4-(2-Benzyloxyethoxycarbonyl)-2-oxetanone, an β-substituted-β-lactones with latent pendent hydroxyl groups,was synthesized from L-aspartic acid. Firstly, bromosuccinic acid was synthesized from L-aspartic acid and i...4-(2-Benzyloxyethoxycarbonyl)-2-oxetanone, an β-substituted-β-lactones with latent pendent hydroxyl groups,was synthesized from L-aspartic acid. Firstly, bromosuccinic acid was synthesized from L-aspartic acid and it was dehydrated to bromosuccinic anhydride by TFFA. Then the anhydride was alcoholysized to the monoester mixture by 2-benzyloxy ethanol. Finally, the novel monomer was got through a intromolecular cyclization of the mixture ester, and then it was further purified by silicon gel chromatogram. The product and the intermediates were characterized by {{}+1H NMR}, {}+{13}C NMR and elemental analysis. In addition, 2-benzyloxy ethanol was synthesized with a simplyified procedure and high yield by using Williamson method.展开更多
Two new substituted calix[4]arene derivatives 2 and 3 were synthesized by the reaction of calix[4]arene with methyl o-bromomethyl-benzoate in the presence of potassium carbonate under nitrogen. Their compositions and ...Two new substituted calix[4]arene derivatives 2 and 3 were synthesized by the reaction of calix[4]arene with methyl o-bromomethyl-benzoate in the presence of potassium carbonate under nitrogen. Their compositions and structures were confirmed by elemental analysis, IR, 1H NMR and 13C NMR. Both the compounds are in the cone conformation. The percent extraction of the tetrasubstituted calix[4]arene derivative 2 for Li +, Na +, K + and Cs + are 6.8, 19.4, 69.8 and 7.1, respectively, indicating that derivative 2 extracts K + better than Li +, Na + and Cs +. The higher selective complexation of compound 2 with K + elucidated that the radius of potassium cation may be matched with the inclusion cavity formed by the carbonyl and phenoxy groups. There is only a little extractivity of disubstituted calix[4]arene derivative 3 for alkali metal ions.展开更多
The synthesis of a novel host blocked in the cone conformation and bearing m-methoxycarbonylbenzyl groups at the lower rim is described. X-ray crystal structure analysis revealed that action of one molecule of compoun...The synthesis of a novel host blocked in the cone conformation and bearing m-methoxycarbonylbenzyl groups at the lower rim is described. X-ray crystal structure analysis revealed that action of one molecule of compound upon one molecule of CH 3CN or one molecule of CH 3NO 2, forms an intramolecular inclusion complex, respectively, by CH 3-π interactions. The complex of L with tetrabutyl ammonium bromide(TBAB), L·TBAB, was obtained. The results of DTA-TG and XRD analysis of L·TBAB can also be considered as an intramolecular inclusion complex.展开更多
R)-Hydroxy-(S)-proline was N-protected by reaction with di-tert-butyl pyrocarbonate to give N-Boc-(4R)-hydroxy-(S)-proline, which was treated with NaH in anhydrous tetrahydrofuran and followed by etherification with P...R)-Hydroxy-(S)-proline was N-protected by reaction with di-tert-butyl pyrocarbonate to give N-Boc-(4R)-hydroxy-(S)-proline, which was treated with NaH in anhydrous tetrahydrofuran and followed by etherification with PhCH 2Br to form the N-Boc-(4R)-benzyloxy-(S)-proline, which, after removal of the protecting group with CF 3COOH gave the title compound. As an efficient catalyst for the direct asymmetryic aldol reaction the compound gave products in yield ranged from 58% to 77% with enantiomeric excess up to 88%.展开更多
文摘4-(2-Benzyloxyethoxycarbonyl)-2-oxetanone, an β-substituted-β-lactones with latent pendent hydroxyl groups,was synthesized from L-aspartic acid. Firstly, bromosuccinic acid was synthesized from L-aspartic acid and it was dehydrated to bromosuccinic anhydride by TFFA. Then the anhydride was alcoholysized to the monoester mixture by 2-benzyloxy ethanol. Finally, the novel monomer was got through a intromolecular cyclization of the mixture ester, and then it was further purified by silicon gel chromatogram. The product and the intermediates were characterized by {{}+1H NMR}, {}+{13}C NMR and elemental analysis. In addition, 2-benzyloxy ethanol was synthesized with a simplyified procedure and high yield by using Williamson method.
文摘Two new substituted calix[4]arene derivatives 2 and 3 were synthesized by the reaction of calix[4]arene with methyl o-bromomethyl-benzoate in the presence of potassium carbonate under nitrogen. Their compositions and structures were confirmed by elemental analysis, IR, 1H NMR and 13C NMR. Both the compounds are in the cone conformation. The percent extraction of the tetrasubstituted calix[4]arene derivative 2 for Li +, Na +, K + and Cs + are 6.8, 19.4, 69.8 and 7.1, respectively, indicating that derivative 2 extracts K + better than Li +, Na + and Cs +. The higher selective complexation of compound 2 with K + elucidated that the radius of potassium cation may be matched with the inclusion cavity formed by the carbonyl and phenoxy groups. There is only a little extractivity of disubstituted calix[4]arene derivative 3 for alkali metal ions.
文摘The synthesis of a novel host blocked in the cone conformation and bearing m-methoxycarbonylbenzyl groups at the lower rim is described. X-ray crystal structure analysis revealed that action of one molecule of compound upon one molecule of CH 3CN or one molecule of CH 3NO 2, forms an intramolecular inclusion complex, respectively, by CH 3-π interactions. The complex of L with tetrabutyl ammonium bromide(TBAB), L·TBAB, was obtained. The results of DTA-TG and XRD analysis of L·TBAB can also be considered as an intramolecular inclusion complex.
文摘R)-Hydroxy-(S)-proline was N-protected by reaction with di-tert-butyl pyrocarbonate to give N-Boc-(4R)-hydroxy-(S)-proline, which was treated with NaH in anhydrous tetrahydrofuran and followed by etherification with PhCH 2Br to form the N-Boc-(4R)-benzyloxy-(S)-proline, which, after removal of the protecting group with CF 3COOH gave the title compound. As an efficient catalyst for the direct asymmetryic aldol reaction the compound gave products in yield ranged from 58% to 77% with enantiomeric excess up to 88%.
