| 41 | Author
| Bruno Perly, GiuseppeC. Pappalardo, Antonio Grassi | Requires cookie* | | Title
| Molecular Determinants for Drug-Receptor Interactions. 6. Proton 500 MHz NMR Spectra of the Narcotic Antagonists Naloxone and Naltrexone by Two- Dimensional *H— Chemical Shift Correlation Spectroscopy  | | | Abstract
| NM R Spectra, T w o-D im ensional NM R, Narcotic A ntagonists, N aloxone, Naltrexone The full analysis of the 'H N M R spectra o f naloxone and naltrexone (hydrochloride salts, in 2H 20 solution) was performed by using an high-frequency (500 M Hz) spectrom eter and the recent technique o f two-dim ensional (2 D) hom onuclear shift spectroscopy. The 'H —'H connec tivities allow ed detection o f correlated resonances and assignm ents of multiplets. The shapes o f the contour levels o f the C O SY 45 spectra were also used to check the relative signs o f coupling constants. The refinement o f spectral parameters o f som e com ponent spin-systems o f the com plex spectra was perform ed by com puterized iterative simulation o f patterns. The spectral analysis provided proton coupling constants that allowed to establish a slightly distorted-chair conformation o f the piperidine ring in both com pounds. The m agnetic non-equivalence found for the protons bonded to C-17 atom (part o f the N-alkyl fragment) was found to be larger in naltrexone than in the analogous naloxone. This fact, while no significant differences were observable in the chemical shifts o f corresponding protons o f the rigid molecular backbone of the two narcotic antagonists under study, was assigned to smaller degree o f internal conformational flexibility of the N-m ethylcyclopropyl group in naltrexone with respect to that o f the N-methylallyl group in naloxone. The above findings appeared in good agreem ent with our previously proposed view s based on results from l3C relaxation tim es studies, which suggested the possible correlation o f the m otional rates o f the N-m ethyl-R group to the pharmacological activity o f antagonist com pounds. This would consist in a direct correlation between decreasing flexibility o f the N -bonded fragment and increasing antagonistic potency. | | |
Reference
| Z. Naturforsch. 41b, 231 (1986); received August 22/N ovem b er 4 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0231.pdf | | | Identifier
| ZNB-1986-41b-0231 | | | Volume
| 41 | |
42 | Author
| ShyamK. Singh, LindsayA. Summers | Requires cookie* | | Title
|  | | | Abstract
| Departm ent o f Chem istry, The U niversity o f N ew castle, Reaction o f 2,3'-bipyridine with dibrom oalkanes affords both r-brom oalkyl-2,3'-bipyridinium bromides and l',l"'-(alkanediyl)-bis-2,3'-bipyridinium dibromides. The latter diquaternary salts react with dimethyl sulfate to afford r,l'" -(alk anediyl)-b is-(l-m ethyl-2,3'-bip yridinium) tetra quaternary salts which are reduced to diradical dications at potentials (E 0) o f about —0.47 V to -0 .6 2 V. | | |
Reference
| Z. Naturforsch. 41b, 239 (1986); received Septem ber 19 1985 | | |
Published
| 1986 | | |
Keywords
| 2, 3'-Bipyridinium Tetraquaternary Salts, Reduction Potentials, Diradical Dications | | |
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| default:Reihe_B/41/ZNB-1986-41b-0239.pdf | | | Identifier
| ZNB-1986-41b-0239 | | | Volume
| 41 | |
43 | Author
| Wolfgang Hillera, M. Anfredo, H. Örner3, A. Nton, R. Ieker, Edgar Streichh | Requires cookie* | | Title
| Chlorination of 3,5-Di-terf-butylphenol+ Crystal Structure of the Keto Tautomer of a Sterically Hindered Phenol A u f der M orgenstelle 18. D -7400 Tübingen  | | | Abstract
| Cyclohexadienones. NM R Spectra, Crystal Structure IR. U V and NM R data reveal that the dichlorination product o f 3,5-di-/m -butylphenol is the keto tautom er (l a) o f 3,5-di-/m -butyl-2,4-di-chlorophenol (3) instead o f the ortho-quinol dichloride (2 a), as assumed by H ew itt et al. (1972). According to the crystal structure determ ina tion, the first one of a m onocyclic keto tautom er, l a crystallizes in the space group P 1 with Z = 4; a = 1052.6(3), b = 1202.6(4), c = 1207.4(4) pm . a = 90.52(4)°, ß = 95.13(4)° and y = 108.59(4)°. The structure was solved by direct m ethods and refined by full-matrix least squares to R — 0.094 for 2176 reflections (I > 3 -cr(I)). Bond lengths and angles show no unusual features; the confor mation is discussed with respect to the acidity o f the sp'-s CH bond. Suggestions for the m echan ism of formation of l a are presented. Historical Background | | |
Reference
| Z. Naturforsch. 41b, 245 (1986); received Septem ber 3 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0245.pdf | | | Identifier
| ZNB-1986-41b-0245 | | | Volume
| 41 | |
44 | Author
| O.H H Ishm At, KhM A Khalil, ShI. El-Naem | Requires cookie* | | Title
| Synthesis of Pyranobenzopyranopyridines and Benzodipyran Derivatives  | | | Abstract
| Pyranobenzopyranopyridines, Benzodipyrans 6-Form yl-7-hydroxy-5-m ethoxy-2-m ethylchrom one on brom ination yields the 8-bromo deriva tive or the 8-brom o-6-form yl-5,7-dihydroxy derivative depending on the reaction condition. Cycli-zation o f both leads to the corresponding 3-acetyl-, 3-benzoyl-, 3-carboxamido-, 3-carbethoxy-benzodipyran derivatives. The 3-acetylbenzodipyran derivative when treated with ethyl acetoacetate or ethyl cyano-acetate in the presence o f am m onium acetate yields the corresponding dihydropyranobenzo-pyranopyridine dione or the dihydropyranobenzopyranopyridine trione. The reaction o f the 3-acetyl derivative with cyanoacetam ide in the presence o f ammonium acetate affords the substituted pyranobenzopyranopyridine dione. The 3-acetyl derivative undergoes self condensation to form the substituted benzopyrano-benzopyran derivative. | | |
Reference
| Z. Naturforsch. 41b, 252 (1986); received April 4/A ugu st 5. 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0252.pdf | | | Identifier
| ZNB-1986-41b-0252 | | | Volume
| 41 | |
47 | Author
| Marian Mikolajczyk, W. Anda, M. Idura | Requires cookie* | | Title
| A N ew , Short Synthesis o f Z-Jasm one  | | | Abstract
| Centre o f Molecular and M acromolecular Studies, Polish Academ y o f Sciences, D epartm ent of Organic Sulphur C om pounds, Z-Jasm one, Synthesis, Ethylene Ketal, 0,0-D iethyl-4-oxo-pentanephosphonate, Z -3-H exen-l-yl Iodide Z-Jasm one (1) was prepared from ethylene ketal o f 0,0-diethyl-4-oxo-pentanephosphonate (2) in four | | |
Reference
| Z. Naturforsch. 41b, 263 (1986); received October 25 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0263_n.pdf | | | Identifier
| ZNB-1986-41b-0263_n | | | Volume
| 41 | |
48 | Author
| ClausO. Meese, Kernforschungszentrum Karlsruhe, Bh | Requires cookie* | | Title
| The Photochromic Reaction of Methyl N-IsopropyI-4-nitrothiobenzimidate Hans Güsten  | | | Abstract
| Photochromic Reaction, Methyl N -Isopropyl-4-nitrothiobenzim idate M ethyl N -isopropyl-4-nitrothiobenzim idate (1) exhibits reversible photochrom ism to a dark blue coloured species in the crystalline state only. E x perimental evidence for a topochem ically controlled nitro-aci-nitro tautomerism o f 1 in the electronic ex cited state is presented. | | |
Reference
| Z. Naturforsch. 41b, 265 (1986); eingegangen am 30. August 1985 | | |
Published
| 1986 | | |
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| 41 | |
50 | Author
| R. Ajib, Lai De, Heinrich Vahrenkamp | Requires cookie* | | Title
| Synthesen neuer Fe—P-Käfigverbindungen Syntheses of New Fe —P Cage Compounds  | | | Abstract
| Four reaction types were used with the aim of obtaining new cage com pounds o f com position F e v(C O)v(P R). with R = M e, Ph. Tol; oxidation of the com pounds Fe2(C O)A(P H R)2. photolysis thereof, reaction betw een RPC12 and Fe2(C O)x:_ , and reaction betw een P —Cl containing iron com plexes and F e(C O)42" . Besides several known products, e.g. F e,(C O)y(P R)2 or F e4(C O)M(P R)2, and derivatives of the Fe2(C O)ft(P R X)2 butterfly type com plexes, the new octabisvalene shaped com pounds Fe4(C O)I2(P R)4 with R = M e. Ph. Tol were obtained and confirm ed by a crystal structure analysis for R = Me. Side products of the oxidative conversions were Fe4(C O),2(P 2M e2) (M e P -C 2H 4-P M e) and Fe4(C O)12(P2T ol2)(P H T ol)2 which can be derived from the octabisvalene type. Side products o f the irradiative conversions were F e,(C O)s(P P h)(P H P h)2 and (C O),F e(a-P H P h)2F e(C O)(Q ,H 8), the structure o f the latter being proved crystallographically. | | |
Reference
| Z. Naturforsch. 41b, 273 (1986); eingegangen am 23. O ktober 1985 | | |
Published
| 1986 | | |
Keywords
| Iron Phosphorus Cage Com pounds, Synthesis, Structure | | |
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| default:Reihe_B/41/ZNB-1986-41b-0273.pdf | | | Identifier
| ZNB-1986-41b-0273 | | | Volume
| 41 | |
51 | Author
| Rajib Lai, DorisW. Olters, Heinrich Vahrenkamp | Requires cookie* | | Title
| Preparation and Reactions of the T etrahedrane Molecule Fe2(CO )6(P-/m -C 4Hg)2  | | | Abstract
| The F e2P2 tetrahedrane com pound Fe2(CO)f,(P—fBu)2 has been obtained by oxidation of Fe2(C O)A («-PH rB u)2. D ue to its short (206 pm) P —P bond it can be called a diphosphene com plex. In contrast to this the P —P bond is its principal centre o f reactivity: CO , C2H 4, and C2H 2 (with concom itant hydrogenation) are inserted, H 2 and HC1 are added with P —P cleavage, and reductive cleavage occurs with L iB H E t,. The crystal structures of the title com pound and of its CO and C2H 4 insertion products have been determ ined. | | |
Reference
| Z. Naturforsch. 41b, 283—291 (1986); eingegangen am 23. Oktober 1985 | | |
Published
| 1986 | | |
Keywords
| Tetrahedrane M olecule F e2P2, Synthesis, Reactivity | | |
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| default:Reihe_B/41/ZNB-1986-41b-0283.pdf | | | Identifier
| ZNB-1986-41b-0283 | | | Volume
| 41 | |
52 | Author
| Chong Zheng, Roald Hoffmann | Requires cookie* | | Title
| An Unusual Electron Count and Electron-Deficient Multi-Center Bonding in One Class of Intermetallics: The BaAl4, CaAl2Zn2, CeMg2Si2 and FCC Al Structures  | | | Abstract
| Intermetallics, Electron-D eficient M ulti-Center Bonding The structural types discussed may be thought o f as being com posed o f two-dim ensional layers cleaved out o f the FCC lattice. Each layer has a square sublattice capped by apical atoms above and below four-fold hollow s. The electronic structure o f such an Al layer is constructed — it has eight low-lying bands per four A l. and two o f these bands are localized in apical Al's. pointing away from the layer. On stacking, bonds are formed betw een apical A l's, leading to the pushing up o f one Al"—A ln o* band, and a gap after 7 bands are filled. This is B aA l4, with Al4 2 A n alternative picture is o f delocalized five-center six-electron bonding in each hollow , closely related to the electron deficient bonding in B^H4. The bonding in C eA l:G a2 and C eM g2Si2 can be derived similarly, by perturbing the original B aA l4 case. A rationale for switching from BaA l4 to the C eM g2Si2 structural type for electron counts exceeding —16 for four atom s is given. Finally we relate these arguments to the high cohesive energy of Al metal. | | |
Reference
| Z. Naturforsch. 41b, 292 (1986); received October 23. 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0292.pdf | | | Identifier
| ZNB-1986-41b-0292 | | | Volume
| 41 | |
54 | Author
| HansJoachim Breunig, Ali Soltani-Neshan, KarlH. Äberle, M. Artin, D. Räger | Requires cookie* | | Title
| Synthese und Kristallstruktur von (PhSb)6 * 1,4-Dioxan, (PhSb)6 * Benzol und (PhSb)6* Toluol. Oxidation von Silylstibanen zu Siloxistibanen Synthesis and Crystal Structure of (PhSb)6 * 1,4-Dioxane, (PhSb)6-Benzene and (PhSb)6-Toluene. Oxidation of Silylstibanes to Siloxistibanes  | | | Abstract
| en, Fachbereich 2 (C h em ie), L eobener Straße, D-2800 Bremen 33 H exaphenyl-cyclo-hexastibane • 1,4-D ioxan e, Tris(trim ethylsiloxi)stibane, Phenylbis(trim ethylsiloxi)stibane, D iphenyl(trim ethylsiloxi)stibane | | |
Reference
| Z. Naturforsch. 41b, 327 (1986); eingegangen am 20. Dezember 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0327.pdf | | | Identifier
| ZNB-1986-41b-0327 | | | Volume
| 41 | |
55 | Author
| Helmut Endres, August Bongart, Dietrich Nöthe, Bernhard Rosenau | Requires cookie* | | Title
| Average Structure of Bis(oxamide oximato)nickel(II) X Dimethyl-tetracyanoquinodimethane, a "Charge Transfer" Compound with Mixed Stacks and Variable Paramagnetism  | | | Abstract
| Charge Transfer C om pound, Mixed Stacks, M odulated Structure The average unit cell o f the m ethanol solvate [Ni(C^HsN 40^),] x C 14H SN 4 x 2C H ,O H . Mr = 589.22 is triclinic. P I , a = 8.539(3). b = 8.937(3), c = 9.418(3) A~ a = 103.39(3). ß = 100.12(2). y = 105.39(2)°, V = 652.2 Ä \ Z = 1, dc = 1.50 gem 3. final Rn = 0.050 for 1580 observed independent reflections. Satellite reflections hint at a m odulation o f the structure in the ac plane. M ixed stacks o f alternating and mainly neutral metal com plex and M e:tcnq m olecules are formed. Crystals grown with electrochem ical reduction show a weak activated paramagnetism, those grown without electrochem ical support are diamagnetic. | | |
Reference
| Z. Naturforsch. 41b, 334 (1986); received Novem ber 22 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0334.pdf | | | Identifier
| ZNB-1986-41b-0334 | | | Volume
| 41 | |
56 | Author
| Helmut Endres, Gisela Liebich-Brudy | Requires cookie* | | Title
| [Bis(oxamidoxim)nickeI(II)]-[Bis(oxalato)platinat(II)]-Dihydrat x [Bis(oxamidoximato)nickel(II)]: Getrennte parallele Stapel im Verhältnis 2:1 [Bis(oxam ide oxim e)nickel(II)] [Bis(oxalato)platinate(II)] Dihydrate x [Bis(oxam ide oxim ato)nickel(II)]: Segregated Parallel Stacks in the Ratio 2:1  | | | Abstract
| Planar Chelate C om plexes, Segregated Stacks The com plex salt [N i(C 2H 6N 40 2) 2][Pt(C 20 4)2] x [N i(C 2H 5N 40 2)2] x 2 H 20 has been crystal lized by interdiffusion o f [N i(C jH 6N 40 2)3]Cl2 and K2[Pt(C20 4)2]. It is triclinic, P I , a = 3.673(1), b = 13.622(4), c = 14.371(4) A , a = 94.01(2), ß = 95.11(2), y = 92.14(2)°, V = 713.7(4) Ä 3, Z — 1, M r = 994.96, D x = 2.31 g e m "3, M oK a, A = 0.710 A, p = 61.3 cm "1, F(000) = 488, room temperature, wR = 0.034 for 3109 observed independent reflections. Segregated parallel stacks of [Pt(C20 4)2]2" anions, [N i(C 2H 6N 40 2)2]2+ cations, and neutral [Ni(C2H 5N 40 2)2] com plex m olecules run along a, and there is a 2:1 ratio o f Ni and Pt com plex stacks, interlinked by a network of strong intermolecular H bridges. The difference betw een the double positive and the neutral Ni com plexes is marginal, as the assignment o f the charges is based upon a slightly asymmetric intermolecular O -H ----O bridge, 1.06(7) and 1.44(8) Ä . | | |
Reference
| Z. Naturforsch. 41b, 339 (1986); eingegangen am 27. Novem ber 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0339.pdf | | | Identifier
| ZNB-1986-41b-0339 | | | Volume
| 41 | |
58 | Author
| Klaus Albert, Bernadette Peters, Ernst Bayer, Ulrich Treiber, Michael Zwilling | Requires cookie* | | Title
| Crosslinking of Gelatin with Formaldehyde; a 13C NMR Study Institute for Organic Chem istry, A u f der M orgenstelle 18, D-7400 Tübingen  | | | Abstract
| Aqueous Formalin Solution Compositions, Gelatin Cross-Linking. Gelatin Hardening, Static and Continuous Flow , 13C NM R The different species formed when gaseous formaldehyde is dissolved in aqueous medium are investigated by a l3C N M R flow-through technique and the spectra of commercial aqueous form aldehyde solutions containing m ethanol com pletely interpreted. I3C H ,0 was used to study the crosslinking reaction with gelatin which leads to m ethylene and oxym ethylene bridges betw een gelatin-am ino-groups. On ageing, hardened gelatin shows an increase in the number o f m ethylene bridges. | | |
Reference
| Z. Naturforsch. 41b, 351 (1986); received November 22 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0351.pdf | | | Identifier
| ZNB-1986-41b-0351 | | | Volume
| 41 | |
59 | Author
| E. Kocha, H. K. Neifelb, E. Bayera | Requires cookie* | | Title
| Synthesis of New Complexons: N-Hydroxy-a,a'-iminodipropionic-and N-Hydroxyiminodiacetic Acid  | | | Abstract
| C om plexons, Synthesis, N-Hydroxyim inodicarboxylic Acids R eaction conditions for the synthesis of N -hydroxy-a,a'-im inodipropionic acid, the ligand o f naturally occurring amavadin, and N-hydroxyiminodiacetic acid, the first m ember o f this class of com plexon s, have been investigated. Am avadin (1), the complex of V O 2* with two m ole cules o f N -hydroxy-a,a'-im inodipropionic acid (2a) is | | |
Reference
| Z. Naturforsch. 41b, 359 (1986); received N ovem ber 12 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0359.pdf | | | Identifier
| ZNB-1986-41b-0359 | | | Volume
| 41 | |
60 | Author
| M.M A Bou-Elzahab, S.N A Yyad, M. T. Zimaity | Requires cookie* | | Title
| Ring Expansion of Carbocyclic ß-Keto-ester with Acetylenic Esters  | | | Abstract
| D iaryl-2-cyclohexen-l-one, B icyclooctadienone, Ring Expansion R eaction. C yclooctadienone The y3-keto-ester lb and 7 reacted with dimethyl acetylenedicarboxylate (D M A D) to give the cyclooctad ienon e derivatives (2a and 3b), the acid hydrolysis o f which afforded the anhydride 4. A lso la , b reacted with ethyl propiolate and gave substituted cyclooctadienone (6a, b). M ichael reaction o f 11 with D M A D gave adduct 12 which underwent cyclization via photo-cycloaddition (2 + 2) to give the photo-product (14). | | |
Reference
| Z. Naturforsch. 41b, 363 (1986); received May 15/N ovem ber 27 1985 | | |
Published
| 1986 | | |
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| default:Reihe_B/41/ZNB-1986-41b-0363.pdf | | | Identifier
| ZNB-1986-41b-0363 | | | Volume
| 41 | |
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