Synthesis of obtusinin and 7-(3′-hydroxymethylbut-2′-enyloxy)-6-methoxy-2H-1-benzopyran-2-one

Obtusinin (1) has been synthesised by the reaction of 6-methoxy-7-(3-methylbut-2-enyloxy)-2H-1-benzopyran-2-one (3) with OsO₄. Synthesis of 7-(3-hydroxymethylbut-2-enyloxy)-6-methoxy-2H-1-benzopyran-2-one (2) has been achieved by the regiospecific oxidation of3 with SeO₂ followed by reduction of the formed aldehyde with KBH₄.

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Synthese von Obtusinin und 7-(3-Hydroxymethylbut-2-enyloxy)-6-methoxy-2H-1-benzopyran-2-on

Zusammenfassung Obtusinin (1) wurde über 6-Methoxy-7-(3-methylbut-2-enyloxy)-2H-1-benzopyran-2-on (3) mit OsO₄ synthetisiert. Die Darstellung von 7-(3-Hydroxymethylbut-2-enyloxy)-6-methoxy-2H-1-benzopyran-2-on (2) wurde mittels regioselektiver Oxidation von3 mit SeO₂, gefolgt von Reduktion des gebildeten Aldehyds mit KBH₄, bewerkstelligt.

     

Synthesis of novel heterocycles from thiazolecarbohydrazides

Cyclization of 2-methyl (or -phenyl)-5-phenylthiazole-4-carbohydrazides (1) and (2) under various conditions gives differing oxadiazoles: 2-(2-substituted-5-phenyl-4-thiazolyl)-1,3,4-oxadiazole-5-thiones (7) and (8), and 2-(2-substituted-5-phenyl-4-thiazolyl)-1,3,4-oxadiazoles (9) and (10). Cyclodehydration of thiazolecarbonyl-thiosemicarbazides (3)–(6) with NaOH givesthe 3-(2-substituted-5-phenyl-4-thiazolyl)-4-substituted-4H-5-mercapto-1,2,4-triazoles (11)–(14), while H ₃ PO ₄ gives the 2-(2-substituted-5-phenyl-4-thiazolyl)-5-phenylamino-1,3,4-thiadiazoles (15) and (16).A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 679–683, March, 1992.     

The reaction of 4-methoxycoumarins with prenyl bromide: Synthesis of 4′,4′,5′-trimethyl-dihydrofurano-coumarins and 2,2-dimethyl-chromenopyrans

The reaction of 7-hydroxy-4-methoxy- (1a), 7-hydroxy-4,5-dimethoxy-(1b) and 5-hydroxy-4,7-dimethoxy (1c) -2H-1-benzopyran-2-ones with prenyl bromide in acetone in the presence of anhydrous potassium carbonate gave the corresponding prenyloxycoumarins1d,1e, and1f. The prenyloxy coumarins1d,1e,1f onClaisen migration by refluxing inN,N-dimethyl aniline gave the corresponding 4,4,5-trimethyl-dihydrofuranocoumarins2a,2b, and3. However, the reaction of1a,1b, and1c with 3-chloro-3-methyl-but-1-yne in acetone in presence of potassium carbonate and potassium iodide gave the corresponding propargyl ethers1g,1h,1i, which on refluxing inN,N-dimethyl aniline gave the corresponding 2,2-dimethylchromenopyrans4a,4b, and5. These can also be obtained directly if the reaction is carried out in the presence of dioxan.

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Die Reaktion von 4-Methoxycumarinen mit Prenylbromid: Synthese von 4,4,5-Trimethyl-dihydro-furanocumarinen und 2,2-Dimethylchromenopyranen

Zusammenfassung Die Reaktion von 7-Hydroxy-4-methoxy-(1a), 7-Hydroxy-4,5-dimethoxy-(1b) und 5-Hydroxy-4,7-dimethoxy-2H-1-benzopyran-2-onen (1c) mit Prenylbromid in Aceton in der Gegenwart von wasserfreiem Kaliumcarbonat ergab die entsprechenden Prenylcumarine1d,1e und1f. Diese ergaben durchClaisen-Wanderung bei Rückfluß inN,N-Dimethylanilin die entsprechenden 4,4,5-Trimethyldihydrofuranocumarine2a,2b und3. Die Reaktion von1a,1b und1c mit 3-Chlor-3-methyl-1-butin in Aceton in Gegenwart von wasserfreiem Kaliumcarbonat und Kaliumjodid ergab die entsprechenden Propargylether1g,1h und1i, die ihrerseits bei Rückfluß inN,N-Dimethylanilin die jeweiligen 2,2-Dimethylchromenopyrane4a,4b und5 ergaben. Letztere können auch direkt erhalten werden, wenn die Reaktion in Gegenwart von Dioxan durchgeführt wird.

     

Electron transfer from dibenzo[b,f]-1-azapentalene dianion: Attempted synthesis of dibenzo[b,f]-1-azapentalene

When dibenzo[b,f]-1-azapentalene dianion (3) was allowed to react with either iron (III) chloride or ethylene bromide, a one-electron transfer from3 took place readily to give the radical anion11. Further electron transfer from11 did not occur presumably due to the antiaromatic character of dibenzo[b,f]-1-azapentalene (1) that would have resulted. The radical anion11 underwent further transformation by hydrogen abstraction from the solvent to give 5,10-dihydroindeno[1,2-b]indole (2) and by dimerization to themeso and (R,S) isomers of 5,5,10,10-tetrahydro-10,10-biindeno[1,2-b]indole (4 a and4 b) respectively.

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Elektronentransfer von Dibenzo[b,f]-1-azapentalen-Dianion: Ein Versuch zur Synthese von Dibenzo[b,f]-1-azapentalen

Zusammenfassung Die Reaktion von Dibenzo[b,f]-1-azapentalen-Dianion (3) mit Eisen (III) oder Ethylenbromid ergab einen Ein-Elektronentransfer zum Radikalanion11. Ein weiterer Elektronentransfer fand nicht statt, vermutlich wegen des antiaromatischen Charakters von Dibenzo[b,f]-1-azapentalen (1), das dabei entstehen müßte. Das Radikalanion11 ergab unter Wasserstoffentzug aus dem Lösungsmittel 5,10-Dihydroindeno[1,2-b]indol (2), das weiter zummeso- bzw. (R,S)-5,5,10,10-tetrahydro-10,10-biindeno[1,2-b]indol (4 a bzw.4 b) dimerisierte.

     

Glykosylazide als Ausgangsbasis zur Gewinnung von Nucleosidanalogen, 3. Mitt. Synthese von Alkylaminotetrazol- und Uretidinonnucleosiden

The -ribofuranosylazide1 is transformed after usual derivatization by suitable protecting groups into the P–N-ylid2, which gives the corresponding N-Glykosyl-N-alkylcarbodiimides4 and a small amount of the glykosylisocyanatde-rivative3 by reaction with alkylisocyanates. The carbodiimides4 were reacted with hydrazoic acid to give the alkylaminotetrazolnucleosides5 and finally the free nucleosidanalogs6. In the case of5 c the 5-aziridinyltetrazolnucleosid5 h was formed by an usual neighbouring group reaction. In addition the compound1 is transformed into the 3,5-diprotected anchor derivative7 by reaction withTIPSCl₂. The latter could be transformed by usual steps into the alkylaminotetra-zolnucleosides8 with a free 2-OH group. In the next step the 2-p-tolylthiocarbo-nates9 were prepared followed by transformation to the 2-desoxynucleosides10 by means of tributyltinhydride. Finally the free 2-desoxynucleosides11 were prepared. By reacting the carbodiimides4 with phenylisocyanate a mixture of the two possible regiouretidinonnucleosidderivatives12 and13 are formed. In the case of the N-glykosyl-N-allylcarbodiimide4 d only the one isomer13 d arises.

Herrn Prof. Dr.A. Neckel mit den besten Wünschen zum 60. Geburtstag gewidmet.     

Aromatische Spirane, 12. Mitt.

The title compounds26 and32 were prepared by systematic mono- and bisanellation of sixmembered rings to the positions 5,6 and 5,6, resp. of 2,2-spirobiindane.S _E acylation and subsequent transformations of the acylgroups afforded many derivatives with substituents in positions 4 and 4 of the parent compounds which were required for testing semiempirical values of chirality functions.5,6,7,8-Tetrahydrobenz[f]indane (9) and several of its 4-substituted derivatives were prepared as models for the anellation and substitution reactions.Tentative preferred conformations of the 4-acylgroups could be deduced from¹H-nmr spectra.

     

Über Heterocyclen, 22. Mitt.: 3,4,6,7-Tetrahydro-5H-pyrrolo[3,4-d]pyrimidin-2(1H), 5-dione

Zusammenfassung Tetrahydro-6-brommethyl-2-oxopyrimidin-5-carbonsäureester reagieren mit Ammoniak bzw. Benzylamin zu Tetrahydro-5H-pyrrolo[3,4-d]pyrimidin-2(1H), 5-dionen. Mit 2-Aminopyridin (A) bilden sich Tetrahydro-6-(2-pyridylaminomethyl)-2-oxopyrimidin-5-carbonsäureester, Tetrahydro-5H-pyrrolo[3,4-d]pyrimidin-2(1H), 5-dione sowie 5-Äthoxycarbony]-2,3,5,6-tetrahydro-2-oxospiro(pyrimidin-4(1H), 2(3H)-1H-imidazo[1,2-a]pyridinium)bromide.

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Heterocycles XXII: 3.4.6.7-Tetrahydro-5H-pyrrolo [3.4-d]-pyrimidine-2(1H)-5-diones

Tetrahydro-6-bromomethyl-2-oxopyrimidine-5-carboxylates react with ammonia and benzylamine, resp., to give tetrahydro-5H-pyrrolo[3.4-d]pyrimidin-2(1H), 5-diones. With 2-aminopyridine (A) tetrahydro-6-(2-pyridylaminomethyl)-2-oxopyrimidine-5-carboxylates, tetrahydro-5H-pyrrolo[3.4-d]pyrimidine-2(1H). 5-diones as well as 5-ethoxycarbonyl-2.3.5.6-tetrahydro-2-oxospiro(pyrimidin-4(1H)-2(3H)-1H-imidazo[1.2-a]-pyridinium) bromides are formed.

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Herrn Prof. Dr.O. Hromatka zum 65. Geburtstag gewidmet.     

Hydrogenation of vermistatin

Summary Hydrogenation of vermistatin, a metabolite ofPenicillium vermiculatum, affordedcis- andtrans-3-(2-carboxy-4,6-dimethoxybenzyl)-6-propyltetrahydro-4H-pyran-4-one and 4,6-dimethoxy-3-(4-propylcyclopentanon-2-yl)phthalide. The latter compound was found to be the strongest inhibitor of RNA synthesis in P 388 leukemia cells of all compounds tested.

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Hydrierung von Vermistatin

Zusammenfassung Bei der Hydrierung von Vermistatin, einem neuen sekundären Metabolit ausPenicillium vermiculatum, wurdencis- undtrans 3-(2-Carboxy-4,6-dimethoxybenzyl)-6-propyltetrahydro-4-pyran-4-on und 4,6-dimethoxy-3-(4-propylcyclopentanon-2-yl)phthalid erhalten und spektroskopisch charakterisiert. Die letztgenannte Verbindung zeigte von allen getesteten Verbindungen die stärkste Hemmwirkung auf die RNA Synthese in P 388 Leukämiezellen.

     

Über 4,4,6-trisubstituierte 3,4-Dihydro-2(1H)-pyrimidinimine,Hexahydro-2(1H)-chinazolinimine bzw.-one bzw.-thione und Spiro[cycloalkan-1,4′(1′H)-cycloalkeno-pyrimidin]-2′ (3′H)-imine

The 2-alken-1-ones2 b, 2 c and3–8, which have very different structures, were reacted with guanidine to give cyclic compounds:2 b and2 c resp. are transformed by guanidine to the trisubstituted 3,4-dihydro-2(1H)-pyrimidinimines1 b and1 c resp., action of guanidine on the cyclo-hexylidenaceton (3) yields 4-methyl-1,3-diaza-4-spiro[5,5]-undecen-2-imine (11); isopropylidencyclohexanone4 and the isomeric (methylcyclohexenyl)ethanone5 condense with guanidine resp. urea resp. NH₄CNS to give 4,4-dimethyl-3,4,5,6,7,8-hexahydro-2(1H)-quinazolinimine (15), resp.-one (16), resp.-thione (17) and 4,8a-dimethyl-3,4,6,7,8,8a-hexahydro-2(1H)-quinazolinthione (19). With the cycloalkyliden-alkanones6–8 guanidine reacts to yield the spiro[cycloalkan-1,4(1H)-cycloalkenopyrimidin]-2(3H)-imines24–26. The structure of the compounds cited is derived from their NMR-and (partially) mass spectra; from most of the bases picrates were also synthesized.

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Herrn Prof. Dr.H. Grubitsch zum 70. Geburtstag gewidmet.     

1-Aryl-6-azauracile, 6. Mitt.: Synthese der isomeren 1-Naphthyl-6-azauracile

Zusammenfassung Auf übliche Art wurden folgende Verbindungen hergestellt: -Naphtylhydrazono-cyanacetylcarbamidsäureäthylester (1 a), 1-(-Naphthyl)-5-cyano-6-azauracil (2 a), 1-(-Naphthyl)-6-azauracil-5-carbonsäure (3 a), 1-(-Naphthyl)-6-azauracil (4 a), Amidoxim der 1-(-Naphthyl)-6-azauracil-5-carbonsäure (5 a), 1-(-Naphthyl)-5-[5-methyl-1,2,4-oxdiazolyl(3)]-6-azauracil (6 a) und die entsprechenden -Isomere aller dieser Verbindungen (1 b–6 b).5. Mitt.:J. Slouka, Mh. Chem.97, 448 (1966).     

Synthesis and characterization of some methyl complexes of palladium(II). Part 2(1)

Summary Dichloro complexes of Pd^II, [Pd(L–L)Cl₂], where L–L=1-(thiomethyl)-2-(diphenylarsino)ethane (S–As) or 1-(thiomethyl)-2-(diphenylphosphino)ethane (S–P) andtrans-[PdL₂Cl₂], where L=diphenyl(2-phenylethyl)-phosphine (PE), diphenyl(1-naphthyl)phosphine (PN) orN-methyl-2-thiophenealdimine (SN), have been prepared and characterized. The reactions of these complexes with MeLi were investigated. The dimethyl complexes [Pd(L–L)Me₂] (L–L=S–As, S–P) and [Pd(PE)Me₂] were isolated and characterized. Reaction of [Pd(L–L)Me₂] (L–L=S–As, S–P) with HCl affords the monomethyl derivatives [Pd(L–L)Me(Cl)]. In contrast to the Pt analogues, [Pd(L–L)Me₂] and [Pd(L–L)Me(Cl)] are relatively less stable than [Pt(L–L)Me₂] and [Pt(L–L)Me(Cl)].     

Metal complexes of 1-hydroxy-2,3-dimethyl-4-(3′-methyl-4′-amino-5′-mercapto-1′, 2′, 4′-triazole)-1,4-diaza-1, 3-butadiene with manganese(II), cobalt(II), nickel(II) and copper(II)

Summary Binuclear metal complexes of the type [M(HDDB)-(H₂O)₂]₂: where HDDB=1-hydroxy-2,3-dimethyl-4-(3-methyl-4-amino-5-mercapto-1, 2, 4-triazole)-1,4-diaza-1, 3-butadiene and M=manganese(II), cobalt(II), nickel(II) and copper(II), have been prepared and characterised by elemental and thermal analyses, magnetic measurements, electronic and i.r. spectra. Octahedral geometry around the metal(II) ions is proposed and the crystal field parameters of the cobalt(II) and nickel(II) complexes are also calculated. Fungicidal screening of the complexes has been made aginstHelminthosporium oryzae andFusarium oxysporium.     

Optisch aktive aromatische Spirane, 13. Mitt.

Several optically active title compounds were obtained from the 4-acetyl-4-carboxylic acid2 or the 4,4-diacetyl derivative4. (–)-2 was accessible by optical resolutionvia its (–)--phenethylamine salts, (+)- and (–)-4 as well as the enantiomeric methylesters3 (of2) were obtained by chromatography on triacetylcellulose in ethanol. The enantiomeric purities were established either from the chromatographic results or from the¹H-NMR spectra of the phenethyl-amine saltes (via the diastereotopic acetyl protons).The chirality (–)-(2R) was deduced for all new compounds from a chemical correlation between (–)-2 and (–)-4 and on the basis of the CD spectra of the latter and of (–)-(2R)-17 of known absolute configuration.From the molar rotations of these 4,4-disubstituted 2,2-spirobiindanes (empirical) ligand parameters were determined which for some cases gave good results in the calculation of the rotations (using the shortened Ansatz). These results are briefly discussed especially in comparison with 5,5-disubstituted 2,2-spirobiindanes.

Herrn Prof. Dr.O. Hromatka mit den besten Wünschen zum 80. Geburtstag gewidmet.     

Diborane as a reducing agent IX: Reduction of aTris(trifluoroacetyl)enaminospiroindoline

Summary Reduction of the title compound (2) with diborane furnishes 1-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)-3-vinylindoline (4), 1-hydroxy-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)indole (5), and 1-methyl-2-trifluoroethyl-1,2,3,4-tetrahydro--carboline (6). However, treatment of2 with lithium aluminum hydride, H₂/Pd on charcoal, and sodium borohydride affords hydroxyspiroindolenine8, hydroxy-bis(trifluoroacetyl)enaminospiroindoline9, andN-ethyltryptamine7, respectively. The results are discussed and the mechanisms of the reactions leading to4–8 are presented.

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Diboran als Reduktionsmittel, 9. Mitt.: Reduktion einesTris(trifluoroacetyl)enaminospiroindolins

Zusammenfassung Reduktion der Titelverbindung (2) mit Diboran ergibt 1-Trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)-3-vinylindolin (4), 1-Hydroxy-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)indol (5) und 1-Methyl-2-trifluoroethyl-1,2,3,4-tetrahydro--carbolin (6). Behandlung von2 mit Lithiumaluminiumhydrid, H₂/Pd auf Aktivkohle und Natriumborhydrid führt jedoch zu Hydroxyspiroindolenin8, Hydroxy-bis(trifluoroacetyl)enaminospiroindolin9 und N-Ethyltryptamin (7). Die Ergebnisse werden diskutiert und die Mechanismen der zu den Produkten4–8 führenden Reaktionen werden vorgestellt.

     

Über Synthesen von 1,3,4-Benzotriazepinderivaten

Zusammenfassung Beim Einwirken von Aldehyden oder Ketonen auf 1,2-Dimethylanthranilsäurehydrazide tritt Ringschluß zu den entsprechenden 2,3,4,5-Tetrahydro-1H-1,3,4-benzotriazepinen ein. Diese heterocyclischen Ringe entstehen auch aus solchen Anthranilsäurehydraziden, bei denen die Aminogruppe unsubstituiert ist (1 a, 1 b) und somit die Bildung von Azomethinen möglich wäre.

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Syntheses of derivatives of 1.3.4.-benzotriazepine

Reaction of 1.2-dimethylanthranilic acid hydrazides with aldehydes or ketones yields the corresponding 2.3.4.5-tetrahydro-1H-1.3.4-benzotriazepines. These compounds are also formed from anthranilic acid hydrazides having an unsubstituted amino group (1 a, 1 b) which hence would allow the formation of azomethines.

     

Zur Mannich-Reaktion von Dihydro-6-methyl-2(1H)-pyrimidinonen

Zusammenfassung Dihydro-4,4,6-trimethyl-2(1H)-pyrimidinone reagieren mit Formaldehyd und sekundären bzw. primären Aminen zu 6-Dialkylaminoäthylidentetrahydro-2(1H)-pyrimidinonen bzw. Hexahydro-2(1H)-pyrido[4,3-d]Pyrimidinonen. Mit Succindialdehyd bzw. Glutardialdehyd und primären Aminen entstehen 5,7-Äthanohexahydro-2(1H)-pyrido[4,3-d]pyrimidinone bzw. Tetrahydro-6,8-propano-6H-pyrimido[1,6-c]pyrimidin-1(2H)-one. Die 6-Dialkylaminoäthylidentetrahydro-2(1H)-pyrimidinone geben mit Phenolen Tetrahydrospiro([1]benzopyran-2,4(1H)-pyrimidin)-2(3H)-one, mit cycl. -Dicarbonylverbindungen Hexahydrospiro([1]benzopyran-2,4(1H)-pyrimidin)-2,5(3H, 6H)-dione bzw. Tetrahydrospiro(2H,5H-pyrano[3,2-c][1]benzopyran-2,4(1H)-pyrimidin)-2(3H),5-dione bzw. mit Malonestern -(Tetrahydro-4,4-dimethyl-2-oxo-6-pyrimidyl)-äthylmalonester.Zusammenfassung Dihydro-4.4.6-trimethyl-2(1H)-pyrimidinones react with formaldehyde and sec. and prim. amines resp. to 6-dialkylaminoethylidentetrahydro-2(1H)-pyrimidinones and hexahydro-2(1H)-pyrido[4.3-d]pyrimidinones, resp. succindialdehyde and glutaraldehyde with primary amines give 5.7-ethanohexahydro-2(1H)-pyrido[4.3-d]pyrimidinones and tetrahydro6.8-propano-6H-pyrimido[1.6-c]pyrimidin-1(2H)-ones, resp. 6-Dialkylaminoethylidentetrahydro-2(1H)-pyrimidinones react with phenols to tetrahydrospiro([1]benzopyran-2.4(1H)-pyrimidin)-2(3H)-ones, with cyclic -dicarbonyl compounds to hexahydrospiro([1]benzopyran-2.4 (1H)-pyrimidin)-2,5 (3H), 6H)-diones and tetrahydrospiro(2H,5H-pyrano[3.2-c][1]benzopyran-2.4(1H)-pyrimidin)-2(3H),5-diones, resp., with malonates -(tetrahydro-4.4-dimethyl-2-oxopyrimidyl-6)-ethylmalonates.

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Mannich reaction with dihydro-6-methyl-2(1H)-pyrimidinones

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Herrn Prof. Dr.F. Kuffner zum 65. Geburtstag gewidmet.     

The preparation by a solid-solid interaction route of aromatic polyamide materials containing sulphone, ether and ketone linkages

The polycondensation reactions between 4,4-[sulphonyl bis(p-benzoyl)(p-phenyleneoxy)]dibenzoic acid (I) andp-phenylenediamine (II), 1,5-diaminonaphthalene (III), 4,4-sulphonyldianiline (IV), 4,4-diaminodiphenylsulphide (V) 4,4-methylenedianiline (VI) and 4,4-oxydianiline (VII) to form aromatic polyamides containing sulphone, ether and ketone linkages were attempted by a solid-solid interaction route. A stoichiometric 11 molar ratio of solid reactants was dynamically heated directly in a TG/DSC apparatus, and simultaneous TG/FT-IR was performed to interpret the mechanism of reaction. The results suggest that the polycondensation is dependent on the diamine used. The formation of polyamide was successful when I interacted with II, III, VI and VII. The interaction with IV and V was in part successful because partial decarboxylation of the diacid, made unstable by the diamine, occurred before the condensation reaction.     

Spectrophotometric determination of vanadium with 4-(1′H-1′,2′,4′-Triazolyl-3′-azo)-2-methylresorcinol

Summary 4-(1H-1,2,4-Triazolyl-3-azo)-2-methylresorcinol reacts with vanadium(V) at pH 8.10 (Tris-HClO₄ buffer solution) to produce a pink-violet 11 complex ( _max=525 nm,=2.55×10⁴l·mol^–1· cm^–1) in a 50% (v/v) methanol-water medium, which allows the spectrophotometric determination of 0.1 to 1.51 ppm of vanadium. The method has been applied for the determination of the vanadium content in low alloy steels.

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Spectrophotometriscbe Bestimmung von Vanadin mit 4-(1H-1,2,4-triazo-lyl-3-azo)-2-methylresorcin

Zusammenfassung Vanadin bildet bei pH 8,10 (Tris-HClO₄-buffer) mit 4-(1H-1,2,4-tri-azolyl-3-azo)-2-methylresorcin ein rosenrot-violettes Chelat, dessen Absorptionsmaximum bei 525 nm in Gegenwart von 50% Methylalkohol gemessen wird. Dieser 11-Komplex entspricht bei einer Vanadin-Konzentration von 0,1–1,51g/ml dem Beerschen Gesetz; seine molare Absorptivität ist 2,55×10⁴l·mol^–1·cm^–1. Das Verfahren wurde zur Bestimmung des Vanadins in Stahl verwendet.

     

Optisch aktive,aromatische Spirane, 11. Mitt.: Synthese optisch aktiver mono- bis heptasubstituierter 5-Methyl- und 5-Ethyl-2,2′-spirobiindane und analoger Naphthalinderivate bekannter Chiralität und enantiomerer Reinheit

Starting from optically active 5,5-dimethyl, diethyl, and 5-ethyl-5-methyl-2,2-spirobiindane as well as from 5-ethyl-spirobiindane-5-carboxylic ester of known enantiomeric purity and configuration 75 mono to polysubstituted 2,2-spirobiindanes have been prepared. Amongst these are several compounds with rings anellated in the 6,7 (and 6, 7) positions, especially a spirohydrocarbon4 x with orthogonal naphthalene units the circular dichroism of which is reported and discussed.Several mono and disubstituted 5-methyl and ethylindanes (1,2) have been prepared as models for synthetic transformations in the spirobiindane series.From the molar rotations of symmetrically diacylated 5,5-dimethyl and diethyl spirobiindanes (4a, 7b, 7c) empirical ligand parameters for acetyl and methoxycarbonyl were determined which gave much better results in the calculation of the rotations of appropriate spirobiindanes (with the shortened polynomal Ansatz) than the -values deduced previously from 5,5-disubstituted spirobiindanes. The significance of these results is briefly discussed.

10. Mitt.:Neudeck, H., Schlögl, K., Angew. Chem.92, 318 (1980), Intern. Ed. Engl.19, 308 (1980).     

Cobalt(II) and nickel(II) chloride and bromide complexes of 2-(2′-methyl-8′-quinolyl)benzoxazole and 2-(2′ or 4′-methyl 8′-quinolyl)benzimidazole

Summary Cobalt(II) and nickel(II) halide complexes of the ligands 2-(2-methyl-8-quinolyl)benzoxazole (mqbo), 2-(2-methyl8quinolyl)benzimidazole (mqbi) and 2-(4-methyl-8-quinolyl)benzimidazole (mqbi) were synthesized and characterized by analytical, thermogravimetric, conductivity and magnetic data, and i.r. and electronic spectra.The ligands are bidentate N-donors yielding complexes where the coordination geometry depends on the metal ion and steric hindrance. All the cobalt complexes have formula [CoL₂X₂] and distorted tetrahedral geometry. Different types of nickel compounds were obtained: i) complexes of formula NiLX₂ · n H₂O (or EtOH) (L = mqbo or mqbi; n=0–1.5) which arepseudo-tetrahedral or five-coordinate and ii) complexes NiL₂X₂ · n H₂O (L = mqbi, n=3 or 4) where the metal is bound to four nitrogen atoms and the overall coordination geometry is tetragonal. The structural changes occurring after removal of water or alcohol from the complexes are also reported.