The Experts below are selected from a list of 432 Experts worldwide ranked by ideXlab platform
Bo Jiang - One of the best experts on this subject based on the ideXlab platform.
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4 2 1 domino cyclization in water for chemo and regioselective synthesis of spiro substituted benzo b furo 3 4 e 1 4 diazepine derivatives
ChemInform, 2011Co-Authors: Chuang Cheng, Bo JiangAbstract:New regio- and chemoselective [4+2+1] domino cyclization consisting of the formation of two spiro rings and five σ bonds has been developed for the synthesis of spiro-substituted benzo[b]furo[3,4-e][1,4]diazepine derivatives. The reaction is a multicomponent domino green process and can be readily performed by reacting inexpensive starting materials of benzene-1,2-diamines, Tetronic Acid and 2,2-dihydroxy-2H-indene-1,3-dione in aqueous solution under microwave irradiation. The present synthesis shows attractive characteristics, such as the use of water as reaction media, convenient one-pot operation, short reaction periods of 10–18 min and reduced waste production without the use of any strong Acids or metal promoters. This synthesis serves as a nice addition to GAP (Group-Assistant-Purification) chemistry in which purificationviachromatography and recrystallization can be avoided, and the pure products were obtained simply by washing the crude products with 95% EtOH.
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facile synthesis of new 4 aza podophyllotoxin analogs via microwave assisted multi component reactions and evaluation of their cytotoxic activity
Bioorganic & Medicinal Chemistry Letters, 2011Co-Authors: Feng Shi, Xiaoning Zeng, Ge Zhang, Bo JiangAbstract:A series of new 4-aza-podophyllotoxin analogs containing thiazole unit were synthesized via multi-component reactions of aldehydes, Tetronic Acid and 2-methylbenzo[d]thiazol-5-amine under microwave irradiation. The method not only provides a valuable tool in design and synthesis of new 4-aza-podophyllotoxin analogs but also has the advantages of atom-economy, environmental-friendliness, good yields and operational simplicity. More importantly, the preliminary evaluation on the cytotoxic activity of this type of new 4-aza-podophyllotoxin analogs has resulted in the finding of several compounds with potent and efficacious cytotoxicity to three carcinoma cell lines M14, MCF7 and SW1116.
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a simple procedure for the synthesis of 4 aza podophyllotoxin derivatives in water under microwave irradiation conditions
Synlett, 2006Co-Authors: Yan Zhang, Junyong Zhang, Bo Jiang, Runhong Jia, Jinpeng ZhangAbstract:4-Aza-podophyllotoxin derivatives were synthesized via the three-component reaction of an aldehyde, an aromatic amine, and either Tetronic Acid or 1,3-indanedione in water under microwave irradiation conditions. This new protocol has the advantages of higher yield, lower cost, reduced environmental impact, and convenient procedure.
Robert J. Capon - One of the best experts on this subject based on the ideXlab platform.
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a new sesterterpene Tetronic Acid from an australian marine sponge psammocinia sp
Australian Journal of Chemistry, 1995Co-Authors: L Murray, H Hamit, John N A Hooper, L Hobbs, Robert J. CaponAbstract:A new sesterterpene Tetronic Acid (5) exhibiting antimicrobial activity has been isolated from an Australian marine sponge, Psammocinia sp., and its structure secured by detailed spectroscopic analysis. The Tetronic Acid (5) possesses almost identical spectroscopic characteristics to, and is a structural isomer of, the known marine natural product (6) previously reported from an Australian sponge.
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two for one structure revision of the marine sesterterpene Tetronic Acid strobilinin to 8z 13e 20z strobilinin and 8e 13z 20z strobilinin
Australian Journal of Chemistry, 1994Co-Authors: Rohan Andrew Davis, Robert J. CaponAbstract:A reinvestigation of the known marine natural product strobilinin has revealed it not to be a single compound (2), but to consist of two naturally occurring geometric isomers, neither of which corresponds to the structure originally assigned. These isomers, (8E,13Z,20Z)- strobilinin (10) and (8Z,13E,20Z)-strobilinin (11), were resolved, characterized and identified as their respective acetate derivatives (6) and (7), and their structures assigned by spectroscopic analysis. It would appear that the absolute stereochemistry of the strobilinins is very likely opposite to that of co-occurring variabilin (1).
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Isopalinurin - a Mild Protein Phosphatase Inhibitor From a Southern Australian Marine Sponge, Dysidea Sp
'CSIRO Publishing', 1993Co-Authors: Murray L, Sim Atr, Rostas Jap, Robert J. CaponAbstract:A new sesterterpene Tetronic Acid, isopalinurin (1), has been isolated from an Australian marine sponge, Dysidea sp., collected in Bass Strait. Isopalinurin (1) was identified as the agent responsible for the antibiotic activity and protein phosphatase inhibitory properties exhibited by the crude ethanol extract, and its structure was secured by detailed spectroscopic analysis
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a new sesterterpene Tetronic Acid and a pentaprenylated p quinol from an australian marine sponge spongia sp
Australian Journal of Chemistry, 1992Co-Authors: D Lumsdon, S G Thomas, Robert J. Capon, A A BeveridgeAbstract:The sesterterpene Tetronic Acid (1) and the pentaprenylated p- quinol (2) have been isolated from a specimen of sponge, Spongia sp., collected at a depth of 23 m from Port Phillip Bay, Australia. Structures were assigned on the basis of detailed spectroscopic analysis.
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cometins a c new furanosesterterpenes from an australian marine sponge spongia sp
Australian Journal of Chemistry, 1992Co-Authors: Sylvia Urban, Robert J. CaponAbstract:The known marine furanosesterterpene furospinosulin-1 (1), together with three new furanosesterterpenes, namely cometin-A (2), cometin-B (3) and cometin-C (4), were isolated from a marine sponge, Spongia sp., collected during commercial trawling operations in the Great Australian Bight. The structures of these metabolites were determined by detailed spectroscopic analysis and chemical derivatization . The antibiotic property of the crude ethanol extract of this sponge was attributed solely to the furanosesterterpene Tetronic Acid cometin -A (2).
Thorsten Bach - One of the best experts on this subject based on the ideXlab platform.
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2 2 photocycloaddition studies on complex Tetronic Acid esters related to the synthesis of cembranoid diterpenes
ChemInform, 2015Co-Authors: Roland Weixler, Thorsten BachAbstract:The synthesis of twelve differently substituted tetronates such as (I), (III), and (V) is described.
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2 2 photocycloaddition studies on complex Tetronic Acid esters related to the synthesis of cembranoid diterpenes
Synthesis, 2014Co-Authors: Roland Weixler, Thorsten BachAbstract:Twelve different Tetronic Acid esters bearing two potentially reactive olefinic groups were prepared and subjected to [2+2] photocycloaddition reactions by irradiation at λ = 254 nm in tert-butanol (5 mM). The diastereoselectivity and regioselectivity of the reaction was studied with regard to the synthesis of cembranoid diterpenes. When the Tetronic Acid core carried an alk-3-enyl substituent in the γ-position and an alk-3-enyloxy substituent in the β-position, the undesired γ-products prevailed and were formed in 48–81% yield. Altering the γ-alk-3-enyl substituent into an alk-3-ynyl or alk-2-ynyl substituent, resulted in formation of the desired β-photocycloaddition products. The latter products were obtained in yields of 56–88%, with two out of three products exhibiting very high regio- and diastereoselectivity.
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conformationally constrained β amino Acid derivatives by intramolecular 2 2 photocycloaddition of a Tetronic Acid amide and subsequent lactone ring opening
Journal of Organic Chemistry, 2005Co-Authors: Birte Basler, Oliver Schuster, Thorsten BachAbstract:The N-Boc-protected N-3-alkenylTetronic Acid amides 9 and 12 were prepared from Tetronic Acid bromide (7) and the corresponding amines 6 and 10 by nucleophilic substitution and subsequent acylation in 71% and 39% overall yield. They underwent an intramolecular [2 + 2]-photocycloaddition upon direct irradiation (λ = 254 nm) to yield diastereoselectively the strained lactones 15 (76%) and 16 (91%) with a 2-azabicyclo[3.2.0]heptane core. In attempts to defunctionalize the 1-hydroxymethyl substituent of the 2-azabicyclo[3.2.0]heptane skeleton, lactone 15 was converted into mesylate 18 (74% overall yield). Intermolecular substitution reactions on this mesylate, however, proceeded sluggishly or failed completely. Lactone 15 could be opened reductively (Dibal-H) or by substitution with benzylamine to the N-Boc-protected 2-azabicyclo[3.2.0]heptanes 21 (71%) and 22 (81%). Conformationally constrained β-amino Acid derivatives were obtained by quantitative N-Boc deprotection of photocycloaddition product 15, followe...
Lixin Wang - One of the best experts on this subject based on the ideXlab platform.
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an organocatalytic domino michael alkylation reaction highly enantioselective construction of spiro cyclopentanoneoxindoles and Tetronic Acid scaffolds
ChemInform, 2015Co-Authors: Jing Zhou, Qilin Wang, Lin Peng, Fang Tian, Lixin WangAbstract:The title reaction of methyleneindolinones with ketoester (II) results in the formation of various spiro-cyclopentanoneoxindoles which are obtained in high yields, good diastereoselectivities and excellent enantioselectivities via α-alkylation.
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an organocatalytic domino michael alkylation reaction highly enantioselective construction of spiro cyclopentanoneoxindoles and Tetronic Acid scaffolds
Chemical Communications, 2014Co-Authors: Jing Zhou, Qilin Wang, Lin Peng, Fang Tian, Lixin WangAbstract:A new organocatalytic asymmetric domino Michael-alkylation reaction of methyleneindolinones and γ-halogenated-β-ketoesters is described. A variety of spiro-cyclopentanoneoxindoles were obtained in high yields (up to 96%), good diastereoselectivities (up to 12 : 1 dr) and excellent enantioselectivities (up to >99% ee) via α-alkylation. Interestingly, O-alkylated products with Tetronic Acid motifs could be obtained by tuning the N-protecting groups on methyleneindolinones with excellent enantioselectivities (up to >99% ee).
Jing Zhou - One of the best experts on this subject based on the ideXlab platform.
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an organocatalytic domino michael alkylation reaction highly enantioselective construction of spiro cyclopentanoneoxindoles and Tetronic Acid scaffolds
ChemInform, 2015Co-Authors: Jing Zhou, Qilin Wang, Lin Peng, Fang Tian, Lixin WangAbstract:The title reaction of methyleneindolinones with ketoester (II) results in the formation of various spiro-cyclopentanoneoxindoles which are obtained in high yields, good diastereoselectivities and excellent enantioselectivities via α-alkylation.
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an organocatalytic domino michael alkylation reaction highly enantioselective construction of spiro cyclopentanoneoxindoles and Tetronic Acid scaffolds
Chemical Communications, 2014Co-Authors: Jing Zhou, Qilin Wang, Lin Peng, Fang Tian, Lixin WangAbstract:A new organocatalytic asymmetric domino Michael-alkylation reaction of methyleneindolinones and γ-halogenated-β-ketoesters is described. A variety of spiro-cyclopentanoneoxindoles were obtained in high yields (up to 96%), good diastereoselectivities (up to 12 : 1 dr) and excellent enantioselectivities (up to >99% ee) via α-alkylation. Interestingly, O-alkylated products with Tetronic Acid motifs could be obtained by tuning the N-protecting groups on methyleneindolinones with excellent enantioselectivities (up to >99% ee).