Synthesis of Multisubstituted Imidazolo[4,5-d]pyridazine Fused Ring System

Synfacts ◽  
2021 ◽  
Vol 18 (01) ◽  
pp. 0031
1974 ◽  
Vol 3 (9) ◽  
pp. 951-954 ◽  
Author(s):  
Joung Hee Lee ◽  
Akira Matsumoto ◽  
Masayuki Yoshida ◽  
Osamu Simamura

1979 ◽  
Vol 57 (16) ◽  
pp. 2114-2117 ◽  
Author(s):  
John M. McIntosh

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.


2021 ◽  
Vol 14 (7) ◽  
pp. 653
Author(s):  
Yu-Chi Tsai ◽  
Racheal A. Nell ◽  
Jonathan E. Buckendorf ◽  
Norbert Kúsz ◽  
Peter Waweru Mwangi ◽  
...  

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.


IUCrData ◽  
2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Yassine Kharbach ◽  
Youssef Kandri Rodi ◽  
Catherine Renard ◽  
El Mokhtar Essassi ◽  
Lahcen El Ammari

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.


2007 ◽  
Vol 63 (11) ◽  
pp. o4340-o4340 ◽  
Author(s):  
Xiao-Bing Wang ◽  
Ling-Yi Kong

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.


2019 ◽  
Vol 21 (24) ◽  
pp. 10081-10084 ◽  
Author(s):  
Takayuki Hoshi ◽  
Eisuke Ota ◽  
Yasuhide Inokuma ◽  
Junichiro Yamaguchi

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

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

2015 ◽  
Vol 71 (9) ◽  
pp. o648-o649
Author(s):  
Rajamani Raja ◽  
Subramani Kandhasamy ◽  
Paramasivam T. Perumal ◽  
A. SubbiahPandi

In the title compound, C22H13BrN2O7·CHCl3, the pyran ring adopts a shallow sofa conformation with the C atom bearing the bromochromene system as the flap [deviation = 0.291 (3) Å]. The dihedral angle between the pyran fused-ring system (all atoms; r.m.s. deviation = 0.032 Å) and the bromochromene ring system (r.m.s. deviation = 0.027 Å) is 87.56 (9)°. An intramolecular N—H...O hydrogen bond closes anS(6) ring. The Cl atoms of the solvent molecule are disordered over two sets of sites in a 0.515 (6):0.485 (6) ratio. In the crystal, inversion dimers linked by pairs of N—H...O hydrogen bonds generateR22(12) loops. The packing also features C—H...O and very weak π–π [centroid–centroid separation = 3.960 (2) Å] interactions, which link the dimers into a three-dimensional network.


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