Glycols medium

A water-soluble phosphine derivative of diazepam allows for more convenient parenteral tranquilizer therapy and avoids some complications due to blood pressure lowering caused by the propylene glycol medium otherwise required for administration. Fosazepam (82) is prepared from benzodiazepine by sodium hydride-mediated alkylation with chioromethyldimethyl phosphine... 

Propylene glycol Medium-chain monoglycerides Polysorbate 20 (Tween 20)... 

Tipranavir/ Aptivus / Boehringer Ingelheim/ HIV Protease inhibitor OH / 1 II CFg 500 mg b.i.d. Soft gelatin capsule 250 mg Ethanol (7% w/w) Cremophor EL Propylene glycol Medium chain mono- and diglycerides 2-8°C, or at room temperature for <2 months... 

Alkaline hydrolysis of 1,2,4,5-tetrachlorobenzene is carried out at a temperature of not less than 160°C in aqueous solution or in a solution of alcohol of low carbon atom number alcohol solution under pressure, or at normal pressure in glycol medium of high boiling point. In the latter case, 2,4,5-trichlorophenol glycolether is formed as a by-product ... 

Illanes A, Wilson L, Raiman L (1999) Design of immobilized enzyme reactors for the continuous production of fructose syrup from whey permeate. Bioproc Eng 21 509-515 Illanes A, Wilson L, TomaseUo G (2000) Temperature optimization for reactor operation with chitin-immobiUzed lactase under modulated inactivation. Enzyme Microb Technol 27 270-278 Illanes A, Anjari S, Altamirano C et al. (2004) Optimization of cephalexin synthesis with immobilized penicillin acylase in ethylene glycol medium at low temperatures. J Mol Catal B Enzym 30 95-103... 

Illanes A, Anjarf S, Altamirano C et al. (2004) Optimization of cephalexin synthesis with immobihzed penicillin acylase in ethylene glycol medium at low temperatures. J Mol Catal B Enzym... 

In most of the emulsions, surfactants alone are not able to sufficiently reduce the interfacial tension between oil and water. Cosurfactants further reduce the interfacial tension and increase the fluidity of the interfacial film. The use of cosurfactants imparts sufficient flexibility to the interfacial film to take up different curvatures, which may be required to form microemulsion over a wide range of proportions of the components. The main role of cosurfactant is to destroy liquid crystalline or gel structures that form in place of a microemulsion phase. Typically used cosurfactants are short chain alcohols (C3-C8), glycols such as propylene glycol, medium chain alcohols, amines, or acids. - Cosurfactants are mainly used in microemulsion formulation for the following reasons ... 

Turov, V.V, Gorbik, P.P., Ogenko, V.M., Shulga, O.V., and Chuiko, A.A. 2001. Characteristic properties of metal-semiconductor phase transitions of vanadium dioxide in a polyethylene glycol medium containing tetraethylammonium bromide. Colloids Surf. A Physicochem. Eng. Aspects 178 105-112. 

In situ synchrotron X-ray diffraction has been used to investigate the crystallization of MeAPO-5 (Me Co, Mn) from the ethylene glycol medium (142). The results indicate a significant change in the nucleation mechanism when the synthesis is performed in ethylene glycol in comparison to the crystallization in... 

S. Chandrasekhar, V. Patro, G. P. K. Reddy, R. Gree, Tetrahedron Lett. 2012, 53, 6223-6225. A hgand-free copper(II)-catalyzed three-component reaction in poly(ethylene glycol) medium a versatile protocol for the preparation of selected 3-indole derivatives. 

Getsova M, Todorovsky D, Enchev V, Wawer I (2007) Cerium(III/IV) and cerium(IV)-titanium(IV) citric complexes prepared in ethylene glycol medium. Monat Chem 138 389 01... 

Di-alkyl ethers of ethylene glycol, ROCHjCHjOR. The dimethyl ether, b.p. 85°/760 mm., is miscible with water, is a good solvent for organic compounds, and is an excellent inert reaction medium. The diethyl ether (diethyl cdloaolve), b.p. 121-57760 mm., is partially miscible with water (21 per cent, at 20°). 

Hydrogenations with coppcr-chromium oxide catalyst are usually carried out in the liquid phase in stainless steel autoclaves at pressures up to 5000-6000 lb. per square inch. A solvent is not usually necessary for hydrogenation of an ester at 250° since the original ester and the alcohol or glycol produced serve as the reaction medium. However, when dealing with small quantities and also at temperatures below 200° a solvent is desirable this may be methyl alcohol, ethyi alcohol, dioxan or methylcyc/ohexane. 

Another method for the hydroxylation of the etliylenic linkage consists in treatment of the alkene with osmium tetroxide in an inert solvent (ether or dioxan) at room temperature for several days an osmic ester is formed which either precipitates from the reaction mixture or may be isolated by evaporation of the solvent. Hydrolysis of the osmic ester in a reducing medium (in the presence of alkaline formaldehyde or of aqueous-alcoholic sodium sulphite) gives the 1 2-glycol and osmium. The glycol has the cis structure it is probably derived from the cyclic osmic ester ... 

The achiral triene chain of (a//-rrans-)-3-demethyl-famesic ester as well as its (6-cis-)-isoiner cyclize in the presence of acids to give the decalol derivative with four chirai centres whose relative configuration is well defined (P.A. Stadler, 1957 A. Escherunoser, 1959 W.S. Johnson, 1968, 1976). A monocyclic diene is formed as an intermediate (G. Stork, 1955). With more complicated 1,5-polyenes, such as squalene, oily mixtures of various cycliz-ation products are obtained. The 18,19-glycol of squalene 2,3-oxide, however, cyclized in modest yield with picric acid catalysis to give a complex tetracyclic natural product with nine chiral centres. Picric acid acts as a protic acid of medium strength whose conjugated base is non-nucleophilic. Such acids activate oxygen functions selectively (K.B. Sharpless, 1970). 

Acetals andKetals. Acetals of 1,3-diols are prepared by refluxing the diol with the aldehyde in the presence of an acid catalyst, even in an aqueous medium. The corresponding ketals are more difficult to prepare in aqueous solution, but cycHc ketals of neopentyl glycol, eg, 2-butyl-2-ethyl-5,5-dimethyl-l,3-dioxane (3), can be prepared if the water of reaction is removed azeotropicaHy (34). 

Resorcinol carboxylation with carbon dioxide leads to a mixture of 2,4-dihydroxyben2oic acid [89-86-1] (26) and 2,6-dihydroxyben2oic acid [303-07-1] (27) (116). The condensation of resorcinol with chloroform under basic conditions, in the presence of cyclodextrins, leads exclusively to 2,4-dihydroxyben2aldehyde [95-01-2] (28) (117). Finally, the synthesis of l,3-bis(2-hydroxyethoxy)ben2ene [102-40-9] (29) has been described with ethylene glycol carbonate in basic medium (118), in the presence of phosphines (119). Ethylene oxide, instead of ethyl glycol carbonate, can also be used (120). 

The most suitable oxidizing agent is potassium ferricyanide, but ferric chloride, hydrogen peroxide ia the presence of ferrous salts, ammonium persulfate, lead dioxide, lead tetraacetate or chromate, or silver and cupric salts may be useful. Water mixed, eg, with methanol, dimethylformamide, or glycol ethers, is employed as reaction medium. 

Medium Boiling Esters. Esterificatioa of ethyl and propyl alcohols, ethylene glycol, and glycerol with various acids, eg, chloro- or bromoacetic, or pymvic, by the use of a third component such as bensene, toluene, hexane, cyclohexane, or carbon tetrachloride to remove the water produced is quite common. Bensene has been used as a co-solvent ia the preparatioa of methyl pymvate from pymvic acid (101). The preparatioa of ethyl lactate is described as an example of the general procedure (102). A mixture of 1 mol 80% lactic acid and 2.3 mol 95% ethyl alcohol is added to a volume of benzene equal to half that of the alcohol (ca 43 mL), and the resulting mixture is refluxed for several hours. When distilled, the overhead condensate separates iato layers. The lower layer is extracted to recover the benzene and alcohol, and the water is discarded. The upper layer is returned to the column for reflux. After all the water is removed from the reaction mixture, the excess of alcohol and benzene is removed by distillation, and the ester is fractionated to isolate the pure ester. 

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

It I. becomes too long, consider using glycol/water mixture or another heat medium liquid and raise the bath temperature above ]9U l i... 

Lead tetraacetate and periodic acid complement one another in their applicability as reagents for glycol cleavage. The water sensitive lead tetraacetate is used in organic solvents, while periodic acid can be used for cleavage of water-soluble diols in aqueous medium. 

Epoxidation of the olefin, 36, affords 40. Solvolysis of the latter in dry formic acid gives a mixture of the desired product, 42 (both a and 3 hydroxyl at 15), as well as a mixture of the glycols (41). Solvolytic recycling of the mixture in the same medium affords eventually about a 45% yield of the product. 

Medium MW hydrocarbons Mineral oil absorbers Amines, glycols... 

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