Showing papers on "Ether published in 1976"

Subvalent Group 4B metal alkyls and amides. Part I. The synthesis and physical properties of kinetically stable bis[bis(trimethysilyl)methyl]-germanium(II), -tin(II), and -lead(II)

Abstract: Two methods are described for the synthesis of the unusual bivalent Group 4B metal alkyls M[CH(SiMe3)2]2(M = Ge, Sn,or Pb)from Li[CH(SiMe3)2] indiethyl ether at 0 to –20°C and (a) the metal(II) chloride (M = Sn or Pb) or (b) M[N(SiMe3)2]2(M = Ge or Sn). At ambient temperature in cyclohexane or benzene the solutions are yellow (Ge), red (Sn), or purple (Pb), and the compounds are monomeric and in a singlet electronic ground state. There are colour changes between the solid and the melt, and the compounds tend to become colourless at –196 °C. The crystal structure of the tin(II) alkyl shows a centrosymmetric dimer with a Sn–Sn bond (2.76 A) similar in length to that in Sn2Ph6, and the two pairs of geminal alkyl groups in a mutually trans arrangement. The solid germanium compound is inferred to be structurally similar because of the presence of a strong polarised Raman line at 300 cm–1. The monomer is believed to be angular with three approximately sp2 hybridised orbitals at the metal, one of which is non-bonding; the dimer. with a SnSn bent double bond, is formed by overlap of the non-bonding orbital of each monomer unit with the orthogonal vacant pz orbital of the other.

Method of sizing paper

Abstract: A size mixture comprising a substituted cyclic dicarboxylic acid anhydride and polyoxyalkylene alkyl or alkyl-aryl ether or the corresponding mono- or di-ester is used to size paper products. In accordance with a preferred embodiment the liquid size mixture is added directly to the paper stock system without prior emulsification.

Metabolism of alkenebenzene derivatives in the rat. II. Eugenol and isoeugenol methyl ethers.

Abstract: 1. The metabolites of 3,4-dimethoxyallylbenzene (eugenol methyl ether) and 3,4-dimethoxypropenylbenzene (isoeugenol methyl ether) in the rat were identified and quantitatively determined by g.l.c. and g.l.c—mass spectrometry.2. The major metabolic reactions of 3,4-dimethoxyallylbenzene were oxidation of the allylic side chain to 2-hydroxy-3-(3,4-dimethoxyphenyl)-propionic acid, 3,4-dimethoxybenzoic acid and 3,4-dimethoxycinnamic acid, the two latter being largely excreted as their glycine conjugates. The formation of the hydroxy acid presumably involved epoxidation of the double bond and subsequent hydration to the diol whereas the formation of 3,4-dimethoxycinnamic acid and 3,4-dimethoxybenzoic acid involved migration of the double bond and the formation of cinnamoyl intermediates. Other reactions were O-demethylation to 4-hydroxy-3-methoxyallylbenzene (eugenol) and 3-hydroxy-4-methoxyallylbenzene in equal amounts, oxidation to l-(3,4-dimethoxyphenyl)-2-propen-l-ol, hydroxylation of the benzene ring to a...

Use of polymers as protecting groups in organic synthesis. III. Selective functionalization of polyhydroxy alcohols

Abstract: Insoluble polymers containing trityl chloride residues were used to block one primary alcohol functional group of several polyhydroxy alcohols. After protecting the remaining hydroxyl groups by benzoylation, the ether linkage between the polymer and the protected alcohol was cleaved in acidic medium. Depending on the reaction conditions and the nature of the starting alcohol, several alcohols or bromides in which only one of the two primary hydroxyls had been esterified, were obtained. In some cases benzoyl migrations were observed. The trityl chloride polymers could be regenerated in one step without degradation or appreciable loss of activity.

Solvent mediator studies on barium ion-selective electrodes based on a sensor of the tetraphenylborate salt of the barium complex of a nonylphenoxypoly-(ethyleneoxy)ethanol

Abstract: The barium ion-selective electrode sensor based on the neutral carrier complex of a nonylphenoxypoly(ethyleneoxy)ethanol containing 12 ethylene oxide units and 2 mol of tetraphenylborate ion per mole of Ba2+(12 EOU. Ba.2TPB) requires a more viscous solvent mediator than 4-nitroethylbenzene for long-life poly(vinyl chloride)(PVC) matrix-membrane barium ion-selective electrodes. Both 2-nitrophenyl octyl ether and di-2-nitrophenyl ether used in conjunction with the sensor in a PVC matrix membrane give functional barium ion-selective electrodes, but those with di-2-nitrophenyl ether mediator are far superior with lifetimes of about 30 d. Barium ion-selective electrodes with the sensor and mediator in liquid membranes can be made for a wide range of nitro-aromatic solvent mediators.Barium ion-selective electrodes made from discs taken from a master membrane containing 0.40 g of a saturated solution of Antarox CO-880. Ba.-2TPB in di-2-nitrophenyl ether can be used as indicator electrodes for the potentiometric titration of SO42– with Ba2+. A role for a potentiometric titration finish in the determination of sulphur in organic compounds by the oxygen-flask method is recommended.

Fabric conditioning compositions containing methyl cellulose ether

Abstract: Fabric conditioning compositions contain a cellulose ether having a molecular weight of from 3,000 to 10,000 and a methyl degree of substitution of from 1.8 to 2.7. The presence of the cellulose ether provides a soil release benefit to fabrics contacted with the disclosed compositions.

Structure determination of polyunsaturated fatty acids by gas chromatography-mass spectrometry-- a comparison of fragmentation patterns of various derivatives.

Abstract: GC-MS has been applied to the characterization of mixtures of polyunsaturated fatty acids by way of their isopropylidene, alkylboronate, methyl ether, and trimethylsilyl ether derivatives. In our studies we found a convenient and efficient method for the oxidation of mixtures of polyunsaturated fatty acid methyl esters by osmium tetroxide. The resulting polyhdroxy compounds are easily converted into apolar derivatives for gas chromatographic separation. The mass spectra of these individual compounds were recorded as to their usefulness for complete structure elucidation. Only the trimethylsilyl ethers proved to yield all information necessary for determination of chain length as well as numbers and positions of double bonds of polyunsaturated fatty acids.

The use of ion‐molecule reactions in the mass spectrometric location of double bonds

Abstract: A method for the location of the positions of carbon-carbon double bonds using high pressure mass spectrometry is proposed. A known olefinic molecular ion reacts with a second, unknown olefin to form a four-centre complex, which fragments with retention of the structural identity of methylene and substituted methylene groups to eliminate a new olefin molecule and to form an unsaturated ion from which the position of the double bond in the unknown olefin can be inferred. Vinyl methyl ether proved to be a convenient reagent gas and its molecular ion undergoes the required reaction with several classes of olefinic compound. Conjugated dienes and unsaturated compounds containing electronegative groups do not undergo this reaction.

Laundering of oil base mud cuttings

Abstract: A process for removing oil base mud adhering to cuttings obtained in well drilling operations, comprising contacting the cuttings with a solvent consisting essentially of a mixture of ethyleneglycol monoisobutyl ether, diethyleneglycol monobutyl ether acetate, ethyl butyl ketone, ethyleneglycol monobutyl ether, ethyleneglycol monomethyl ether acetate, diethyleneglycol diethyl ether, and diethyleneglycol mono-n-hexyl ether, together with paraffin oil, in relative proportions of from 10:90 to 80:20. This forms a mixture of oil and solvent on the cuttings which is readily removable; as by washing or centrifuging or a combination of the two.

Séparation et étude structurale des espéces moléculaires de monomycolates et de dimycolates de α-d-tréhalose présents chez Mycobacterium phlei

Abstract: Separation and Structural Studies of the Molecular Species of Monomycolates and Dinzycolates of α-d-Trehalose present in Mycobacterium phlei Mixtures of dimycolates of α-d-trehalose (cord factor) and monomycolates have been isolated from Mycobacterium phlei and separated as trimethylsilyl derivatives according to the polarity of the fatty acid residues. The free glycolipids can be recovered by mild hydrolysis. Silylation and desilylation reactions did not induce any isomerisation. The structure of these trehalose esters has been determined by using a series of reactions elaborated on synthetic acyl-sugar models. Free hydroxyl groups are transformed into tetrahydropyran ethers, deacylated by dimsyl sodium, methylated and the sugar derivatives are hydrolyzed. The O-methylsugars obtained contain a methyl ether group located at the position where the acyl group was present initially. Identification by gas chromatography of the 0-methyl-sugars thus allows the location of the fatty acid residues in the glycolipid. It has been demonstrated that no migration occurs. Two types of 6-monomycoloyl-α-d-trehalose have been isolated, differing by the nature of the mycolic acid residues. One of them, called MA, contains “α-phlei mycolic acid”. The other one, called MB, contains “α-phlei mycolic acid” which is the,ester of 2-eicosanol with the α-carboxyl function of a dicarboxylic mycolic acid. Three types of 6,6′-dimycoloyl-α-d-trehalose (cord factor) have been obtained. Two of them are symmetrical diesters, containing either two residues of mycolic acid, or two residues of α-mycolic acid. The last one is an unsymmetrical diester, the hydrolysis of which gives one mole of a-mycolic acid and one mole of α-mycolic acid. The ratio of the different diesters in the cord factor fraction might be explained by some equilibration between the different 6-ester groups or by a transformation in situ of one species into another one by biochemical modification of the mycolic acid residues

Hydrogen migrations in mass spectrometry. I—The loss of olefin from phenyl-n-propyl ether following electron impact ionization and chemical ionization

Abstract: Using specifically labelled compounds we have made a detailed study of the source of the hydrogen transferred in the elimination of C3H6 from the molecular ion of phenyln-propyl ether following electron impact ionization and from the protonated (and ethylated) molecule following chemical ionization. The migrating hydrogen originates from all three positions of the npropyl group but not in the ratio expected for randomization of the alkyl hydrogens prior to transfer. The source of the migrating hydrogen is similar for both electron impact ionization and chemical ionization, indicating that the factors governing the rearrangement are the same for both modes of ionization. From a comparison of the results for labelled 2,6-dimethyl phenyl n-propyl ethers with the results for the unsubstituted ether it is concluded that hydrogen transfer occurs only to the ether oxygen and not to the phenyl ring. A two-step mechanism involving a set of competing reversible hydrogen transfer reactions followed by CO bond cleavage is proposed to explain the results.

Process for preparing carboxylic acid anhydrides

Abstract: A carboxylic acid anhydride such as acetic anhydride, is prepared from a carboxylate ester or a hydrocarbyl ether in carbonylation processes comprising the use of a halide, carbon monoxide and a Group VIII noble metal in the presence of promoters comprising at least one metal of Groups IVB, VB, and VIB or a non-noble metal of Group VIII, or their compounds and an organo-nitrogen compound or an organo-phosphorus compound wherein the nitrogen and phosphorus are trivalent.

Complete regiospecificity in the benzylation of a cis-diol by the stannylidene procedure

Abstract: While conventional monobenzylation of benzyl 6-O-allyl-2-O-benzyl-α-D-galactopyranoside (1) gives a four component mixture, treatment of the OO′-dibutyl-stannylidene derivative of (1) with benzyl bromide provides only the 3-O-benzyl ether (2) in 66% isolated yield.

Vibration spectra and rotational isomerism of chain molecules. I. Methyl propyl ether, ethyl propyl ether, and butyl methyl ether.

Abstract: The Raman and infrared spectra of methyl propyl ether, ethyl propyl ether, and butyl methyl ether were measured for the gaseous, liquid, glassy and crystalline states. The normal vibration frequencies were calculated, a consistent set of force constants explaining the frequencies of basic aliphatic ethers being assumed. The rotational isomerism was studied and the following conclusions were obtained. (1) Only the all-trans form exists in the crystalline state. (2) Another form which takes the gauche conformation about the OC–CC axis and the trans conformation about the CC–CC and CO–CC axes exists in the glassy state. (3) Other forms also exist in the liquid state. These results confirmed that the repulsive force between nonbonded hydrogen atoms was one of the important factors influencing the stability of molecular conformations. The stable conformations of the ether molecules were correlated with those of polyether chains.

No Catalyst Copolymerization by Spontaneous Initiation Mechanism

Abstract: A new type of copolymerization is presented here, which requires no added initiator. A zwitterion 1 is generated by the interaction between two monomers; one monomer has nucleophilic reactivity (MN) and the other possesses electrophilic reactivity (ME). Two moles of the genetic zwitterion 1 react with each other to produce a dimeric zwitterion 2. The dimeric zwitterion 2 grows by its reaction with 1 to polymeric zwitterion 3. Intermolecular reaction of macro-zwitterions (dimeric 2 and polymeric 3) also occurs, which brings about a sharp increase in molecular weight. In a series of studies, six MN monomers and six ME monomers have been investigated. As the MN monomer, cyclic imino ether, exo-imino cyclic ether, azetidine, Schiff base and cyclic phosphonite have been selected. As the ME monomer, lactone, cyclic anhydride, sultone (sulfolactone), acrylic acid, acrylamide and β-hydroxyethyl acrylate have been successfully used. Thus, thirty-six combinations (six times six) of copolymerization have now become conceivable. The present paper gives a survey of elemental reactions of selected combinations of copolymerization. The emphasis is laid on the discussions of recent results.

Synthesis of spiro[isobenzofuran-1(3H),4'-piperidines] as potential central nervous system agents. 1

Abstract: Synthesis of 1'-methyl-3-phenylspiro[isobenzofuran-1(3H),4'-piperidine] (7a, HP 365) and the demethyl analogue 9a (HP 505) was prompted by recognition of an aminoalkyl(aryl)isobenzofuran moiety common to the antidepressants talopram (Lu 3-010) and trans-10,11-dihydro-5,10-epoxy-5-[3-(methylamino)propyl]-5H-dibenzo[a,d]cyclohepten-11-ol (MK-940). Convenient laboratory synthesis of 7a was provided by lithiation of 2-bromobenzhydryl methyl ether, followed by addition of 1-methyl-4-piperidone and acid-catalyzed cyclization. N-Dealkylation by standard methods afforded 9a. Synthesis of analogues was stimulated by discovery of marked inhibition of tetrabenazine-induced ptosis for lead compounds 7a and 9a. Optimal antitetrabenazine activity is associated with the 3-phenylspiro-[isobenzofuran-1(3H),4'-piperidine] moiety where nitrogen is basic. Modification of this moiety by introduction of large nitrogen substituents or a C-3 substituent greater than H significantly reduced antitetrabenazine activity. A series of analogues with aromatic substituents was investigated; however, few of these compounds were significantly more active than 7a and 9a. Compound 9a was selected for additional studies.