Sulfur-containing polymers. VII. Alternating copolydisulfides

A variety of copolydisulfides have been synthesized in high yields by the fragmentation polymerization of bis(sulfenyl thiocarbonates) with dithiols in the presence of triethylamine. The structures of the copolymers were investigated by x-ray and NMR studies. Alkylene–arylene copolydisulfides were alternating. Alkylene–arylene copolymers derived from arylene dithiols were alternating, and those prepared from alkylene dithiols were generally random. It was concluded that the present procedure makes it possible to prepare various kinds of alternating copolydisulfides by using appropriate combinations of a bis(sulfenyl thiocarbonate) and a dithiol.     

Picrylamino-substituted heterocycles. II. Furazans

This paper describes the synthesis of the various picrylamino- and nitro-substituted furazans and bifurazanyls. Except for 3,4-bis(picrylamino)furazan, which was obtained by nitrating 3,4-dianilinofurazan, the picrylaminofurazans were prepared by condensing the appropriate amino-furazan with picryl fluoride in the presence of triethylamine. The various aminofurazans were oxidized with peroxytrifluoroacetic acid to the corresponding nitro derivatives.     

Comparative gas chromatographic analysis of narcotics. II. Amphetamine sulphate.

Trace impurities in amphetamine sulphate were studied by a highly sensitive gas chromatographic method. The concentration of these impurities varied considerably between batches whereas the variations within the batches were usually very small. The method is used for the assignment of seizures of amphetamine sulphate to common sources, which in turn may permit chains of illicit distribution of this drug to be traced.     

Pseudomonas cytochrome c peroxidase. XIII. pH-denaturation of the enzyme.

The effect of pH on the oxidized Pseudomonas cytochrome c peroxidase molecule was studied by measuring the peroxidatic activity, the sedimentation velocity, the circular dichroic spectra in the far UV and Soret regions, and the optical absorption spectra of the enzyme in the pH range 2.5-13.0 at a constant ionic strength (micron = 0.1). The enzyme was stable in a narrow pH region, pH 6.0 - 7.4. In the low pH range the gross tertiary structure was observed to change quite simultaneously with the enzymatic activity and secondary structure. The optical absorption spectra indicated that there were no coordinated internal protein liqands in the 6th coordination positions of the heme prosthetic groups at the lowest pH studied. In the high pH range the secondary structure and the protein environment of hemes were observed to remain stable after the tertiary structure had changed and the activity had decreased. According to the optical absorption spectra the 6th internal protein ligands of hemes were retained at the highest pH studied.     

Comparative gas chromatographic analysis of narcotics. III. Phenmetrazine hydrochloride.

Chemical signatures of phenmetrazine hydrochloride were studied by gas chromatography. The inter-batch variations of the signatures were found to be large whereas the intra-batch variations were usually small. The method is used for the tracing of seized phenmetrazine hydrochloride samples to common sources, which in turn may permit further tracing back to chains of illicit distribution of this drug. The applicability of the method to other narcotics is also discussed.     

Chemiebücher des 18. und 19. Jahrhunderts. Für Frauen

Already in the early enlightenment a number of books on studies on nature were addressed to women. They were written in a popular manner. In consequence of the later dominating idea of gender polarity botany and chemistry were accepted as sciences suited especially for women. Women were allowed to learn natural sciences at such a level that they could be interesting partners in conversations, teachers for their children and that they could use the results in household. The revised books stress the third aim, as it is common in other popular books, too. It seems that the addressing “to women” should underline the understandability of the text and increase the chance for a successful selling of the books.     

Legionella moravica sp. Nov. and Legionella brunensis sp. Nov. Isolated from cooling-tower water

Two Legionella-like organisms were isolated from cooling-tower water samples in Czechoslovakia. They were presumptively identified as legionellae by their growth on buffered charcoal-yeast extract agar (BCYE) containing L-cysteine and their absence of growth on BCYE without L-cysteine. Both strains contained predominantly branch-chained cellular fatty acids and were therefore definitively placed in the genus Legionella. They were serologically distinct from other described Legionella species and were shown by DNA studies to constitute two new Legionella species, Legionella moravica (type strain 316-36; ATCC 43877) and Legionella brunensis (type strain 441-1; ATCC 43878).     

Carborane polymers. IV. Polysiloxanes

Carboranes attached to silicon through straight-chain alkyl groups were prepared and characterized for thermal stability by TGA and molecular weight change on heating. The monomers for these polymers were prepared generally by platinum-catalyzed addition of a silylhydride to an alkenyl or dialkenyl carborane. Polymerization was effected by hydrolysis-condensation of chlorosilanes, ring opening of cyclosiloxanes, and condensation of alkoxy and chlorosilanes. Two types of polymer structures were prepared, one contained m-carborane in the chain backbone, the other contained o-carborane as pendant alkylcarborane groups. Both types were obtained as elastomers; however, higher proportions of carborane in the polymers reduced elasticity and finally resulted in nonelastomers. TGA of the backbone carborane siloxane polymer indicated degradation at 370°C. in nitrogen and at 235°C. in air. Chain scission, as determined by molecular weight decrease, was observed on heating in nitrogen at 350°C. TGA of the pendant carborane siloxane polymer indicated that degradation in nitrogen and in air occurred at greater than 400°C. However, chain scission, as determined by molecular weight decrease, was observed upon heating at 300°C. in nitrogen.     

Heat-resistant polymers containing bipyridyl units. I. Polyimides

Polyimides containing bipyridyl units were synthesized. The bipyridyl units were successfully incorporated by polymerization of various bipyridyl diamines with aromatic tetracarboxylic acid dianhydrides. The resulting polyamic acids had inherent viscosities in the range 0.07 to 2.26, and they were converted to the polyimides by thermal cyclization. The polyimides containing the bipyridyl units exhibited varying degrees of solubility in dimethylacetamide and m-cresol and were found to be very soluble in dichloroacetic acid.     

Regular Copolyamides. IX. Some Aliphatic Aromatic Copolyoxamides

Abstract

Aromatic/aliphatic regular copolyoxamides were prepared from aromatic diamine-oxamides and aliphatic diacid chlorides of various lengths of methylene groups by solution polymerization. The aromatic diamine oxamides, N,N′-bis(4-aminophenyl)oxamide and N,N′-bis(3-aminophenyl)oxamide were prepared and both were reacted with adipoyl chloride, suberoyl chloride, and sebacoyl chloride to form six new regular copolyoxamides. The polymers formed were soluble in sulfuric acid and also in some polar amide solvents. All copolyoxamides were high melting, with the meta-phenylene copolyoxamides melting from 346 to 373°C with decreasing length of the aliphatic diacid chloride, and the para-phenylene copolyoxamides decomposing prior to melting at near 400°C. The new polymers were characterized by UV spectrophotometry, differential scanning calorimetry, and thermal gravitational analysis.     

Phospha-S-triazines. VI. Polymeric systems

Two types of polymeric phospha-s-triazines were synthesized: poly(perfluoroalkylethermonophospha-s-triazines) and monocyclic mono- and diphospha-s-triazines substituted on the carbon ring atoms by poly- (perfluoroalkylether) chains. The polymeric system consisting of the monophospha-s-triazine rings joined by perfluoroalkylether chains were found to have lower thermal oxidative stability than that shown by the corresponding dumbbell compounds. The monocyclic materials substituted by poly(perfluoroalkylether) chains possessed good thermal and oxidative stability, in addition to exhibiting anticorrosive and antioxidative properties.     

Heterocyclic compounds. VII. Synthesis of thiadiazasteroid analogs

The synthesis of a number of β-northiadiaza steroid analogs has been described. Suitable o-aminonitriles were acylated with γ-chlorobutyryl chloride. These amidonitriles were cyclized to substituted γ-lactams and subsequently to the tetracyclic products. To functionalize the “17-position” in these steroids, the intermediate γ-lactams were converted to arylidene derivatives before cyclization to the tetracyclic derivatives.     

Antiulcer agents. 2. Pyridyl oxime ethers

A large number of pyridinecarboxaldehyde (and ketone) O-substituted oximes were prepared by alkylating the oxime or by treating the parent aldehyde (or ketone) with an O-substituted hydroxylamine. Many of these were converted to the N-oxide. Screening revealed that many of these oxime ethers were active in preventing gastric ulcers in rats. Data on selected examples is given.     

Picrylamino-substituted heterocycles. IV. Pyrazoles

This paper describes the synthesis of various picryl- and picrylamino-substituted pyrazoles. These compounds were prepared by condensing the appropriate pyrazole or aminopyrazole with a picryl halide or picrylpyrazole. Some of these materials could be nitrated under carefully controlled conditions to the corresponding nitropyrazole derivatives. The products were identified by n.m.r. spectroscopy, and their crystal densities and thermal stabilities were determined. Drop-weight impact sensitivities were measured for some of the more interesting compounds.     

E.S.R. investigation of helix inversion in induced cholesteric phases

The phenomenon of a reversible helix inversion in induced cholesteric mesophases caused by variation of the temperature has been investigated by E.S.R. spectroscopy using the nitroxide radical tempone as spin probe. Chiral esters of optically active (R)-(+)-2,2'-dihydroxy-1,1'-binaphthyl were added as dopants to the nematic mixture RO-TN 404. The inversion temperatures and the handedness of the helices were determined. In addition to the distortion parameter which is a measure of the helix pitch, order parameters and rotational correlation times of the spin probe were obtained from line-shape analyses.     

An E.P.R. study of peptides after U.V. irradiation

Abstract— Various peptides of Gly, Ala, Phe, Tyr, and Trp have been irradiated with U.V. light in the solid state or in frozen aqueous solution. The radicals produced were studied by E.P.R. spectroscopy at low temperature and at room temperature. Radicals seem to occur preferentially on Gly or Ala when in the C-terminal position and there is evidence for a photosensitization of these amino acids by aromatic amino acids.     

Die Cardenolide der Samen von Mansonia altissima,A. CHEV. Glykoside und Aglykone, 286. Mitt.

The seeds of Mansonia altissima A. Chev. were found to contain ca. 1% cardiac glycosides. A total of 30 substances has been traced by paper chromatography, of which only 8 (E, K, O, P, Q, R, S, and T) were present in amounts large enough to be traced without prior enrichment of the extracts. These substances could be isolated either in pure form or as enriched mixtures. Substances E, K, O, and S were obtained in crystalline form. Apart from these substances a large amount of a mixture (N) was obtained comprising 7 components. The substances E (mansonin) and O (strophallosid) could be identified with known cardenolides. The structure of O was known; the structures of E and K (strophothevosid) are reported in the following publication. The structures of the other isolated and enriched substances (P, Q, R, S, and T) were only partially elucidated.     

Thermoplasticization of wood. I. Benzylation of wood

A study of converting wood into thermoplastic materials was undertaken to develop a new technique in effective utilization of wood wastes. Thermoplasticizatoin of wood carried out by means benzylation. Various reaction parameters, such as alkalinity of reaction media, reaction temperature, and time were taken into account to produce benzylated wood with different degrees of substitution (based on weight gain) FTIR, DSC, DMTA, SEM and x-ray crystallography were used to characterize the chemical and mechanical properties of benzylated wood. Experimental data showed that preswelling and reaction temperature had critical effects on benzylation reaction. Lignin in wood appeared to inhibit benzylation but extractives had little effect. Different species showed some variation in reaction rates. The thermoplasticized wood exhibited good melting properties and were readily molded into bulk materials or extruded into films and sheets. A wide range of glass transition temperatures from 66 to 280°C for the benezylatedwoods was achieved, and they were larely dependent on the weight gain. The molded and extruded products exhibited acceptable mechanical strength for structural engineering applications. The property and structure relationship for the thermoplasticized wood were discussed     

Triterpenoid saponins from Ilex mamillata C.Y. Wu ex C.J. Tseng

Two new triterpenoid saponins, ilemaminosides A and B (1 and 2) along with six known saponins (3-8) were isolated from 70% ethanolic extract of the leaves of Ilex mamillata C.Y. Wu ex C.J. Tseng. The new saponins were characterised as 3-O-α-L-arabinopyranosyl-ilexgenin B (1) and 3-O-β-D-glucopyranosyl-(1?→?3)-α-L-arabinopyranosyl-ilexgenin B (2). The structures of compounds 1 and 2 were elucidated on the basis of the chemical and spectroscopic methods, and the structures of known compounds were identified by comparison of their spectroscopic data with those reported in the literature. The compounds showed inhibitory activities in anti-inflammatory assay in?vitro with IC(50) values in the range 25.37-38.33?μg?mL(-1).     

Die Glykoside der Wurzeln von Kanahia laniflora (FORSSK.) R. BR. 1. Mitteilung: Isolierungen. Glykoside und Aglykone, 299. Mitteilung

The roots of Kanahia laniflora (FORSSK .) R. BR . contain, in addition to small quantities of cardenolides, a large amount of ester glycosides which are difficulty separable from one another. However, two of these ester glycosides were obtained in a nearly pure form. The crude mixture of ester glycosides, after mild acidic hydrolysis, gave a mixture of acyl-genins and three sugars: D -oleandrose, D -digitoxose and D-canarose, all of which were obtained in crystalline form. Acetic acid, benzoic acid and another unidentified acid were obtained on alkaline hydrolysis of the mixture of acyl-genins along with 17-isolineolon, lineolon, deacetylmetaplexigenin and a small amount of sarcostin-ketone. Besides these known genins, three probably new genins (α, τ, λ) were obtained in small, but crystalline amounts.