- Biphenylene dimer. Molecular fragment of a two-dimensional carbon net and double-stranded polymer
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Biphenylene dimers, which may be considered as 'macrocyclic' 2 x 2 fragments of net 1 and dimeric fragments of a double-stranded polymer, 5, are prepared. X-ray crystallography on two polymorphs of the dimer 9 reveals that its bond alternation is analogous to that in biphenylene; the tetraphenylene part of 9 has approximately C(2h) symmetry with a small dihedral angle (.-,M+ (M = Li, K) and 92-,2M+ (M = Li, K), were generated and characterized by ESR, NMR, and UV-vis spectroscopies. The spectral data for the dianions are compatible with classical structures; no evidence for 'in-plane aromaticity' is found. For polymer 5, a localized band and large density of states near the Fermi level are found, using extended Huckel theory calculations.
- Rajca, Andrzej,Safronov, Andrej,Rajca, Suchada,Ross II, Charles R.,Stezowski, John J.
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- Transmetalation and Reverse Transmetalation on Ortho-Activated Aromatic Compounds: A Direct Route to o,o'-Disubstituted Benzenes
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Mercury Substitution ortho to appropriately activated benzenes was achieved by using the reagent lithium tetramethylpiperidide (LiTMP)/ mercuric chloride.LiTMP provides for lithiation ortho to the activating group; HgCl2 functions as an in situ trap effecting mercury-for-lithium transmetalation.Ortho, ortho'-dimercuration was also observed; this occurs by iteration of the transmetalation process.The effects of major variables on these reactions were studied by using primarily N,N-diethylbenzamide as the activated substrate.Isopropyl benzoate, 2-phenyl-4,4-dimethyloxazoline, etc. were found to behave similarly.The mercurated aromatics could be converted to the corresponding haloaromatics in excellent yield, providing, for example, a good synthesis of o,o'-diiodo-N,N-diethylbenzamide, otherwise difficultly accessible.Reverse transmetalation methodology was employed to prepare o,o'-dilithiated-N,N-diethylbenzamide, which was characterized by its reactions with electrophiles.
- Eaton, Philip E.,Martin, Ronald M.
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- BORON-CONTAINING SMALL MOLECULES
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This invention provides novel compounds, methods of using the compounds, and pharmaceutical formulations comprising the compounds.
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Paragraph 0331; 0332
(2013/06/04)
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- 1-Aryl-3,3-dialkyltriazenes: A convenient synthesis from dry arenediazonium o-benzenedisulfonimides - A high yield break down to the starting dry salts and efficient conversions to aryl iodides, bromides and chlorides
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This research comprises three parts. The first part regards the synthesis of 1-aryl-3,3-dialkyltriazenes 3 by reaction of dry arenediazonium o-benzenedisulfonimides 1, also coming from weakly basic aromatic amines with dimethylamine or diethylamine in aqueous solution at 0-5 °C. Yields were usually greater than 90% and there was the possibility of recovering the o-benzenedisulfonimide (5), which could be reused to prepare the salts 1. In the second part it was demonstrated that there is the possibility of reconverting the triazenes 3 into the starting stable dry salts 1 by using 5 as acid. The reactions were carried out in glacial acetic acid at 50-55 °C and normally afforded salts 1 in yields of around 90-99%. The third part concerns the setting up of two procedures for the conversion of 3 to aryl iodides 9, bromides 10 and chlorides 11. Procedure A used the corresponding aqueous hydrogen halides in acetonitrile at r.t. or 60 °C, sometimes in the presence of aqueous HBF4, sometimes Cu powder (25 examples, yields 65%-88%). Procedure B usually used anhydrous methanesulfonic acid and tetraalkylammonium halides in anhydrous acetonitrile at temperatures varying from r.t. to 80 °C, sometimes in the presence of Cu (16 examples, yields 65-88%).
- Barbero,Degani,Diulgheroff,Dughera,Fochi
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p. 2180 - 2190
(2007/10/03)
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