6790-63-2Relevant academic research and scientific papers
Anti-acanthamoeba activity of brominated sesquiterpenes from laurencia johnstonii
García-Davis, Sara,Sifaoui, Ines,Reyes-Batlle, María,Viveros-Valdez, Ezequiel,Pi?ero, José E.,Lorenzo-Morales, Jacob,Fernández, José J.,Díaz-Marrero, Ana R.
, (2018)
Focused on our interest to develop novel antiparasistic agents, the present study was aimed to evaluate the biological activity of an extract of Laurencia johnstonii collected in Baja California Sur, Mexico, against an Acantamoeba castellanii Neff strain. Bioassay-guided fractionation allowed us to identify the amoebicidal diastereoisomers α-bromocuparane (4) and α-isobromocuparane (5). Furthermore, bromination of the inactive laurinterol (1) and isolaurinterol (2) yielded four halogenated derivatives, (6)-(9), which improved the activity of the natural sesquiterpenes. Among them, the most active compound was 3α-bromojohnstane (7), a sesquiterpene derivative which possesses a novel carbon skeleton johnstane.
The total synthesis of (-)-aplysin via a lithiation-borylation- propenylation sequence
Fletcher, Catherine J.,Blair, Daniel J.,Wheelhouse, Katherine M.P.,Aggarwal, Varinder K.
, p. 7598 - 7604 (2012/09/21)
A concise, highly enantioselective synthesis of sesquiterpene natural products (-)-debromoaplysin and (-)-aplysin has been completed. The key steps included lithiation-borylation of a secondary benzylic carbamate to give a tertiary boronic ester followed by propenylation which installed the quaternary stereocenter with complete enantioselectivity. Subsequent RCM followed by deprotection and in situ cyclization led to debromoaplysin with good diastereoselectivity from which the target compound was prepared in just eight overall steps.
A Remarkable Substituent Effect on the Enantioselectivity of Tandem Asymmetric Epoxidation and Enantiospecific Ring Expansion of Cyclopropylidene Alcohols: A New Enantiocontrolled Synthesis of (-)-Debromoaplysin and (-)-Aplysin
Nemoto, Hideo,Nagamochi, Masatoshi,Ishibashi, Hiroki,Fukumoto, Keiichiro
, p. 74 - 79 (2007/10/02)
A remarkable substituent effect by the tert-butyldimethylsiloxy group on the enantioselectivity of the tandem asymmetric epoxidation and enantiospecific ring expansion of 2--2-cyclopropylideneethanol (18), affording (S)-(-)-2--2-hydroxymethylcyclobutanone (21) in high yield and high enantiomeric excess, was observed.This enabled us to accomplish a concise and highly enantioselective total synthesis of (-)-debromoaplysin (2) and (-)-aplysin (1), providing a new and general strategy for the enantioselective synthesis of biologically important substances having the dihydrobenzofuran framework.
ENANTIOCONTROLLED SYNTHESES OF THE CUPARENE SESQUITERPENES, (-)-HERBERTENE, (+)-β-CUPARENONE, (-)-DEBROMOAPLYSIN, AND (-)-APLYSIN
Takano, Seiichi,Moriya, Minoru,Ogasawara, Kunio
, p. 329 - 332 (2007/10/02)
Enantiocontrolled syntheses of the Cuparene sesquiterpenes, (-)-herbertene, (+)-cuparenone, (-)-debromoaplysin, and (-)-aplysin, have been achieved starting from the optically active tricyclic dienone by employing a Fischer indolization reaction under non-acidic conditions as the key step.
The rearrangement of some cyclopentanone-aryloximes: Synthesis of (±)-aplysin, (±)-filiformin and of their debromo analogues
Laronze, J. Yves,El Boukili, Rachida,Patigny, Dominique,Dridi, Seloua,Cartier, Dominique,Levy, Lean
, p. 10003 - 10014 (2007/10/02)
Upon acid catalyzed rearrangement after Sheradsky, the aryloximes A gave the tricyclic aminals C, which suffered hydrolysis to lactols E. The unique alcohol 29 was then prepared through a highly stereoselective equilibration-reductive alkylation of the epimeric mixture of lactols 22a,b. Two routes, one of which was stereospecific, allowed cyclization of 29 to (±)-aplysin 34. The yield was 2.5 % from oximes 2a,b. The isomeric epi-aplysin 35 and filiformin 36 were also obtained from 29. The debromo analogues 37,38 and 39 and their trideutero derivatives 41,42 and 43 were synthesized along similar line and allowed unequivocal structure elucidation by NMR spectroscopy.
THE SHERADSKY REARRANGEMENT OF α,α-DISUBSTITUTED CYCLOPENTANONE ARYLOXIMES: A SYNTHESIS OF THE SESQUITERPENES (+/-)-APLYSIN AND (+/-)-FILIFORMIN
Laronze, Jean-Yves,Boukili, Rachida El,Cartier, Dominique,Laronze, Jacqueline,Levy, Jean
, p. 2229 - 2232 (2007/10/02)
Lactols 6a,b, obtained by the Sheradsky rearrangement of aryloximes o, were alkylated in to 9a, in which three contiguous chiral centers were controlled.Cyclization of 9a gave the marine sesquiterpenes (+/-)-aplysin 11 and (+/-)-filiformin 13.
Total Synthesis of (-)-Aplysin and (-)-Debromoaplysin
Ronald, Robert C.,Gewali, Mohan B.,Ronald, Bruce P.
, p. 2224 - 2229 (2007/10/02)
The total synthesis of optically active (-)-aplysin (1) and (-)-debromoaplysin (2) employing novel (isopinocampheyloxy)methyl ethers for phenolic hydroxyl protection and diastereomeric resolution is described.A key transformation is the unusual cyclization of the diastereomeric chlorohydrins 12 and 13 in methanolic base to form the enantiomeric tricyclic alcohols (-)-16 and (+)-16 with cleavage of the acetal-linked (isopinocampheyloxy)methyl resolving/protecting group.This transformation was followed by substitution of the tertiary hydroxyl via the derived chloride with a methyl group by Grignard coupling with methylmagnesium bromide.The methyl insertion occurred with retention of configuration and resulted in formation of the natural aplysin system from 12 in just three steps.The conversion of the methylated tricyclic ether 20 to (-)-debromoaplysin (2) was accomplished in two steps by double bond isomerization and selective reduction.Bromination of (-)-2 afforded (-)-aplysin (1).
