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.

Stereoselective Construction of an Unprecedented 7−8 Fused Ring System in Micrandilactone A by [3,3]-Sigmatropic Rearrangement

2008 ◽  
Vol 10 (4) ◽  
pp. 665-668 ◽  
Author(s):  
Yan-Dong Zhang ◽  
Wei-Wu Ren ◽  
Yu Lan ◽  
Qing Xiao ◽  
Kai Wang ◽  
...  
Keyword(s):  
Ring System ◽  
Sigmatropic Rearrangement ◽  
Fused Ring ◽  
Fused Ring System

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

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.

scholarly journals 1-Benzyl-5-bromoindoline-2,3-dione

IUCrData ◽  
2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Yassine Kharbach ◽  
Youssef Kandri Rodi ◽  
Catherine Renard ◽  
El Mokhtar Essassi ◽  
Lahcen El Ammari
Keyword(s):  
Hydrogen Bonds ◽  
Ring System ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Compound C ◽  
Centroid Distance ◽  
Fused Ring ◽  
Common Plane ◽  
The Mean ◽  
Fused Ring System

In the title compound, C15H10BrNO2, the indoline ring system, the two ketone O atoms and the Br atom lie in a common plane, with the largest deviation from the mean plane being 0.073 (1) Å for the Br atom. The fused-ring system is nearly perpendicular to the benzyl ring, as indicated by the dihedral angle between them of 74.58 (10)°. In the crystal, molecules are linked by weak C—H...O hydrogen bonds and by π–π interactions [inter-centroid distance = 3.625 (2) Å], forming a two-dimensional structure.

2-(2-Chlorophenyl)-7-methyl-4H-chromen-4-one

2007 ◽  
Vol 63 (11) ◽  
pp. o4340-o4340 ◽  
Author(s):  
Xiao-Bing Wang ◽  
Ling-Yi Kong
Keyword(s):  
Least Squares ◽  
Title Compound ◽  
Ring System ◽  
Mean Deviation ◽  
Stacking Interactions ◽  
Compound C ◽  
Centroid Distance ◽  
Fused Ring ◽  
Fused Ring System ◽  
Cl Atom

The title compound, C16H11ClO2, is a synthetic flavonoid. The fused-ring system is almost planar, with a mean deviation from the least-squares plane of 0.0204 (2) Å. The dihedral angle between the chromene group and the chlorophenyl ring is 50.9 (6)°, due to unfavourable steric interactions with the Cl atom. Aromatic π–π stacking interactions between the fused benzene (π-rich) and pyran (π-deficient) rings are observed, with a centroid–centroid distance of 3.578 Å.

Asymmetric Synthesis of a 5,7-Fused Ring System Enabled by an Intramolecular Buchner Reaction with Chiral Rhodium Catalyst

2019 ◽  
Vol 21 (24) ◽  
pp. 10081-10084 ◽  
Author(s):  
Takayuki Hoshi ◽  
Eisuke Ota ◽  
Yasuhide Inokuma ◽  
Junichiro Yamaguchi
Keyword(s):  
Asymmetric Synthesis ◽  
Ring System ◽  
Rhodium Catalyst ◽  
Fused Ring ◽  
Fused Ring System

Lithocaldehydes A and B, polyketones from the deep sea-derived fungus Phomopsis lithocarpus FS508

2020 ◽  
Vol 18 (37) ◽  
pp. 7326-7329
Author(s):  
Huibo Liu ◽  
Zhaoming Liu ◽  
Haohua Li ◽  
Haibo Tan ◽  
Qingbo Zhang ◽  
...  
Keyword(s):  
Deep Sea ◽  
Ring System ◽  
Fused Ring ◽  
Fused Ring System

Lithocaldehydes A (1) and B (2), a pair of novel diastereoisomers possessing an unprecedented 6/6/5/5/6 highly-fused ring system that forms an earring-like skeleton, were isolated from the deep sea-derived fungus, Phomopsis lithocarpus FS508.

ChemInform Abstract: A New Strained Angularly Fused Ring System: 8-Hydroxy-1,2,3-trimethoxybenz[a]anthracene-7,12-dione.

ChemInform ◽  
2010 ◽  
Vol 30 (26) ◽  
pp. no-no
Author(s):  
Ilia A. Guzei ◽  
Alex Melekhov ◽  
George A. Kraus
Keyword(s):  
Ring System ◽  
Fused Ring ◽  
Fused Ring System
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