Ethers 1,4-addition

Eor curing copolymers of tetrafluoroethylene and perfluorovinyl ether, addition of ca 4% TAG has been proposed (118). TEE—propylene copolymers have been cured by TAG and organic peroxide (119). Copolymers of TEE-propylene-vinyUdene fluoride are cured with TAG by heating at 200°C. 

Addition compounds form with those organics that contain a donor atom, eg, ketonic oxygen, nitrogen, and sulfur. Thus, adducts form with amides, amines, and A/-heterocycles, as well as acid chlorides and ethers. Addition compounds also form with a number of inorganic compounds, eg, POCl (6,120). In many cases, the addition compounds are dimeric, eg, with ethyl acetate, in titanium tetrachloride-rich systems. By using ammonia, a series of amidodichlorides, Ti(NH2) Cl4, is formed (133). 

Reaction of alkenes with a disulfide and BF3 etherate Addition of H2S to carbonyl compounds or imines... 

Glycidyl ether additives are obtained by esterification of alkoxylated primary fatty amines and additives of polyether-block polymers and glycidyl ethers with dicarboxylic acids [1025], They are used as demulsifiers to break up oil emulsions and, as quatemized products, they are suitable as corrosion inhibitors. 

R. Kupfer, W. Bose, M. Hille, R. Bohm, and F. Staiss. Esterified glycidyl ether additives and their application (Veresterte Glycidylether-Additionsprodukte und deren Verwendung). Patent EP 333135,1989. 

A number of other chiral catalysts can promote enantioselective conjugate additions of silyl enol ethers, silyl ketene acetals, and related compounds. For example, an oxazaborolidinone derived from allothreonine achieves high enantioselectivity in additions of silyl thioketene acetals.323 The optimal conditions for this reaction also include a hindered phenol and an ether additive. 

Any nitro- or amino-aromatic compound may be considered a potential source of interference until demonstrated otherwise. For example, DN-111 in benzene was processed in the usual manner. During the reduction step a pink color developed which was insoluble in petroleum ether addition in proper sequence of the dye-producing reagents resulted in the development of a deep purple color within 10 minutes. 

To a solution of 4 g. of silver nitrate in 8 ml. of water is added 60 ml. of 3.4% aqueous sodium hydroxide plus 1.3 g. of 2-(4-acetyl-5-methylpyrrole-2)diglycolaldehyde. The mixture is heated under reflux on a steam bath for forty minutes. After cooling, the suspension is filtered and the filtrate is neutralized (to Congo Red) with dilute nitric acid. On further cooling, a solid separates this is slightly soluble in water and very soluble in ether. Additional product is obtained by extracting the filtrate three times with ether. The united ether extracts are dried with anhydrous sodium sulfate, filtered, and the filtrate evaporated to dryness. The residue is combined with the first solid fraction, and recrystallized from ether, affording pale-yellow crystals yield, lg. m. p., 200°. 

Rosenthal and co-workers (91, 92) studied the cobalt hydroformylation of various unsaturated carbohydrates. As with other a,j8-unsaturated ethers, addition of the formyl group occurred almost exclusively at the double-bond carbon a to the oxygen. High yields of product were obtained, but hydrogenation to alcohol was facile, even under mild conditions, as noted in Eq. (43) ... 

Enol ether additives were used to probe the protonation of 3-cyclopen-tenylidene (127). Treatment of A-nitroso-A-(2-vinylcyclopropyl)urea (124) with sodium methoxide generates 2-vinylcyclopropylidene (126) by way of the labile diazo compound 125 (Scheme 25). For simplicity, products derived directly from 126 (allene, ether, cycloadduct) are not shown in Scheme 25. The Skat-tebpl rearrangement of 126 generates 127 whose protonation leads to the 3-cyclopentenyl cation (128). In the presence of methanol, cyclopentadiene (130) and 3-methoxycyclopentene (132) were obtained.53 With an equimolar mixture of methyl vinyl ether and methanol, cycloaddition of 127 (—> 131)... 

Besides the allylation reactions, imines can also undergo enol silyl ether addition as with carbonyl compounds. Carbon-carbon bond formation involving the addition of resonance-stabilized nucleophiles such as enols and enolates or enol ethers to iminium salt or imine can be referred to as a Mannich reaction, and this is one of the most important classes of reactions in organic synthesis.104... 

Lipid material Extraction with pet. ether, partition with acetonitrile, addition of satd. aq NaCI to back-extract pesticides to pet. ether, additional processing GC/ECD or GC/MS No data No data Walters 1986... 

The arylation of potassium phenoxide has been studied by Litvak and Shein (1976). In the absence of crown ether the rate of reaction with p-nitrobromobenzene in various solvents increases in the order dioxan < methanol < pyridine < DMSO. In the presence of either 18-crown-6 [3] or dibenzo-18-crown-6 [11], the order of the reaction rates in dioxan and methanol is reversed (Table 22). The effect of crown ether addition on the rate... 

The present procedure is an improved modification of that described by Balaban for the corresponding perchlorate. 2,4,6-Triphenylpyrylium tetrafluoroborate has also been prepared from the corresponding tetrachloroferrate with fiuoboric acid, from acetophenone and boron trifluoride, and from acetophenone, benzaldehyde, and boron trifluoride etherate. Additional methods for the preparation of pyrylium salts have been reviewed. ... 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

H2SO4, produces ethers. Addition of alcohol to an unsymmetrical alkene follows Markovnikov s rule. The reaction proceeds via protonation to give the more stable carhocation intermediate. The mechanism is the reverse of that for dehydration of ethers. 

The influence of diphenyl ether and anisole on the association of the polystyryllithium and 1,1-di-phenylmethyllithium active centers has been measured. Severe disaggregation of the polystyryllithium dimers, present in pure benzene, was found to occur at levels of ether addition at which several reliable kinetic studies reported in the literature unequivocally demonstrate a 1/2 order dependence upon polystyryllithium. These results indicate that a necessary connection between the degree of aggregation of organo1ithium polymers and the observed kinetic order of the propagation reaction need not exist. 

When 18-crown-6 was co-lyophilized with a-chymotrypsin, a 470-fold activation was seen over the free enzyme in the transesterification of APEE with 1-propanol in cyclohexane (Scheme 3.2) [96]. There was a low apparent specificity for the size and macrocyclic nature of the crown ether additives, suggesting that, during lyophilization, 18-crown-6 protects the overall native conformation and acts as a lyoprotectant. To examine this global effect, FTIR was used to examine the effect of crown ethers on the secondary structure of enzymes. In one study [98], subtilisin Carlsberg was shown to retain its secondary structure in 1,4-dioxane when lyophi-lized in a 1 1 ratio with 18-crown-6. In addition, examination of FTIR spectra from varying incubation temperatures indicated that an increase in crown ether content in the final enzyme preparation resulted in a decreased denaturation temperature in the solvent, indicating a more flexible protein structure. 

Incompatible Mixtures. Even at very low levels, many of the poly-ether additives led to incompatible mixtures. These blends were not successfully milled to a smooth sheet under any conditions tried. Instead, a mass of crumbs was obtained. These crumbs could be molded into a coherent mass, but the physical properties were poor. For example, addition of 8.75 parts of polybutene-1 oxide to Masterbatch B for CPVC alone gave a brittle, free-flowing material with these properties notched Izod impact strength, 0.7 lb/in notch, flow rate 452 g/10 min. This is a particularly interesting result, since PBO has the same chemical formula as PTHF but structurally is a substituted ethylene oxide polymer rather than a linear homopolymer. No further studies were made of such blends. 

The reaction of diethylzine with benzaldehyde has been reported12 to be first-order in diethylzine and first-order in benzaldehyde. At the temperature of refluxing ether (presumably 35 °C) the second-order rate coefficient was found to be 1.0xlO-2 1.mole-1.min-1 in solvent ether. Addition of small quantities ( 1 mole % of the initial concentration of diethylzine) of zinc or magnesium halides considerably increased the value of the rate coefficient. 

Boron Trifluoride Diethyl Etherate. Addition of lumps of LiAlH4 to etherate-containing peroxide caused explosion.6... 

Diethyl Ether and Dimethyl Ether. Addition of ether to 50% aqueous HN03 can cause an explosion.20 A mixture of the ether, HN03, and H2S04 explodes violently.2 21 1,1-Dimethylhydrazine. Reacts vigorously with HN03.22... 

After setting up a calibration curve (r = 0.996), unknown aminosilane concentrations in toluene solvent could be quantified. The total deposited amount of APTS was calculated from analysis of the residual amount of aminosilane in the solvent. Analysis was performed after two hours of reaction and consecutive filtration under ambient atmosphere. 150 /d aliquots of the salicylic aldehyde and the diethylether were added to 10 ml samples of the filtrate. Absorbance was measured one hour after the ether addition. The calculated loading value yields the total surface loading, including chemical and physical deposition, in the loading step. 

Lithiobenzotellurophene was formed upon treatment of benzotellurophene with an equimolar amount of butyl lithium in diethyl ether. Addition of dimcthylformamide produced 2-formylbenzotellurophene. Reaction of 2-lithiobenzotellurophene with carbon dioxide yielded 2-carboxybenzotellurophene1. 

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