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Isidro S. Marcos Rosalina F. Moro Isabel Costales Miguel A. Escola Pilar Basabe David Díez Julio G. Urones 《Tetrahedron》2009,65(49):10235-1011
A new cyclisation of 3-(but-3-enyl) indole derivatives that produces policyclic compounds with a hexahydrocarbazole structure is described. In this reaction three stereogenic centres are generated in one step, and this process can be considered as evidence of the biogenetic relationship between anominine and tubingensin A. 相似文献
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24.
Reino JL Durán-Patrón RM Daoubi M Collado IG Hernández-Galán R 《The Journal of organic chemistry》2006,71(2):562-565
[reaction: see text] The biosynthetic origin of the botcinolide skeleton was investigated by means of feeding 13C- and 2H-labeled precursors to Botrytis cinerea. Three new compounds, two homobotcinolide derivatives, 3-O-acetylhomobotcinolide (5) and 8-methylhomobotcinolide (6), and a new 11-membered lactone (7), were isolated. Their structures were elucidated on the basis of spectroscopic data, including one-bond and long-range 1H-13C correlations. The relative stereochemistries were determined by combined analyses of NOE data and 1H-1H coupling constants. According to the results of feeding experiments with 13C- and 2H-labeled acetate and l-S-methylmethionine, 5 is an acetate-derived polyketide whose methyl groups originate from l-S-methylmethionine. This is a rare example of the incorporation of a methyl from methionine into a supposed C3 starter unit of the polyketide synthesis. 相似文献
25.
de Souza GG Oliveira TS Takahashi JA Collado IG Macías-Sánchez AJ Hernández-Galán R 《Organic & biomolecular chemistry》2012,10(16):3315-3320
Here we describe the biotransformation of clovane derivatives by filamentary fungi Pestalotiopsis palustris and Penicillium minioluteum, and the application of the latter to the synthesis and determination of the absolute configuration of rumphellclovane A (2). Methoxyclovanol (1), a growth inhibitor of the phytopathogen Botrytis cinerea, is metabolised by P. palustris to yield rumphellclovane A (2), a natural compound recently isolated from the gorgonian coral Rumphella antipathies, two new compounds, (1R,2S,5S,8R,9S,10R)-2-methoxyclovane-9,10-diol (5) and (1S,2S,5S,7R,8R,9R)-2-methoxyclovane-7,9-diol (6), hydroxylated in positions not easily accessed by classic synthetic chemistry, and clovanodiols 3 and 4. P. minioluteum is able to selectively transform methoxyclovanol (1) into clovanodiols 3 and 4 and, in turn, lactone 8, the putative intermediate in the above mentioned synthesis of rumphellclovane A (2), into compound 2 via a domino process. The ability of P. minioluteum to carry out the cleavage of ethers on clovane derivatives is also evaluated. 相似文献
26.
We study continuous product domains in the space of all continuousE-valued functions on , where is a compact Hausdorff topological space and E is an arbitrary JB-triple, and discuss the group of holomorphic automorphisms of domains of that type.
Received November 9, 1998; in final form March 23, 1999 / Published online May 8, 2000 相似文献
27.
The pion-rho exchange three-body force is derived by means of lagrangians which are approximately invariant under chiral and gauge transformations. The leading contribution to the potential arises from a seagull diagram, which corresponds to forces that are dominantly repulsive and comparable to those due to the exchange of two pions. The qualitative features of our results are analysed by means of plots of the energy of the trinucleon system. 相似文献
28.
A bijective linear mapping between two JB-algebrasA andB is an isometry if and only if it commutes with the Jordan triple products ofA andB. Other algebraic characterizations of isometries between JB-algebras are given. Derivations on a JB-algebraA are those bounded linear operators onA with zero numerical range. For JB-algebras of selfadjoint operators we have: IfH andK are left Hilbert spaces of dimension ≥3 over the same fieldF (the real, complex, or quaternion numbers), then every surjective real linear isometryf fromS(H) ontoS(K) is of the formf(x)=UoxoU
−1 forx inS(H), whereτ is a real-linear automorphism ofF andU is a real linear isometry fromH ontoK withU(λh)=τ(λ)U(h) for λ inF andh inH.
Supported by Acción Integrada Hispano-Alemana HA 94 066 B 相似文献
29.
Pilar Basabe Olga Bodero Isidro S. Marcos David Diez Mónica de Román Araceli Blanco Julio G. Urones 《Tetrahedron》2007,63(48):11838-11843
The γ-acetoxybutenolide (+)-lagerstronolide was synthesized from (+)-sclareol, with an overall yield of 10%. The absolute stereochemistry for the natural compound (−)-lagerstronolide has been correctly established. 相似文献
30.
Díez D Garcia P Marcos IS Garrido NM Basabe P Broughton HB Urones JG 《Organic letters》2003,5(20):3687-3690
[reaction: see text] A new amino acid methyl ester with a cyclopropanol has been synthesized starting from the allyl sulfone 10. The starting material, 10, could be obtained in both enantiomeric forms. The stereoselectivity of the cyclopropane formation has been studied by molecular modeling. 相似文献