Synthesis and molecular structure of 2,4,8a-triaryl-6-methylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines

Condensation of arylboronic acids with 4-hydroxy-3-(-hydroxybenzyl)-1-methyl-4-phenylpiperidine afforded 2,4,8a-triarylperhydro[1,3,2]dioxaborinino[5,4-c]pyridines. The molecular structure of 6-methyl-2,4,8a-triphenylperhydro[1,3,2]dioxaborinino[5,4-c]pyridine was established by X-ray diffraction analysis.     

[f]-Fused purine-2,6-diones: Synthesis of new [1,3,5]- and [1,3,6]-thiadiazepino-[3,2-f]-purine ring systems

Summary 6-Phenyl-1,3-dimethyl-2,4-dioxo-1,2,3,4,8,9-hexahydro-[1,3,5]-thiadiazepino-[3,2-f]-purine (5) was obtained by a three-step synthesis from 8-mercapto-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione (1) and 2-(benzoylamino)-ethyl chloride (2)via 8-(benzoylaminoethylthio)-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione (3) and its chloromido derivative4. The analogous 9-phenyl-1,3-dimethyl-2,4-dioxo-1,2,3,4,6,7-hexahydro-[1,3,6]-thiadiazepino-[3,2-f]-purine (7) was synthesized either from compound1 and N-(2-chloroethyl)-benzimido chloridevia N-(chloroethyl)-S-(1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydro-7H-purin-8-yl)-benzothioimide (6), or alternatively from 7-(2-benzoylaminoethyl)-8-bromo-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione (9), its 8-mercapto derivative10 and the corresponding chloroimido compound11 being the intermediates.Part of this paper was presented as a preliminary report at the Congress of Czech and Slovak Chemical Societies, Olomouc, Czech Republic, September 13–16, 1993     

Spectrophotometric study of the supramolecular complexes of [60]- and [70]Fullerenes with biscalix[6]arene and crown[4]calix[6]arene

[60]- and [70]Fullerenes have been shown to form 1:1 supramolecular complexes with bis[2-(5,11,17,23,29,35-hexa-tert-butyl-37,38,39,40,41-pentahydroxycalix[6]arenyl-oxy ethyl ether) (1) and 5,11,17,23,29,35-hexa-tert-butyl-37,38,40,41-tetra hydroxyl-39,42-(crown-4)calix[6]arene (2) in CHCl3 medium by electronic absorption spectroscopy. Formation constants (K) of the complexes of [60]- and [70]fullerenes with 1 and 2 have been determined at room temperature from which free energy of formation values of the complexes have been estimated. The very high formation constant value of [60]fullerene/1 complex (5900 dm3 mol-1) in indicative of formation of inclusion complex. Moreover, PM3 calculations reveal that intermolecular interaction between [60]fullerene and 1 proceeds through quite deep energy molecular orbital.     

Electrochemical behavior of benzo[b][1,6]naphthyridine derivatives

The electroreduction of benzo[b][1,6]naphthyridine derivatives in anhydrous media by the polarographic method was studied. It is found that the first step of the process is the transfer of an electron to position 10 of the molecule, which is consistent with the addition of nucleophilic reagents to this particular position of the tricyclic system in question.     

Synthesen von 4-Amino-thieno[2,3—b]pyridinen

The Cyclization of 2-(1,1-dicyanovinylamino)-thiophenes2 by treatment with AlCl₃ yield 4-amino-5-cyano-thieno[2,3-b]pyridines3. 2-(1-acylvinyl-amino)-3-cyano-thiophenes7, obtainable from 2-amino-3-cyano-thiophenes and -diketones, react in the presence of AlCl₃ to form 4-acylamino-thieno[2,3-b] pyridines8. This reaction is connected with the transfer of the acyl group from C- to the N-atom. 4-Amino-5-cyano-thieno[2,3-b]pyridones-(6)11 are synthesized from 2-amino-3-cyano-thiophenes and ethyl cyano acetate in the presence of sodium ethoxide.

     

Studies on Thiazolopyridines. Part 3: Reactivity of Thiazolo[3,2- a ]-3-aza[1,8]naphthyridine Towards Some Nucleophiles

A variety of new thiazolo[3,2- a ]pyridine derivatives 2a-h having 3-indolyl group were produced by refluxing 1a with different benzylidenemalononitrile derivatives. Reactivity of compound 4 toward some nitrogen nuclcophiles was investigated. Thus, the novel pyrazoles 6a , b were obtained when compound 4 was allowed to react with hydrazine and phenyl hydrazine in ethanol under reflux. On the other hand, pyrazolo[3',4':4,5]thiazolo[3,2- a ]-3-aza[1,8]naphthyridine 8 was formed by condensation of compound 4 with benzoyl hydrazine. Finally, condensed heterocyclic compounds containing pyran rings 9 and 10 were obtained by treatment compound 4 with active ethylene compounds.     

Reactions of [60]fullerene with 2-azidopyrimidines

The reaction of [60]fullerene with 2-azidopyrimidines affords fullerenoimidazopyrimidines, whose electron affinity is higher than that of nonmodified C₆₀.     

Conformational rigidity and flexibility of the paracyclophane skeleton in substituted [2.2]paracyclophanes

The character of distortions of the paracyclophane skeleton in various substituted [2.2]paracyclophanes was analyzed based on X ray diffraction data. The rigidity of the skeleton is provided by ethylene bridges and flexibility of the benzene rings, which adopt a boat conformation. The flexibility of the skeleton is manifested in the displacement of the benzene rings with respect to each other and conformational changes of ethylene bridges. The changes in these characteristics are very sensitive to intra- and intermolecular steric factors and are indicative of the absence of strong specific stacking interactions between the be nzene rings. Precision X-ray diffraction study and quantum-chemical calculations for unsubstituted [2.2]paracyclophane and 4,7-benzoquinono[2.2]paracyclophane demonstrated that there are no attractive interactions between the benzene rings, and the electron density is localized predominantly on the outer surface of the rings. This fact can be considered as the cage molecular effect of the [2.2]paracyclophane skeleton.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1707–1732, September, 2004.     

Notiz zur [1,2]-Heterorest-Verschiebung in einem Sulfinamidin

Reaction of methyl 1-pyrroline-2-carboxylate (3 a) with N,N-Ditosylsulphur-diimide affords the pyrrol-2-carboxylic acid derivative7. The sulfenamide function in7 is cleaved by trimethyl phosphite leading to8. Presumably the reaction sequence (3 a 7) takes its course via the sulfinamidine4 a and the rearrangement product5 a followed by elimination of tosylamide. An analogous reaction starting with the dimethyl-1-pyrrolin-2-carboxylate3 b yields the stable sulfinamidine4 b, which undergoes a rearrangement reaction with base producing6 b with the thioaminal5 b as the intermediate.

Herrn Prof. Dr. Dr. h. c.K. Kratzl zum 70. Geburtstag herzlich gewidmet.     

Ringsubstituierte [1]titanocenophane

The ring-substituted bis(cyclopentadienyl)silanesMe ₂Si(C₅H₅) (MeC₅H₄) (1a) andMe ₂Si(MeC₅H₄)₂ (2a) could be prepared by the reactions ofMe ₂SiCl₂ with C₅H₅Na andMeC₅H₄Na or only withMeC₅H₄Na, respectively. Metallation of1 a or2 a withn-BuLi and following reaction with TiCl₄ led to the first ringsubstituted [1]titanocenophanes,Me ₂Si(C₅H₄) (MeC₅H₃)TiCl₂ (1 b) orMe ₂Si(MeC₅H₃)₂ TiCl₂ (2 b), respectively. On reaction with NaI,1 b yieldedMe ₂Si(C₅H₄) (MeC₅H₃)TiI₂ (1 c). Structural assignments of the compounds could be made on the basis of their¹H NMR spectra.

     

TheSemmler-Wolff aromatization andSchmidt reaction applied to some pyrido[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]benzotriazines

Pyrido[2,3:3,4]pyrazolo[5,1-c][1,2,4]benzotriazin-4(1H)ones were transformed via their oximes in aSemmler-Wolff aromatization process in the tetracyclic heteroaromatic amines4 or bySchmidt reaction into a mixture of the same amine4 and a ring enlarged lactam3. Syntheses of some halo pyrazolo[3,4-b]pyridines and a photochemical transformation of 3-azidopyrazolo[3,4-b]pyridine are also described.

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Über dieSemmler-Wolff- undSchmidt-Reaktion einiger Pyrido[2,3:3,4]pyrazolo[5,1-c][1,2,4]benzotriazine

Zusammenfassung Pyrido[23:3,4]pyrazolo[5,1-c][1,2,4]benzotriazin-4(1H)one werden über Oxime in einerSemmler-Wolff-Reaktion in die tetracyklischen aromatischen Amine4 umgewandelt. In einerSchmidt-Reaktion wurden dieselben Ketone in ein Gemisch aus Amin4 und Lactam3 übergeführt. Synthesen von halogensubstituierten Pyrazolo[3,4-b]pyridinen und photochemische Umwandlung von 3-Azidopyrazolo[3,4-b]pyridin werden beschrieben.

     

磺化杯[4]芳烃与双正电荷季铵盐的键合作用

采用核磁波谱和等温微量热滴定等手段研究了磺化杯[4]芳烃与3个双正电荷季铵盐相互作用的键合比、 键合模式以及热力学参数. 结果表明, 磺化杯[4]芳烃与3个双正电荷季铵盐以不同的键合模式形成1: 1络合物, 其键合常数均超过10⁵ L/mol, 键合作用主要由焓变驱动, 同时伴随着微弱的正负熵变.     

Synthesis and transformations of 1,3,5-triazabicyclo[3.1.0]hexanes

The conditions for the condensation of 1,2-nonsubstituted diaziridines with CH₂O and NH₃ (or AlkNH₂) to the corresponding 1,3,5-triazabicyclo[3.1.0]hexanes have been found and 3-phenylsulfonyl, 3-trimethylsilyl, 3-nitroso, and 3-nitro derivatives of the latter have been obtained.For the previous communication, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2091–2095, December, 1993.     

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.

     

New Facile Route to Synthesize Furo[3,2-e][1,2,4]triazolo[4,3-c]pyrimidine and Furo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine Derivatives

A new facile route for synthesis of 3-(aryl)-8,9-diphenylfuro[3,2-e][1,2,4]triazolo pyrimidines derivative from the same starting material, 2-amino-4,5-diphenylfuran-3-carbonitrile, has been developed through heterocyclization of the corresponding arylidene-hydrazono-5,6-diphenylfuro[2,3-d]pyrimidine and N-(arylmethylene)-4-imino-5,6-diphenylfuro[2,3-d]pyrimidin-3(4H)-amine under refluxing condition with acetic anhydride followed by air oxidation. The products were obtained in good yield with an easy workup along with the purification of products by a nonchromatographic method. This general synthetic procedure can be extended to the preparation of a wide range of isomeric triazoles using 2-amino 3-carbonitrile bifunctional derivatives.     

Synthesis of 8-tert-Butyl-9-oxo-1,2,4-triazolo[4,5-b]-1,2,4-triazolo[3,4-c]-1,2,4-triazine

8-tert-Butyl-9-oxo-1,2,4-triazolo[4,5-b]-1,2,4-triazolo[3,4-c]-1,2,4-triazine has been synthesized by the interaction of 6-tert-butyl-3-hydrazino-1,2,4-triazolo[3,4-c]-1,2,4-triazin-5-one with formic acid. The conditions of carrying out the reaction are discussed. Spectral characteristics are given.