35660-94-7Relevant articles and documents
A BULKY LIGAND AND ITS ORGANOMETALLIC COMPOUND: SYNTHESIS OF HEPTAMETHYLINDENE AND A FERROCENE-TYPE COMPLEX, Fe(η5-C9Me7)2
Miyamoto, T. Ken,Tsutsui, Minoru,Chen, Li-Ban
, p. 729 - 730 (1981)
A bulky new indene, 1-H-1,2,3,4,5,6,7-heptamethylindene, has been synthesized and its application to organometallic chemistry is suggested.
An expeditious synthesis of (±)-desepoxy-4,5-didehydromethylenomycin A methyl ester
Balczewski, Piotr,Mikolajczyk, Marian
, p. 1153 - 1154 (2000)
A total synthesis of the racemic methyl ester of desepoxy-4,5-didehydromethylenomycin A has been achieved in six steps with an overall yield of 31% starting from diethyl methanephosphonate. The key steps include the Nazarov cyclization of the dienone 7 leading to the α-phosphoryl cyclopentenone 8 and the Horner-Wittig reaction of the latter employed for the introduction of the exocyclic methylene moiety.
Chemo- and Regioselective Functionalization of Nortrilobolide: Application for Semisynthesis of the Natural Product 2-Acetoxytrilobolide
Doan, Nhu Thi Quynh,Crestey, Fran?ois,Olsen, Carl Erik,Christensen, S?ren Br?gger
, p. 1406 - 1414 (2015)
The difference in reactivity of the hexaoxygenated natural product thapsigargin (1) and the pentaoxygenated nortrilobolide (3) was compared in order to develop a chemo- and regioselective method for the conversion of nortrilobolide (3) into the natural product 2-acetoxytrilobolide (4). For the first time, a stereoselective synthesis of 2-acetoxytrilobolide (4) is described, which involves two key reactions: the first chemical step was a one-pot substitution-oxidation reaction of an allylic ester into its corresponding α,β-unsaturated ketone. The second process consisted of a stereoselective α′-acyloxylation of the key intermediate α,β-unsaturated ketone to afford its corresponding acetoxyketone, which was converted into 2-acetoxytrilobolide (4) in a few steps. This innovative approach would allow the synthesis of a broad library of novel and valuable penta- and hexaoxygenated guaianolides as potential anticancer agents.
Chemistry of renieramycins. Part 13: Isolation and structure of stabilized renieramycin type derivatives, renieramycins W-Y, from Philippine blue sponge Xestospongia sp., pretreated with potassium cyanide
Tatsukawa, Mari,Punzalan, Louvy Lynn C.,Magpantay, Hilbert D.S.,Villase?or, Irene M.,Concepcion, Gisela P.,Suwanborirux, Khanit,Yokoya, Masashi,Saito, Naoki
, p. 7422 - 7428 (2012)
Three new bistetrahydroisoquinoline marine natural products, renieramycins W (1w), X (1x), and Y (1y), along with two known renieramycins M (1m) and T (1t), were isolated from the pretreated Philippine blue sponge Xestospongia sp. with KCN and their structures were elucidated by comparing their spectral data with those of 1m, 1t, and N-acetylsafracin B (11). Renieramycins W (1w) and X (1x) are the first examples of tiglic acid ester derivatives at the C-1 side chain. Renieramycin Y (1y) possesses a characteristic substitution pattern in A-ring and isolation of it from marine organism strongly evidences to link the possible precursor 3-hydroxy-5-methyl-O-methyltyrosine with both renieramycin and ecteinascidin marine natural products.
Synthesis, characterisation, and polymerisation studies of hexamethylindenyl zirconocenes and hafnocenes
Arnold, Thomas A.Q.,Buffet, Jean-Charles,Turner, Zo? R.,O'Hare, Dermot
, p. 55 - 65 (2015)
Abstract A family of group 4 metallocene complexes based on the hexamethylindenyl ligand (C9Me6H; Ind#) have been prepared and fully characterised. The complexes rac-Ind#2ZrCl2 (rac-1), meso-Ind#2ZrCl2 (meso-1), rac-Ind#2HfCl2 (rac-2), meso-Ind#2HfCl2 (meso-2) were prepared by the reaction of Ind#Li with the corresponding MCl4 (where M = Zr, Hf); and rac-Ind#2Zr(CH2Ph)2 (rac-3) was derived from rac-1 using two equivalents of potassium benzyl (KCH2Ph). All five species were characterised by NMR spectroscopy, single crystal X-ray diffraction and studied using density functional theory. The zirconocenes were tested for their activity as solution-phase ethylene polymerisation catalysts and rac-1 was found to outperform the meso-1 at most temperatures. The benzyl analogue, rac-3, peaked at more than double the activity reported for the dihalide species.
Stereoselective Total Synthesis of (-)-Renieramycin T
Yokoya, Masashi,Toyoshima, Ryoko,Suzuki, Toshihiro,Le, Vy H.,Williams, Robert M.,Saito, Naoki
, p. 4039 - 4047 (2016)
A stereoselective total synthesis of (-)-Renieramycin T (1t) from a key tetrahydroisoquinoline intermediate previously utilized in our formal total synthesis of Ecteinascidin 743 is described. The synthesis features a concise approach for construction of the pentacyclic framework using a Pictet-Spengler cyclization of bromo-substituted carbinolamine 17, which obviates the regioselectivity problem of the Pictet-Spengler cyclization. The results of cytotoxicity studies are also presented.
Chemistry of renieramycins. Part 14: Total synthesis of renieramycin i and practical synthesis of cribrostatin 4 (renieramycin H)
Yokoya, Masashi,Kobayashi, Keiichiro,Sato, Mitsuhiro,Saito, Naoki
, p. 4915 - 4933 (2015)
The first total synthesis of (±)-renieramycin I, which was isolated from the Indian bright blue sponge Haliclona cribricutis, is described. The key step is the selenium oxide oxidation of pentacyclic bis-p-quinone derivative (3) stereo- and regioselectively. We also report a large-scale synthesis of cribrostatin 4 (renieramycin H) via the C3-C4 double bond formation in an early stage based on the Avenda?o's protocol, from readily available 1-acetyl-3-(3-methyl-2,4,5-trimethylphenyl)methyl-piperazine-2,5-dione (8) in 18 steps (8.3% overall yield). The synthesis provides unambiguous evidence supporting the original structure of renieramycin I.
Chemistry of renieramycins. Part 11: Total synthesis of (±)-cribrostatin 4
Yokoya, Masashi,Ito, Hiroshi,Saito, Naoki
, p. 9185 - 9192 (2011)
A 19-step synthesis of (±)-cribrostatin 4 (1) from readily available piperazine-2,5-dione derivative 6 is described. The synthesis features the concise construction of a pentacyclic framework, followed by the base-catalyzed epimerization of the C-1 stereo center of aldehyde (11). The results of cytotoxicity studies are also presented.
Synthetic Studies on Selective, Proapoptotic Isomalabaricane Triterpenoids Aided by Computational Techniques
Boyko, Yaroslav D.,Huck, Christopher J.,Ning, Shang,Shved, Alexander S.,Yang, Cheng,Chu, Tiffany,Tonogai, Emily J.,Hergenrother, Paul J.,Sarlah, David
supporting information, p. 2138 - 2155 (2021/02/09)
The isomalabaricanes comprise a large family of marine triterpenoids with fascinating structures that have been shown to be selective and potent apoptosis inducers in certain cancer cell lines. In this article, we describe the successful total syntheses of the isomalabaricanes stelletin A, stelletin E, and rhabdastrellic acid A, as well as the development of a general strategy to access other natural products within this unique family. High-throughput experimentation and computational chemistry methods were used in this endeavor. A preliminary structure-activity relationship study of stelletin A revealed the trans-syn-trans core motif of the isomalabaricanes to be critical for their cytotoxic activity.
Erratum: Synthetic Studies on Selective, Proapoptotic Isomalabaricane Triterpenoids Aided by Computational Techniques (J. Am. Chem. Soc. (2021) 143:4 (2138-2155) DOI: 10.1021/jacs.0c12569)
Boyko, Yaroslav D.,Chu, Tiffany,Hergenrother, Paul J.,Huck, Christopher J.,Ning, Shang,Sarlah, David,Shved, Alexander S.,Tonogai, Emily J.,Yang, Cheng
supporting information, p. 12418 - 12418 (2021/08/30)
Figure 2c and the accompanying text on page 2140, as well as the SI, mistakenly stated the use of AD-mix-a. AD-mix- ? was used for the transformation from 11 to (+)-13. All structures drawn are correct, and all conclusions remain the same. A revised Supporting Information document that reflects this correction is also available.
