Synthesis and Biological Activity of the C′D′E′F′ Ring System of Maitotoxin

Here we show the facile synthesis of 132-173-bacteriochlorophyllone a (12), with a distinct seven-membered exocyclic F-ring formed by 132-173-cyclization of bacteriopheophorbide a(16). This is the latest reported bacteriochlorin with such an exocyclic F-ring since 1975 (132-173 cyclobacteriopheophorbide a-enol, 11), and is an analog of previously described natural exocyclic F-ring-containing porphyrins (1–4) and chlorins (5–10). The structure of 12 was confirmed using a combination of 1D 1 H NMR, 2D COSY 1 H NMR, Jmod 13 C NMR and HRMS analysis. The biological activity of 12 was explored, and we found that this compound does not possess strong antioxidant activity like its natural product counterparts, but is a capable photosensitizer for photodynamic therapy.

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Looking for Changes in the Saturnian System Between Voyager and Cassini

Symposium - International Astronomical Union ◽

10.1017/s007418090009094x ◽

1992 ◽

Vol 152 ◽

pp. 53-64

Author(s):

Nicole Borderies

Keyword(s):

Ring System ◽

Time Dependent ◽

Planetary Rings ◽

Small Satellites ◽

Irregular Structures ◽

Saturnian System ◽

Long Time ◽

Recession Rates ◽

F Ring

This paper reviews a number of time-dependent phenomena that are relevant to our understanding of the dynamics of planetary rings and that will be investigated using Voyager and Cassini data. A long time baseline may help us decipher the physics of the spokes, understand better the morphology of the F ring and the rigid precession of non-circular ringlets, measure more precisely than has been done so far the satellites' torques and the viscosity of the A ring, and discover small satellites in the Saturnian ring system. Two exciting possibilities are those of determining the recession rates of the small satellites that border the rings, and of observing changes due to viscous diffusion in the irregular structures of the B ring.

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ChemInform Abstract: Inhibitors of Farnesyl Protein Transferase. Synthesis and Biological Activity of Amide and Cyanoguanidine Derivatives Containing a 5,11-Dihydro[1]benzthiepin, Benzoxepin, and Benzazepin[4,3-b]pyridine Ring System.

ChemInform ◽

10.1002/chin.199902173 ◽

2010 ◽

Vol 30 (2) ◽

pp. no-no

Author(s):

R. WOLIN ◽

M. CONNOLLY ◽

J. KELLY ◽

J. WEINSTEIN ◽

S. ROSENBLUM ◽

...

Keyword(s):

Biological Activity ◽

Pyridine Ring ◽

Ring System ◽

Farnesyl Protein Transferase

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Crystal Structures of 1,3-Thiaza-4-one Heterocycles

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314082229 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1777-C1777

Author(s):

Hemant Yennawar ◽

Lee Silverberg ◽

John Tierney ◽

Kevin Cannon ◽

Ryan Bendinsky ◽

...

Keyword(s):

Biological Activity ◽

Crystal Structures ◽

Ring System ◽

Medicinal Use ◽

Wide Range

The five-, six-, and seven-membered 1,3-thiaza-4-one heterocycles are known for their bioactivity. Five-membered 1,3-thiazolidin-4-ones are known to have a very wide range of biological activity, so much that the ring system has been referred to as a "magic moiety" or "wonder nucleus" [1]. Six-membered 1,3-thiazin-4-ones have often been investigated for their biological activity and are of potential medicinal use [2]. The activity of seven-membered 1,3-thiazepan-4-ones is exemplified by the investigational compound omapatrilat [3]. Crystal structures of 1,3-thiaza-4-one heterocycles recently obtained in our laboratory will be presented.

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