Synthesis of 3-thienyl-substituted isothiazolines-2 and 1,2,4-thiadiazoles based on nitrile sulfides of the thiophene series

The reaction of substituted - and -thienylcarboxamides with chlorocarbonylsulfenyl chloride gave 5-thienylsubstituted 1,3,4-oxathiazol-2-ones. Decarboxylation of the latter by heating in o-dichlorobenzene generated in situ - and -thienylnitrile sulfides, which in the presence of dipolarophiles [dimethyl fumarate, N-phenylmaleinimide, chloro(trichloro)acetonitrile] give the corresponding 3-thienyl-substituted ²-isothiazolines and 5-chloromethyl(trichloromethyl)-1,2,4-thiadiazoles.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1892–1897, August, 1992.     

Ergebnisse dehnungskalorimetrischer Untersuchungen an einigen Poly-[α-aminosäuren]

Zusammenfassung Dehnungskalorimetrische Untersuchungen an Folien von Copolymeren ausL-Alanin undL-Cystein im Molverhältnis 973, 955 und 9010 ergaben einmal, daß im Unterschied zu homopolymerem (Ala) _n selbst bei Dehnungen bis zu 10% [(l- l _o)/l _o =0,1] kein exothermer Vorgang auftritt. Weiterhin ist der zu Beginn der Dehnung beobachtete energieelastische Vorgang praktisch vollständig reversibel, wie der beim Entlasten auftretende, dem Betrag nach gleiche exotherme Peak zeigt.Dieses vom Homopolymeren abweichende Verhalten ist anscheinend durch die Bildung interchenarer Disulfidbrücken (-S-S-) durch Oxidation von SH-(Thiol-)Gruppen in den Folien bedingt. Die entsprechenden Copolymeren, in denen die Thiolgruppen durch Carbobenzoxygruppen (-OCOCH₂C₆H₅) geschützt und daher die Bildung von-S-S-Brücken nicht möglich ist, zeigen ein dem Homopolymeren ähnliches Verhalten. Die recht unterschiedlichen Ergebnisse, die an den jeweils entsprechenden Copolymeren (-SH bzw.-S-OCOCH₂C₆H₅) erhalten wurden, können einmal sterisch und andererseits durch die unterschiedlichen zwischenmolekularen Wechselwirkungen der Seitengruppen der Comonomeren bedingt sein.Gegenüber den o. a. Polymerfolien sind die aus Poly--methyl-D-glutamat] (PMDG) wesentlich dehnbarer. Bei stufenweiser Dehnung tritt > 2.4% Dehnung außer dem anfangs beobachteten energieelastischen Peak ein exothermer Vorgang auf, dem beim Entlasten kein endothermer Prozeß entspricht. Dabei handelt es sich also um einen offensichtlich durch plastisches Fließen bedingten irreversiblen Vorgang.Bei kontinuierlicher Dehnung bis um ca. 50% wird nach dem anfänglichen endothermen Vorgang ein sehr starker exothermer Prozeß beobachtet, währenddem die Kraft praktisch konstant bleibt. Der stufenartige Verlauf des exothermen Peak deutet auf diskontinuierliche Umordnungsvorgänge im Material hin. Wie die IR-Spektren der Folien vor und nach dem Verstrecken zeigen, tritt eine Konformationsänderung dabei kaum auf. Dies ist anscheinend auf die Überstruktur der aus 1,2-Dichlorethan gegossenen Folien zurückzuführen, da hierbei die-helicalen Aggregate isoliert in einer Matrix vorliegen. Dadurch kann der für eine Konformationsumwandlung erforderliche Zug nicht auf die-Helices übertragen werden, so wie es bei Folien mit netzwerkartig angeordneten-Helices der Fall ist [4].Ähnliche Resultate wurden an Folien aus Poly-[L-leucin] und einem 11 Copolymeren ausL-Leucin undL-Methionin erhalten. Hierbei steigt allerdings die Kraft während des exothermen Vorgangs an, was darauf zurückgeführt werden kann, daß entanglements gelöst werden müssen.

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Stretching calorimetric experiments on films of copolymers ofL-alanine and L-cysteine (mole ratio 973, 955 and 9010) show that in contrast to (Ala)_n no exothermic process occurs also at (l- l _o )/l _o =0.1. Furthermore, the initially occurring energyelastic process is a practical completely reversibel one.This behaviour deviating from that of the homopolymer is probably due to the formation of interchain disulfide crosslinks (-S-S-) by oxidation of thiol (-SH) groups. The behaviour of the corresponding copolymers, in which the thiol groups are blocked by carbobenzoxy (-OCOCH₂C₆H₅) groups, is similar to that of the homopolymer. The remarkable differences in the results obtained with the corresponding copolymers containing -SH or -S-OCOCH₂C₆H₅ may be due to sterical reasons and/or to differences in the intermolecular interactions of the comonomer side-chains.Films made of poly-[-methyl-D-glutamate] (PMDG) have a much higher stretchability than that of (Ala)_n and the copolymers mentioned above. Stepwise stretching of PMDG-films at (l- l _o)/l _o above 0.024 causes-besides the initially occurring endothermic peak — an exothermic process. No corresponding endothermic peak during deloading is observed. This irreversible process obviously is caused by plastic flow of the PMDG.During continuously stretching to about (l- l _o )/l _o , 0.5 a pronounced exothermic peak at almost constant force is observed. The stepwise character of this peak suggests discontinuously changes in the order of the material.According to the IR-spectra of the films before and after stretching conformation changes of the PMDG are negligible. This is probably due to the superstructure of the films cast from 1,2-dichloroethane solution. In this case there are rodlike-helical aggregates dispersed in a low ordered matrix and therefore the stress essential for a conformation change from to is not exerted to the-helices [4] like in the case of networks built from-helices.Similar results were obtained on films made of poly-[L-leucine] and a 11 copolymer ofL- leucine andL-methionine. In this case however the force increases during the exothermic process, which may be caused by entanglements.

     

α-Cyclopropylalkyl cations of a spiro[2.4] heptane system

-Cyclopropylalkyl cations of a spiro[2.4]heptane system, which are possible intermediates in solvolytic reactions of the corresponding cyclopropylalkanol derivatives, have been generated from compounds of the spiro(indan-2,1-cyclopropane), spiro(indan-1,1-cyclo-propane), and spiro[acenaphthylene-1(2H),1-cyclopropane] classes under long life conditions (HSO{in3}F-SO{in2}FCl-CD{in2}Cl{in2}, –100 °C).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2194–2198, December, 1994.This work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-4715).     

Silicon-containing esters of α-cyanoacrylic acid: synthesis and properties

A number of cyanoacetates have been synthesized: cyanoacetoxymethyitrimethylsilane (1), cyanoacetoxymethylpentamethyldisiloxane (2), cyanoacetoxyetoxymethylpentamethyldisiloxane (3). They were converted by the Knoevenagel reaction to novel esters of a-cyanoacrylic acid (4–13) containing silicon atoms in the ester groups and having the general formula RCH=C(CN)COOCH₂X (where R=H, 4-MeOC₆H₄, MeCH=CH, 2-furyl; X=SiMe₃, SiMe₂OSiMe₃, CH₂OCH₂SiMe₂OSiMe₃). These compounds are capable of copolymerization with esters of cyanoacrylic acid which are the precursors to adhesives for cold curing.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 949–952, May, 1993.     

Preparation and reactivity of metal-containing monomers

The stability constants of some bi- and trivalent metal complexes with methyl-, trifluoromethyl-, and phenyl-substituted 6-heptene-1,3-diones have been determined by pH-metric titration at 20 °C and an ionic strength = 0.1. It is proposed that vinyl groups of ligands are involved in complexation.For Part 44 seeIzv. Akad. Nauk, Ser. Khim., 1995, 1827 [Russ. Chem. Bull., 1995,44, 1758 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2404–2408, December, 1995.This work was partially financially supported by the International Science Foundation (Grant No. NJB000).     

Determination of velocity distribution of metallic atoms in plasma devices with a rapid-frequency-scan dye laser

A rapid-frequency-scan dye laser was developed for the measurement of the velocity-distribution functions of impurity atoms sputtered due to the high-temperature plasma-surface interaction. In order to confirm the effectiveness of this rapid-scan technique, measurements of the Doppler profiles of Fe atoms sputtered by Ar ion-beam bombardment with energy 3 keV were performed. A scanning range of more than 40 pm at 300 nm was obtained with a spectral bandwidth of 1.5 2 pm and good linearity. Doppler profiles were determined in various scattering conditions, and excellent performance of this technique was demonstrated. The distortion error caused by line saturation was analytically discussed, and it is shown that the effect of this error is not so serious (less than 10%) even for highly saturated excitation.     

The geometry of intermolecular interactions in some crystalline fluorine-containing organic compounds

The propensity of C-F groups to form C-F H-C interactions with C-H groups on other molecules has been analyzed. Crystal structures of molecules containing only carbon, hydrogen, and fluorine, but no oxygen, nitrogen, or other hydrogen-bond-forming elements, were chosen for an initial study in which the intermolecular interactions in crystal-structure determinations of polycyclic aromatic hydrocarbons and their analogous fluoro derivatives were analyzed. It is found that C-F H-C interactions occur, but they are weak, as judged by the intermolecular distances and the angles involved. In a study of crystal structures of molecules containing other elements in addition to carbon, hydrogen, and fluorine, it was found that when an oxygen atom is in a neighboring position on an interacting molecule, a C-O group is more likely than a C-F group to form a linear interaction to the hydrogen atom of a C-H group. Thus, in spite of the high electronegativity of the fluorine atom, a C-F group competes unfavorably with a C-O^–, C-OH, or C=O group to form a hydrogen bond to an O-H, N-H, or C-H group. It is found, however, particularly for polycyclic aromatic hydrocarbons with substituted CF₃ groups that, in the absence of other functional groups that can form stronger interactions, C-F H-C interactions may serve to align molecules and give a different crystal packing from that in the pure hydrocarbon (where fluorine is replaced by hydrogen). Thus, C-F H-X (X = C, N, O) interactions are very weak, much weaker than C=O H-X interactions, but they cannot be ignored in predictions of modes of molecular packing in complexes and in crystals.     

A study on the doubleMannich reaction with 1,3-diphenylacetone

DoubleMannich reaction of the title compound1 with morpholine acetate in ethanol gave the symmetrical bis-base2, whereas such reaction in acetic acid afforded the vinyl-ketonic base3. Reactions of3 with morpholine, piperidine, thiophenol and dimethyl phosphite were investigated.Mannich reaction of2 with primary amines gave di-basically substituted -piperidones6a-b. Compound1 reacts with ethylenediamine and formaldehyde to give the diazatricyclic system7.

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Untersuchungen zur doppeltenMannich-Reaktion mit 1,3-Diphenylaceton

Zusammenfassung Die Doppel-Mannichreaktion der Titelverbindung1 ergab mit Morpholinacetat in Ethanol die symmetrische Bis-Base2, in Essigsäure erhielt man jedoch die Vinyl-keton-base3. Die Reaktionen von3 mit Morpholin, Piperidin, Thiophenol und Dimethylphosphit wurden untersucht. DieMannich-Reaktion von2 mit primären Aminen ergab di-basisch substituierte -piperidone6a-b. Verbindung1 reagiert mit Ethylendiamin und Formaldehyd unter Ausbildung eines Diaza-tricyclischen Systems7.

     

聚二乙烯苯型多孔吸附剂的纳米孔结构表征

采用氮气吸附法 ,研究聚二乙烯苯多孔吸附剂的纳米孔结构 .结果表明 ,以甲苯 液体石蜡 (2 :1)为致孔剂制备的聚二乙烯苯多孔吸附剂 ,其比表面和孔体积随致孔剂用量增大而增加 .在二乙烯苯总含量相当时 ,m 二乙烯苯与p 二乙烯苯等比例混合制备的吸附剂 ,具有最大的比表面和孔体积 ,而聚m 二乙烯苯吸附剂和聚p 二乙烯苯吸附剂依次下降 .中孔分布研究说明 ,各种吸附剂的中孔主要分布在 2～ 2 0nm之间 ,其中在5nm附近存在一个明显的分布峰 ,是吸附剂在制备时由于致孔剂的存在而在微核 微核之间形成的孔 .微孔分布研究发现 ,聚m 二乙烯苯吸附剂和聚p 二乙烯苯吸附剂的微孔集中分布在 0 .4～ 1.2nm之间 ,这些微孔可能是微核内部不规整聚集的高分子链之间的缝隙和紧密接触的微核之间的缝隙 .用扫描电镜观察吸附剂内部 ,显示吸附剂的确是由微核聚集形成的 ,其间存在着大小不同的纳米尺度的空隙