- Microwave-assisted synthesis of bidentate chiral unsymmetrical urea derivatives of p-tert-butylcalix[4]arene and their anion recognition properties
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Four new derivatives of p-t-butylcalix[4]arene containing two (1,3-distal) chiral unsymmetrical urea moieties at the lower rim were synthesised in four steps. Their anion recognition properties toward MeCO2-, H2PO4-, NOsu
- Wang, Xiaohong,Zhao, Zhigang,Chen, Bailing,Li, Xiaoxiao,Liu, Min
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- Synthesis of novel chiral cholic acid-based molecular tweezers containing unsymmetrically disubstituted urea units using microwave irradiation
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An efficient procedure has been developed for the synthesis of new chiral cholic acid molecular tweezer artificial receptors by linking an unsymmetrically disubstituted urea to methyl deoxycholate via a carbonate chain using microwave irradiation. The structures of these new receptors were confirmed by 1H NMR, IR, MS spectra and elemental analysis. Their binding properties were examined by UV-Vis spectra titration. The preliminary results indicate that these molecular tweezers not only recognised anions, but also showed good enantioselectivity for D-amino acid methyl esters.
- Zeng, Bitao,Zhao, Zhigang,Zhou, Lijun,Li, Qinghan
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scheme or table
p. 206 - 209
(2012/09/08)
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- Solvent-free synthesis of novel chiral unsymmetrical urea molecular tweezers under microwave irradiation
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Seven novel chiral unsymmetrical urea molecular tweezers based on 1, 3-phenoxyacetic acid have been designed and synthesised using solid K 2CO3 as supporter in the solvent-free conditions under microwave irradiation. This method is simple, fast, efficient and eco-friendly. The structures of target compounds were characterised by IR, 1H NMR, MS spectra and elemental analyses and their molecular recognition properties were investigated by UV-Vis spectral titration. The preliminary results indicated that these molecular tweezers possess good selectivity for D/L amino acid methyl esters and some anions.
- Zhao, Zhigang,Xia, Zhenyang,Li, Xiaorui,Shi, Peiyu
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scheme or table
p. 47 - 50
(2011/05/04)
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- The synthesis of novel chiral cholic acid-based molecular clefts containing unsymmetrically disubstituted urea unit
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A novel type of chiral molecular clefts has been designed and synthesized by linking an unsymmetrically disubstituted urea to methyl deoxycholate via a carbonate chain. The structures of these new receptors 3a-d were confirmed by 1H NMR, IR, MS
- Mu, Qi Ming,Xue, Cui Hua,Zhang, Qing Hua,Chen, Shu Hua
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p. 3055 - 3061
(2007/10/03)
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- Investigation of the Mitsunobu reaction of N-(2-hydroxyethyl)-N'- phenyl-ureas
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The Mitsunobu reaction of N-(2-hydroxyethyl)-ureas 1 using PPh3 and EtO2CN=NCO2Et led to the mixture of N- and O-alkylation products or a single isomer depending on the substrates.
- Kim, Taek Hyeon,Lee, Gue-Jae,Cha, Mi-Hyun
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p. 2753 - 2758
(2007/10/03)
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