Showing papers on "Ether published in 1971"

Permeability of Red Cell Membranes to Small Hydrophilic and Lipophilic Solutes

Abstract: The permeability coefficients of a series of amides, ureas, and diols have been measured on red cells of man and dog using the minimum volume method of Sha'afi et al. When the molecules are grouped according to their ether-water partition coefficients, k(ether), the behavior of the hydrophilic molecules, with k(ether) less than water, is different from that of the lipophilic molecules, characterized by k(ether) greater than water. The rate of permeation of the hydrophilic molecules through an aqueous pathway is determined by the molar volume, a parameter in which the geometrical measure of molecular volume is modified by hydrogen-bonding ability. This indicates the importance of chemical interactions within the aqueous path. The permeation of the lipophilic molecules is determined in the first instance by k(ether), taken as a measure of the ease with which the molecule can escape from its aqueous environment. Within the membrane, lipophilic permeability is modified both by steric factors and by the formation of hydrogen bonds with membrane components. These data allow one to infer that lipid-soluble molecules travel through an organized structure within the lipid membrane and come into contact with polar moieties.

Synthesis of 2,2-dimethylchromens

Abstract: α,α-Dimethylpropargyl ethers of simple phenols are readily prepared in high yields. Thermal rearrangement of them affords 2,2- dimethylchromens, also in high yields. These reactions are used to prepare the natural products, ageratochromen, evodionol methyl ether, lapachenole, seselin, luvangetin, and braylin. A base-catalysed Wessely-Moser rearrangement is reported.

Steroid Trimethylsilyl Ethers. Derivative Formation for Compounds with Highly Hindered Hydroxyl Groups

Abstract: Highly hindered hydroxyl groups in steroids (17α-ol groups in steroids with a 17α, 20α, 21- or 17α,20β,21-triol structure) maybe converted to TMSi ether groups by reaction with N-trimethylsilylimidazole, alone or in combination with bis-trimethylsilylacetamide and with or without trimethylchlorosilane as a catalyst. At or above 150°C, the rates of catalyzed and non-catalyzed silylation reactions with these reagents are s imilar. This method may be used to prepare fully silylated MO-TMSi and TMSi derivatives of human steroid metabolites; the derivatives are stable, have good GC properties and show no adsorption (trailing) on column packings.

Functional fluid compositions

Abstract: A functional fluid composition consisting essentially of (1) a phosphorus compound, preferably a phosphate ester containing at least two alkyl groups such as tributyl phosphate or di-n-butyl phenyl phosphate, alone or particularly in combination with a phosphate ester containing at least two aromatic groups, such as n-butyl diphenyl phosphate or tricresyl phosphate, and (2) a polyalkylene glycol material, e. g. a polypropylene glycol ether having a molecular weight ranging from about 600 to about 1200, and particularly a combination of at least two polyalkylene glycol materials, e.g. two polypropylene glycol ethers having substantially different molecular weights.

Synthesis of diphytanyl ether analogues of phosphatidic acid and cytidine diphosphate diglyceride.

Abstract: The chemical synthesis of 2,3-di-O-phytanyl-sn-1-glycerophosphate was carried out in two ways: (a) by phosphorylation of 2,3-diphytanyl-sn-glycerol with diphenylphosphoryl chloride in pyridine, followed by catalytic hydrogenolysis of the phenyl groups; and (b) by condensation of 1-iodo-2,3-di-O-phytanyl-sn-glycerol with silver di-p-nitrobenzyl phosphate in anhydrous benzene, followed by catalytic hydrogenolysis of the p-nitrobenzyl groups. The free diether phosphatidic acid obtained was converted to the dipotassium and disodium salts. The diether phosphatidic acid was also converted to the diether analogue of cytidine diphosphate diglyceride by condensation with cytidine monophosphate morpholidate in pyridine. The physical properties of these diether analogues are described, as well as their stabilities towards acid hydrolysis.

Hydrogen Bonding in the Gas Phase: The Thermodynamic Properties of Hydrogen Fluoride-Ether Complexes and their Far Infrared Spectra

Abstract: The equilibrium constants of gas-phase complexes of HF with dimethyl, methyl ethyl and diethyl ether have been measured at several temperatures using the Benesi-Hildebrand approximation on the absorption band of the HF stretching vibration in the complex. From these, values of $\Delta $H of -43, -38 and -30 kJ mol$^{-1}$ respectively, have been determined. They are interpreted in terms of conformational rearrangements of the ethers when they form hydrogen bonds. The far infrared spectra of the complexes with both HF and DF have also been recorded and in each case a band observed at around 180 cm$^{-1}$ which is assigned to the intermolecular stretching mode of vibration. For the complex between HF and dimethyl ether a rotational contour has been observed at about 10 cm$^{-1}$.

Products formed from rhodium trichloride trihydrate and allyl alcohol or diallyl ether; the crystal and molecular structure of [Rh2Cl4(C6H11O)2],CH3OH

Abstract: The structure of the complex [Rh2Cl4(C6H11O)2],CH3OH formed from RhCl3,3H2O and allyl Alcohol is reported as well as a very efficient rhodium-catalysed cyclisation of diallyl ether.

Polyethers containing terminal amino groups

Abstract: COMPOUNDS HAVING TERMINAL AMINO GROUPS AND THE GENERAL FORMULA ((2-NH2-PHENYL)-CO-X-)N-R WHEREIN N IS AN INTEGER OF FROM 2 TO 8, X IS OXYGEN OR SULPHUR, AND R IS AN N-VALENT RADICAL OBTAINED BY THE REMOVAL OF HYDROXYL GROUPS OR MERCAPTO GROUPS FROM AN N-VALENT POLYALKYLENE ETHER POLYOL OF MOLECULAR WEIGHT 600 TO 10,000 OR FROM AN N-VALENT ALKYLENE THIOETHER POLYTHIOL OF MOLECULAR WEIGHT 600 TO 10,000. THESE COMPOUNDS ARE PREPARED BY REACTION POLYOLS WITH ISATOIC ACID, ANHYDRIDE AND ARE USEFUL IN REACTION WITH ORGANIC POLYISOCYANATES TO PREPARE ALL TYPE OF POLYURETHANE POLYMERS.

Process of drying ethers

Abstract: 1. A PROCESS COMPRISING REACTING A TERTIATY OLEFIN CONTAINING FROM FROM 4 TO 6 CARBON ATOMS WITH AN ALCOHOL CONTAINING FROM 1 TO 3 CARBON ATOMS TO FORM AN ETHER HAVING THE STRUCTURE R-O-R'' WHEREIN R IS A TERTIARY ALKYL GROUP CONTAINING 1 TO 3 CARBON ATOMS AND R'' IS AN ALKYL GROUP CONTAINING 1 TO 3 CARBON ATOMS, WASHING THE PRODUCT MIX CONTAINING SAID ETHER WITH WATER TO REMOVE UNREACTED ALCOHOL WHEREBY AN ETHER PRODUCT CONTAINING FROM 0.5 TO 2.0 VOLUME PERCENT WATER IS PRODUCED, BLENDING SAID ETHER PRODUCT WITH A COMPOSITION CONSISTING ESSENTIALLY OF ONE OR MORE PARAFFINS CONTAINING FROM 5 TO 10 CARBON ATOMS TO FORM A BLEND CONSISTING PRINCIPALLY OF THE ETHER AND THE PARAFFIN WHICH BLEND CONTAINS FROM 20 TO 90 VOLUME PERCENT ETHER, MAINTAINING SAID BLEND AT FROM 30 TO 150*F., PERMITTING SAID BLEND TO FORM TWO SEPARATE PHASES ONE OF WHICH CONSISTS ESSENTIALLY OF WATER AND THE OTHER WHICH CONSISTS ESSENTIALLY OF ETHER AND PARAFFIN FROM THE WATER AND RECOVERING A BLEND OF SAID ETHER AND SAID PARAFFIN CONTAINING A REDUCED AMOUNT OF WATER WHICH BLEND IS THEN FURTHER BLENDED WITH GASOLINE TO FORM A GASOLINE CONTAINING UP TO ABOUT 10 VOLUME PERCENT OF THE ETHER.

Crystal structures of complexes between alkali-metal salts and cyclic polyethers. Part II. Complex formed from sodium bromide and 2,3,11,12-dibenzo-1,4,7,10,13,16-hexaoxacyclo-octadeca-2,11-diene (‘di-benzo-18-crown-6’)

Abstract: Sodium bromide reacts in methanol with the cyclic ether dibenzo-18-crown-6(L) to yield crystals of formula NaBrL,2H2O. Three-dimensional X-ray crystal structure analysis has shown that there are two kinds of sodium complex in the crystal, (A) a complexed cation, and (B) a complexed ion-pair. In both, the sodium ions have a hexagonal bipyramidal environment, with six oxygen atoms from L in the equatorial plane; the apices are occupied by water molecules at 2·31 and 2·27 A in (A), while one apex is occupied by a water molecule at 2·35 A, and the other by a bromide ion at 2·82 A in (B). Hydrogen bonding involving the unco-ordinated molecule of water and the unco-ordinated bromide ion, as well as the co-ordinated water molecules and bromide ion, results in a chain parallel to the b axis of the crystal with the two complexes alternately along it. Both molecules of cyclic ether have normal bond lengths and angles and the same conformation as found previously in the (Rb0·55, Na0·45)NCS complex. Sodium–oxygen (ether) distances average 2·705 A(2·64–2·84 A) in (A), and 2·72 A(2·54–2·89 A) in (B).Two formula units, C20H24O6, NaBr, 2H2O, comprise the asymmetric unit in a monoclinic unit cell with a= 10·558, b= 14·036, c= 30·677 A, β= 91·3°, and space group P21/c. Intensities were measured with a four-circle diffractometer. Non-hydrogen atoms were located from Patterson and Fourier syntheses and their parameters were refined by full-matrix least-squares methods to a final R of 0·083 for 2880 observations.

Synthesen der stereoisomeren (±)‐γ‐Damascone

Abstract: Under the conditions of the Wharton reaction, the (±)-epoxy-γ-dihydroionones 2 and 3 are transformed into the allylic alcohols 4–10. γ-Damascols 4, 5 and 8 were oxidised to cis- and trans-γ-damascone 12 and 13. Alternatively, dehydro-γ-damascol 18 was obtained by Wittig rearrangement of butinyl ether 17, and converted into damascones 12 and 13.

Novel N-3-aminoalkyl amides, polymers thereof, and method for their preparation

Abstract: N-3-Aminoalkyl propionamides with an ether substituent on the beta carbon atom are prepared by the reaction of analogous N-3oxohydrocarbon-substituted amides with an amine in the presence of a reducing agent, preferably hydrogen and a hydrogenation catalyst. The resulting compounds can be converted to acrylamides by pyrolysis in the presence of a strong base. The latter compounds may also be prepared by the reaction of an Alpha , Beta -unsaturated amine with an acrylonitrile in the presence of sulfuric acid. They are useful for improving dyeability of fiberforming polymers and may be polymerized to form compositions which improve paper strength and (in their quaternized form) are excellent flocculants.

Reductions with Sulfurated Borohydrides. VI. The Reduction of Nitro, Nitrile, Amide, and Nitroso Groups

Abstract: Aromatic nitro compounds can be reduced with sulfurated sodium borohydride to the corresponding amine in high yields (≈80%) without affecting ester, nitrile, ether, halide or olefinic groups also p...

Intermediates in the decomposition of aliphatic diazo-compounds. Part VIII. The mechanism of ether formation from diarylmethylenes and alcohols

Abstract: The thermal decomposition of diphenyldiazomethane and its 4,4′-dichloro-, 4,4′-dimethoxy-, and 4,4′-dimethyl analogues at 85 °C in acetonitrile containing methyl and t-butyl alcohols (ca. 1M) has been studied. Kinetic studies indicate that the major reaction product, the alkyl diarylmethyl ether, is formed by attack of intermediate diarylmethylene on the alcohol. The relative reactivities of methyl and t-butyl alcohols towards the series of diarylmethylenes have been determined: methyl alcohol is the more reactive in all cases, but the difference in reactivity between the two alcohols decreases with increasing electron release by the 4-substituents. By examining the radioactivity of the product ethers formed by reaction of diarylmethylenes with hydroxyl-tritiated alcohols, substantial kinetic isotope effects on ether formation have been detected. The isotope effects are in all cases greater for formation of t-butyl ethers than for methyl ethers. The compatibility of these observations with three possible mechanisms of ether formation has been assessed, and it is concluded that the most likely route is that in which the carbene attacks the oxygen atom of the alcohol to form an ylid which is subsequently transformed by a prototropic rearrangement into the ether.

An addition compound of oxidized tocopherol and linoleic acid

Abstract: There is evidence that an addition compound of oxidizeddl-alpha-tocopherol and linoleic acid is formed when the components are absorbed in mixed monolayer on silica gel at a molecular ratio of 1∶20, and subjected to heating in air at 80C. A relatively nonpolar tocopheryl quinone is also formed in smaller amounts. These are the major tocopherol oxidation products isolated in this system and do not correspond to any known to the authors. The addition compound has about the same mobility as linoleic acid in most thin layer chromatography (TLC) and chromatographic systems, but can be isolated by successive chromatography on silica and gel filtration on Sephadex LH-20. It yields a single spot in TLC in several systems. The elemental analysis is reproducible and consistent with a simple addition compound of linoleic acid and bivalently oxidized tocopherol. The compound has a carboxyl group which can be esterified. The ester has about the same TLC mobility as methyl linoleate. The molecular weight of the ester is 722.6. The UV spectrum shows a single peak, 2 max ETOH =3000 A, E=4.74. The IR spectrum shows a very strong chroman ether band at 9.12 μ, a strong methyl band at 7.24 μ and carboxyl but no hydroxyl absorption. The NMR spectrum shows, in contrast to that of tocopherol, a reduction in aromatic methyl protons, a carboxyl proteon exchangeable with deuterium oxide, but no hydroxy proton. The compound does not reduce Emmerie-Engel reagent prior to treatment with concentrated hydriodic acid, nor do the ether-extractable products after such treatment. The present data are consistent with an addition product whose bridging group is a new chroman ring.