doi: 10.1080/10426509708044192pmid: N/A
Abstract This is a scanned image of the original Editorial Board page(s) for this issue.
Tlahuextl, Margarita; Martínez-martínez, ; De Jesús Rosales-Hoz, María; Contreras, Rosalinda
doi: 10.1080/10426509708044194pmid: N/A
Abstract Four new tricyclophosphoranes 1b-4b were synthesized derived from N,N′-bis[2-hydroxy phenyl]ethylenediamine (1a), N,N′-bis[2-hydroxyphenyl]oxamide (a), N,N′-bis[(-)-norephedrinelethylene (3a), N,N′-bis[(-)-norpseudoephedrine]oxalyl (4a), The syntheses of compounds 3b and 4b were completely stereoselective giving only one epimer in each case (epimer helix Δ, 3b; helix Λ, 4b). For both the phosphorus configuration was established. The phosphorus atoms in 1b-4b adopt a trigonal bipyramid geometry with an oxygen and a nitrogen atoms in apical positions as deduced from 31P, 13C, 1H and 1H/13C HETCOR NMR studies and confirmed by the x-ray diffraction structure of 3b. Compound 1b reacts with BH3-THF giving the N→BH3 adduct 1c; borane coordinates to the tetrahedral apical nitrogen atom. Compound 3b reacted with BH3 giving two isomeric adducts, 3c and 3c'. The main product 3c came from attack of BH3 on the equatorial nitrogen followed by epimerization of the phosphorus atom giving the molecule with the N→BH3 group in an apical position and helicoidal structure Λ. The minor isomer 3c' came directly from addition of BH3 Sn an apical nitrogen atom giving the Δ helix.
Lartigue, Marie-Laure; Caminade, Anne-Marie; Majoral, Jean Pierre
doi: 10.1080/10426509708044195pmid: N/A
Abstract The synthesis of phosphoryl-based dendrimers is described, using the reiteration of a two-steps process which gives alternatively aldehyde and P(O)Cl2 end groups. The synthesis has been carried out up to the third generation, to give a compound which bears 24 chlorine atoms on the surface. Preliminary experiments on the first generation of the dendrimer possessing either 6 CHO or 6 Cl groups show that these compounds display a versatile reactivity. For instance, α, β-unsaturated esters, crown ethers, chiral phosphine sulfides or diallylamine are grafted on the surface, and the resulting dendrimers are isolated in good to nearly quantitative yields.
Levsen, Steven M.; Peterson, Andrew C.; Cremer, Sheldon E.
doi: 10.1080/10426509708044196pmid: N/A
Abstract The secondary phosphonate ester endo-2-(diethoxyphosphoryl)bicyclo[2.2.1]heptane 6 was prepared in stereoselective fashion for the first time by hydrogenation of 2-(diethoxyphosphoryl)bicyclo[2.2.1]hept-2-ene 1. The precursor vinylphosphonate 1 was prepared by two different routes. Of these, the direct preparation of phosphonate 6 from norbornene in 76% overall yield proved to be the most convenient. Treatment of 6 with PCI5 at 105 °C gave exclusively endo dichloride 7. This same reaction at 120–140 °C gave a 3:1 ratio of endo- to exo-phosphonic dichlorides 7 and 8, respectively. When pure 7 or 8 were exposed to PC15 at 120–140 °C isomerization of each occurred.
Zimmer, Hans; Mark, Harry B.; Wehmeier, Mike
doi: 10.1080/10426509708044197pmid: N/A
Abstract A convenient synthesis of a number of 3,3′-bridged-bis-2,2′-thienyls as potential building blocks for novel conducting polymers is reported. The UV-spectra and oxidation potentials of these novel compounds are given. Although the UV-spectra correlated to the degree of coplanarity of these species, the oxidation potentials did not correlate, and no tendency to polymerize was observed for the N-bridged thienyls, 1a-1d, 2a-2c.This behavior is in contrast to results found for other 2,2′-bithienyls. These findings are explained by nitrogen and sulfur adsorption orientation of the N-bridged biethienyl molecules on the electrode surface prior to electron transfer
Münchenberg, J.; Thönnessen, H.; Jones, P. G.; Schmutzler, R.
doi: 10.1080/10426509708044198pmid: N/A
Abstract The N-(N′,N′,N′,N′-tetraorgano)guanidine-substituted dichlorophosphines 3a - 3c were prepared by the reaction of phosphorus trichloride with the corresponding guanidine or N-lithiated guanidine. The high-field shift of the α(31P) values of 3a - 3c reflects the strong electron-donating effect of the guanidinyl substituents. Attempts to achieve further substitution of chlorine in PCl3 by N′,N′,N′,N′-tehamethylguanidine (HTMG) 1a (employed as such or as its N-trimethylsilyl derivative, TMSTMG, 2) led to the formation of tris-N-(N′,N′,N′,N′-tetramethyl)guanidinylphosphonium salts such as 4. A salt containing the same cation was obtained from the reaction of bis-N-(N′,N′,N′,N′-tetramethyl)guanidinyltrichlorophosphorane 5 with magnesium. Difluoro-N-(N′,N′,N′,N′-tetramethyl)guanidinylphosphine 6 was obtained from difluorochlorophosphine and HTMG 1a. Hydrolysis of 6 led, depending upon the conditions of the reaction, either to N′,N′,N′,N′-tetramethylguanidinium phosphonofluoridate 7 or tris-N-(N′N,N′,N′-tetramethyl)guanidinylphosphonium pentafluorophosphate 8. A single crystal X-ray structure determination of 8 revealed a disordered anion and a cation with short P-N bonds, attributed to pπ-dπ: interaction. Dimethylamino-bis-N-(N′,N′,N′,N′-tetramethyl)guanidinyl-phosphine 9 and the chloro-diorganoamino-N-(N′,N′,N′,N′-tetramethyl)guanidinyl-phosphines 10 and 11 were obtained from the corresponding dichlorodiorganoaminophosphines and HTMG 1a or N-trimethylsilyl-(N′,N′,N′,N′-tetramethyl)guanidine 2.
doi: 10.1080/10426509708044199pmid: N/A
Abstract The synthesis of amino functionalized cyclotrisiloxanes 4a and 4b can be achieved by novel routes. Controlled hydrolysis of the dichloroaminosilanes 1a, 1b in the presence of triethylamine leads to the novel bis(amino)chlorosilanols 2a, 2b. They are colourless solids which sublime without decomposition despite the fact that they combine a Cl and OH function at the silicon atom. In the crystalline phase the compounds form tetramers by oxygen hydrogen bridges as found from X-ray diffraction on single crystals of 2b. On treatment of 2a and 2b with BuLi the lithium salts 3a and 3b are formed, which crystallize as tetramers in a cubane like oxygen/lithium cage, in which the lithium atoms are coordinated by three oxygen and one chlorine atom (X-ray structure analysis on 3a (Li-O 1.923(6) - 1.993(6)Å Li-C12.626(6)Å). The lithium compounds 3a and 3b show an exceptional thermal stability. They can be recrystallized in hot non-polar solvents without elimination of LiCl. Boiling 3a and 3b in THF for 50 hours nevertheless leads to the elimination of LiCl and the formation of the amino functionalized cyclotrisiloxanes 4a and 4b as colourless, sublimable compounds. These compounds have been characterized by single X-ray diffraction techniques: they have a planar Si3O3 ring in common with three spirocyclic silicon atoms. Die Synthese von amino-funktionalisierten Cyclotrisiloxanen 4a und 4b über einen neuen Syntheseweg wird beschrieben. So führt zunächst die kontrollierte Hydrolyse der Dichlorocyclodisilazane 1a, 1b in Gegenwart von Triethylamin zu neuen Bis(amino)chlorsilanolen 2a und 2b. 2a und 2b stellen farblose Feststoffe dar, die ohne Zersetzung sublimieren, obwohl sie am Siliciumatom eine Cl und OH Funktion beinhalten. Im kristallinen Zustand liegen die Verbindungen durch Ausbildung von Sauerstoff-Wasserstoff- Sauerstoff-Brücken als Tetramere vor, wie durch eine Röntgenstrukturanalyse an 2b gezeigt werden kann. Mit n-Butyllithium reagieren 2a und 2b zu den Lithiumverbindungen 3a und 3b. die als Tetramere nit einem Sauerstoff/Lithium-Cubangerüst im Inneren kristallisieren, in welchem das Lithiumatom durch drei Sauerstoffatome und ein Chloratom koordiniert ist (Röntgenstrukturanalyse von 3a, Li-O 1.923(6) - 1.993(6)Å, Li-Cl 2.626(6)Å). Die Lithiumverbindungen 3a und 3b zeigen eine außrordentliche thermische Stabilität. Sie können aus siedenden unpolaren Lösemitteln ohne LiCl-Eliminierung umkristallisiert werden. Erst 50 h Kochen unter Rückfluß in Tetrahydrofuran führt zur LiCl-Abspaltung und zur Bildung der aminfunktionalisierten Cyclotrisiloxanen 4a und 4b, die farblose, sublimierbare Verbindungen darstellen. Die Charakterisierung durch Einkristallröntgenstrukturanalysen zeigt einen planaren Si3O3- Ring mit drei spirocyclischen Siliciumatomen.
Nifantiev, E. E.; Zavalishina, A. I.; Orzhekovskaya, E. I.; Nurkulov, N. N.; Vasyanina, L. K.; Bekker, A. R.; Belskii, V. K.; Stash, A. I.
doi: 10.1080/10426509708044200pmid: N/A
Abstract The synthesis, structure and chemical features of a new class of tricyclic phosphorus-containing heterocycles are reported. Special attention is paid to the dynamics of molecules and their tendency to enter into elimination reactions. A possibility to synthesize relatively stable dibenzo-1,3,2-diazaphosphepene containing a two-coordinated phosphorus atom is considered.
doi: 10.1080/10426509708044201pmid: N/A
Abstract Reaction of dialkyl 1-hydroxy aminophosphonates with aldehydes leads to a nitrone bearing phosphonate moiety. The phosphoryl nitrone thus obtained provides (Z) 2-substituted isoxazolinyl methylphosphonates upon reaction with maleic anhydride as a 1,3-dipolar cycloaddition product.
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