TY - JOUR A1 - Yenesew, Abiy A1 - Kiplagat, John T. A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Kabaru, Jacques M. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Two unusual rotenoid derivatives, 7a-O-methyl-12a-hydroxydeguelol and spiro-13-homo-13-oxaelliptone, from the seeds of Derris trifoliata N2 - The crude methanol extract of the seeds of Derris trifoliata showed potent and dose dependent larvicidal activity against the 2nd instar larvae of Aedes aegypti. From this extract two unusual rotenoid derivatives, a rotenoloid (named 7a-O-methyl-12a-hydroxydeguelol) and a spirohomooxarotenoid (named spiro-13-homo-13-oxaelliptone), were isolated and characterised. In addition a rare natural chromanone (6,7-dimethoxy-4-chromanone) and the known rotenoids rotenone, tephrosin and dehydrodeguelin were identified. The structures were assigned on the basis of spectroscopic evidence. The larvicidal activity of the crude extract is mainly due to rotenone. (c) 2006 Elsevier Ltd. All rights reserved Y1 - 2006 UR - http://www.sciencedirect.com/science/article/pii/S0031942206000045 U6 - https://doi.org/10.1016/j.phytochem.2006.01.002 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Irungu, Beatrice A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Two prenylated flavonoids from the stem bark of Erythrina burttii N2 - From the stem bark of Erythrina burttii, a new isoflavone, 5,2',4'-trihydroxy-7-methoxy-6-(3- methylbut-2-enyl)isoflavone (trivial name, 7-O-methylluteone) and a new flavanone, 5,7-dihydroxy-4'-methoxy- 3'-(3-methylbutadienyl)-5'-(3-methylbut-2-enyl)flavanone (trivial name, burttinonedehydrate) along with three known isoflavonoids (8-prenylluteone, 3-O-methylcalopocarpin and genistein) were isolated. The structures were detd. on the basis of spectroscopic evidence. Y1 - 2003 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Meisner, M. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Two prenylated flavanones from stem bark of erythrina burttii Y1 - 1998 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Schanzenbach, Dirk A1 - Peter, Martin G. T1 - Two Isoflavanones from the Stem Bark of Erythrina sacleuxii N2 - From the stem bark of Erythrina sacleuxii two new isoflavanones, (R)-5,7-dihydroxy-2',4',5'- trimethoxyisoflavanone (trivial name, (R)-2,3-dihydro-7-demethylrobustigenin) and (R)-5-hydroxy- 2',4',5'-trimethoxy-2'',2''- dimethylpyrano[5'',6'':6,7]isoflavanone (trivial name, (R)-saclenone) were isolated. In addition the known compounds shinpterocarpin, 2,3-dehydrokievitone, abyssinone V, abyssinone V-4'-methyl ether, erythrinasinate and 4'-O-methylsigmoidin B were isolated. The structures were determined on the basis of spectroscopic evidence. Y1 - 2000 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Guchu, S. M. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Three iosoflav-3-enes and a 2-arylbenzofuran from the root bark of Erythrina burttii N2 - From the root bark of Erythrina burttii three new isoflav-3-enes, 7,4'-dihydroxy-2'-methoxy-6- (1'',1''-dimethylallyl)isoflav-3-ene (trivial name, burttinol-A), 4'-hydroxy-2'- methoxy-(2'',2''-dimethylpyrano[5'',6'':8,7]isoflav-3-ene (trivial name, burttinol-B), 7,4'-dihydroxy-2'-methoxy-8-(3'',3''-dimethylallyl)isoflav-3-ene (trivial name, burttinol-C), and a new 2-arylbenzofuran, 6,4'-dihydroxy-2'-methoxy-5- (1'',1''-dimethylallyl)-2-arylbenzofuran (trivial name, burttinol-D) were isolated. In addition, the known compounds, abyssinone V-4'-methyl ether, bidwillol A, calopocarpin, erybraedin A, erythrabyssin II, isobavachalcone, phaseollidin and phaseollin were identified. The structures were determined on the basis of spectroscopic evidence. Y1 - 2002 ER - TY - JOUR A1 - Wanjohi, John M. A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Peter, Martin G. A1 - Dreyer, M. A1 - Reichert, M. A1 - Bringmann, Gerhard T1 - Three dimeric anthracene derivatives from the fruits of Bulbine abyssinica N2 - From the fruits of Bulbine abyssinica three new dimeric anthracene derivatives, (P)-8,9,1',8'- tetrahydroxy-3,3'-dimethyl[10,7'-bianthracene]-1,4,9',10'- tetraone (trivial name abyquinone A), (10R)-1,4,8,1',8-pentahydroxy-3,3'-dimethyl-[10,7'-bianthracene]9,9',10' (10H)-trione (trivial name abyquinone B), and (10R)-3,4'-dihydro-1,4,8,3',8',9'-hexahydroxy-3,3'- dimethyl-[10,7'-biant hracene]9,1'(10H,2'H)-dione (trivial name abyquinone Q were isolated. Despite their structural differences, these three compounds are connected to each other by the apparently biomimetic conversion of abyquinone C (a preanthraquinonylanthrone with two stereogenic centers) into B (an anthraquinonylanthrone with one stereogenic center) and finally into A (an axially chiral bianthraquinone) under mild conditions, involving a highly efficient center-to-axis chirality transfer. In addition, the known anthraquinones islandicin and chrysophanol were identified. The structures were determined on the basis of spectroscopical evidences, chemical transformations, and quantum chemical CD calculations. (C) 2005 Elsevier Ltd. All rights reserved Y1 - 2005 SN - 0040-4020 ER - TY - JOUR A1 - Peter, Martin G. A1 - Andersen, S. O. T1 - The molecular architecture of the insect exoskeleton Y1 - 1994 ER - TY - JOUR A1 - Struszczyk, Marcin Henryk A1 - Ratajska, M. A1 - Boryniec, Stefan A1 - Peter, Martin G. A1 - Loth, Fritz T1 - The determination of the degree of N-acetylation of chitosan Y1 - 1997 ER - TY - JOUR A1 - Ratajska, M. A1 - Struszczyk, Marcin Henryk A1 - Boryniec, Stefan A1 - Peter, Martin G. A1 - Loth, Fritz T1 - The degree of acetylation of chitosan : optimization of the IR Method Y1 - 1997 ER - TY - JOUR A1 - Peter, Martin G. T1 - The Bio-organic chemistry of melanogenesis Y1 - 1995 ER - TY - JOUR A1 - Juma, Wanyama P. A1 - Akala, Hoseah M. A1 - Eyase, Fredrick L. A1 - Muiva, Lois M. A1 - Heydenreich, Matthias A1 - Okalebo, Faith A. A1 - Gitu, Peter M. A1 - Peter, Martin G. A1 - Walsh, Douglas S. A1 - Imbuga, Mabel A1 - Yenesew, Abiy T1 - Terpurinflavone an antiplasmodial flavone from the stem of Tephrosia Purpurea JF - Phytochemistry letters N2 - The stem extract of Tephrosia purpurea showed antiplasmodial activity against the D6 (chloroquine-sensitive) and W2 (chloroquine-resistant) strains of Plasmodium falciparum with IC(50) values of 10.47 +/- 2.22 mu g/ml and 12.06 +/- 2.54 mu g/ml, respectively. A new prenylated flavone, named terpurinflavone, along with the known compounds lanceolatin A, (-)-semiglabrin and lanceolatin B have been isolated from this extract. The new compound, terpurinflavone, showed the highest antiplasmodial activity with IC(50) values of 3.12 +/- 0.28 mu M (D6) and 6.26 +/- 2.66 mu M (W2). The structures were determined on the basis of spectroscopic evidence. KW - Tephrosia purpurea KW - Leguminosae KW - Stem KW - Flavone KW - Terpurinflavone KW - Antiplasmodial Y1 - 2011 U6 - https://doi.org/10.1016/j.phytol.2011.02.010 SN - 1874-3900 VL - 4 IS - 2 SP - 176 EP - 178 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rottmann, Antje A1 - Synstad, Bjoenar A1 - Eijsink, Vincent G. H. A1 - Peter, Martin G. T1 - Synthesis of N-acetylglucosaminyl and diacetylchitobiosyl amides of heterocyclic carboxylic acids as potential chitinase inhibitors Y1 - 1999 ER - TY - JOUR A1 - Ley, J. P. A1 - Peter, Martin G. T1 - Synthesis of N-(2-Acetamido-2-deoxy-ß-D-glucopyranosyl)- and of N-(N,N-Diacetylchitobiosyl)-amide of lhistidine Y1 - 1994 SN - 0039-7881 ER - TY - JOUR A1 - Ley, J. P. A1 - Peter, Martin G. T1 - Synthesis of L-histidine and (-)-spinacine chitooligosyl amides Y1 - 1996 ER - TY - JOUR A1 - Schanzenbach, Dirk A1 - Matern, Christa-Maria A1 - Peter, Martin G. T1 - Synthesis of glycosylamines and glycopeptides Y1 - 1997 ER - TY - JOUR A1 - Krösche, Christian A1 - Crescenzi, Orlando A1 - Hoffbauer, Wilfried A1 - Jansen, Martin A1 - Napolitano, Alessandra A1 - Prota, Guiseppe A1 - Peter, Martin G. T1 - Synthesis of dopamines labelled with 13C in the alpha- or beta-side chain positions, and their application for structure studies on melanins by solid state NMR spectroscopy Y1 - 1994 ER - TY - JOUR A1 - Schumacher-Wandersleb, Michael H. M. G. A1 - Peter, Martin G. T1 - Synthesis of chitobiosyl pyrrolidines Y1 - 1995 ER - TY - JOUR A1 - Peter, Martin G. A1 - Ley, J. P. A1 - Petersen, Stefan A1 - Londershausen, M. A1 - Schumacher-Wandersleb, Michael H. M. G. A1 - Spindler, Klaus-Dieter A1 - Spindler-Barth, Margarethe A1 - Turberg, Andreas T1 - Synthesis of chitinase inhibitors Y1 - 1994 ER - TY - JOUR A1 - Thiele, Gabriela A1 - Rottmann, Antje A1 - Germer, Antje A1 - Kleinpeter, Erich A1 - Spindler, Klaus-Dieter A1 - Synstad, Bjoenar A1 - Eijsink, Vincent G. H. A1 - Peter, Martin G. T1 - Synthesis and conformational analysis of pseudosugar analogues of chitotriose N2 - In this article, the synthesis of analogs of N,N',N''-triacetylchitotriose in which the central sugar residue was replaced by a succinic acid is presented. Mol. modeling calcns. revealed that the pseudotrisaccharides exist in low energy extended conformations which show similar space filling as N,N',N''-triacetylchitotriose. Of the N,N',N''-triacetylchitotriose pseudosugar analogs tested as chitinase inhibitors, none showed any appreciable competition (numerical data not presented). The conformational anal. along with further synthetic efforts will hopefully lead to more efficient pseudosaccharides as chitinase inhibitors. Y1 - 2002 ER - TY - JOUR A1 - Fettke, Anja A1 - Peikow, Dirk A1 - Peter, Martin G. A1 - Kleinpeter, Erich T1 - Synthesis and conformational analysis of glycomimetic analogs of thiochitobiose N2 - The synthesis of six analogs of N,N;-diacetylchitobiose is reported, including a novel transglycosylation reaction for the preparation of S-aryl thioglycosides. The conformations of the compounds were studied by a combination of NMR spectroscopy and molecular modeling, using force field calculations. In the case of the S-aryl thioglycosides with exclusively S-glycosidic linkages, dihedral angles of the disaccharidic S-glycosidic bonds, ;; and ;; and of the S-arylglycoside bonds, ; and ;, were found to be similar, whereas they were different in mixed glycosides and in a thiazoline derivative. An adequate correlation between the calculated H,H-distances of the local minima and the measured NOE contacts was achieved by applying population-weighted averages over participating conformers based on weighted relative energies. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/00404020 U6 - https://doi.org/10.1016/j.tet.2009.03.067 SN - 0040-4020 ER -