- Synthesis of alkylammonium tosylates with poly{[4-hydroxy(tosyloxy)iodo] styrene}
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Several primary carboxamides (RCONH2) were converted to the corresponding alkylammonium tosylates (RN+H3 -OTs) with poly{[4-hydroxy (tosyloxy) iodo]styrene} (PSHTIB) in yields ranging from 60% to 90%.
- Liu, Shi Juan,Zhang, Ji Zhen,Tian, Guan Rong,Liu, Ping
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p. 823 - 827
(2007/10/03)
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- New upper rim pyridine-bridged calix[4]arenes: Synthesis and complexation properties toward neutral molecules and ammonium ions in organic media
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A new series of calix[4]arenes, diametrically bridged at the upper rim with pyridino systems, has been synthesized. The shape, rigidity, and chemical structure of the bridge influence the host-guest complexation properties of these systems in solution toward several neutral molecules having acidic C-H bonds. Additionally, selective complexation of methylammonium tosylate in comparison with other ammonium salts has been observed and the strength of this complexation enhanced by electron-donor ability of the p-substituent on the pyridine moiety of the calixarene host. X-ray crystal structures of endo complexes of host 5 with malononitrile and nitromethane have been resolved, verifying specific C-H bonding with the hard oxygen and nitrogen atoms of the bridge and the soft aromatic ring of the calixarene.
- Arduini, Arturo,McGregor, William M.,Pochini, Andrea,Secchi, Andrea,Ugozzoli, Franco,Ungaro, Rocco
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p. 6881 - 6887
(2007/10/03)
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- Direct Conversion of Aliphatic Carboxamides to Alkylammonium Tosylates with benzene
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The utility of benzene (2) as a "Hofmann reagent" has been explored.Treatment of various primary, aliphatic carboxamides (RCONH2, R = methyl, ethyl, isopropyl, tert-butyl, n-pentyl, n-heptyl, undecyl, allyl, benzyl, cyclobutyl, cyclohexyl) with 2 in acetonitrile at reflux gave the corresponding alkylammonium tosylates (RN+H3-OTs) in yields ranging from 57percent to 94percent.The alkylammonium tosylates separated directly from the solvent when the reaction mixtures were kept at room temperature or below.When α-phenylacetamide was allowed to react with 2 in ethanol, ethyl benzylcarbamate (4) was obtained in 50percent yield, a result consistent with the intermediate existence of benzyl isocyanate in this reaction.A mechanism for the conversion of carboxamides by 2 to alkylammonium tosylates, involving the initial formation of N-phenyl iodonio amides and their collapse to iodobenzene and alkyl isocyanates, is proposed.The reaction of malonamide with 2 in acetonitrile followed a divergent course: 2-(tosyloxy)malonamide (3) was obtained in ca. 81percent yield (crude).
- Lazbin, I. Mark,Koser, Gerald F.
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p. 2669 - 2671
(2007/10/02)
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