A general stereocontrolled approach to the 5-8 fused ring system. Application to the total synthesis of the marine natural product (.+-.)-precapnelladiene

1987 ◽  
Vol 52 (13) ◽  
pp. 2875-2881 ◽  
Author(s):  
Goverdhan Mehta ◽  
A. Narayana Murthy
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
System Application ◽  
Ring System ◽  
Marine Natural Product ◽  
Fused Ring ◽  
Fused Ring System

Total Synthesis of the Diterpenoid Alkaloid Arcutinidine Using a Strategy Inspired by Chemical Network Analysis

2019 ◽  
Author(s):  
Kyle Owens ◽  
Shelby McCowen ◽  
Katherine Blackford ◽  
Sohei Ueno ◽  
Yasuo Hirooka ◽  
...  
Keyword(s):  
Natural Products ◽  
Network Analysis ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Diterpenoid Alkaloids ◽  
Oxidative Dearomatization ◽  
Diterpenoid Alkaloid ◽  
Fused Ring ◽  
Fused Ring System

Arcutinidine and other arcutinidine-type diterpenoid alkaloids feature an intricate polycyclic, bridged framework with unusual connectivity. A chemical network analysis approach to the arcutane skeleton enabled the identification of highly simplifying retrosynthetic disconnections, which indicated that the caged structure could arise from a simpler fused ring system. On this basis, a total synthesis of arcutinidine is reported herein, featuring an unprecedented oxopyrrolium Diels–Alder cycloaddition which furnishes a key tetracyclic intermediate. In addition, the synthesis utilizes a diastereoselective oxidative dearomatization/cycloaddition sequence and a SmI2-mediated C–C coupling to forge the bridged framework of the natural products. This synthetic plan may also enable future investigations into the biosynthetic relationships between the arcutanes, the related diterpenoid atropurpuran, and other diterpenoid alkaloids.

Total Synthesis of the Diterpenoid Alkaloid Arcutinidine Using a Strategy Inspired by Chemical Network Analysis

2019 ◽  
Author(s):  
Kyle Owens ◽  
Shelby McCowen ◽  
Katherine Blackford ◽  
Sohei Ueno ◽  
Yasuo Hirooka ◽  
...  
Keyword(s):  
Natural Products ◽  
Network Analysis ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Diterpenoid Alkaloids ◽  
Oxidative Dearomatization ◽  
Diterpenoid Alkaloid ◽  
Fused Ring ◽  
Fused Ring System

Arcutinidine and other arcutinidine-type diterpenoid alkaloids feature an intricate polycyclic, bridged framework with unusual connectivity. A chemical network analysis approach to the arcutane skeleton enabled the identification of highly simplifying retrosynthetic disconnections, which indicated that the caged structure could arise from a simpler fused ring system. On this basis, a total synthesis of arcutinidine is reported herein, featuring an unprecedented oxopyrrolium Diels–Alder cycloaddition which furnishes a key tetracyclic intermediate. In addition, the synthesis utilizes a diastereoselective oxidative dearomatization/cycloaddition sequence and a SmI2-mediated C–C coupling to forge the bridged framework of the natural products. This synthetic plan may also enable future investigations into the biosynthetic relationships between the arcutanes, the related diterpenoid atropurpuran, and other diterpenoid alkaloids.

Progress Toward The Total Synthesis Of The Marine Natural Product Karlotoxin 5

Planta Medica ◽  
2013 ◽  
Vol 79 (10) ◽  
Author(s):  
M Albadry ◽  
Y Zou ◽  
Y Takahashi ◽  
A Waters ◽  
M Hossein ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Marine Natural Product

scholarly journals NEW ROUTES TO 1,2-DIAZOLES WITH A FUSED RING SYSTEM BY REDUCTIVE AND OXIDATIVE CYCLIZATIONS

1974 ◽  
Vol 3 (9) ◽  
pp. 951-954 ◽  
Author(s):  
Joung Hee Lee ◽  
Akira Matsumoto ◽  
Masayuki Yoshida ◽  
Osamu Simamura
Keyword(s):  
Ring System ◽  
Oxidative Cyclizations ◽  
Fused Ring ◽  
Fused Ring System

Regiospecific preparation of 10-allyl-1-ketoquinolizidine and an unexpected disproportionation during its Wolff–Kischner reduction

1979 ◽  
Vol 57 (16) ◽  
pp. 2114-2117 ◽  
Author(s):  
John M. McIntosh
Keyword(s):  
Ring System ◽  
Sigmatropic Rearrangement ◽  
High Yield ◽  
Reaction Conditions ◽  
Fused Ring ◽  
Fused Ring System

Regiospecific formation of 10-allyl-1-ketoquinolizidine (7) is achieved in high yield by a [2.3] sigmatropic rearrangement of N-allyl-1-ketoquinolizidinium bromide (6). Wolff–Kischner reduction of 7 affords 10-allylquinolizidine (8) contaminated by the 10-propyl and 10-ethynyl analogs in amounts which depend on the reaction conditions. The carbon-13 spectrum of 8 indicates a trans-fused ring system with an axial substituent at C-10.

scholarly journals Bioactive Compounds from Euphorbia usambarica Pax. with HIV-1 Latency Reversal Activity

2021 ◽  
Vol 14 (7) ◽  
pp. 653
Author(s):  
Yu-Chi Tsai ◽  
Racheal A. Nell ◽  
Jonathan E. Buckendorf ◽  
Norbert Kúsz ◽  
Peter Waweru Mwangi ◽  
...  
Keyword(s):  
Antiretroviral Therapy ◽  
Lactone Ring ◽  
Ring System ◽  
Primary Mechanism ◽  
Fused Ring ◽  
Cd69 Expression ◽  
K 13 ◽  
Latent Hiv ◽  
Fused Ring System ◽  
Hiv 1

Euphorbia usambarica is a traditional medicine used for gynecologic, endocrine, and urogenital illnesses in East Africa; however, its constituents and bioactivities have not been investigated. A variety of compounds isolated from Euphorbia species have been shown to have activity against latent HIV-1, the major source of HIV-1 persistence despite antiretroviral therapy. We performed bioactivity-guided isolation to identify 15 new diterpenoids (1–9, 14–17, 19, and 20) along with 16 known compounds from E. usambarica with HIV-1 latency reversal activity. Euphordraculoate C (1) exhibits a rare 6/6/3-fused ring system with a 2-methyl-2-cyclopentenone moiety. Usambariphanes A (2) and B (3) display an unusual lactone ring constructed between C-17 and C-2 in the jatrophane structure. 4β-Crotignoid K (14) revealed a 250-fold improvement in latency reversal activity compared to crotignoid K (13), identifying that configuration at the C-4 of tigliane diterpenoids is critical to HIV-1 latency reversal activity. The primary mechanism of the active diterpenoids 12–14 and 21 for the HIV-1 latency reversal activity was activation of PKC, while lignans 26 and 27 that did not increase CD69 expression, suggesting a non-PKC mechanism. Accordingly, natural constituents from E. usambarica have the potential to contribute to the development of HIV-1 eradication strategies.

Total Synthesis of the Marine Natural Product Hemiasterlin by Organocatalyzed α-Hydrazination

2017 ◽  
Vol 23 (52) ◽  
pp. 12714-12717 ◽  
Author(s):  
Jan Hendrik Lang ◽  
Peter G. Jones ◽  
Thomas Lindel
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Marine Natural Product
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