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Publications - Bioorganic Chemistry

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Publications

Wessjohann, L. A.; Voigt, B.; Rivera, D. G.; Diversity Oriented One-Pot Synthesis of Complex Macrocycles: Very Large Steroid-Peptoid Hybrids from Multiple Multicomponent Reactions Including Bifunctional Building Blocks Angew. Chem. Int. Ed. 44, 4785-4790, (2005) DOI: 10.1002/anie.200500019

Up to 16 new bonds connect 12 building blocks to form 54‐membered macrocycles (46‐membered example shown) in a one‐pot procedure combining bifunctional components with multicomponent reactions. The large rings are not made of repetitive subunits and form an ideal basis for the fast construction of libraries of chiral host molecules.
Publications

Wessjohann, L. A.; Voigt, B.; Rivera, D. G.; Diversity Oriented One-Pot Synthesis of Complex Macrocycles: Very Large Steroid-Peptoid Hybrids from Multiple Multicomponent Reactions Including Bifunctional Building Blocks Angew. Chem. 117, 4863-4868, (2005) DOI: 10.1002/ange.200500019

Bis zu 54‐gliedrige Makrocylen (z. B. der 46‐gliedrige, im Bild gezeigte Ring) entstehen im Eintopfverfahren aus 12 Bausteinen unter Knüpfung von bis zu 16 neuen Bindungen durch die geschickte Kombination difunktioneller Bausteine mit Multikomponentenreaktionen. Die Riesenringe ohne repetitive Elemente sind damit eine ideale Grundlage für die schnelle Synthese von Bibliotheken chiraler Wirtmoleküle.
Publications

Voigt, B.; Porzel, A.; Adam, G.; Golsch, D.; Adam, W.; Wagner, C.; Merzweiler, K.; Synthesis of 2,24-Diepicastasterone and 3,24-Diepicastasterone as Potential Brassinosteroid Metabolites of the Cockroach Periplaneta americana Collect. Czech. Chem. Commun. 67, 91-102, (2002) DOI: 10.1135/cccc20020091

Investigations of the metabolic conversion of the phytohormone 24-epicastasterone (1) in the cockroach Periplaneta americana (L.) required the synthesis of 2,24-diepicastasterone (4), 3,24-diepicastasterone (7b) and 2-dehydro-3,24-diepicastasterone (9) as reference standards. 2,24-Diepicastasterone (4) was synthesized from 2α,3α-epoxy derivative 2 as well as from the 2β,3β-epoxy-22,23-diol 3 by acid-catalyzed water addition to the epoxy function leading to the desired 2β,3α-trans functionality. 3,24-Diepicastasterone (7b) was prepared by NaBH4-reduction of the 3-oxo derivative 6. Upon deprotection conditions from the ketol acetonides 6 and 8 in both cases 2-dehydro-3,24-diepicastasterone (9) was obtained. The structure of 2,24-diepicastasterone (4) was confirmed by X-ray analysis.
Publications

Schmidt, J.; Richter, K.; Voigt, B.; Adam, G.; Metabolic Transformation of the Brassinosteroid 24-Epi-castasterone by the Cockroach Periplaneta americana Z. Naturforsch. C 55, 233-239, (2000) DOI: 10.1515/znc-2000-3-415

After feeding of 24-epi-castasterone to the cockroach Periplaneta americana an organspecific epimerization of the brassinosteroid to 2,24-depi-castasterone could be detected in female insects. The metabolite being observed only in the ovaries and not in the testes of the insect was identified by GC/MS in comparison with a synthesized authentic sample. Contrary, 24-epi-brassinolide is not metabolized in the sexual organs of Periplaneta americana. This is the first evidence of a metabolic transformation of a brassinosteroid in insects.
Books and chapters

Schmidt, J.; Spengler, B.; Voigt, B.; Adam, G.; Brassinosteroids - Structures, Analysis and Synthesis Recent Advances in Phytochemistry 34, 385-407, (2000) DOI: 10.1016/S0079-9920(00)80013-1

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Publications

Lichtblau, D.; Porzel, A.; Schmidt, J.; Voigt, B.; Adam, G.; Synthesis of a novel brassinosteroid type with an annelated dioxonane side chain J. Chem. Soc., Perkin Trans. 1 1999, 53-58, (1999) DOI: 10.1039/A807078D

In studies directed towards the synthesis of 25-hydroxybrassinolide 1 we found, that upon reaction of intermediate 7 with trimethylaluminium–n-butyllithium an alkylating fission of the epoxide ring and rearrangement of the tetrahydropyranyl unit takes place to afford after deprotection the new dioxonane-annelated brassinosteroid 9.
Publications

Drosihn, S.; Porzel, A.; Voigt, B.; Brandt, W.; Wagner, C.; Merzweiler, K.; Adam, G.; Conformational studies of two new brassinosteroid analogues with a 22,23-trans diol function J. Chem. Soc., Perkin Trans. 2 1999, 233-238, (1999) DOI: 10.1039/A807440B

22,24-Diepiteasterone (3) and 23,24-diepiteasterone (4) were synthesized starting from a mixture of the corresponding (22S,23S)- and (22R,23R)-epoxides. Using detailed NOE investigations and molecular dynamic simulations with explicit solvent, the preferred conformations of both compounds were determined in solution. For both compounds 3 and 4 a preferred conformation of the side chain was found. For 4, by X-ray analysis the conformation in crystalline state was determined which differs distinctly from that in solution.
Publications

Voigt, B.; Porzel, A.; Bruhn, C.; Wagner, C.; Merzweiler, K.; Adam, G.; Synthesis of 24-epicathasterone and related brassinosteroids with modified side chain Tetrahedron 53, 17039-17054, (1997) DOI: 10.1016/S0040-4020(97)10146-6

The synthesis of 24-epicathasterone (20), 22-deoxy-24-epiteasterone (22) and 24-hydroxy-6-oxo-24-epicampestanol (24) via 22,23-epoxy- and 22,23-bromohydrin intermediates starting with ergosterol is reported. The structures of the new brassinosteroids were determined especially by X-ray analysis of intennediate bromohydrins.The synthesis of 24-epicathasterone, 22-deoxy-24-epiteasterone and 24-hydroxy-6-oxo-24-epicampestanol via 22,23-epoxy- and 22,23-bromohydrin intermediates starting with ergosterol is reported. The structures of the new brassinosteroids were determined especially by X-ray analysis of intermediate bromohydrins.
Books and chapters

Schmidt, J.; Spengler, B.; Voigt, B.; Adam, G.; New brassinosteroids from Ornithopus sativus and Apium graveolens 229-233, (1996)

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Books and chapters

Adam, G.; Porzel, A.; Schmidt, J.; Schneider, B.; Voigt, B.; New Developments in Brassinosteroid Research Stud. Nat. Prod. Chem. 18, 495-549, (1995) DOI: 10.1016/S1572-5995(96)80033-0

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