- Diamination of phenylene dihalides catalyzed by a dicopper complex
-
Diamination of phenylene dihalides with aqueous ammonia to give the corresponding phenylenediamines can be achieved by using a dicopper complex [Cu2(bpnp)(OH)(CF3COO)3] (1) (bpnp = 2,7-bis(pyridine-2-yl)-l,8-naphthyridine) as the catalyst in the presence of Bu4NBr and Cs2CO3 in high yields. In addition, 1,3,5-tribromobenzene was converted into benzenetriamine quantitatively under the same conditions. This method offers a new opportunity, particularly simplifying steps and increasing yields, for the preparation of aryl diamines.
- Liao, Bei-Sih,Liu, Shiuh-Tzung
-
experimental part
p. 6653 - 6656
(2012/10/07)
-
- Design and synthesis of urea-linked aromatic oligomers-a route towards convoluted foldamers
-
Herein we report the design and synthesis of crescent-shaped and helical urea-based foldamers, the curvature of which is controlled by varying the constituent building blocks and their connectivity. These oligomers are comprised of two, three or five alternating aromatic heterocycles (pyridazine, pyrimidine or pyrazine) and methyl-substituted aromatic carbocycles (tolyl, o-xylyl or m-xylyl) connected together through urea linkages. A crescent-shaped conformational preference is encoded within these π-conjugated urea-linked oligomers based on intramolecular hydrogen bonding and steric interactions; the degree of curvature is tuned by the urea connectivity to the heterocycles and the aryl groups. NMR characterization of these foldamers confirms the intramolecular hydrogen-bonded conformation expected (Z,E configuration of the urea bond) in both the pyridazyl and pyrimidyl foldamers in solution. An X-ray crystal structure of the N3,N6-diisobutylpyridazine-4,6- diamine-o-tolyl urea-linked foldamer (4) confirms the presence of N-H...N hydrogen bonds between the heterocyclic nitrogen atom and the free hydrogen of the urea linkage. Additionally, the tolyl methyl group interacts unfavourably with the urea carbonyl oxygen, thus destabilising the alternate planar conformation.
- Mousseau, James J.,Xing, Liyan,Tang, Nathalie,Cuccia, Louis A.
-
supporting information; experimental part
p. 10030 - 10038
(2010/06/15)
-
- Methodology for easy access to large sidewall bis-troeger's bases
-
4,6-Bis(bromomethyl)-N1,N3-bis(terf-butoxycarbonyl) benzene-1,3-diamine is intioduced as a general starting compound for the preparation of bis-Troeger's base (bisTB) derivatives In excellent yield in just two steps. The synthetic se
- Havlik, Martin,Kral, Vladimir,Dolensky, Bohumil
-
p. 392 - 402
(2008/09/19)
-
- Energetics of a low barrier hydrogen bond in nonpolar solvents
-
A measure of the strength of a low barrier hydrogen bond (LBHB) in apolar organic media was obtained using synthetic molecules derived from Kemp's triacid. The structures feature unusually rigid conformations that enforce intramolecular hydrogen bonds in
- Kato, Yoko,Toledo, Leticia M.,Rebek Jr., Julius
-
p. 8575 - 8579
(2007/10/03)
-
- N,N-Diacylaminoperfluoroalkanesulfonanilides and derivatives thereof
-
Disclosure is made of certain optionally substituted N,N-diacylaminoperfluoroalkanesulfonanilides and agriculturally acceptable salts thereof which are useful as herbicides and plant growth regulators.
- -
-
-
- Catalytic Reduction of Dinitroaromatic Compounds with Hydrogen Sulfide-Carbon Monoxide. A Novel, Low-cost Replacement for Elemental Hydrogen
-
A mixed reducing gas consisting of H2S and CO, when used with sulfided Fe on Al2O3 heterogeneous catalysts, has successfully reduced dinitroaromatic to diaminoaromatic compounds in high yield and conversion.
- Ratcliffe, Charles T.,Pap, Geza
-
p. 260 - 261
(2007/10/02)
-