- Silicon-29 NMR spectra of tert-butyldimethylsilyl and trimethylsilyl derivatives of some non-rigid diols
-
29Si NMR spectra of trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBDMS) derivatives of selected diols were measured under standardized conditions (i.e., in diluted CDCl3 solutions). Application of the recently reported correlation between the chemical shifts in TMS and TBDMS derivatives revealed considerable and systematic deviations which exceeded experimental errors and error estimates from the correlation. Two possible explanations of the deviations are considered: interaction between the two bulky substituent groups and invalidity of the reported correlation for simple hydroxy derivatives. An independent study of analogous derivatives of monohydroxy compounds has shown that the linear correlation holds but the slope and intercept are significantly different from those reported previously on the basis of a study of amino acid derivatives. The data obtained for the diol derivatives fit the new correlation very well and no indication of an interaction between the bulky TBDMS groups was noticed. However, deviations do occur in branched diol derivatives in which branching reduces accessibility of the oxygen atoms surface to associate with proton donors. The largest deviation was found when intramolecular hydrogen bond was formed.
- Kvicalova, Magdalena,Blechta, Vratislav,Kobylczyk, Krzysztof,Piekos, Ryszard,Schraml, Jan
-
-
Read Online
- Fast and efficient method for Silylation of alcohols and phenols with HMDS in the presence of bis-thiourea complexes of cobalt, nickel, copper and zinc chlorides
-
Bis-thiourea complexes of cobalt, nickel, copper and zinc chlorides were used efficiently for rapid and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) in CH3CN. All reactions were carried out at room temperature within immediate-120?min timeframe to afford trimethylsilyl ether derivatives in high to excellent yields. Investigation of the results exhibited that the prepared bis-thiourea metal complexes show the activity as Co(tu)2Cl2> Ni(tu)2Cl2> Cu(tu)2Cl2> Zn(tu)2Cl2 in their silylation reactions.
- Zeynizadeh, Behzad,Sorkhabi, Serve
-
p. 127 - 135
(2018/02/06)
-
- Magnesium hydrogensulfate [Mg(HSO4)2] as an efficient catalyst for the preparation of silyl ethers, dibenzo[a,j]xanthenes, and octahydroxanthene derivatives
-
Magnesium hydrogensulfate [Mg(HSO4)2], as a heterogeneous solid acid catalyst, has been used for the mild formation of trimethylsilyl (TMS) ethers from various primary, secondary, and tertiary aliphatic alcohols; aromatic alcohols; a
- Shaterian, Hamid Reza,Doostmohammadi, Razieh,Khorami, Fahimeh,Ghashang, Majid
-
experimental part
p. 171 - 180
(2010/04/05)
-
- Silica-supported ferric chloride (silica-FeCl3): A reusable, easily controllable catalyst for the protection of hydroxyl groups under mild and ambient conditions
-
Diverse alcohols, phenols, and naphthols were converted into their corresponding trimethylsilyl ether effectively with hexamethyldisilazane in the presence of silica-FeCl3 under solvent-free and ambient conditions with short reaction time in good to excellent yields. Work up procedure is easy, and the catalyst can be recovered by simple filtration and reused. Copyright Taylor & Francis Group, LLC.
- Shaterian, Hamid Reza,Ghashang, Majid,Hosseinian, Asghar
-
experimental part
p. 2108 - 2118
(2009/07/18)
-
- An efficient method for the silylation of hydroxyl groups with hexamethyldisilazane (HMDS) catalyzed by aluminum tris(dihydrogen phosphate) under solvent-free and ambient conditions
-
A highly efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, benzylic, secondary, hindered secondary, tertiary, phenols, and oximes with hexamethyldisilazane (HMDS), using Al(H2PO4)3 as a recyclable heterogeneous catalyst at room temperature in a few minutes with excellent yields under solvent-free conditions is described.
- Shaterian, Hamid Reza,Ghashang, Majid,Riki, Nassrin Tajbakhsh,Asadi, Manijeh
-
p. 841 - 845
(2008/12/20)
-
- Alumina perchloric acid (Al2O3-HClO4) as an efficient heterogeneous catalyst for modified preparation of trimethylsilyl ethers
-
A highly efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, benzylic, secondary, hindered secondary, tertiary, phenols, and oximes with hexamethyldisilazane (HMDS) using alumina perchloric acid (Al2O3-HClO4) as recyclable heterogeneous catalyst in excellent yields with short reaction times (3-65 min) under ambient conditions is described. Copyright Taylor & Francis Group, LLC.
- Shaterian, Hamid Reza,Khorami, Fahimeh,Amirzadeh, Azita,Ghashang, Majid
-
experimental part
p. 2865 - 2874
(2009/09/25)
-
- A highly efficient method for the silylation of alcohols, phenols, and naphthols using HMDS in the presence of zinc oxide (ZnO) as economical heterogeneous catalyst
-
Variety alcohols, phenols, and naphthols were effectively converted into their corresponding trimethylsilyl ether with hexamethyldisilazane in the presence of zinc oxide under very mild and ambient conditions with short reaction time in good to excellent yields.
- Shaterian, Hamid Reza,Ghashang, Majid
-
p. 194 - 204
(2008/12/21)
-
- Alumina sulfuric acid as an efficient and recyclable heterogeneous catalyst for the O-silylation of alcohols, phenols, and oximes
-
Alumina sulfuric acid as a recyclable catalyst conducts the transformation of various types of alcohol, phenols, and oximes with hexamethyldisilazane (HMDS) to the corresponding O-trimethylsilylated compounds in good to excellent yields under mild and ambient conditions with short reaction times. The method is highly selective for the conversion of primary alcohols in the presence of secondary and tertiary alcohols. Additionally, the catalyst can be easily recovered and reused at least eight times without detectable loss of reactivity.
- Shaterian, Hamid Reza,Khorami, Fahimeh,Amirzadeh, Azita,Ghashang, Majid,Hosseinian, Asghar
-
scheme or table
p. 2584 - 2595
(2009/08/15)
-
- A mild, simple, efficient, and selective protection of hydroxyl groups using silica-supported sodium hydrogen sulfate as a heterogeneous catalyst
-
A mild, simple, novel, and highly efficient method for the rapid protection of various primary, secondary, tertiary aliphatic alcohols, aromatic alcohols, and oximes using hexamethyldisilazane (HMDS) in the presence of silica-supported sodium hydrogen sulfate (NaHSO4-SiO2), as an active, inexpensive, nontoxic, heterogeneous, and readily available catalyst under ambient conditions is described. Timethylsilyl ethers were prepared in high to excellent yields, with short reaction times under mild and almost neutral reaction conditions at room temperature. Copyright Taylor & Francis Group, LLC.
- Shaterian, Hamid Reza,Doostmohammadi, Razieh,Ghashang, Majid,Rahmani, Mashaallah
-
experimental part
p. 3127 - 3135
(2009/09/25)
-
- Efficient and practical protocol for silylation of hydroxyl groups using reusable lithium perchlorate dispread in silica gel under neutral condition
-
A very efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, allylic, benzylic, secondary, hindered secondary, tertiary, and phenols with hexamethyldisilazane on the surface of silica gel dispersed with LiClO4 in room temperature at few minutes in excellent yields under neutral conditions is reported. This procedure also allows the excellent selectivity under LP-SiO2 system for silylation of alcohols in the presence of amine and phenolic hydroxy groups.
- Azizi, Najmedin,Yousefi, Rozbeh,Saidi, Mohammad R.
-
p. 817 - 820
(2007/10/03)
-
- Process for the preparation of O-silylated hydroxyl compounds and their use for the preparation of isocyanates containing ester groups
-
This present invention relates to a process for the preparation of O-silylated aliphatic hydroxyl, compounds by the reaction of aliphatic hydroxyl compounds with triorganochlorosilanes and removal of the resulting gaseous hydrogen chloride from the reaction mixture, characterized in that the reaction is carried out in the presence of phase transfer catalysts in the absence of solvent. The invention also relates to the use of the O-silylated hydroxyl compounds obtained by this process as starting materials for the preparation of isocyanates containing ester groups by a reaction with isocyanato carboxylic acid chlorides.
- -
-
-
- OZONOLYSIS OF ALKENES AND REACTIONS OF POLYFUNCTIONAL COMPOUNDS. XIX. SYNTHESIS OF α,ω-BIFUNCTIONAL REGULAR (Z)-1,5-POLYENES
-
α,ω-Dihydroxy- and ω-oxo-α-carboxy-(Z)-1,5-polyene aliphatic compounds were synthesized by selective ozonolysis of (Z)-1,4-polybutadiene (synthetic divinyl rubber) followed by reduction or hydrolysis of the oligomeric ozonides.They were converted into bis(trimethylsilyl) ethers and diacetates or tetramethyl derivatives, differing in the number of (Z)-butenylene units in the aliphatic chain.
- Odinokov, V. N.,Ignatyuk, V. K.,Tolstikov, G. A.,Rafikov, S. R.
-
p. 1220 - 1229
(2007/10/02)
-
- PROTECTION OF ALCOHOLS AND ACIDS WITH ALLYLSILANES CATALYZED BY IODINE OR IODOTRIMETHYLSILANE IN CHLORINATED HYDROCARBON
-
Many triorganosilyl ethers and esters were prepared by the reaction of allylsilanes with alcohols catalyzed by iodine or iodotrimethylsilane in excellent yields.Bromine and bromotrimethylsilane were also effective catalysts.
- Hosomi, Akira,Sakurai, Hideki
-
-