Chloroform as solvent

In conclusion, a scaleable process for the preparation of 2,4-subsituted imidazole from amidines and a-halo ketones is described. This method avoids the use of chloroform as solvent and affords the desired products in consistently good to excellent yields. 

Optically active peracids such as percamphoric acid have been used to oxidize selectively one sulphoxide enantiomer in a racemic mixture. These reactions involve the use of 0.5 molar equivalents of the peracid in either ether or chloroform as solvent. The presence of nitro groups causes the oxidant to be consumed without oxidation of the sulphoxide functionality. This method is usually used to obtain an optically active sulphoxide by recovery of the unreacted material after oxidation. 

Apparently, the microwave conditions are suitable to drive the equilibrium between the two diastereomers toward the thermodynamically more stable syn-syn isomer, which was confirmed in a separate control experiment [382]. Similar results were obtained by Holzgrabe and coworkers for related systems using chloroform as solvent under microwave conditions [383]. 

With chloroform as solvent without added co-catalyst (water being the putative cocatalyst), and with [TiClJ = (3 - 48) x 10"3 mole/1, and also with CC13C02H as cocatalyst ([TiCl4]/[CCl3C02H] 3-4, [TiClJ = (5-8) x 10 3 mole/1) Imanishi et al. [79] found that the Mayo monomer plots were linear at -20°, -50°, and -78°. The values of kjkp calculated from these are shown in Table 4. With CC13C02H as co-catalyst kjkp is almost the same as with water. ... 

Method. The corticosteroid is dissolved in 0.1 ml of dry acetone. A 0.2-ml volume of a solution of EDTN (S mg/ml in dry acetone) is added followed by 0.025 ml of 0.1 M sodium carbonate. The tube is stoppered and incubated at 45 °C for 2 h. The contents of the tube are cooled, and 2 ml of water, 0.7 g of sodium chloride and 5 ml of methylene chloride are added. The steroid derivative is extracted into the methylene chloride phase. An aliquot portion of this layer is used for TLC on plates of silica gel G with acetone-chloroform or ethyl acetate-chloroform as solvent. The composition of the solvent used is dependent on the nature of the primary alcohol. The developed plates are observed under UV light at 366 nm. The excitation and emission of the derivatives in alcohol solution occurs at 352 nm and 419 nm respectively. Amounts of less than 100 ng per spot can be detected. 

Lemieux and Brice33 have studied the rearrangement under the conditions employed by Pacsu,80 involving the use of stannic chloride as catalyst, with pure chloroform as solvent. The reaction was shown to be specific for the anomeric center, and the following observations appear to establish definitely the main features of the mechanism for this reaction. A quantitative yield of silver chloride was obtained on treating silver acetate with an excess of stannic chloride in chloroform, and it seemed probable that there results a chloroform solution of stannic chloride and stannic trichloride acetate (LVIII). The solution was able to catalyze the anomerization. 

Walker et al. [114] examined several methods and solvents for use in the extraction of petroleum hydrocarbons from estuarine water and sediments, during an in situ study of petroleum degradation in sea water. The use of hexane, benzene and chloroform as solvents is discussed and compared, and quantitative and qualitative differences were determined by analysis using low-resolution computerised mass spectrometry. Using these data, and data obtained following the total recovery of petroleum hydrocarbons, it is concluded that benzene or benzene-methanol azeotrope are the most effective solvents. 

An alternative access to L-amino acids was found by using chloroform as solvent in the asymmetric Strecker synthesis with galactosyl imines [24], This interesting reverse of asymmetric induction compared to the reactions shown in Scheme 5 can be explained by considering the zinc complex A as the crucial reactive species. Due to the exo anomeric effect, which is a delocalization of the 7r-electrons into the a of the ring C-O-bond, the imines adopt the conformation represented in Scheme 8. 

Bis[4-methoxyphenyl] Tellurium Diacetate (Chloroform as Solvent)4 5 g (14 mmol) of bis[4-methoxyphenyl] tellurium oxide are suspended in 30 ml of chloroform, 1.44 g (1.33 ml 14 mmol) of acetic anhydride is added dropwise to the stirred suspension, and, when all the tellurium oxide has dissolved, the mixture is heated under reflux for a short time. The mixture is then filtered, the filtrate is evaporated, and the residue is recrystallized from benzene/petroleum ether yield 6.4 g (100%) m.p. 136°. 

In Fig. 19 the spectra of the methyl methacrylate-styrene copolymers are shown, together with those of the homopolymers. The spectra of the homopolymers and of the copolymers from the 10 90 and 25 75 methyl methacrylate-styrene feed ratios are shown as recorded. For the other copolymers, the left-hand portion of the spectrum with the aromatic peaks is shown as recorded in carbon tetrachloride as solvent the remainder of the spectrum is shown as recorded in chloroform as solvent. 

Lyle and LaMattina selectively hydrogenated 4-substituted 2,6-dinitroanilines to the corresponding nitrophenylenediamines over 10% Pd-C in 1,2-dimethoxyethane-chloroform as solvent (eq. 9.56).135 With use of ethanol instead of 1,2-di-methoxyethane, 4-trifluoromethyl-2,6-dinitroaniline was completely hydrogenated to give the corresponding triaminobenzene. 

Figure 6 Diffusional stimulated echo attenuations of CHCl3 (x) and PSs [PS (Mw = 4000) (O), PS (Mw = 19,000) ( ), PS (Mw = 29,000) ( ) and PS (Mw = 400,000) ( )] in the PMMA gel with deuterated chloroform as solvent by varying field-gradient strength g at room temperature with the diffusing time A=40 ms.

Proton magnetic resonance (PMR) spectra were recorded on a Varian A 60A spectrometer using ordinary chloroform as solvent and tetramethylsilane as internal reference. Melting points were not corrected. 

Reductive decarboxylation has been achieved by heating the acid with LTA in chloroform as solvent and hydrogen donor. Only a moderate number of examples are known. The more facile oxidation of secondary and tertiary radicals by LTA e ectively limits the method to primary carboxylic acids. It should be noted that stoichiometric quantities of trichloromethyl radicals are generated in the course of this reaction. 

The most widely used and, presumably, the most chemoselective reagents for the epoxidation of nucleophilic C—C double bonds are the peroxycarboxylic acids (see Houben-Weyl, Vol. IV/ 1 a, p 184, Vol. Vl/3, p 385, Vol. E13/2, p 1258). Using chloroform as solvent, epoxidation rates are particularly high79. Reactive or acid/base sensitive epoxides can often be obtained with dimethyldioxirane (see Houben-Weyl, Vol. R13/2, p 1256 and references 15, 16, 87-90), peracid imides (see Houben-Weyl, Vol. IV/1 a, p 205, Vol. VI/3, p 401, Vol. E13/2, p 1276) (prepared in situ from nitriles and hydrogen peroxide), hydroperoxy acetals (see Houben-Weyl, Vol. El3/2, p 1253) or peroxycarbonic acid derivatives (see Houben-Weyl, Vol. IV/la, p 209 and references 17-19) as oxidants. For less reactive alkenes, potassium hydrogen persulfate is a readily available reagent for direct epoxidation20. 

METER SE-30 COLUMN CHLOROFORM AS SOLVENT PROGRAM I75-230 C 4 C/inln INJECTOR AND DETECTOR 300 C... 

I he imhydrotis reagent in methylene chloride or chloroform as solvent served bifll for the oxidalion of anilines to nitrobenzenes, particularly those with negative tUhiitilncnlN. In the example cited the solvent was chloroform, and the yield is... 

Polystyrene-supported tethered l-ethyl-3-(3-dimethylamino-propyl)carbodiimide hydrochloride (PS-EDC or PS-EDCI, 11) is also a commercially available, frequently used resin-supported carbodiimide [25], which is highly effective in the coupling of carboxylic acids and amines, in the absence of any additive the use of chloroform as solvent is essential. 

It was noted above that laser flash photolysis of carotene in chloroform as solvent, led to carotenoid cation radical production and a corresponding transient absorption in the infrared. However, Mortensen and Skibsted (1996b) have also shown that, in carbon tetrachloride as solvent, whilst the parent carotenoid was bleached, no infrared absorbing species arose. Possibly the neutral carotene radical (CAR ) was produced via hydrogen atom transfer ... 

Poly(3- hexylthiophene) Chemical oxidative polymerization with anhydrous FeCl3 as oxidant, 3-hexylthiophene as monomer and chloroform as solvent Methyl orange >400 [595]... 

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