The study of the structure of solutions of the H-complexes of diesters of tetracarboxylic acids with diamines by light scattering

The parameters of the hypermolecular orientation order in H-complexes of the dimethyl ester of 3,3,4,4-benzophenonetetracarboxylic acid with 1,6-hexamethylenediamine (BPE · HMDA) and 4,4-diaminodiphenylmethane (BPE · DADPM) in methanol and aqueous methanol have been investigated using the angular dependences of the isotropic and anisotropic components of scattered light. The radii of the inertias of the fluctuation domains and the factors of the orientation order of their scattering elements were determined. A model for the structure of the solutions of the complexes considered is presented. The experimental values of optical anisotropy have been compared with those calculated by the valence-optical scheme. The inversion of the calculated and experimental values of optical anisotropy is explained by the nature of the bonds fixing the ester and diamines in both complexes.For part 2, seeRuss. Chem. Bull, 1994,43, 1153.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1596–1599, September, 1994.     

Polyimides from complexes of benzophenonetetracarboxylic acid diesters with diamines. 5. Mechanism of thermal cyclization of H-complexes

The results of a study, by thermal mass spectrometric analysis and NMR spectroscopy, of the polycondensation of H-complexes are presented from which it is possible to propose a mechanism for the reaction. It is shown that conversion of the H-complexes into polyimides takes place through the formation of intermediate zwitterions with an amino acid bond after initial separation of methanol, following which elimination of water commences in one stage to form an imide ring. The role of theortho position of the functional groups in the acid ester during the formation of the hydrogen bond is discussed.Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004 St. Petersburg. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2517–2524, November, 1992.     

Investigation of polyimide formation from the complexes of the diester of benzophenonetetracarboxylic acid with diamines 7. Role of theo-carboxylic group of acid diester in the formation and imidization of H-complexes

The kinetics of thermal imidization of various H-complexes of semiesters of bis(o-phthalic) acids with diamines was studied. The activation energy of the imidization was shown to increase with increasing pK_a value of the diamine andE _a value of the dianhydride and with decreasing nucleophilicity of the alcohol used for the synthesis of H-complexes. The experimental kinetic data and the results of quantum chemical calculations of the heats of formation of the initial H-complexes and transition states made it possible to propose a mechanism for the imidization reaction. This mechanism takes into account the catalytic effect of the carboxylic group of the semiester in theo-position with respect to the ester group.For report 6, seeIzv. Akad. Nauk, Ser. Khim., 1993, 300 [Russ. Chem. Bull., 1993,42, 255 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1060–1065, June, 1995.     

Zur Chemie des „Dinaphthyldichinhydron”

Dinaphthyldiquinhydrone (4) first obtained byStenhouse andGroves ² reacts as well as 4,4-bi-(1,2-naphthoquinone)¹ with aniline and substituted anilines to give anilinoquinones2 a-h. However, yields of2 are considerable higher if4 is used. The IR-Spectrum of4 is very similar to that of 2,11-dihydroxy-3,10-perylenquinone, therefore we suggest for4 a the structure of a 3,3-dihydroxy-4,4-dioxo-1,1, 4,4-tetrahydro-1,1-binaphthylidene, at least in the solid state.

Herrn Prof. Dr.G. Zigeuner in traditionsverbundener Freundschaft zum 60. Geburtstag gewidmet.     

Charge-transfer complexes betweenp-toluidine and iodine in solution: A kinetic study

The kinetics of charge-transfer interaction betweenp-toluidine and iodine in methylene chloride was investigated in depth. Thethermal process of formation of theinner complex was found to proceed to an equilibrium. Thephotochemical process follows a different reaction coordinate, going through the formation of an exciplex between the excitedouter complex and the amine ground state. In both cases the same ionic complex (Am ₂I⁺I ₃ ^– , whereAm stands forp-toluidine) was detected as the final product.

---

Kinetische Untersuchung der Charge-Transfer-Komplexe zwischenp-Toluidin und Jod

Zusammenfassung Die Kinetik der Charge-Transfer-Wechselwirkung zwischenp-Toluidin und Jod in Methylenchlorid wurde ausführlich untersucht. Derthermische Prozeß, der zur Bildung desinner-Komplexes führt, geht bis zu einem Gleichgewicht. Derphotochemische Prozeß folgt einer unterschiedlichen Reaktionskoordinate und verläuft über die Bildung eines Exziplexes zwischen dem angeregtenouter-Komplex und dem Amin im Grundzustand. In beiden Fällen wurde derselbe ionische Komplex (Am ₂I⁺I ₃ ^– , wobeiAm fürp-Toluidin steht) als Endprodukt festgestellt.

     

Convergent synthesis of 2′,3′-dideoxy-3′-mercapto nucleosides — Potential anti-HIV agents

Summary Methyl 3-benzoylthio-5-O-tert-butyldiphenylsilyl-2,3-dideoxy--D-erythro-pentofuranoside (4) and its corresponding anomer5 were synthesized in four steps from 2-deoxy-D-ribose and used as substrates for the synthesis of nucleosides by condensation with silylated thymidine and N⁶-isobutyryladenine. The nucleosides were deprotected by treatment with Bu₄NF inTHF followed by reaction with MeONa in MeOH to give 3-deoxy-3-mercaptothymidine (8), 2,3-dideoxy-3-mercaptoadenosine (15) and its corresponding anomer16. In the latter reactions it was important to use degassed solvents to minimize formation of the corresponding disulfides of purine nucleosides. Using Bu₄NF, without subsequent reaction with MeONa in the deprotection reaction, resulted in intermolecular transesterification reactions.On leave from Chemistry Department, Faculties of Science and Education, Tanta University, Tanta, Egypt     

Synthesis of 2′,3′-dideoxynucleosides from 5-alkoxymethyluracils

Summary A modified synthesis of protected 2,3-dideoxyribose5 starting fromL-glutamic acid (1) is described. Reaction of5 with silylated 5-hydroxymethyluracil7 a and 5-alkoxymethyluracils7 b–e in the presence of trimethylsilyl triflate afforded an anomeric mixture of 2,3-dideoxyuridine derivatives8 a–e and9 a–e. Deprotection with methanolic ammonia and separation by chromatography gave the corresponding nucleosides10 a–e and11 a–e. Treatment of9 b–e with tri(1H-1,2,4-triazol-1-yl)phosphine oxide and subsequent reaction of12 b–e with ammonia in dioxane afforded the cytosine derivatives13 b–e which on treatment with methanolic ammonia gave the corresponding 2,3-dideoxycytidine derivatives14 b–e and15 b–e. In contrast with the parent compounds, these alkoxymethyl derivatives had no appreciable activity against human immunodeficiency virus (HIV-1).

---

Synthese von 2,3-Dideoxynucleosiden aus 5-Alkoxymethyluracilen

Zusammenfassung Ausgehend vonL-Glutaminsäure (1) wird eine modifizierte Synthese von geschützter 2,3-Dideoxyribose (5) beschrieben. Reaktion von5 mit silyliertem 5-Alkoxymethyluracilen7 b–e in Gegenwart von Trimethylsilyltriflat ergab anomere Mischungen der 2,3-Dideoxyuridinderivate8 a–e und9 a–e. Abspaltung der Schutzgruppe mit methanolischen Ammoniak und chromatographische Trennung ergab die entsprechenden Nucleoside10 a–e und11 a–e. Behandlung von9 b–e mit Tri(1H-1,2,4-triazol-1-yl)phosphinoxid und nachfolgende Reaktion von12 b–e mit Ammoniak in Dioxan ergab die Cytosinderivate13 b–e, welche nach Behandlung mit methanolischem Ammoniak die entsprechenden 2,3-Dideoxycytidinderivate14 b–e und15 b–e ergaben. Im Gegensatz zur Stammverbindung hatten diese Alkoxymethylderivate keine nennenswerte Wirksamkeit gegen den menschlichen Immunschwächevirus (HIV-1).

     

2,2′-Diphenyl-Δ3,3′-bi-3H-indole-1,1′-dioxide: Molecular interactions and crystal structure

The Dinitrone 2,2-diphenyl-^3,3-bi-3H-indole-1,1-dioxide acts as a demethylating and dehydrogenating agent. The mechanism of interaction of the dinitrone with donors and acceptors does not involve intermediate charge-transfer complexes probably due to a self association between dinitrone molecules (as supported by X-ray determinations). The crystal structure of the dinitrone was obtained by direct methods;a=9.967 (2),b=19.817 (3),c=10.875 (2) Å, =111.2 (2)°, space group P2₁/n. The finalR andR _w were 0.089 and 0.063 for all measured reflexes.

---

2,2-Diphenyl-^3,3-bi-3H-indol-1,1-dioxid: Molekulare Wechselwirkungen und Kristallstruktur

Zusammenfassung Das Dinitron 2,2-Diphenyl-^3,3-bi-3H-indol-1,1-dioxid wirkt als Demethylierungs- und Oxydationsmittel. Die Wechselwirkung des Dinitrons mit Elektronen-Acceptoren und Elektronen-Donatoren geht wegen der Selbstassoziation zwischen den Dinitron-Molekülen ohne die dazwischenliegende Bildung eines Charge-Transfer-Komplexes vor sich; das wird auch von Röntgenstrukturuntersuchungen gestützt. Die Kristallstruktur wurde mit direkten Methoden ermittelt:a=9.967 (2),b=19.817 (3),c=10.875 (2) Å; =111.2 (2)°. P2₁/n. Die endgültigen WerteR undR _w waren 0.089 und 0.063 für alle gemessenen Reflexe.

     

4,4′-Dipyridyl and 2,2′-dipyridyl complexes of rare-earth perchlorates

4,4-Dipyridyl and 2,2-dipyridyl complexes of rare-earth perchlorates of the formulaLn(4-dipy)₈(ClO₄)₃HClO₄ · 4H₂O (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, 4-dipy=4,4-dipyridyl) andLn(2-dipy)₃(ClO₄)₃ · 6H₂O (Ln=Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, 2-dipy = 2,2-dipyridyl) have been synthesized. The IR spectra of these compounds and other physical properties are discussed.

---

4,4-Dipyridyl- und 2,2-Dipyridylkomplexe von Seltenerdmetallperchloraten

Zusammenfassung Es wurden 4,4-Dipyridylkomplexe des TypsLn(4-dipy)₈(ClO₄)₃HClO₄ · · 4 H₂O mitLn=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y und 2,2-Dipyridylkomplexe des TypsLn(2-dipy)₃(ClO₄)₃ · 6 H₂O mitLn=Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu und Y dargestellt. Die IR-Spektren und andere physikalische Eigenschaften werden diskutiert.

     

Molecular structure of 1′,3′,3′-trimethyl-6-trifluoromethylsulfonyl-spiro-(indoline-2,2′-benzo[b]pyran)

Photochromic 1, 3, 3 -trimethyl-6-trifluoromethylsulfonyl-spiro(indoline-2,2-ben-zo[b]pyran) (1) was studied by X-ray diffraction analysis. In compound1, the C_spiro-O bond (1.49(1) Å (average)), broken on photoexcitation, is the longest of all the indoline spiropyrans studied.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1969–1971, November, 1994.     

2,2′-Diphenyl-Δ3,3′-bi-3H-indole-1,1′-dioxide: Competitive demethylation and redox reactions

Competitive demethylation and redox reactions induced by 2,2-diphenyl-^3,3-bi-3H-indole-1,1-dioxide,1 (dinitrone) on several nitrogen bearing compounds (pyridines, amides, indoles, hydrazones and amines) are reported.Es wird über kompetitive Demethylierungen und Redoxreaktionen an stickstoffhaltigen Verbindungen (Pyridine, Amide, Indole, Hydrazone und Amine) berichtet, die durch das Dinitron 2,2-Diphenyl-3,3-bi-3H-indol-1,1-dioxid induziert werden.

---

2,2-Diphenyl-3,3t-bi-3H-indol-1,1t-dioxid: Kompetitive Demethylierung und Redoxreaktionen

     

O-Heterocycles by the cyclization of side-chain bromomethoxylated 2′-acetoxychalcones

Summary The title chalcone derivatives react with aqueous sodium hydroxide of various concentrations to form aurones as the major product, together with small amounts of flavones. However, the introduction of 4-nitro or 4-chloro substituents resulted in the formation of flavones as the major product.

---

O-Heterocyclen mittels Cyclisierung von an der Seitenkette brommethoxylierten 2-Acetoxychalconen

Zusammenfassung Die im Titel genannten Chalconderivate reagieren mit Natronlauge in verschiedenen Konzentrationen, wobei Aurone zusammen mit geringen Mengen an Flavonen entstehen. Die Einführung von 4-Nitro- oder 4-Chlor-Substituenten führte jedoch zur bevorzugten Bildung von Flavonen.

     

Elucidation of a common structure of selective fibrinogen receptor antagonists

In this paper, we investigate the common structural and electrostatic parameters of a series of specific inhibitors of the IIb3 integrin. Molecular dynamics simulations with an explicit aqueous environment led to an original theoretical pattern. Our results may suggest that the studied non-peptide IIb3 antagonists developed upon the Arg-Gly-Asp ubiquitous recognition sequence, in fact, should mimic the C-terminus part of the fibrinogen chain. This assumption could, therefore, explain their specificity with respect to other Arg-Gly-Asp-dependent integrins.     

Natural product chemistry. Part 121. Synthesis of dicoumarinyl ethers with the structures proposed for fatagarine and oreojasmine

Synthesis of the 7,8-dicoumarinyl ethers: 7-methoxy-7,8-oxydicoumarin and 6,7-dimethoxy-7,8-oxydicoumarin, established that the structures of fatagarine and oreojasmine for which these two structures have been proposed, have to be revised. Synthesis of 7-methoxy-5,7-oxydicoumarin and 8-methoxy-7,7-oxydicoumarin exclude the possibility of these dicoumarinyl ether structures for fatagarine.

---

Naturstoffchemie. 121. Mitt.: Synthese von Dicumarinylethern mit den für das Fatagarin und das Oreojasmin vorgeschlagenen Strukturen

Zusammenfassung Durch die Synthese der 7,8-Dicumarinylether: 7-Methoxy-7,8-oxydicumarin und 6,7-Dimethoxy-7,8-oxydicumarin, ließ sich nachweisen, daß die für das Fatagarin und Oreojasmin vorgeschlagenen Strukturen revidiert werden müssen. Die Darstellung des 8-Methoxy-7,7-oxydicoumarin und 7-Methoxy-5,7-oxydicumarin schließen die Möglichkeit dieser Strukturen für das Fatagarin aus.

     

Reaction of aminals of conjugated unsaturated ω-dimethylaminoaldehydes with 1,2-, 1,3-, 1,4-, 1,5-, and 1,6-diketones

The condensation of aminals of -dimethylaminoacrolein and 5-dimethylaminopenta-2,4-dienal with cyclic and acyclic 1,2-, 1,3-, 1,4-, 1,5-, and 1,6-diketones was studied. A series of previously unknown bis(,-dimethylaminopolyenyl)diketones was synthesized; their structures were established by means of¹H and¹³C NMR spectroscopies. The electron absorption spectra were employed to study the mutual influence of -aminopolyene chromophores separated by two C=O groups.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1235–1241, July, 1993.     

Investigation of the process of polyimide formation from complexes of the diester of benzophenonetetracarboxylic acid with diamines

The kinetics of thermal imidization of the H-complexes derived from the diethyl ester of 3,3,4,4-benzophenonetetracarboxylic acid (EBZP) and various diamines have been studied. A comparison of kinetic parameters obtained for the imidization of H-complexes based on ethyl or methyl esters of this acid has disclosed the differences in the behavior of each of the two H-bonds and the contribution of each bond to the mechanism of polyimide formation from the respective H-complexes.For part 5, see ref.¹ Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 300–303, February, 1993.     

New route for the synthesis of 2-thiouracil analogues of 3′-azido-2′,3′-dideoxy nucleosides

Summary Reaction of 3-azido-5-O-tert-butyldiphenylsilyl-2,3-dideoxy-D-erythro-pentofuranoside (5) with silylated 2-thiouracil and 5-alkoxy-2-thiouracils in the presence of trimethylsilyl trifluoromethanesulfonate afforded an anomeric mixture of the corresponding 3-azido-2,3-dideoxy-2-thiouridine derivatives with the -anomer as the main product. Deprotected nucleosides were obtained by treatment with tetrabutylammonium fluoride.

---

Ein neuer Weg zur Synthese von 2-Thiouracil-Analogen von 3-Azido-2,3-dideoxy-Nucleosiden

Zusammenfassung Die Reaktion von 3-Azido-5-O-tert-butyldiphenylsilyl-2,3-dideoxy-D-erythro-pentofuranosid (5) mit silyliertem 2-Thiouracil und 5-Alkoxy-2-thiouracil in Gegenwart von Trimethylsilyltrifluormethansulfonat ergab eine anomere Mischung der entsprechenden 3-Azido-2,3-dideoxy-2-thiouridin-Derivate, wobei das -Anomer das Hauptprodukt darstellte. Die ungeschützten Nucleoside wurden mittels Behandlung mit Tetrabutylammoniumfluorid erhalten.

     

Some aspects of chemical analysis of isolates by AAS

The paper describes some practical elements of atomic absorption spectrometry applications in the analysis of phase isolates. Attention was paid to the optimization of measuring conditions. It is pointed out that less sensitive analytical lines are more profitable. This paper presents the ranges of their practical application. The results of chemical analyses of the phase isolates are presented together with the morphological changes of the phase precipitations at different ageing temperatures.Dedicated to Professor Günther Tölg on the occasion of his 60th birthday     

Synthesis and crystal structure of a pyrazole derivative of artemisia ketone

The oxime of artemisia ketone is smoothly converted to the pyrazole derivative by sodium nitrite and acetic acid in CHCl₃. The structure of the pyrazole was found by x-ray structural analysis. The PMR and¹³C NMR spectra were interpreted using two-dimensional¹H–¹³C NMR (COSY, COLOC).Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 121–123, March–April, 2000.