- Synthesis and Bowl-in-Bowl Assembly of a Geodesic Phenylene Bowl
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A phenylene multiring with a corannulenoidal skeleton was synthesized. Geodesic constraints over 20 phenylene panels resulted in its nanometer-sized, bowl-shaped molecular structure, which was unequivocally revealed by crystallographic analysis. The crystal structure also showed the presence of a bowl-in-bowl dimeric assembly, which was driven by entropic factors in solution.
- Ikemoto, Koki,Kobayashi, Ryo,Sato, Sota,Isobe, Hiroyuki
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- Access to "friedel-Crafts-Restricted" tert -alkyl aromatics by activation/methylation of tertiary benzylic alcohols
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Herein we describe a two-step protocol to prepare m-tert-alkylbenzenes. The appropriate tertiary benzylic alcohols are activated with SOCl2 or concentrated HCl and then treated with trimethylaluminum, affording the desired products in 68-97% yields (22 examples). This reaction sequence is successful in the presence of a variety of functional groups, including acid-sensitive and Lewis-basic groups. In addition to t-Bu groups, 1,1-dimethylpropyl and 1-ethyl-1-methylpropyl groups can also be installed using this method.
- Hartsel, Joshua A.,Craft, Derek T.,Chen, Qiao-Hong,Ma, Ming,Carlier, Paul R.
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p. 3127 - 3133
(2012/05/20)
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- PROCESS FOR HALOGENATION OF BENZENE AND BENZENE DERIVATIVES
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In a process of halogenation of benzene or benzene derivatives, di-substituted halobenzene derivatives having para-aromatic compounds or tri-substituted halobenzene derivatives having 1,2,4-substituted aromatic compounds are selectively produced. In halogenation of benzene or benzene derivatives, a fluorine-containing zeolite catalyst such as L-type zeolite, or a zeolite catalyst having the crystal size of at most 100 nm is used. The reaction is preferably effected in the presence of a solvent, and the solvent is preferably a halogenated compound.
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Page/Page column 19; 20
(2008/06/13)
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- Versatility of Zeolites as Catalysts for Ring or Side-Chain Aromatic Chlorinations by Sulfuryl Chloride
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Zeolites catalyze chlorination of aromatics by sulfuryl chloride SO2Cl2.It is possible by an appropriate choice of the catalyst to effect at will, with very high selectivity, either the ring or the side-chain chlorination.Zeolite ZF520 is the choice catalyst for the former, because of its high Broensted acidity.Zeolite NaX (13X) is a fine catalyst for the latter, free-radical chlorination; the reaction is best effected in the presence of a light source; the catalyst can be reused many times with no loss in activity.Both reaction modes, the ionic (ring chlorination)and the radical (side-chain substitution), are likely to occur outside of the channel network in the microporous solid.The effects of various experimental factors - such as the nature of the solvent, the reaction time and temperature, the Broensted acidity of the solid support, the presence of radical inhibitors, and the quantity of catalysts - were investigated.The procedures resulting from this study are very easy to implement in practice and are quite effective.
- Delaude, Lionel,Laszlo, Pierre
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p. 5260 - 5269
(2007/10/02)
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- Highly para-Selective Mono-Chlorination of Aromatic Compounds Under Mild Conditions by t-Butyl Hypochlorite in the Presence of Zeolites
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t-Butyl hypochlorite supported on H(1+), Na(1+) faujasite X (zeolite X) produces para-selective monochlorination of alkyl-, phenyl-, and halobenzenes under mild conditions; for example, chlorobenzene in acetonitrile (at 40 deg C) is chlorinated in high yield of isolated product (92percent) to give dichlorobenzene with an isomer ratio 97percent para/3percent ortho.
- Smith, Keith,Butters, Michael,Nay, Barry
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p. 1157 - 1158
(2007/10/02)
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