A series of trans-4, 5-disubstituted -γ-butyrolactones are found to assume two different envelope conformations by means of nuclear magnetic resonance spectroscopy.
A pair of Z and E isomers of cyclization of γ-ketoacid 7, which was prepared in six steps from 2,5-dimethoxyphenyl acetic acid 1, gave a pair of Z(20%) and E (4%) isomers of (2,5-dimethoxyphenyl)
Two newα,β-unsaturated butyrolactone derivatives,4-(4″-hydroxybenzyl)-3-(3′-hydroxy-phenethyl)furan-2(5H)-one(1)and 3-(3′-hydroxyphenethyl)furan-2(5H)-one(2),together with one known phenolic compound(3),were isol...Two newα,β-unsaturated butyrolactone derivatives,4-(4″-hydroxybenzyl)-3-(3′-hydroxy-phenethyl)furan-2(5H)-one(1)and 3-(3′-hydroxyphenethyl)furan-2(5H)-one(2),together with one known phenolic compound(3),were isolated from the tubers of Pleione bulbocodioides(Franch.)Rolfe.Their structures were elucidated by analysis of spectroscopic data.展开更多
Cyclopropylamine is synthesized with γ butyrolactone and isopropanol by five steps of ring opening esterification, cyclization, hydrolysis, acylation and Hofmann degradation. Cyclization and hydrolysis are key steps ...Cyclopropylamine is synthesized with γ butyrolactone and isopropanol by five steps of ring opening esterification, cyclization, hydrolysis, acylation and Hofmann degradation. Cyclization and hydrolysis are key steps in the process, and Phase Transfer Catalysis (PTC) is used in the two steps respectively. In the cyclization reaction, because solid liquid PTC, sodium hydroxide is applied instead of expensive sodium alcoholate, the reaction can be carried out in mild conditions. The optimum re action conditions are as follows: 0.03∶1∶1.5 mole ratio of BTEAC to ester to sodium hydroxide, reacting at 50 ℃ for 2 h with yield of 92%. Hydrolysis of isopropyl cyclopropanecarboxylate is accelerated by liquid liquid PTC, and the order of catalytic activity is BTEAC>BTMAC>CTMAB>TBAB. The results show that the new synthesis method is superior to those from literature and feasible for production with simple routes, mild reaction conditions, cheap materials and total yield of 52.6%.展开更多
The somatic cell nuclear transfer (SCNT) technique has been applied successfully in a range of mammalian species giving rise to offspring, however, the efficiency of development to term has remained low. Oocyte meioti...The somatic cell nuclear transfer (SCNT) technique has been applied successfully in a range of mammalian species giving rise to offspring, however, the efficiency of development to term has remained low. Oocyte meiotic arrest is an important option to make the SCNT more flexible and increase the number of cloned embryos produced. This paper showed that the use of butyrolactone I to arrest the meiotic division for 24 h prior to in vitro maturation (IVM) provided bovine oocytes capability of supporting development of blastocysts as efficiently as non arrested oocytes. In the SCNT group, cleavage rates were not affected by prematuration when adding butyrolactone I during IVM (57.9% vs. 62.4%; control vs. 10 μmol ? L-1 butyrolactone I), developmental rates to blastocyst were unaffected (22.0% vs. 20.3%; control vs. 10 μmol ? L-1 butyrolactone I, p>0.05) by the addition of butyrolactone I during IVM in cloned embryos. Moreover, the total cell numbers of blastocyst were not affected by butyrolactone I (total nucleus numbers, 132±16.5 vs. 128±19.4, p>0.05). In conclusion, the SCNT embryos from butyrolactone I- prematured bovine oocytes had the same developmental potential as the non treated one. The present study provided a method for laboratories of in vitro embryos production, mainly those working on the SCNT, where prematuration could be used to increase the flexibility of the procedure.展开更多
The conformations ofγ-butyrolactone ring in solution were deduced on the basis of ~1H NMR spectra of geminal protons of the butyrolactone ring.A series of optically pure(Z)-(-)-4-(1'-alkoxyl-1'-carbalkoxy-met...The conformations ofγ-butyrolactone ring in solution were deduced on the basis of ~1H NMR spectra of geminal protons of the butyrolactone ring.A series of optically pure(Z)-(-)-4-(1'-alkoxyl-1'-carbalkoxy-methylene)-5(R)[(1R)-menthyloxy]-γ-butyr-olactones with a stable planar conformation of γ-butyrolactone ring were found.展开更多
A novel 1,6-asymmetric induction has been observed in the iodolactonization of γ,δ-unsa-turated amides. The optically active γ-butyrolactone was synthesized by employing iodolactonizationreaction as a key step.
文摘A series of trans-4, 5-disubstituted -γ-butyrolactones are found to assume two different envelope conformations by means of nuclear magnetic resonance spectroscopy.
文摘A pair of Z and E isomers of cyclization of γ-ketoacid 7, which was prepared in six steps from 2,5-dimethoxyphenyl acetic acid 1, gave a pair of Z(20%) and E (4%) isomers of (2,5-dimethoxyphenyl)
文摘Two newα,β-unsaturated butyrolactone derivatives,4-(4″-hydroxybenzyl)-3-(3′-hydroxy-phenethyl)furan-2(5H)-one(1)and 3-(3′-hydroxyphenethyl)furan-2(5H)-one(2),together with one known phenolic compound(3),were isolated from the tubers of Pleione bulbocodioides(Franch.)Rolfe.Their structures were elucidated by analysis of spectroscopic data.
基金The Science and Research Foundation of Education Commission of Hunan Province
文摘Cyclopropylamine is synthesized with γ butyrolactone and isopropanol by five steps of ring opening esterification, cyclization, hydrolysis, acylation and Hofmann degradation. Cyclization and hydrolysis are key steps in the process, and Phase Transfer Catalysis (PTC) is used in the two steps respectively. In the cyclization reaction, because solid liquid PTC, sodium hydroxide is applied instead of expensive sodium alcoholate, the reaction can be carried out in mild conditions. The optimum re action conditions are as follows: 0.03∶1∶1.5 mole ratio of BTEAC to ester to sodium hydroxide, reacting at 50 ℃ for 2 h with yield of 92%. Hydrolysis of isopropyl cyclopropanecarboxylate is accelerated by liquid liquid PTC, and the order of catalytic activity is BTEAC>BTMAC>CTMAB>TBAB. The results show that the new synthesis method is superior to those from literature and feasible for production with simple routes, mild reaction conditions, cheap materials and total yield of 52.6%.
基金Supported by the Scientific Research Fund of Heilongjiang Provincial Education Department (11531028)Heilongjiang Postdoctoral Fund (LBH-Z11245)
文摘The somatic cell nuclear transfer (SCNT) technique has been applied successfully in a range of mammalian species giving rise to offspring, however, the efficiency of development to term has remained low. Oocyte meiotic arrest is an important option to make the SCNT more flexible and increase the number of cloned embryos produced. This paper showed that the use of butyrolactone I to arrest the meiotic division for 24 h prior to in vitro maturation (IVM) provided bovine oocytes capability of supporting development of blastocysts as efficiently as non arrested oocytes. In the SCNT group, cleavage rates were not affected by prematuration when adding butyrolactone I during IVM (57.9% vs. 62.4%; control vs. 10 μmol ? L-1 butyrolactone I), developmental rates to blastocyst were unaffected (22.0% vs. 20.3%; control vs. 10 μmol ? L-1 butyrolactone I, p>0.05) by the addition of butyrolactone I during IVM in cloned embryos. Moreover, the total cell numbers of blastocyst were not affected by butyrolactone I (total nucleus numbers, 132±16.5 vs. 128±19.4, p>0.05). In conclusion, the SCNT embryos from butyrolactone I- prematured bovine oocytes had the same developmental potential as the non treated one. The present study provided a method for laboratories of in vitro embryos production, mainly those working on the SCNT, where prematuration could be used to increase the flexibility of the procedure.
文摘The conformations ofγ-butyrolactone ring in solution were deduced on the basis of ~1H NMR spectra of geminal protons of the butyrolactone ring.A series of optically pure(Z)-(-)-4-(1'-alkoxyl-1'-carbalkoxy-methylene)-5(R)[(1R)-menthyloxy]-γ-butyr-olactones with a stable planar conformation of γ-butyrolactone ring were found.
文摘A novel 1,6-asymmetric induction has been observed in the iodolactonization of γ,δ-unsa-turated amides. The optically active γ-butyrolactone was synthesized by employing iodolactonizationreaction as a key step.
