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951.
952.
Mária InczeIstván Moldvai Eszter Temesvári-MajorGábor Dörnyei Mária Kajtár-PeredyCsaba Szántay 《Tetrahedron》2003,59(24):4281-4286
Starting from N-pivaloyl-Uhle's ketone a new synthetic approach to the ergoline skeleton has been elaborated. Ring D of the tetracyclic skeleton was formed by an intramolecular Dieckmann-condensation of a diester, obtained in a Reformatsky reaction of a properly substituted derivative of N-pivaloyl Uhle's ketone followed by elimination of water. 相似文献
953.
Valentin A. Semenov Dmitry O. Samultsev Leonid B. Krivdin 《International journal of quantum chemistry》2020,120(19):e26348
The PBE0/pcSseg-2//pcseg-2 calculations of 1H and 13C NMR chemical shifts were performed for a classical series of 12 Strychnos alkaloids (except for the earlier studied parent strychnine), namely akuammicine, isostrychnine, rosibiline, tsilanine, spermostrychnine, diaboline, cyclostrychnine, henningsamide, strychnosilidine, strychnobrasiline, holstiine, and icajine. It was found that the calculated 1H and 13C NMR chemical shifts show markedly good correlations with available experimental data, as characterized by a mean absolute error of 0.22 ppm for the range of 8 ppm for protons and 1.97 ppm for the range of 180 ppm for carbons. Complementarily, the present results provide essential NMR update and fill a gap in the NMR data of this distinguished group of vitally important natural products. 相似文献
954.
Prenylated Indole Alkaloid Derivatives from Marine Sediment‐Derived Fungus Penicillium paneum SD‐44 下载免费PDF全文
Three new prenylated indole alkaloids, including two β‐carbolines, penipalines A and B ( 1 and 2 , resp.), and one indole carbaldehyde derivative, penipaline C ( 3 ), as well as two known indole derived analogs, 4 and 5 , were isolated from the deep‐sea‐sediment derived fungus Penicillium paneum SD‐44 cultured in a 500‐l bioreactor. The structures of the new compounds were determined on the basis of 1D‐ and 2D‐NMR spectroscopy, as well as by high‐resolution mass spectrometry. The new compounds 2 and 3 showed potent cytotoxic activities against A‐549 and HCT‐116 cell lines. 相似文献
955.
Three diprenylated indole alkaloids, mangrovamides A–C (1–3), featured a bicyclo [2.2.2] diazaoctane core and possessed a novel γ-methyl proline and isoprene derived dimethyl γ-pyrone functionalities hitherto unknown among the family of paraherquamides, were isolated from the fungus Penicillium sp., which was separated from a mangrove soil sample. The structures were elucidated based on NMR, X-ray, and CD methods. The possible biosynthetic pathway of these compounds is proposed. 相似文献
956.
Li Zhang Chun-Jiang Zhang Dong-Bo Zhang Juan Wen Xiao-Wei Zhao Ya Li Kun Gao 《Tetrahedron letters》2014
A novel alkaloid, 17-nor-excelsinidine (1), possessing an unusual 1-azoniatricyclo [4.3.3.0] undecane moiety was isolated from the twigs and leaves of Alstonia scholaris alongside its biogenetically related strictamine (2). The structure and absolute stereochemistry of compound 1 were rigorously determined by a combination of NMR spectroscopy and X-ray crystallography. The 17-nor-excelsinidine (1) and strictamine (2) showed significant inhibitory activity against herpes simplex virus (HSV) and adenovirus (ADV). 相似文献
957.
Back Cover: Total Synthesis of 7‐ and 8‐Oxygenated Pyrano[3,2‐a]carbazole and Pyrano[2,3‐a]carbazole Alkaloids via Boronic Acid‐Catalyzed Annulation of the Pyran Ring (Chem. Eur. J. 28/2014) 下载免费PDF全文
958.
Total Synthesis of 7‐ and 8‐Oxygenated Pyrano[3,2‐a]carbazole and Pyrano[2,3‐a]carbazole Alkaloids via Boronic Acid‐Catalyzed Annulation of the Pyran Ring 下载免费PDF全文
Dr. Konstanze K. Julich‐Gruner Dr. Olga Kataeva Dr. Arndt W. Schmidt Prof. Dr. Hans‐Joachim Knölker 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8536-8540
The boronic acid‐catalyzed annulation of citral opens up a short route to oxygenated cyclized monoterpenoid pyranocarbazole alkaloids. Thus, murrayamine‐D is available in only three steps and 55% overall yield from the corresponding carbazole precursor. 相似文献
959.
Short Chemoenzymatic Total Synthesis of ent‐Hydromorphone: An Oxidative Dearomatization/Intramolecular [4+2] Cycloaddition/Amination Sequence 下载免费PDF全文
Vimal Varghese Prof. Tomas Hudlicky 《Angewandte Chemie (International ed. in English)》2014,53(17):4355-4358
A short synthesis of ent‐hydromorphone has been achieved in twelve steps from β‐bromoethylbenzene. The key transformations involved the enzymatic dihydroxylation of the arene to the corresponding cis‐dihydrodiol, Mitsunobu coupling with the ring A fragment, oxidative dearomatization of the C3 phenol, and the subsequent [4+2] cycloaddition to form ring B of the morphinan. The synthesis was completed by intramolecular amination at C9. 相似文献
960.
Roberto Ballette Dr. Maria Pérez Dr. Stefano Proto Prof. Dr. Mercedes Amat Prof. Dr. Joan Bosch 《Angewandte Chemie (International ed. in English)》2014,53(24):6202-6205
Madangamines are a group of bioactive marine sponge alkaloids, embodying an unprecedented diazapentacyclic skeletal type. The enantioselective total synthesis of madangamine D has been accomplished, and represents the first total synthesis of an alkaloid of the madangamine group. It involves the stereoselective construction of the diazatricyclic ABC core using a phenylglycinol‐derived lactam as the starting enantiomeric scaffold and the subsequent assembly of the peripheral macrocyclic rings. The synthesis provides, for the first time, a pure sample of madangamine D and confirms the absolute configuration of this alkaloid family. 相似文献