- MICROBIAL TRANSFORMATION OF (-)-VERNOLIC ACID INTO (4R,5R)-5-HYDROXY-γ-DECALACTONE
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(-)-Vernolic acid, isolated and purified from seeds of Euphorbia lagascae was administered to cultures of Sporobolomyces odorus. (4R,5R)-5-Hydroxy-γ-decalactone 1 accumulated as the main product.The configuration of the product was determined by synthesis of all four stereoisomers and comparison of spectroscopic and chromatographic data.
- Albrecht, Wolfgang,Tressl, Roland
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- Liebeskind-Srogl cross-coupling on γ-carboxyl-γ-butyrolactone derivatives: Application to the side chain of amphidinolides C and F
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The synthetic approach for the C20-C29 and C20-C34 fragments of amphidinolide F and C was based on an original Liebeskind-Srogl cross-coupling reaction with a glutamic acid-derived building-block. Further highly diastereoselective reduction of the ketone was achieved by using an uncommon Ph3SiH/TBAF/HMPA system. The amphidinolide C side chain was built through a reductive elimination of chiral epoxide to install the stereogenic center at C29.
- Fenneteau, Johan,Vallerotto, Sara,Ferrié, Laurent,Figadère, Bruno
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p. 3758 - 3761
(2015/06/08)
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- On the thermodynamic equilibrium between (R)-2-hydroxyacyl-CoA and 2-enoyl-CoA
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A combined experimental and computational approach has been applied to investigate the equilibria between several α-hydroxyacyl-CoA compounds and their 2-enoyl-CoA derivatives. In contrast to those of their β, γ and α counterparts, the equilibria for the α-compounds are relatively poorly characterized, but qualitatively they appear to be unusually sensitive to substituents. Using a variety of techniques, we have succeeded in measuring the equilibrium constants for the reactions beginning from 2-hydroxyglutaryl-CoA and lactyl-CoA. A complementary computational evaluation of the equilibrium constants shows quantitative agreement with the measured values. By examining the computational results, we arrive at an explanation of the substituent sensitivity and provide a prediction for the, as yet unmeasured, equilibrium involving 2-hydroxyisocaproyl-CoA.
- Parthasarathy, Anutthaman,Buckel, Wolfgang,Smith, David M.
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experimental part
p. 1738 - 1746
(2011/04/18)
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- Development of a multigram asymmetric synthesis of 2-(R)-2-(4,7,10-tris tert-butylcarboxymethyl-1,4,7,10-tetraazacyclododec-1-yl)-pentanedioic acid, 1-tert-butyl ester, (R)-tert-Bu4-DOTAGA1
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A process for the multigram asymmetric synthesis of the chiral tetraazamacrocycle 2-(R)-2-(4,7,10-tris tert-butylcarboxymethyl- 1,4,7,10-tetraazacyclododec-1-yl)-pentanedioic acid, 1-tert-butyl ester ((R)-tert-Bu4-DOTAGA, 4) has been devised and demonstrated. The nine-step synthesis features an improved synthesis of 2-(S)-5- oxotetrahydrofuran- 2-carboxylic acid, tert-butyl ester 8, the precursor to the novel alkylating agent (S)-5-benzyl 1-tert-butyl 2-(methylsulfonyloxy) pentanedioate 12, which was used to introduce an orthogonally protected chiral glutarate arm to the 1,4,7,10-tetraazacyclododecane (cyclen) nucleus in high optical purity. Cyclen derivative (R)-t-Bu4-DOTAGA, 4, a key intermediate for the manufacture of a magnetic resonance imaging (MRI) candidate, was produced with high chemical (≥95%) and optical (ee ≥ 97%) purity. The process developed was successfully applied to the kilogram-scale cGMP synthesis of (R)-t-Bu4-DOTAGA.
- Levy, Stuart G.,Jacques, Vincent,Zhou, Kevin Li,Kalogeropoulos, Shirley,Schumacher, Kelly,Amedio, John C.,Scherer, Jonathan E.,Witowski, Steven R.,Lombardy, Richard,Koppetsch, Karsten
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experimental part
p. 535 - 542
(2010/04/22)
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- Total synthesis and structural confirmation of (+)-longicin
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(Chemical Equation Presented) A stereocontrolled total synthesis of (+)-longicin, a representative of the class of mono-THF-acetogenins, is described. The strategy involves the utilization of D- and L-glutamic acids as chirons that correspond to two five-carbon segments harboring stereogenic centers at C4 and at C17 of the C32 polyketide-derived natural product. The use of Grubbs' RCM reaction as a novel "chain elongation" strategy for the synthesis of acetogenin-type structures and a new protocol for butenolide incorporation are also described.
- Hanessian, Stephen,Giroux, Simon,Buffat, Maxime
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p. 3989 - 3992
(2007/10/03)
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- Lactones, part 28: EPC-Synthesis, structure and pharmacology of 'lactonized' and 'lactamized' analogues of acetylcholine
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The enantiopure γ-aminomethyl-γ-butyrolactones (S)- and (R)-4a-d represent constrained analogues of acetylcholine, which were synthesized from D- or L-glutamic acid following two different routes. In addition, the corresponding lactames (S)- and (R)-10 were prepared by enantioselective synthesis. Only moderate activity was found at acetylcholine sites at the guinea pig atrium.
- Pieper,Trankle,Nieger,Mohr,Lehmann
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- Enantioselective synthesis of (R)- and (S)-5-dimethylaminomethyl-4,5-dihydro-2(3H)-furanone methobromide - Constrained analogues of acetylcholine
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S6 and R6 represent constrained analogues of acetylcholine. Two effective routes to synthesize the enantiopure title compounds starting from either D- or L-glutamic acid are reported.
- Lehmann,Pieper
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p. 1537 - 1538
(2007/10/02)
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- 5,5-Dialkyl-δ-valerolactone Derivatives as New Chiral Dopants for Ferroelectric Liquid Crystals
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(S)-2-(4'-Octyloxybiphenyl-4-carboxy)-5,5-dipropyl-δ-valerolactone showed interesting properties as the chiral dopant for ferroelectric liquid crystals (FLCs).The FLC mixture containing only 2percent by mol of this compound exhibited the magnitude of spontaneous polarization (Ps) as large as 9.6 nC/cm2 and the response time as fast as 75 μs at 25 deg C in the electric field of +/- 5 V/μm.
- Sakashita, Keiichi,Nakaoka, Yuriko,Ikemoto, Tetsuya,Terada, Fumiko,Kageyama, Yoshitaka,et al.
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p. 1727 - 1730
(2007/10/02)
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- Renin inhibiting peptides with polar end groups
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The present invention provides novel renin-inhibiting peptides having a noncleavable transition state insert corresponding to the 10,11- position of the renin substrate (angiotensinogen) and a polyhydroxy-substituted alkyl moiety bonded directly through carbon or nitrogen to the N-terminus. Such inhibitors are useful for the diagnosis and control of renin-dependent hypertension and other related diseases.
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- SYNTHESIS OF D-AMICETOSE AND L-RHODINOSE FROM L-GLUTAMIC ACID
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L-Glutamic acid has been converted into a separable mixture of D-amicetono- and L-rhodinono-γ-lactones by a sequence involving transformation into (S)-γ-carboxy-γ-butyrolactone (2), conversion of 2 into the corresponding methyl ketone by the diazoketone route, and selective reduction with zinc borohydride or boranemethyl sulfide.Reduction of the two lactones with di-isobutylaluminium hydride gave the corresponding deoxy sugars.In spite of some improvements in the preparation of 2, the optical yield of this step was only ca. 80percent, but one crystallisation from chloroform raised the optical purity to 96percent.The subsequent steps produced a loss in optical purity of only 4percent.
- Berti, Giancarlo,Caroti, Paola,Catelani, Giorgio,Monti, Luigi
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