Development of an Alkaloid-Pyrone Annulation: Synthesis of Pleiomaltinine
作者:Robert E. Ziegler、Shin-Jowl Tan、Toh-Seok Kam、John A. Porco
DOI:10.1002/anie.201204093
日期:2012.9.10
Odd Couple: A method for the synthesis of alkaloid‐pyrones using a novel pyrone annulation of β‐carbolines and indoles with 3‐siloxy‐4‐pyrones is reported. The approach has enabled synthesis of the unusual alkaloid‐pyrone pleiomaltinine from the plant‐derived indole‐alkaloid pleiocarpamine (see Scheme; TBS= tert‐butyldimethylsilyl).
Surprising Coordination Geometry Differences in Ce
<sup>IV</sup>
‐ and Pu
<sup>IV</sup>
‐Maltol Complexes
作者:Géza Szigethy、Jide Xu、Anne E. V. Gorden、Simon J. Teat、David K. Shuh、Kenneth N. Raymond
DOI:10.1002/ejic.200800144
日期:2008.5
the detailed coordination behavior of Pu(IV), single crystal X-ray diffraction structures have been determined for Pu(IV) and Ce(IV) complexes with the naturally-occurring ligand maltol (3-hydroxy-2-methyl-pyran-4-one) and its derivative bromomaltol (5-bromo-3-hydroxy-2-methyl-pyran-4-one). Although Ce(IV) is generally accepted as a structural analog for Pu(IV), and the maltolcomplexes of these two
Preparation of 2<i>H</i>-Furo[2,3-<i>c</i>]pyran-2-one Derivatives and Evaluation of Their Germination-Promoting Activity
作者:Gavin R. Flematti、Ethan D. Goddard-Borger、David J. Merritt、Emilio L. Ghisalberti、Kingsley W. Dixon、Robert D. Trengove
DOI:10.1021/jf0633241
日期:2007.3.1
The butenolide, 3-methyl-2H-furo[2,3-c]pyran-2-one (1), has recently been identified as the germination stimulant present in smoke that promotes the germination of seeds from a wide range of plant species. In this paper, we describe the preparation of a number of analogues of 2 and compare their efficacy in promoting seed germination of three highly smoke-responsive plant species, Lactuca sativa L. cv. Grand Rapids (Asteraceae), Emmenanthe penduliflora Benth. (Hydrophyllaceae), and Solanum orbiculatum Poir. (Solanaceae). The results show that the methyl substituent at C-3 in 1 is important for germination-promoting activity while substitution at C-7 reduces activity. In contrast, bioactivity is mostly retained with analogues substituted at C-4 or C-5.
A Convenient Synthesis of 3-Hydroxy-4H-pyran-4-one Derivatives Having a Halo or Hydroxy Group at the 5-Position
作者:Hisashi Takao、Yoshinori Endo、Tokunaru Horie
DOI:10.3987/com-92-6090
日期:——
The reaction of 4,5-epoxy-4-halo-6-methoxy-2-methyl-tetrahydropyran-3-ones (4b and 5b) in acidic media was examined and the following results were found: The reaction of 4b or 5b with 1% sulfuric acid afforded a mixture of 3,5-dihydroxy-4H-pyran-4-one (1b) and 5-halo-3-hydroxy-4H-pyran-4-one (2b or 3b), but the use of concentrated acid formed the corresponding 5-halo-4H-pyran-4-one (2b or 3b) only. The reaction was applicable for a general method for synthesizing 3,5-disubstituted 4H-pyran-4-ones (1, 2, and 3).
Synthesis of 5-Aryl-3-hydroxy-4H-pyran-4-ones
作者:Hisashi Takao、Yoshinori Endo、Tokunaru Horie
DOI:10.3987/com-93-6364
日期:——
The palladium-catalyzed coupling reaction of 3-benzyl-oxy-5-bromo-2-methyl-4H-pyran-4-one (2b) with phenylboronic acid afforded efficiently 3-benzyloxy-2-methyl-5-phenyl-4H-pyran-4-one (3b-1), and the benzyloxy group of the resultant product was cleaved by hydrolysis with conc. hydrochloric acid in acetic acid to give 5-phenyl-3-hydroxy-2-methyl-4H-pyran-4-one (4b-1) in high yield. This method was applicable as a general method for synthesizing 5-aryl-3-hydroxy-4H-pyran-4-ones (4) from the 5-bromo-4H-pyran-4-ones(1).