87038-26-4Relevant articles and documents
A stereoselective synthesis of the C9-C19 subunit of (+)-peloruside A
Raghavan, Sadagopan,Vinoth Kumar
, p. 2847 - 2858 (2013/05/08)
The stereoselective synthesis of a C9-C19 fragment of the potent antitumor agent peloruside A is disclosed. The C11 stereogenic centre was created by a vinylogous Mukaiyama aldol reaction following Carreira's protocol, with excellent stereocontrol. The C13 stereogenic centre was introduced by a substrate controlled reduction. The C15 stereocentre was fashioned using Noyori's asymmetric transfer hydrogenation while the Z-trisubstituted double bond was formed by a regioselective hydrostannation of an alkyne followed by methylation of the resultant vinyl stannane using Lipshutz's protocol. The C18 chiral centre was introduced by a chemoenzymatic route.
Benzoaxathiepin derivatives and their use as medicines
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Page/Page column 16, (2008/06/13)
The invention concerns 3-arylthio-propyl-amino-3,4-dihydro-2H-1,5-aryloxathiepin derivatives of general formula (I), wherein: R1 and R2, identical or different, represent a hydrogen atom, a fluorine atom or a chlorine atom, a hydroxy group, an alkyl, cyclopropyl, alkoxy, cyclopropoxy radical or when they occupy adjacent positions, form with the carbon atoms bearing them a carbon-containing cycle or an oxygen-containing heterocycle with five non-aromatic rings; R3 represents an alkyl radical, a hydroxy group or a methoxy radical; R4 represents a hydrogen atom or a methyl radical; and R5 ?and R6, identical or different represent a hydrogen atom, an alkyl, alkoxy, alkylthio, alkylamino radical, or the groups OR4 and R5 form with the carbons which bear them a non-aromatic heterocycle with five or six rings containing at least an oxygen atom; and their pharmaceutically acceptable additions salts. 1
Total Synthesis of Myxovirescins, 2. Assembly of the "Northwestern" Part
Sefkow, Michael,Neidlein, Axel,Sommerfeld, Thimo,Sternfeld, Francine,Maestro, Miguel A.,Seebach, Dieter
, p. 719 - 730 (2007/10/02)
The part of the target molecules myxovirescins A and M containing the atoms C(15)-C(28) is described in this paper (for retrosynthetic analysis see Scheme 1).There are three stereogenic centers which are incorporated by using (S)-2-hydroxymethyl-butanoic acid and the appropriate enantiopure diastereoisomeric 2,4-dimethyl-glutaric acids as building blocks (Schemes 2-4).These are joined by the achiral unit 4-oxo-hex-5-enoic acid.The key steps of the assembly are a cuprate Michael addition (Scheme 5) and a nucleophilic addition of a Li derivative to an aldehyde (Scheme 6).In both cases the organometallic reagents are generated by I/Li exchange using two equiv. of tBuLi.The chiral building blocks are prepared by yeast reduction of ethyl 2-formyl-butanoate and by resolution of the 2,4-dimethyl-pentanedioic acid monomethyl ester with phenethylamine; both enantiomers derived from the meso-2,4-dimethyl-glutaric acid are converted to the same aldehyde (5a; "meso-trick", Schemes 3 and 4).The "northwestern" parts for the final synthesis are actually hydroxy sulfones (2 in Scheme 6), the termini of which are ready for Julia coupling and oxidation to a carboxylic acid group.The preparation of the intermediates on gram scales is described and all new compounds are fully characterized by their physical properties, by spectroscopy (IR, 1H- and 13C-NMR spectra) and by elemental analysis. - Key Words: Myxovirescins / Myxococcus virescens / Antibiotics / Macrolides / Lactones / Lactams / Iodine-lithium exchange / Michael additions
