Dynamic shear modulus in the splitting region of poly(alkyl methacrylates)

A systematic study of the dynamic shear modulusG ^*=G+G in three poly(alkyl methacrylates) (PEMA, PnPMA, PnBMA) at frequencies between 0.001 and 500 rad/s is presented. As the splitting frequencies _s are low, aging effects can be observed in the splitting region. There is a systematic shift of the splitting frequency _s to lower values with increasing length of the alkyl side group. In PnBMA a separate shear appearance is observed about two frequency decades below the local mode . This is discussed in terms of the concept of minimal cooperativity. Aging effects are: Shift of the maximum loss frequency to lower values, peak sharpening of the relaxation, and intensity changes of and . These effects are discussed in terms of the sequential aging concept. Aging leads to a pronounced bending of the traces upwards from the equilibrium line in the Arrhenius diagram. These non-equilibrium phenomena are promoted by the small slope m=d(log )/dT of the trace in the splitting region.Dedicated to Prof. E. W. Fischer at the occasion of his 65th Birthday Lieber Herr Fischer, die Hallenser Polymerphysiker danken Ihnen aufrichtig für die warmherzige und effektive Förderung der Polymerwissenschaften im Raum Halle-Merseburg.     

Aminoalkylation of sulfazone

2-(-Acetamidobenzil)sulfazone and 2-benzalsulfazone were obtained by reacting 3-ketothiamorpholine dioxide (sulfazone) with benzylidenebisacetamide in boiling acetic acid. The double bond in 2-benzalsulfazone can add alcohols (methanol, ethanol) to give correspondingly 2-(-methoxybenzil)- and 2-(-ethoxybenzil) sulfazone. Reaction of sulfazone with benzylidenebisurea in boiling acetic acid gave 2-(-ureidobenzyl)sulfazone.     

Synthesis of acetals of purin-9-ylpropionaldehydes and purin-9-yl-α-aminobutyric acids

6-Chloro-, 6-mercapto-, 6-methylthio-, and 6-amino-9-(3,3-diethoxypropyl)purines, -(6-mercaptopurin-9-yl)--aminobutyric acid, and -(6-methylthiopurin-9-yl)--aminobutyric acid have been synthesized.     

Investigations in the field of lipids

Summary 1. The synthesis of the following neutral plasmalogens has been effected: -O-(octadec-1-enyl)-, distearoylglycerol, -O-(octadec-1-enyl)-, -dipalmitoylglycerol, -O-(hexadec-1-enyl)-, -distearoylglycerol, and -O-(pentadec-1-enyl)-, -dipalmitoylglycerol.2. During the synthesis, the following compounds were isolated and characterized by their physicochemical constants: the -octadec-1-enyl ether of glycerol, -(2-hydroxyoctadecyl) , -isopropylideneglyceryl ether, the tosylate of -(2-hydroxyoctadecyl) , -isopropylideneglyceryl ether, and -O-(2-tosyloxyoctadecyl) glycerol.3. The IR spectra of the -octadec-1-enyl ether of glycerol and the neutral plasmalogens have been studied.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 6, pp. 367–371, 1966     

Borylation of o-Hydroxyphenyl phosphorus derivatives

The reactions of isobutyl diphenylborate with 0,0-diethyl o-hydroxyphenylphosphonate and o-hydroxyphenylphosphine gave 5,6-benzo-2-phenyl-4-ethoxy-4-oxo 1,3,2,4-dioxaboraphosphorinane and o-diphenylboryloxyphenylphosphine, respectively. The borylation only at the-hydroxyalkyl fragments of bis(,,-trichloro--hydroxyethyl)(o-hydroxyphenyl)phosphine and the conversion of the o-boryloxyphenyl phosphorus derivative to an-boryloxyalkyl derivative upon the action of chloral indicates the greater stability of compounds with the P-C-O-B fragment than that for compounds with the P-C-C-O-B fragment.The data of the x-ray diffraction structural analysis will be published later.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 477–482, February, 1991.     

Steroid compounds from the starfish Lysastrosoma anthosticta collected in the Sea of Japan

Six polyhydroxylated steroids and their derivatives were isolated from the starfish Lysastrosoma anthosticta collected in the Posyet Bay, Sea of Japan. These include a new glycoside of the steroid polyol, lysastroside A (1), which was identified as (25S)-26-O--d-xylopyranosyl-5-cholestane-3,6,8,15,16,26-hexaol, and the previously known pycnopodioside C monoglycoside (2), marthasterone sulfate (3), (25S)-5-cholestane-3,6,8,15,16,26-hexaol (4), (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (5), and (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (6). The compounds were tested for the haemolytic activity and the action on the embryogenesis of the sea urchin Strongylocentrotus intermedius.     

Formation constants and thermodynamic parameters of α-pyridoin thiosemicarbazones with divalent metal ions

The proton–ligand stability constants of -pyridoin thiosemicarbazone, -pyridoin 2–methylthiosemicarbazone, -pyridoin 4–methylthiosemicarbazone and -pyridoin (4–phenylthiosemicarbazone) as well as the formation constants of their chelates with CuII, NiII, CoII, ZnII and MnII have been determined. The Calvin–Bjerrum pH titration techniques, as modified by Irving and Rossotti, were employed in aqueous media at different ionic strengths and temperatures. The stability constants of the complexes follow the order: CuII > NiII > CoII > ZnII >MnII which is in accord with the Irving–Williams series. The chelates derived from -pyridoin 4–phenylthiosemicarbazone have relatively higher stability constants, which may be attributed to the presence of the benzene ring in the chain.     

Study of the Three-component Reaction of α-Nitrocarbonyl Compounds, Aromatic Aldehydes, and Cyanothioacetamide

The reaction of benzaldehyde, -nitro ketone, and cyanothioacetamide in the presence of morpholine has given the novel 3,4-trans-2-R-5-cyano-2-hydroxy-3-nitro-4-phenyl-1,2,3,4-tetrahydropyridine-6-thiolates. It was found that the reaction occurs via the formation of 1-amino-2-cyano-4-nitro-5-oxo-3-phenyl-1,2-pentene-1-thiolate. In the case of -nitroacetophenone, 3,4-trans-4,5-trans-5-cyano-2-hydroxy-3-nitro-2,4-diphenylhexahydropyridine-6(1H)-thione was also obtained. The use of -nitroesters in place of the nitro ketones in the reaction leads to morpholinium 2-aryl-1-carbethoxy-3-cyano-1-nitro-3-thiocarbamoylpropyl-1-ates as the single product.     

Polyhydroxysteroids from the Far-Eastern starfishCtenodiscus crispatus

Four new polyhydroxysteroids, 5-cholesta-3,5,6,15,16,25,26-heptaol, 24-ethyl-5-cholesta-3,5,6,15,28,29-heptaol-29-sulfate, (22E)-24-methyl-5-cholest-22-ene-3,5,6,15,25,26-hexaol-26-sulfate, 24-propyl-5-cholesta-3,5,6,8,15,28,29-heptaol, and the known 5-cholesta-3,5,6,15,16,26-hexaol, have been isolated from the starfishCtenodiscus crispatus.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1821–1825, October, 1994.     

Transformed steroids. 121. Synthesis of the δ-lactone of 3β-acetoxy-16α-hydroxy-6-oxo-24-nor-5α-chol-17(20)-en-23-oic acid

The synthesis of the ¹⁷⁽²⁰⁾-16 analog of natural chiogralactone is described. Attempts to introduce a 6-oxo group directly into the -lactone proved unsuccessful, since the first stage — saponification — took place with the formation of three products: the 3-hydroxy--lactone, the 3-hydroxy-²⁰⁽²²⁾-lactone, and the 15,17(20)-dienoic acid. The synthesis of the desired compound was effected from the ethyl ester of the 5,16-dienoic acid by the scheme 3-acetate3-tosylate6-hydroxy-3,5-cyclosteroid6-oxo-3,5-cyclosteroid6-oxo-5H--lactone. It has been shown that the cyclopropane ring in the 3,5-cyclosteroid -lactone is extremely stable under the conditions of acid treatments.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 184–187, March–April, 1981.     

Prostanoids: LXXVII. Synthetic Approaches to Sterically Overcrowded Cyclopentenones

Condensation of (±)-5-allyl-2,3,5-trichloro-4,4-dimethoxy-2-cyclopentenone with phenylethynylmagnesium bromide in THF gave (±)-5-allyl-2,3,5-trichloro-4,4-dimethoxy-1-phenylethynyl-2-cyclopenten-1-ol which chemoselectively reacted with ozone at the terminal double bond, affording (±)-2,3,5-trichloro-5-formylmethyl-4,4-dimethoxy-1-phenylethynyl-2-cyclopenten-1-ol. Oxidation of the latter with H₂CrO₄ yielded a mixture of the expected product, (±)-5-carboxymethyl-2,3,5-trichloro-4,4-dimethoxy-1-phenylethynyl-2-cyclopenten-1-ol, and anomalous profound oxidation product, (±)-2,3,5-trichloro-5-carboxymethyl-4,4-dimethoxy-1-(2-oxo-2-phenylacetyl)-2-cyclopenten-1-ol. Attempts to remove protective methoxy groups in these compounds under standard conditions were unsuccessful.     

Synthesis and Investigation of Ring-chain Isomerism of the Derivatives of N-Amino-5-hydroxy-1,2,3-triazole-4-carboxylic Acid

A series of sodium salts of 4-substituted 1-amino-5-hydroxy-1,2,3-triazoles was obtained by the diazo transfer reaction to arylmethylene-protected -ethoxycarbonyl- and -(methylcarbamoyl)-acetohydrazides. In DMSO solution the corresponding neutral hydroxytriazoles exist in equilibrium with the isomeric diazo compounds with an open chain. Electron-donating substituents stabilize the cyclic form. A good correlation was obtained between the equilibrium constants and the Hammett -constants. During the diazotization of benzaldehyde -amino--cyanoacetylhydrazone the initially formed diazo compound undergoes spontaneous cyclization in solution to hydroxytriazole. Removal of the arylmethylene protection leads to N-unsubstituted sodium salts of 1-amino-5-hydroxytriazoles, but acidification of the latter leads to diazoacetohydrazides with an open chain.     

Neue (Hetero-)Triarylmethan-Derivate

The following groups of title substances according to general formula I where prepared: substituted , -diphenyl-2-thenyl-derivatives (mainly of heterocyclic secondary amines), chlorinated -phenyl--(2-thienyl)-4-pyridinemethanoles and substituted (mainly chlorinated) tri- and tetraphenylmethanes.     

Triterpene glycosides ofCauliphyllum robustum. The structures of caulosides B and C

Summary Two triterpene glycosides — caulosides b and c — have been isolated from a methanolic extract of the leaves ofCaulophyllum robustum maxim. Cauloside b has been identified as hederagenin 3--L-rhamnopyranosyl-(12)--L-arabinopyranoside, while cauloside c has the structure of hederagenin 3-0--L-arabinopyranosyl(13)--L-pyranosyl-(12)--L-arabinopyranoside.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center of the Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 174–176, March–April, 1979.     

Synthesis of potential antagonists to amino acids in the quinoline series

The following potential antagonists to amino acids were synthesized: -(6-quinolyl)--alanine, -(8-quinolyl)--alanine, and -(2-phenyl-4-carboxy-6-quinolyl)--alanine.     

Synthesis and Dehydrohalogenation of 3 β-Chloro-5 α,7 α-dibromo-6-ketosteroids of the Stigmastane and Cholestane Series

3-Chloro-5,7-dibromo-6-ketosteroids 5a and 5b are synthesized from -sitosterol (1a) and cholesterol (1b). Dehydrohalogenation of these forms 7-bromo-2,4-dien-6-ones (6a-b), 2,4-dien-6-ones (7a-b), and 14-hydroperoxy-2,4,7-trien-6-ones (8a-b). Woodward hydroxylation of dienone 6a produces 2-iodo-7-bromo-3-acetoxy-⁴-6-ketone 9 and 7-bromo-2,3-diacetoxy-⁴-6-ketone 10. 2-Iodo-3-acetoxy-^4,7,14-trien-6-one 11 is prepared analogously from trienone 8a.     

Steroid compounds of marine sponges. VII. Preparation of derivatives of sokotrasterol and halistanol sulfates and structure-activity interrelationships among these compounds

Five new sulfated derivatives of sokotrasterol and halistanol have been obtained: 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate); 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate) 23-palmitate; 24,25-dimethyl-5-cholestane-2,3,6-triol 3-(sodium sulfate); 24,25-dimethyl-5-cholestane-2,3,6-triol 6-(sodium sulfate); and 24,25-dimethyl-5-cholestane-2,3,6-triol 2,6-di(sodium sulfate). The inhibiting and membranolytic properties of the polysulfated steroids from sponges and their derivatives have been studied. It has been shown that physiological activity in this series of compounds depends on biphilicity.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 441–445, July–August, 1986.     

Synthesis and transformations of the 20-substituted derivatives of 16α,17α-epoxy-5α-pregnane-3Β,21-diol-20-ones

A new and more effective sequence of reactions is proposed for the production of 16,17-isopropylidenedioxy-5-pregnane-3,21-diol-20-one. It uses methods previously unused for 5-H-steroids and involves 21-hydroxylation of 16,17-epoxy-5-pregnan-3-ol-20-one with diacetoxyiodobenzene and cis-opening of the obtained 21-hydroxy-16,17-epoxy-5-pregnane-3,21-diol-20-one by acetic acid in the presence of epoxycarbonylhydrazine, followed by condensation of the obtained product with acetone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1185–1188, May, 1991.     

Synthesis of macrocyclic compounds that are condensed with a pyrazole ring

2-Carbethoxy-[11]--cyclothien-1-one, 2-carbethoxycyclopentadecanone, and 2,15-dicarbethoxy-[9,9]--cyclodithiene-1,14-dione were converted to 2-phenyl-1-methyl-[11]--cyclothieno [1,2-d] pyrazol-3-one, 2-phenyl-1-methyl-4,5-tridecamethylenepyrazol-3-one, and 2,16-diphenyl-1, 15-dimethyl- [9,9]-, -cyclodithienobis [(1,2-d, 14,15-d) pyrazole]-3,17-dione, respectively, by condensation with phenylhydrazine and subsequent methylation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 920–923, July, 1980.     

Formation of Supramolecular Polymers Constructed by Cyclodextrins with Cinnamamide

-Cyclodextrin having cinnamamide at 6- or 3-positions (6-CiNH--CD, 3-CiNH--CD) and -cyclodextrin with cinnamamide on 6-position (6-CiNH--CD) have been prepared. Supramolecular structures were formed in the solid state or aqueous solutions and characterized by measurements of NMR and vapor pressure osmometry (VPO). The results indicate that 6-CiNH--CD formed insoluble supramolecular polymers in the solid state, while 6-CiNH--CD and 3-CiNH--CD formed supramolecular complexes in aqueous solutions. 6-CiNH--CD was found to form a dimer in an aqueous solution. 3-CiNH--CD formed intermolecular complexes to give supramolecular polymers. The differences of the position of guest part on cyclodextrins caused to give a variety of supramolecular structures in aqueous solutions.