- Synthesis of Tetranuclear Iron-Sulphur Protein Analogues with Tetrathiol Ligands attached to Macrocycles which provide Intramolecular Hydrophobic Domains
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A new type of active-site analogues for 4Fe-4S iron-sulphur proteins is introduced, where the active site core is surrounded by an intramolecular hydrophobic domain formed by a 36-membered ring consisting of a methylene backbone.An efficient synthesis of the macrocyclic ligands 1,10,19,28-tetra(4-mercaptobenzoyl)-1,10,19,28-tetra-azacyclohexatriacontane and 1,10,19,28--1,10,19,28-tetra-azacyclohexatriacontane and 1,10,19,28-tetra-(3-mercapto-3-methylbutanoyl)-1,10,19,28-tetra-azacyclohexatriacontane is described.Their reaction with t)4>2- afforded novel clusters in good yields (70 - 90percent) as black powders with m.p. > 300 deg C.They dissolve in dimethylformamide, dimethyl sulphoxide, and propylene carbonate.Complex formation with Fe4S4 clusters was mainly demonstrated by u.v.-visible and n.m.r. studies and the properties of the new clusters are discussed.
- Okuno, Hiroaki (Yohmei),Uoto, Kouichi,Tomohiro, Takenori,Youinou, Marie-Therese
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- MACROHETEROCYCES. XXXVI. A CONVENIENT METHOD FOR SYNTHESIS OF DI- AND POLYAZACROWN ETHERS
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A method is proposed for the production of di- and polyazacrown ethers by the condensation of bissulfonamides with dibromides or ditosyloxy derivatives in a two-phase aqueous alkali-toluene (benzene) system.The optimum concentration range for the substrate and the alkylating agent is 0.017-0.1 M.The catalytic activity of the quaternary ammonium salts decreases in the order (Bu)4NI > (Bu4)NBr > (Bu4)NCl > (Bu4)NHSO4 > (C2H5)3C6H5CH2NCl >> (Et)4NI > (Et)4NBr.The highest yields of te 12-membered azacrown ethers are obtained in the presence of lithium hyroxide, and the largest yields of the crown ethers with larger ring sizes are obtained in the presence of sodium or potassium hydroxide, and this is probably due to the matrix effects of the cation.
- Luk'yanenko, N.G.,Basok, S.S.,Filonova, L.K.
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p. 1562 - 1571
(2007/10/02)
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- Preferential Introduction of a Pyridylmethyl Group into Sulfonamides as an Approach to an Intramolecular Transimination
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N,N'-Bis(p-tolylsulfonyl)-α,ω-alkanediamine disodium salts (n=3, 4, 5, 6, 7, 8, 9, 10) were subjected to monopyridylmethylation by the reaction with 5'-deoxy-5'-chloro- or 5'-deoxy-2'-chloro-3,4'-O-isopropylidenepyridoxine hydrochloride, accompanied by th
- Iwata, Masaaki,Kuzuhara, Hiroyoshi
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p. 2153 - 2157
(2007/10/02)
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- Dynamic Protection of Amines using 18-Crown-6
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The regioselectivity of diamine monoacylation has been controlled by selective complexation with 18-crown-6 and a proton source.
- Barrett, Anthony G. M.,Lana, J. Carlos A.,Tograie, Shahrzad
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p. 300 - 301
(2007/10/02)
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