Compound 1 as a key intermediate of 1, 7, 9-trideoxytaxol was synthesized in ten steps from a biosynthetically available taxane, Sinenxan A. The key steps in the synthesis were deoxygenation at C-14, allylic oxidatio...Compound 1 as a key intermediate of 1, 7, 9-trideoxytaxol was synthesized in ten steps from a biosynthetically available taxane, Sinenxan A. The key steps in the synthesis were deoxygenation at C-14, allylic oxidation at C-13 and construction of the oxetane ring.展开更多
The structures of five metabolites (2-6) of agarofuran 1 were confirmed by synthesis. The configuration of the secondary hydroxyl in 7 was determined by Horeau抯 method. The configuration of C-2 in compound 4 and 5 ...The structures of five metabolites (2-6) of agarofuran 1 were confirmed by synthesis. The configuration of the secondary hydroxyl in 7 was determined by Horeau抯 method. The configuration of C-2 in compound 4 and 5 was determined by their stereochemistry and NMR.展开更多
Deacetoxy-13-oxo sinenxan A (1) was converted to 9a-hydroxy-13-oxo-2a, 5a, 10b-triacetoxy-4(20),11-taxadiene (2) and 10b-hydroxy-13-oxo-2a,5a,9a-triacetoxy- 4(20), 11- taxadiene (3) by Ginkgo cell suspension cultures ...Deacetoxy-13-oxo sinenxan A (1) was converted to 9a-hydroxy-13-oxo-2a, 5a, 10b-triacetoxy-4(20),11-taxadiene (2) and 10b-hydroxy-13-oxo-2a,5a,9a-triacetoxy- 4(20), 11- taxadiene (3) by Ginkgo cell suspension cultures in 45% and 15% yields, respectively.展开更多
A new synthetic route for α -agarofuran(1b) is described. Several agarofuran derivatives were synthesized in similar way. Derivative 1d was also synthesized in a novel way, in which the substitution at C-4 was perfor...A new synthetic route for α -agarofuran(1b) is described. Several agarofuran derivatives were synthesized in similar way. Derivative 1d was also synthesized in a novel way, in which the substitution at C-4 was performed quantitatively. An ideal condition for cyclization of diol 7 to agarofuran (1) was found.展开更多
Compound 2 with 14β-hydroxyl group was successfully converted into its epimerized α-counterpart via oxidation - reduction.The elimination product (6) was auto-oxidized to epoxide 8,even in the solid state
1α- and 1β-methyl agarofuran 1 and 2 were stereoselectively synthesized. the key intermediates being synthesized through stereoselective Robinson annulation.The conjugated double bond was redined in an improved way...1α- and 1β-methyl agarofuran 1 and 2 were stereoselectively synthesized. the key intermediates being synthesized through stereoselective Robinson annulation.The conjugated double bond was redined in an improved way. Alkylation of imine 7 with enone 8, 9, 10 was performed展开更多
Nor-ketoagarofuran (1), one of the furanoids isolated from grnd Oil, has been Synthesed in a preprative scale in high yield from olefin 3 in 3 steps. Reaction of norketoagarofuran (1) with CH3MgI afforded 4 (2), an an...Nor-ketoagarofuran (1), one of the furanoids isolated from grnd Oil, has been Synthesed in a preprative scale in high yield from olefin 3 in 3 steps. Reaction of norketoagarofuran (1) with CH3MgI afforded 4 (2), an another naturallyoccurring tetrahydrofuran derivative.展开更多
-An oxetane ring can be constructed from 5 α-acyloxy-Δ4(20) -taxoids with osmylation as the first step in the usual manner. The innovation reported here is the use of an intramolecularly available acyl group for the...-An oxetane ring can be constructed from 5 α-acyloxy-Δ4(20) -taxoids with osmylation as the first step in the usual manner. The innovation reported here is the use of an intramolecularly available acyl group for the protection of 20-OH by an unexpected 5-to 20-migration under slightly basic conditions.展开更多
Reduction of epoxides 1, 2, 3 with LAH and LAH/AlCl3 has been studied. The products of reduction with LAH were controlled by Steric and stereoelectronic effects. The reduction with LAH/AlCl3 seemed to involve an inter...Reduction of epoxides 1, 2, 3 with LAH and LAH/AlCl3 has been studied. The products of reduction with LAH were controlled by Steric and stereoelectronic effects. The reduction with LAH/AlCl3 seemed to involve an intermediate in which one aluminum ion was shared by both oxygen atoms from the epoxide and the tetrahydrofuran ring.展开更多
14-Nor-3-oxodihydroagarofuran (2) was prepared in high yield. From 2, derivatives12 and 13 were synthesized by Grignard addition. In order to identify the configuration of C-3 in compound 12 and 13, the sterospecific ...14-Nor-3-oxodihydroagarofuran (2) was prepared in high yield. From 2, derivatives12 and 13 were synthesized by Grignard addition. In order to identify the configuration of C-3 in compound 12 and 13, the sterospecific synthesis of compound 12 has been carried out in 5 steps from octalone (14).展开更多
基金This research work was financially supported by NNSFC.
文摘Compound 1 as a key intermediate of 1, 7, 9-trideoxytaxol was synthesized in ten steps from a biosynthetically available taxane, Sinenxan A. The key steps in the synthesis were deoxygenation at C-14, allylic oxidation at C-13 and construction of the oxetane ring.
文摘The structures of five metabolites (2-6) of agarofuran 1 were confirmed by synthesis. The configuration of the secondary hydroxyl in 7 was determined by Horeau抯 method. The configuration of C-2 in compound 4 and 5 was determined by their stereochemistry and NMR.
基金This work is supported by the National Natural Science Foundation of China(to Jungui Dai,No.30100230).
文摘Deacetoxy-13-oxo sinenxan A (1) was converted to 9a-hydroxy-13-oxo-2a, 5a, 10b-triacetoxy-4(20),11-taxadiene (2) and 10b-hydroxy-13-oxo-2a,5a,9a-triacetoxy- 4(20), 11- taxadiene (3) by Ginkgo cell suspension cultures in 45% and 15% yields, respectively.
基金This work was suppol-ted by the National Natural Science Foundation of China.
文摘A new synthetic route for α -agarofuran(1b) is described. Several agarofuran derivatives were synthesized in similar way. Derivative 1d was also synthesized in a novel way, in which the substitution at C-4 was performed quantitatively. An ideal condition for cyclization of diol 7 to agarofuran (1) was found.
文摘Compound 2 with 14β-hydroxyl group was successfully converted into its epimerized α-counterpart via oxidation - reduction.The elimination product (6) was auto-oxidized to epoxide 8,even in the solid state
文摘1α- and 1β-methyl agarofuran 1 and 2 were stereoselectively synthesized. the key intermediates being synthesized through stereoselective Robinson annulation.The conjugated double bond was redined in an improved way. Alkylation of imine 7 with enone 8, 9, 10 was performed
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(No.39370809)National New Drug Foundation(No.92-08-N).
文摘AF-5 was synthesized through a convergent method. The key step was the Robinson annulation using a key intermediate pentyl vinyl ketone.
文摘Nor-ketoagarofuran (1), one of the furanoids isolated from grnd Oil, has been Synthesed in a preprative scale in high yield from olefin 3 in 3 steps. Reaction of norketoagarofuran (1) with CH3MgI afforded 4 (2), an another naturallyoccurring tetrahydrofuran derivative.
文摘-An oxetane ring can be constructed from 5 α-acyloxy-Δ4(20) -taxoids with osmylation as the first step in the usual manner. The innovation reported here is the use of an intramolecularly available acyl group for the protection of 20-OH by an unexpected 5-to 20-migration under slightly basic conditions.
基金the National Natural Science Foundation of China.
文摘Reduction of epoxides 1, 2, 3 with LAH and LAH/AlCl3 has been studied. The products of reduction with LAH were controlled by Steric and stereoelectronic effects. The reduction with LAH/AlCl3 seemed to involve an intermediate in which one aluminum ion was shared by both oxygen atoms from the epoxide and the tetrahydrofuran ring.
文摘14-Nor-3-oxodihydroagarofuran (2) was prepared in high yield. From 2, derivatives12 and 13 were synthesized by Grignard addition. In order to identify the configuration of C-3 in compound 12 and 13, the sterospecific synthesis of compound 12 has been carried out in 5 steps from octalone (14).
