Dichloromethane and tetrahydrofuran

Figure 5.17 Stability of optical encoding towards oligonucleotide reagents. Organosilica microspheres covalently labelled with ATTO 550 dye are stable towards each of the reagents used in phosphoramidite oligonucleotide synthesis. In contrast, optically encoded polystyrene-divinylbenzene (DVB) beads are unstable in most steps, in particular those involving dichloromethane and tetrahydrofuran. (Reproduced from ref. 28, with permission.)...

In acetonitrile, the ionic and covalent forms coexist in a clean equilibrium. This compound is the first hydrocarbon that only exists covalently in solution [292], In acetone, dichloromethane, and tetrahydrofuran, a radical, derived from Kuhn s anion by singleelectron transfer (SET), was detected in addition to the two ionic species. Thus, all three types of elementary organic species (ion, radical, and a covalent compound) are shown to be able to coexist in a solution equihbrium, depending on the solvent used [292]. For reviews on solvent-dependent equilibria, including radical pairs (produced by bond heterolysis) and radical ion pairs (produced by electron transfer), see references [291, 400, 401]. 

As chloroplatinic acid is an excellent catalyst, only a small quantity is necessary, usually in the range of 10 mol/mol of hydrosilane. In some cases, as little as 10 mol/mol of reactant has been successfully used . Solvents are not usually employed, but sometimes benzene, toluene, xylene, chloroform, dichloromethane, and tetrahydrofuran have been used. ... 

PPN] [FeRu3H(CO)i3] is an air-stable, black, crystalline solid. It is insoluble in nonpolar organic solvents such as hexane and soluble in polar organic solvents such as diethyl ether, dichloromethane, and tetrahydrofuran. Solutions of [PPN] [FeRu3H(CO)i3] are stable in air for several weeks. The compound is best characterized by its IR spectrum, which shows the following bands in dichloromethane solution 2073 (w), 2032 (s), 2013 (s), 1998 (s), 1970 (sh), 1940 (sh), 1844 (w), 1809 (br) cm"1. The H nmr spectrum at -80° in acetone-of6 exhibits a single resonance at 5 = -15.6 ppm.12 The crystal structure of the compound as determined by a neutron diffraction study has also been reported.12... 

One such example is 2-methyl tetrahydrofuran. As a solvent, it possesses similar characteristics to the widely used dichloromethane and tetrahydrofuran solvents, but... 

Polythiophene is readily produced by inserting a working electrode, counterelectrode, and reference electrode into a nonaqueous electrolyte in which 0.1 to 1.0 M thiophene is dissolved and then increasing the cell potential to greater than 1.6 V (versus SCE). Salts such as lithium or tetrabutylammonium perchlorate, hexafluo-rophosphate, or trifluoromethylsulfonate are typical electrolytes. Acetonitrile, ben-zonitrile, dichloromethane, and tetrahydrofuran are suitable solvents. As previously discussed for polypyrrole, polythiophene has been prepared in aqueous solutions [247]. A conductive, electroactive poly thiophene film was polymerized from a phosphoric acid-water-thiophene system using mild electrochemical polymerization conditions. 

Solubility soluble in dichloromethane and tetrahydrofuran, low solubility in hexanes. 

The aprotic solvents most commonly used for nucleophilic substitution reactions are given in Table 9.4. Of these, dimethyl sulfoxide (DMSO), acetonitrile, N,N-dimethylformamide (DMF), and acetone are classified as polar aprotic solvents. Dichloromethane and tetrahydrofuran (TFIF) are moderately polar aprotic solvents. Diethyl ether, toluene, and hexane are classified as nonpolar aprotic solvents. 

Materials. Poly(ethylene glycol) diisocyanate with PEG molecular weight 3,400 and M /M = 1.03 was obtained from Shearwater Polymers and was stored at -10°C under nitrogen atmosphere prior to use. Triethylamine, 3,5-dihydroxybenzylalcohol, 18-crown-6 and l,l,l-tris(4-hydroxyphenyl) ethane -all from Aldrich a- bromo-p-tolunitrile, LiAlH4 and K2CO3 from ACROS (Fisher Scientific), were used without further purification. Dichloromethane and tetrahydrofuran (THF) were dried over P2O5 and benzophenone-sodium, respectively, and distilled immediately before use. 

Iron(III) iodide [15600-49-4], Fefy, is prepared by the oxidative photodecarbonylation of diiodotetracarbonylkon(II) ki the presence of dkodine (7). The black soHd obtained is extremely hygroscopic, spariagly soluble only ki dichloromethane, and decomposes to kon(II) iodide and dkodine when exposed to donor solvents such as tetrahydrofuran, acetonitrile, water, or pyridine. It also decomposes when exposed to light. 

Dilongifolyl borane [77882-24-7] M 422.6, m 169-172 . Wash with dry Et20 and dry in a vacuum under N2. It has m 160-161 in a sealed evacuated capillary. It is sparingly soluble in pentane, tetrahydrofuran, carbon tetrachloride, dichloromethane, and chloroform but the suspended material is capable of causing asymmetric hydroboration. Disappearance of solid indicates that the reaction has proceeded. [J Org Chem 46 2988 1981.]... 

Linear non-cross-linked polystyrene has been used for organic synthesis since it is readily soluble in common organic solvents (i.e., dichloromethane, chloroform, tetrahydrofuran, toluene, ethyl acetate, and pyridine) but precipitates upon addition of water or methanol [123-126]. However, no examples of the use of this polymer in conjunction with microwave chemistry have been reported. 

General Considerations. The following chemicals were commercially available and used as received 3,3,3-Triphenylpropionic acid (Acros), 1.0 M LiAlH4 in tetrahydrofuran (THF) (Aldrich), pyridinium dichromate (Acros), 2,6 di-tert-butylpyridine (Acros), dichlorodimethylsilane (Acros), tetraethyl orthosilicate (Aldrich), 3-aminopropyltrimethoxy silane (Aldrich), hexamethyldisilazane (Aldrich), tetrakis (diethylamino) titanium (Aldrich), trimethyl silyl chloride (Aldrich), terephthaloyl chloride (Acros), anhydrous toluene (Acros), and n-butyllithium in hexanes (Aldrich). Anhydrous ether, anhydrous THF, anhydrous dichloromethane, and anhydrous hexanes were obtained from a packed bed solvent purification system utilizing columns of copper oxide catalyst and alumina (ether, hexanes) or dual alumina columns (tetrahydrofuran, dichloromethane) (9). Tetramethylcyclopentadiene (Aldrich) was distilled over sodium metal prior to use. p-Aminophenyltrimethoxysilane (Gelest) was purified by recrystallization from methanol. Anhydrous methanol (Acros) was... 

C. Methyl 3,3-dimethyl-4-oxobutanoate (3). A 50-mL flask, connected to a gas bubbler and equipped with a magnetic stirring bar, is charged with 20 mL of dichloromethane (or tetrahydrofuran), 2.16 g (10.0 mmol) of siloxycyclopropane 2 and 3.64 g (30.0 mmol) of triethylamine hydrofluoride (NEt3-HF) prepared in situ (Note 15). This mixture is stirred for 1 hr at room temperature (Note 16) and diluted with 20 mL of water. The aqueous phase is extracted with three 20-mL portions of dichloromethane. The combined organic phases are dried with magnesium sulfate, filtered, and concentrated on a rotary evaporator (bath temperature below 40°C). Crude product 3 is distilled with a Kugelrohr oven (oven temperature 105°C, 10 mm) to provide 1.26 g (87%) of pure 3 as a colorless liquid (Note 17). 

A total of 10.0 g (8.9 mmol) SASRIN resin2 (note 1) was washed with N,N-dimethyIfonnamide (DMF 2 x 25 mL), methanol (MeOH 2 x 25 mL), and dichloromethane (DCM note 2 2 x 25 mL), and dried under vacuum (0.5 torr) at 70°C overnight. To a suspension of the dried SASRIN resin in lOOmL of methyl sulfoxide (DMSO note 2) and 25 mL of DCM was added 12.4 mL (89 mmol, 10.0 Eq.) triethylamine (note 2) followed by 7.1 g (44.5 mmol, 5.0 Eq.) sulfur trioxide-pyridine complex (note 2). The suspension was shaken on a radial arm at room temperature overnight (note 3) filtered on a glass frit and washed with DCM (3 x 100mL), DMSO (3 x lOOmL), DCM (3 x lOOmL), and tetrahydrofuran (THF 3 x 100 mL) and dried under vacuum (0.5 torr) at room temperature to give 10.0 g Ameba resin (notes 4 and 5). 

Diphenyl telluropyran-4-one (typicalprocedure)7° 120 mL (0.12 mol) of a 1.0 M solution of lithium triethylborohydride in tetrahydrofuran are added to 7.65 g (60 mmol) of powdered tellurium under nitrogen, and the mixture stirred at 20°C for 4 h. A solution of sodium ethoxide (prepared from 5.52 g (0.24 mol) of sodium and 240 mL of absolute alcohol) is added to the dilithium telluride, 13.8 g (60 mmol) of bis(phenylethynyl) ketone are dissolved in a mixture of 150 mL of tetrahydrofuran and 150 mL of 1 M sodium ethoxide in ethanol this solution is poured as quickly as possible into the deep-purple-coloured dilithium telluride soluhon. The flask containing the reaction mixture is immediately placed in a water bath at 50°C and the temperature slowly increased over 30 min until ethanol begins to condense on the side of the flask. The water bath is removed and the mixture is stirred overnight at 20°C. Dichloromethane (400 mL) is then added, the resultant mixture is washed with 800 mL of water, and the organic phase is separated and concentrated to an oil. The oil is dissolved in 600 mL of dichloromethane, and the solution is filtered through a pad of sand. The filtrate is washed with 200 mL of 2% aqueous sodium chloride soluhon, dried with anhydrous sodium sulphate, filtered and evaporated. The brownish solid residue is triturated with 20 mL of butanenitrile and the fine yellow solid is collected by filtration yield 10.9 g (51%) m.p. 126-129°C (from acetonitrile). 

Carotenoids A large number of solvents have been used for extraction of carotenoids from vegetables matrices, such as acetone, tetrahydrofuran, n-hexane, pentane, ethanol, methanol, chloroform [427-431], or solvent mixtures such as dichloromethane/methanol, tetrahydrofuran/methanol, -hexane/acetone, or toluene or ethyl acetate [424,432-435], SPE has been used as an additional purification step by some authors [422,426], Supercritical fluid extraction (SEE) has been widely used, as an alternative method, also adding CO2 modifiers (such as methanol, ethanol, -hexane, water, methylene chloride) to increase extraction efficiency [436-438], In addition, saponification can be carried out, but a loss of the total carotenoid content has been observed and, furthermore, direct solvent extraction has been proved to be a valid alternative [439],... 

Tetracarbonylfoctahydrotriborato(l-)] manganese is an air-sensitive liquid that decomposes slowly (about 5% in 4 days) at room temperature as a neat liquid in a vacuum. It is soluble in benzene, toluene, dichloromethane, diethyl ether, and tetrahydrofuran (THE), but decomposes upon heating at reflux in these solvents (especially in THF). Gas-phase thermal decarbonylation or solution photodecarbonylation of (CO)4Mn(B3H8) yields the novel and reactive compound (CO)3Mn(B3H8), in which the octahydrotriborate(l-) ligand is tridentate.3... 

Pentafluorophenyl)(tetrahydrothiophene)gold(I) is a white crystalline solid, which is air and moisture stable at room temperature. It decomposes before melting (109 °C). It is very soluble in acetone, benzene, dichloromethane, diethyl ether, nitromethane, and tetrahydrofuran, soluble in ethanol and methanol, and insoluble in hexane. 

These solvents include tetrahydrofuran (THF), 1,4-dioxane, chloroform, dichloromethane, and chlorobenzene. The relatively broad solubility characteristics of PSF have been key in the development of solution-based hollow-fiber spinning processes in the manufacture of polysulfone asymmetric membranes (see Hollow-fibermembranes). The solvent list for PES and PPSF is short because of the propensity of these polymers to undergo solvent-induced crystallization in many solvents. When the PES structure contains a small proportion of a second bisphenol comonomer, as in the case of RADEL A (Amoco Corp.) polyethersulfone, solution stability is much improved over that of PES homopolymer. 

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