Browsing by Author "Teigo Asai"
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PublicationArticle Artabotryols A-E, new lanostane triterpenes from the seeds of artabotrys odoratissimus(2010) Chitrasen Gupta; Subedar Prasad; Mahendra Sahai; Teigo Asai; Noriyuki Hara; Yoshinori FujimotoSix new lanostane triterpenes, artabotryols A, B, C1, C2, D, and E (1, 2, 3a, 3b, 4, and 5, resp.) have been isolated from the seeds of Artabotrys odoratissimus (Annonaceae). Their structures have been established as (3α,22S,25R)-3-hydroxy-22,26-epoxylanost-8-en-26-one (1), (3α,22S,25R)-22,26-epoxylanost-8-ene-3,26-diol (2), (3α,22S,25R,26R) -26-methoxy-22,26-epoxylanost-8-en-3-ol (3a), (3α,22S,25R, 26S)-26-methoxy-22,26-epoxylanost-8-en-3-ol (3b), (3α,22S,25R)-3,22- dihydroxylanost-8-en-26-oic acid (4) and (3α,7α,11α,22S,25R)- 3,7,11-trihydroxy-22,26-epoxylanost-8-en-26-one (5) by spectroscopic studies and chemical correlations. © 2010 Verlag Helvetica Chimica Acta AG, Zürich, Switzerland.PublicationArticle Hyosgerin, a new optically active coumarinolignan, from the seeds of Hyoscyamus niger(2006) Begum Sajeli; Mahendra Sahai; Roderich Suessmuth; Teigo Asai; Noriyuki Hara; Yoshinori FujimotoHyosgerin, a new optically active coumarinolignan, has been isolated and characterized along with three other coumarinolignans, venkatasin, cleomiscosin A and cleomiscosin B, from the seeds of Hyoscyamus niger L. The structure was determined on the basis of spectroscopic analysis and chemical conversion. The optical properties and absolute stereochemistry of these coumarinolignans have also been studied and discussed. © 2006 Pharmaceutical Society of Japan.PublicationArticle Hyosmin, a new lignan from Hyoscyamus niger L.(Scientific Reviews Ltd., 2006) Ahil Sajeli Begum; Shweta Verma; Mahendra Sahai; Teigo Asai; Noriyuki Hara; Yoshinori FujimotoHyosmin (1) a new lignan has been isolated from the seeds of Hyoscyamus niger L. (Solanaceae), and its structure shown to be the 3-{[(2R)-2- carbomethoxy-2-hydroxy]ethyl}benzoate ester of {(2R,3S,4S)-2-(4-hydroxy-3- methoxyphenyl)-3-hydroxymethyl-4-[(4-hydroxy-3-methoxyphenyl)methyl] tetrahydrofuran.