1.2- Dimethoxyethane, as solvent for

Although not so generally applicable for the preparation of dicyclopentadienyl metal compounds as the sodium cyclopenta-dienide method, the amine procedure represents the simplest preparation of ferrocene. The amine procedure can also be employed for dicyclopentadienylnickel (about 80% yield), using nickel bromide obtained by the action of bromine on nickel metal powder and 1,2-dimethoxyethane as the solvent. The method of preparation given here is a modified version of that originally described. ... 

In another experiment we tested the utility of 1,2-dimethoxyethane as a solvent for the reaction. The results obtained in this experiment revealed that the coal polyanion was formed to the same extent as in tetrahydrofuran. In addition, the alkylation of the polyanion with butyl mesylate gave the same quantity of soluble product in 1,2-dimethoxy-ethane as it did in tetrahydrofuran. Hence both solvents are equally useful for the alkylation reaction. 

In their paper on the preparation of trimethylsilyl enol ethers, House et al. [1] illustrate the generation of lithium enolates with the reaction between 2-methylcyclohexanone and LDA using 1,2-dimethoxyethane as a solvent. The authors do not indicate a temperature range for the lithiation of the ketone, but we found the deprotonation of a variety of ketones to proceed extremely fast and with excellent results at temperatures in the region of — 70 °C. In view of the possibility of aldol condensation, dropwise addition of the ketone to the LDA solution seems advisable. Attempts to prepare enolates from aldehydes RCH2CH=0 and LDA gave, after quenching with trimethylchlorosilane, only unidentified resinous products. 

Preparation.— Two procedures for the production of ethers from alky] halides have been mentioned earlier in this Report. From a study of fluoride salts on alumina as reagents for the alkylation of phenols and alcohols, potassium or caesium fluoride on alumina, in acetonitrile or 1,2-dimethoxyethane as the solvent, has been found to be the best combination for general use. A recently reported one-pot synthesis of phenyl ethers from phenol acetates involves their treatment, in solution in acetone, first with potassium carbonate and then with an alkyl halide. Another interesting new procedure for the alkylation of phenols utilizes the gas-liquid phase-transfer catalysis technique that was discussed above. In this case a phenol (or a thiophenol) and an alkyl halide, both gaseous, are passed through a bed of solid K2CO3 (or NaHCOs) at 170°C in the presence of a PEG e,g. Carbowax 6000) as the catalyst. ... 

The Suzuki reaction has been successfully used to introduce new C - C bonds into 2-pyridones [75,83,84]. The use of microwave irradiation in transition-metal-catalyzed transformations is reported to decrease reaction times [52]. Still, there is, to our knowledge, only one example where a microwave-assisted Suzuki reaction has been performed on a quinolin-2(lH)-one or any other 2-pyridone containing heterocycle. Glasnov et al. described a Suzuki reaction of 4-chloro-quinolin-2(lff)-one with phenylboronic acid in presence of a palladium-catalyst under microwave irradiation (Scheme 13) [53]. After screening different conditions to improve the conversion and isolated yield of the desired aryl substituted quinolin-2( lff)-one 47, they found that a combination of palladium acetate and triphenylphosphine as catalyst (0.5 mol %), a 3 1 mixture of 1,2-dimethoxyethane (DME) and water as solvent, triethyl-amine as base, and irradiation for 30 min at 150 °C gave the best result. Crucial for the reaction was the temperature and the amount of water in the... 

Using a soliddiquid two-phase system of the sodium arenesulphinite in 1,2-dimethoxyethane, or in the complete absence of a solvent, permits the use of less reactive haloalkanes [3,4], This is a particularly good method for the preparation of sulphones where the sulphinic acid salts are readily available and, in addition to the synthesis of the tolyl sulphones listed in Table 4.28, it has been used to prepare phenyl sulphones [3]. Phenyl sulphones have also been prepared in good yield using a polymer supported catalyst [5] (Table 4.29). As the system is not poisoned by iodide ions, reactive iodoalkanes can be used and there is the additional advantages in the ease of isolation of the product and the re-use of the catalyst. 

By media variables we mean the solvent, electrolyte, and electrodes employed in electrochemical generation of excited states. The roles which these play in the emissive process have not been sufficiently investigated. The combination of A vV-dimethylformamide, or acetonitrile, tetra-n-butylammonium perchlorate and platinum have been most commonly reported because they have been found empirically to function well. Despite various inadequacies of these systems, however, relatively little has been done to find and develop improved conditions under which emission could be seen and studied. Electrochemiluminescence emission has also been observed in dimethyl sulfite, propylene carbonate, 1,2-dimethoxyethane, trimethylacetonitrile, and benzonitrile.17 Recently the last of these has proven very useful for stabilizing the rubrene cation radical.65,66 Other electrolytes that have been tried are tetraethylam-monium bromide and perchlorate1 and tetra-n-butylammonium bromide and iodide.5 Emission has also been observed with gold,4 mercury,5 and transparent tin oxide electrodes,9 but few studies have yet been made1 as to the effects of electrode construction and orientation on the emission character. 

Among various candidates, 1,2-dimethoxyethane (DME) in toluene was found to be the best promoter providing the cycloaddition products in high yields, but required a higher pressure of CO (7 atm). Water was less efficient under the same conditions, but provided the comparable yield at higher concentrations. Nevertheless, use of DME as the solvent instead is detrimental to the reaction under the conditions. Once again, one should notice that there must be a competition between the demetallation from the alkyne-cobalt complex and the catalytic cycle for the PKR products. 

Usually, after an enolate ion is generated from an a,p-unsaturated ketone, it is converted to the p-alkylated product as shown above. But it is often possible to have the enolate react with some other electrophile (tandem vicinal difunctionalization), in some cases at the O and in other cases at the C.483 For example, if an alkyl halide R X is present (R" = primary alkyl or allylic), and the solvent is 1,2-dimethoxyethane, the enolate 57 can be alkylated... 

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