Structural analysis of <Emphasis Type="Italic">w</Emphasis>/<Emphasis Type="Italic">o</Emphasis>/<Emphasis Type="Italic">w</Emphasis> multiple emulsions by means of DSC

Summary The properties of the inner and the external aqueous phases, were studied in w/o/w multiple emulsions with light microscopic image analysis and differential scanning calorimetry (DSC). The importance of multiple emulsions lies in the presence of these aqueous phases, making them available for sustained, controlled drug delivery systems. Differentiation of these two aqueous phases, studying the effect of manufacturing technology on droplet structure, quantitative determination of phase volumes and any changes occurring during storage are essential when planning w/o/w emulsions. The present study uses microscopic observations combined with DSC measurements in order to identify the formed structure, at developmental stage in case of different components, preparation methods, and stirring rates. These tools are beneficial during manufacturing as in process controls, or to ensure product quality.     

Functionalization of sterically hindered <Emphasis Type="Italic">o</Emphasis>-benzoquinones: amino-substituted 3,6-di(<Emphasis Type="Italic">tert</Emphasis>-butyl)-<Emphasis Type="Italic">o</Emphasis>-benzoquinones

New sterically hindered functionalized o-quinones were synthesized by the 1,4-nucleophilic addition of secondary cyclic amines to 3,6-di(tert-butyl)-o-benzoquinone. The ability of these o-quinones to form o-semiquinone complexes with transition and main-group metals was studied by ESR spectroscopy in solution. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1786–1793, September, 2007.     

Synthesis of novel dibenzo-2,6,9-triazabicyclo[3.3.1]nonanes from <Emphasis Type="Italic">o</Emphasis>-tosylamino- and <Emphasis Type="Italic">o</Emphasis>-mesylaminobenzaldehydes

Condensation of o-tosylaminobenzaldehyde with γ-aminobutyric, 4-aminophenylthioacetic, and p-aminobenzoic acids and β-alanine gave 6,12-epimino-5,11-ditosyl-5,6,11,12-tetrahydrodibenzo[b, f]-1,5-diazocines with carboxyl-containing substituents at the bridging N atoms. The structures of three products were examined by X-ray diffraction analysis. Condensation of o-mesylaminobenzaldehyde (prepared by the McFadyen-Stevens reaction) with NH₄OAc and primary amines afforded 6,12-epimino-5,11-dimesyl-5,6,11,12-tetrahydrodibenzo[b, f]-1,5-diazocine derivatives.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2165–2171, October, 2004.     

<Emphasis Type="Italic">o</Emphasis>-Semiquinone metal complexes as derivatives of sterically hindered di-<Emphasis Type="Italic">o</Emphasis>-quinone

ESR spectroscopy was used to study a series of mono- and binuclear o-semiquinone metal complexes, viz., derivatives of sterically hindered di-o-quinone 1,2-bis(2,5-di-tert-butylcyclohexadiene-1,5-dion-3,4-yl)ethane (1). Hindered rotation was found in the o-semiquinone moiety of the generated complexes. Magnetochemical measurements for polymeric bis(o-semiquinolate)copper(II) based on di-o-quinone 1 showed two antiferromagnetic channels of interaction between the paramagnetic centers. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1580–1584, July, 2005.     

Synthesis of magnesium catecholate and <Emphasis Type="Italic">o</Emphasis>-semiquinone complexes by oxidation of the metal with 3,6-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-<Emphasis Type="Italic">o</Emphasis>-benzoquinone

Oxidation of amalgamated magnesium metal with 3,6-di-tert-butyl-o-benzoquinone (1) in different aprotic organic solvents afforded magnesium catecholate and bis-o-semiquinolate complexes. The catecholate derivatives of magnesium CatMgL₂ (Cat is the 3,6-di-tert-butyl-o-benzoquinone dianion, L = THF or Py) were synthesized in high yields in pyridine and tetrahydrofuran, respectively. The reactions in diethyl ether or dimethoxyethane produced hexacoordinated metal bis-o-semiquinolates SQ₂MgL_n (SQ is the 3,6-di-tert-butyl-o-benzoquinone radical anion, L = Et₂O, n = 2; L = DME, n = 1). The reaction with the use of toluene as the solvent gave a magnesium bis-o-semiquinolate complex containing the coordinated unreduced o-quinone molecule. The molecular structures of the [CatMgPy₂]₂ and SQ₂Mg·DME complexes were established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 92–98, January, 2007.     

Synthesis of Spiroheterocyclic Systems from Barbituric Acids and <Emphasis Type="Italic">N,N</Emphasis>-Disubstituted <Emphasis Type="Italic">o</Emphasis>-Aminobenzaldehydes

Reactions of barbituric, 1,3-dimethylbarbituric, and 2-thiobarbituric acids with 2-(1-pyrrolidinyl)benzaldehyde, its 6- and 7-membered homologs, and 4-phenylpiperazine and morpholine analogs lead to formation of fused systems with a spirocyclic 2,4,6-trioxopyrimidine fragment. The process involves intermediate formation of labile 5-arylmethylidenebarbituric acids which exhibit t-amino effect and undergo spontaneous isomerization to give the final products. The observed spirocyclizations are characterized by an anomalously high rate.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 920–925.Original Russian Text Copyright © 2005 by Krasnov, Kartsev.     

Enthalpies of mixing of <Emphasis Type="Italic">o</Emphasis>- and <Emphasis Type="Italic">m</Emphasis>-isomers at 298.15 K

Excess enthalpies (H ^E) of 17 binary mixtures of o- and m-isomers of dichlorobenzene, difluorobenzene, methoxymethylbenzene, dimethylbenzene, dimethoxybenzene, aminofluorobenzene, fluoronitrobenzene, diethylbenzene, chlorofluorobenzene, fluoroiodobenzene, bromofluorobenzene, chloromethylbenzene, fluoromethylbenzene, bromomethylbenzene, iodomethylbenzene, fluoromethoxybenzene, dibromobenzene at 298.15 K were measured. All excess enthalpies measured were very small, and those of o-+m-isomers of aminofluorobenzene, dibromobenzene and iodomethylbenzene were negative but 14 other binary mixtures of isomers were positive over the whole range of mole fractions. H ^E of o-+m-isomers of dimethoxybenzene showed the largest enthalpic instability and those of aminofluorobenzene showed the largest enthalpic stability. There was a correlation between dipole–dipole interaction, dipole–induced dipole interaction or entropies of vaporization and excess partial molar enthalpies at infinite dilution.     

Synthesis of <Emphasis Type="Italic">o</Emphasis>-Diorganylphosphino-substituted Benzoic Acids and Their Derivatives

o-Substituted dialkyl- and alkylphenylphosphinobenzoic acids, as well as their esters, nitriles, and amides, including those containing three different substituents on the phosphorus atom, were prepared for the first time by two different synthetic procedures. The most general procedure involves metal-halogen exchange in bromo- and iodoarenes, followed by phosphorylation of the resulting lithium derivatives.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 7, 2005, pp. 1122–1131.Original Russian Text Copyright © 2005 by Veits, Neganova, Vinogradova.     

Synthesis of new <Emphasis Type="Italic">N</Emphasis>-aminoglycosides based on halo-substituted <Emphasis Type="Italic">p</Emphasis>-phenylenediamines and <Emphasis Type="Italic">p</Emphasis>-aminophenols

Condensation of the monosaccharides D-glucose and D-galactose with synthesized halo-substituted p-phenylenediamines and 4-amino-2,6-dibromophenol was studied. It was found that glycosylation occurred only at the 4-amino group that was sterically unhindered by the halogen atom. The position of the aglycon in the glycoside was established by PMR spectroscopy.     

Unsteady mass transfer into a sphere under equilibrium condition <Emphasis Type="Italic">y</Emphasis> = <Emphasis Type="Italic">Ax</Emphasis> + <Emphasis Type="Italic">B</Emphasis>

We obtained an analytical solution of a problem of unsteady mass transfer under the equilibrium condition y = Ax + B to compare results with a problem solution in the case of equilibrium condition looking as y = Ax.     

Synthesis from geraniol of (2<Emphasis Type="Italic">E</Emphasis>,6<Emphasis Type="Italic">E</Emphasis>,10<Emphasis Type="Italic">E</Emphasis>,14<Emphasis Type="Italic">E</Emphasis>)-16-hydroxygeranylgeraniol and some of its derivatives

Several α,ω-bifunctional derivatives of E,E,E-geranylgeraniol were prepared via convergent synthesis starting with geraniol (8), which was converted in three steps into the tetrahydropyranyl ether of 8-chlorogeraniol (9) and 8-hydroxygeranylphenylsulfone (10). Combination of synthons 9 and 10 with subsequent reductive removal of the phenylsulfonyl group produced the tetrahydropyranyl ether of ω-hydroxygeranylgeraniol (5), hydrolysis of which gave exclusively trans-ω-hydroxygeranylgeraniol (1). Derivatives 5–7 of geranylgeraniol were synthesized using standard methods. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 231–234, May–June, 2007.     

4H-3,1-benzoxazines from <Emphasis Type="Italic">o</Emphasis>-aminoacylbenzenes

A new efficient method has been proposed for the synthesis of 4H-3,1-benzoxazines from 2-aminoacylbenzenes. This reaction sequence may be used either for 2-aminoaryl alkyl ketones or 2-aminobenzophenones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 941–954, June, 2007.     

Synthesis of mixed-ligand alkali earth element dipivaloylmethanates with <Emphasis Type="Italic">o</Emphasis>-phenanthroline

A one-step method for the synthesis of volatile barium and strontium complexes [M(Thd)₂(Phen)₂] (M = Ba, Sr; Thd is the dipivaloylmethane anion) was developed. The method is based on the reaction of metal hydroxide octahydrates with dipivaloylmethane (HThd) and o-phenanthroline (Phen) accompanied by removal of water from the reaction mixture as a solvent-water azeotrope. In the case of calcium hydroxide monohydrate, a similar interaction causes destruction of the dipivaloylmethanate ligand to give a mixed-ligand calcium complex with the pivalate anion and o-phenanthroline.     

Stereochemical Features of the Condensation of Lithiated (<Emphasis Type="Italic">S</Emphasis>)-<Emphasis Type="Italic">N,N</Emphasis>-Dimethyl-1-phenylethylamine with <Emphasis Type="Italic">o</Emphasis>-Methoxybenzophenones

The condensation of lithiated (S)-N,N-dimethyl-1-phenylethylamine with o-methoxybenzophenones occurs in a nonstereoselective fashion due to possible coordination of lithium not only at the carbonyl group but also at the oxygen atom of the ortho-methoxy group.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 567–570.Original Russian Text Copyright © 2005 by Dem’yanovich, Shishkina, Gritsyuk, Potekhin, Chesnova, Ashkinadze.     

Kinetic Isotope Effect in the Photoreduction of <Emphasis Type="Italic">o</Emphasis>-Benzoquinones in the Presence of <Emphasis Type="Italic">N,N</Emphasis>-Dimethylaniline

The kinetics of photoinduced reduction of a series of 3,5- and 3,6-di-tert-butylbenzoquinones-1,2 was studied in the presence of N,N-dimethylaniline, its deuterated analog, and a series of para-substituted N, N-dimethylanilines. On passing from the endothermic to the exothermic range of the free energy of electron transfer ΔG _e , the effective rate constants k _H and k _D and the quantum yields ϕ_H and ϕ_D of the reaction varied nonmonotonically with a maximum at ΔG _e of approximately +0.1 eV. For the reactant pairs relevant to the ascending (left-hand) branch of the plot k _H = f(ΔG _e ), the H/D isotope effect takes place, varying from two to five in magnitude. For the reactant pairs at the maximum and in the descending (right-hand) branch of the plot k _H = f(ΔG _e ), there is no isotope effect or its value is insignificant.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 348–352.Original Russian Text Copyright © 2005 by Abakumov, Shurygina, Chesnokov, Druzhkov, Lopatin, Chechet, Cherkasov.