins. The catalytic efficiency is truly remarkably with turnover numbers of 100,000 and turnover frequencies of up to 5700 h-1 at catalyst loadings down to 0.001 mol%. The computationally supported mechanistic interpretation emphasizes the hydrogen bond assisted heterolysis of the alcohol and concomitant preferential stabilization of the oxyanion hole in the transition state. Georg Thieme Verlag Stuttgart.
- Kotke, Mike,Schreiner, Peter R.
-
p. 779 - 790
(2008/01/03)
-