T-butyl Ethers Research Articles

Identification of Ethyl and t-Butyl Glyceryl Ethers Using Gas Chromatography Coupled with Mass Spectrometry

The ethers produced through the etherification reaction of glycerol with ethanol or t-butanol are used as oxygenated fuel additives, intermediates in the pharmaceutical industry, and non-ionic surfactants. However, the identification of these ethers has not been accurately done, because only some mass spectra of these compounds are available in the libraries. Moreover, there is a lack of discussion on their identification in the literature. In this work, a detailed identification of all ethers produced in the etherification of glycerol with ethanol or t-butanol was performed considering the mass spectra of isolated products and the comparison of the retention times. The elution order of the products was: tri-alkyl, 1,3-dialkyl, 2,3-dialkyl, 3-monoalkyl and 2-monoalkyl. In all mass spectra of the ethyl ethers, the base peak was m/z 61, while in the case of t-butyl ethers it was m/z 57.

Acid- and isobutylene-free synthesis of t-butyl ethers by in situ formation of 2-t-butoxy-1-methylpyridinium triflate

The title reagent is formed in situ by alkylation of 2-t-butoxypyrine. The subsequent addition of an alcohol substrate leads to the formation of t-butyl ethers without the need for isobutylene gas or acid activators.

Comparison of Diesel Fuel Oxygenate Additives to the Composition-Explicit Distillation Curve Method. Part 3: t-Butyl Glycerols

In this paper (the third in a series of papers on the properties of mixtures of diesel fuel with oxygenating additives), we present the application of the technique to mixtures of diesel fuel with the potential fuel additive t-butyl glycerol, which is a blend of mono-, di-, and triglycerol t-butyl ethers (GTBEs). These compounds are derived from glycerol, a byproduct of biodiesel fuel production. Four t-butyl glycerol blends were examined: blends 1 and 2 are mostly composed of di-GTBE; blend 3 is mostly composed of tri-GTBE; and blend 4 is mostly composed of mono-GTBE. We found that blend 4 was not soluble in diesel fuel at room temperature at concentrations above 3% (vol/vol), and thus, no reliable measurement could be made with this blend additive. We present the results for the initial boiling behavior and the distillation curve temperatures and track the di- and tri-GTBEs throughout the distillations. These data will aid in determining the suitability of these types of compounds as oxygenate additives and fuel extenders for diesel fuel.

Thermal Cleavage of the Fmoc Protection Group

The Fmoc protection group is among the most commonly used protection groups for the amino function. A fast method for the thermal deavage of this protection group under base-free conditions without the need for dibenzofulvene scavengers is presented. The advantages of this method include straightforward testability by means of a simple high-temperature NMR experiment, usually high yields, and good selectivity towards the BOC protection group and t-butyl ethers.

Recent Development about the Use of Pyrocarbonates as Activator in Organic Synthesis: A Review

In the last years, the use of pyrocarbonates and particularly di-tert-butyldicarbonate (Boc2O) has found a renaissance in organic synthesis. Together with the classical couple Boc2O/DMAP, new synthetic strategies have been developed in the presence of environmentally benign Lewis Acids. So new syntheses of protected Boc-amines and alcohols have appeared in literature. Moreover, the use as activator in the synthesis of esters and anhydrides has received attention from different research groups. Finally an interesting and unexpected synthesis of t-butyl ethers has appeared. This review aims to cover all the literature since 1998, but not the application to the synthesis of natural products. Keywords: Pyrocarbonates, di-tert-butyldicarbonate, Lewis acid, ether, ester, anhydride, protected amines, protected alcohols

Unusual and Unexpected Reactivity of t‐Butyl Dicarbonate (Boc2O) with Alcohols in the Presence of Magnesium Perchlorate. A New and General Route to t‐Butyl Ethers.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Unusual and Unexpected Reactivity of t-Butyl Dicarbonate (Boc2O) with Alcohols in the Presence of Magnesium Perchlorate. A New and General Route to t-Butyl Ethers

[reaction: see text] A new mild method for protecting alcohols as t-butyl ethers is reported. The reaction proceeds with Mg(ClO4)2 and Boc2O and shows general applicability. The deprotection of t-butyl ethers has also been revisited. Preliminary results indicate the CeCl3 x 7H2O/NaI system is a very suitable catalyst for their removal.

Montmorillonite Clay: A Novel Reagent for the Chemoselective Hydrolysis of t-Butyl Esters

A mild and highly selective hydrolysis of t-butyl esters has been achieved in high yields using montmorillonite KSF in refluxing acetonitrile. The method is compatible with a variety of protecting and functional groups such as BOC, Cbz, propargyl, allyl, benzyl, t-butyl ethers, allyl, methyl and benzyl esters present in the molecule.

A mild and selective method for the cleavage of tert-butyl esters

A method for the cleavage of t-butyl esters using silica gel in refluxing toluene is reported. Good yields of the corresponding carboxylic acids are obtained, and the reaction is selective for t-butyl esters over t-butyl ethers and trimethylsilylethyl (TMSE) esters.

One-pot conversion of benzyl carbamates into fluorenylmethyl carbamates

A simple one-pot procedure smoothly converted N-benzyloxycarbonyl groups into N-fluorenylmethoxycarbonyl groups via hydrogenation with a poisoned catalyst in the presence of Fmoc-OSu. Functional groups such as t-butyl esters, t-butyl ethers, and N-Boc were stable under the reaction conditions.

ChemInform Abstract: Protection of Phenols as t-Butyl Ethers under Mild Conditions.

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.

Protection of phenols as t-butyl ethers under mild conditions

Zinc mediated selective O-y-butylation of phenols has been carried out in good to excellent yields under mild conditions. No trace of C-t-butylation was observed.

Formula omitted] synthesis of aryl t-butyl ethers and application to the first synthesis of 4-chlorobenzofuran

Pd P(t- Bu) 3 catalyzed reaction of aryl halides with sodium t-butoxide effectively to give aryl t-butyl ethers. The high catalytic activity realized the formation of aryl t-butyl ethers from not only electron-deficient aryl halides but also electron-rich aryl halides. Moreover, the first synthesis of 4-chlorobenzofuran was attained utilizing the selective mono- t-butoxylation of aryl dihalide.

Convenient preparations of t-butyl esters and ethers from t-butanol

Abstract A one-pot preparation of t-butyl esters and ethers is described that proceeds from the carboxylic acid or alcohol and t-butanol using only anhydrous magnesium sulfate and catalytic sulfuric acid as additional reagents. The method affords t-butyl esters and ethers in good yields and is applicable to a variety of substrates.

Hydrogenolysis and One-Electron Reduction of Alkoxy Sulfones

The readily available 1-t-butoxyalkyl sulfones were converted by hydride reduction into alkyl t-butyl ethers. Reductive coupling with sodium metal or amalgam in an aprotic solvent led to glycol bis-1,2-O-t-butyl ethers. Polyethers such as 18-crown-6 can be synthesized by this procedure.

Cationic polymerization of vinyl monomers initiated by 10-methylphenothiazine cation radicals

A small quantity of 10-methylphenothiazine cation radical (MPT .+ ), electrochemically prepared and stocked in acetonitrile solution, initiated cationic polymerizations of n-butyl, t-butyl, and 2-methoxyethyl vinyl ethers and p-methoxystyrene, while no initiation occurred for phenyl vinyl ether, styrene, methyl methacrylate, and phenyl glycidyl ether. 1 H-NMR studies of oligomers and low molecular weight compounds isolated from the reaction mixture for the polymerization of t-butyl vinyl ether in the presence of a small amount of D 2 O indicated that electron transfer from the monomer to MPT .+ was involved in the initiation step

C 4 alkene separation process using solid acid catalysis

A two-step procedure for separating isobutene from mixed C 4 hydrocarbon streams, such as Raffinate-1, has been demonstrated using solid acid catalysis. The procedure involves initial etherification of the C 4 mixture with a suitable aliphatic diol, such as ethylene glycol or 1,2-propylene glycol, to give the corresponding glycol mono- t-butyl ethers, followed by deetherification of the said monoethers at higher temperatures to yield pure isobutene plus regenerated glycol. Suitable classes of solid acid catalysts include acidified montmorillonite clays and heteropoly acids dispersed on Group IV oxides, such as 12-tungstophosphoric acid on titania. Preliminary etherification parameter, and catalyst characterization, studies for these two very different classes of strongly acidic catalyst are also detailed herein.

Iodocyclization of olefinic t-butyl ethers : an easy stereocontrolled synthesis of cis-substituted tetrahydrofurans.

The iodoalkoxylation of δ,ϵ olefinic t-butyl ethers leads, with a very high selectivity, to cis substituted tetrahydrofurans.

Mild protection and deprotection of alcohols as ter-butyl ethers in the field of pheromone synthesis

α,ω-Halohydrins and Ω-acetylenic alcohols are protected as t-butyl ethers by reaction with isobutene and an acid catalyst : Amberlyst H-15. t-Butyl ethers are, in turn, cleaved to acetates by Ac 2O and 10% FeCl 3 in Et 2O solvent. Under these mild conditions conjugated dienic systems are neither destroyed nor isomerized.

A new method for the preparation of tertiary butyl ethers and esters

T-butyl 2,2,2-trichloroacetimidate ( 1), readily prepared by addition of t-butanol to trichloroacetonitrile, is an efficient reagent for the preparation of t-butyl ethers and esters in the presence of a catalytic amount of boron trifluoride etherate.