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Publikation

Kolbe, A.; Porzel, A.; Schmidt, J.; Adam, G.; A new synthesis of [26,28-2H6]brassinolide and [26,28-2H6]castasterone via an unusual methyl migration J. Label. Compd. Rad. 46, 231-242, (2003) DOI: 10.1002/jlcr.662

Deuterium‐labelled brassinosteroids, namely [26,28‐2H6]castasterone, 8 , and [26,28‐2H6]brassinolide, 9 , were synthesized starting from 6,6‐ ethylenedioxy‐20‐formyl‐2α,3α‐isopropylidenedioxy‐5α‐pregnane, 1 , and 3‐[2H3]methyl‐but‐1‐yne‐[4,4,4‐2H3], 11 . Upon alkylating cleavage of the epoxide 6 with trimethylaluminium‐n‐butyllithium an unusual migration of a neighbouring [2H3]methyl group takes place to afford deuteriation at positions 26 and 28.
Publikation

Lien, T. P.; Kamperdick, C.; Schmidt, J.; Adam, G.; Sung, T. V.; Apotirucallane triterpenoids from Luvunga sarmentosa (Rutaceae) Phytochemistry 60, 747-754, (2002) DOI: 10.1016/S0031-9422(02)00156-5

The leaves of Luvunga sarmentosa (Bl.) Kurz. yielded eight apotirucallane triterpenoids named luvungins A–G, and 1α-acetoxyluvungin A. Characteristic of the structure are the seven-membered lactone-ring A, the α-hydroxyl or α-acetoxyl group at C-7 and an oxygen bridge in the side chain giving five-, six- or seven-membered rings, respectively. Because of a hemiacetal function at C-21, luvungin C occurred as a mixture of 21-epimers. The structures have been elucidated on the basis of MS and NMR spectral data. In addition, two known coumarins ostruthin (6-geranyl-7-hydroxycoumarin) and 8-geranyl-7-hydroxycoumarin as well as five known triterpenes friedelin, flindissone, melianone, niloticin and limonin were isolated.The leaves of Luvunga sarmentosa (Bl.) Kurz. yielded eight apotirucallane triterpenoids named luvungins A–G and 1α-acetoxyluvungin A. Characteristic for the luvungins were the seven-membered lactone-ring A, the α-hydroxyl or α-acetoxyl group at C-7 and an oxygen bridge in the side chain giving five-, six- or seven-membered rings.
Publikation

Kolbe, A.; Fuchs, P.; Porzel, A.; Baumeister, U.; Kolbe, A.; Adam, G.; Synthesis and crystal structure of [26,27-2H6] 24-epi-cathasterone J. Chem. Soc., Perkin Trans. 1 2002, 2022-2027, (2002) DOI: 10.1039/B203323B

The first synthesis of [26,27-2H6]24-epi-cathasterone 8via (20S)-3β-acetoxy-6,6-(ethylenedioxy)-20-formyl-5α-pregnane 5 starting from stigmasterol is described. The aldehyde 5 was alkylated with lithium butyldimethyl-(E)-2,3-dimethyl[3,3,3,4,4,4-2H6]butenylaluminate 6 prepared from 3-[2H3]methyl[4,4,4-2H3]but-1-yne. The structure was determined using spectral data and X-ray crystallographic analysis.
Publikation

Kolbe, A.; Kramell, R.; Porzel, A.; Schmidt, J.; Schneider, G.; Adam, G.; Syntheses of Dexamethasone Conjugates of the Phytohormones Gibberellin A3 and 24-Epicastasterone Collect. Czech. Chem. Commun. 67, 103-114, (2002) DOI: 10.1135/cccc20020103

The syntheses of N-[10-(9α-fluoro-11β,17α-dihydroxy-16α-methyl-3-oxoandrosta-1,4-diene-17β-carboxamido)decyl]gibberellamide (7) and 6-[({N-[10-(9α-fluoro-11β,17α-dihydroxy- 16α-methyl-3-oxoandrosta-1,4-diene-17β-carboxamido)decyl]carbamoyl}methoxy)imino]-24-epicastasterone (10) are described. [(Benzotriazol-1-yl)oxy]bis(pyrrolidin-1-yl)methylium hexafluorophosphate (HBPyU) was used as the coupling agent for the reaction of gibberellic acid as well as of 24-epicastasterone-O-(carboxymethyl)oxime with N-(10-aminodecyl)- 9α-fluoro-11β,17α-dihydroxy-16α-methyl-3-oxoandrosta-1,4-diene-17β-carboxamide (4). The gibberellic acid conjugate 7 was also synthesised by the coupling of succinimidyl gibberellate 6 with amine 4.
Publikation

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.
Publikation

Anh, N. T. H.; Sung, T. V.; Wessjohann, L.; Adam, G.; The iridois and iridoid glycosid from the Rehmanuia glutinosa Rhizome Vietnam J. Chem. 40, 17-22, (2002)

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Publikation

Anh, N. T. H.; Sung, T. V.; Wessjohann, L. A.; Adam, G.; Some hydroxycinnamic acid esters of phenylethyl alcohol glycosides from Rehmannia glutinosa Libosch Vietnam J. Chem. 40, 175-179, (2002)

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Publikation

Buske, A.; Schmidt, J.; Porzel, A.; Adam, G.; Alkaloidal, Megastigmane and Lignan Glucosides from Antidesma membranaceum (Euphorbiaceae) Eur. J. Org. Chem. 2001, 3537-3543, (2001) DOI: 10.1002/1099-0690(200109)2001:18<3537::AID-EJOC3537>3.0.CO;2-A

Two novel alkaloidal glucosides derived from the recently discovered antidesmone (1 ), together with four known megastigmane and three lignan glucosides, two of which had not previously been described, were isolated from 1‐butanol extracts of Antidesma membranaceum (Euphorbiaceae). The structural elucidation of (17RS )‐17‐(β‐D ‐glucopyranosyloxy)antidesmone (2 ) and (17RS )‐8‐deoxo‐17‐(β‐D ‐glucopyranosyloxy)antidesmone (3 ) is based on 1H, 13C, COSY, NOESY, HMQC and HMBC NMR spectra, together with LC/ESI‐CIDMS and CD data. Determination of the absolute configuration at C‐17 was accomplished by comparison with 1H NMR spectroscopic data for alk‐2‐yl β‐D ‐glucopyranosides, an approach that also proved useful for the megastigmane glucosides blumenyl C β‐D ‐glucopyranoside (4 ), 3‐oxo‐α‐ionyl β‐D ‐glucopyranoside (5 ), blumenyl B β‐D ‐glucopyranoside (6 ) and blumenyl A β‐D ‐glucopyranoside (7 ). The lignan glucosides lyoniresin‐4‐yl β‐D ‐glucopyranoside (8 ), 4′‐O‐methyllyoniresin‐4‐yl β‐D ‐glucopyranoside (9 ) and secoisolariciresin‐4‐yl β‐D ‐glucopyranoside (10 ), featuring an unusual glucosylation position, were investigated with the aid of 1H and 2D NMR, CD and MS data.
Publikation

Franke, K.; Porzel, A.; Masaoud, M.; Adam, G.; Schmidt, J.; Furanocoumarins from Dorstenia gigas Phytochemistry 56, 611-621, (2001) DOI: 10.1016/S0031-9422(00)00419-2

A series of linear and angular prenylated furanocoumarins and a benzofuran derivative were isolated from leaves and twigs of Dorstenia gigas (Moraceae), a plant occurring endemically on Socotra Island (Yemen). The structures were elucidated by spectroscopic methods (NMR, MS, UV) and chemical derivatization.
Publikation

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.
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