The absolute stereochemistry of the New Zealand shellfish toxin gymnodimine

Identification of gymnodimine D and presence of gymnodimine variants in the dinoflagellate Alexandrium ostenfeldii from the Baltic Sea

“…1) are cyclic imines produced by two species of marine planktonic dinoflagellates, Karenia selliformis and Alexandrium ostenfeldii. Gymnodimine A (2) was found first in New Zealand oysters in 1994 (Seki et al, 1995;Stewart et al, 1997), and since then, it has been detected in several other locations around the world, and supposedly produced by K. selliformis. The hydroxylated analogues, gymnodimine B (3) and C (4), have also been isolated from K. selliformis (Miles et al, 2000(Miles et al, , 2003.…”

Synthesis of vinyl selenides and tellurides using PEG-400

“…4 Besides, organoselenium and organotellurium compounds have attracted increased interest because of their unique biological and pharmacological properties. 5 In this way, various methods are mentioned for the preparation of alkenyl selenides and tellurides and the most common ones involve the addition of organo chalcogenols, or the respective chalcogenolate anions, to terminal or internal alkynes.…”

“…1,6 On the other hand, the development of environmentally benign and clean synthetic methods, including those involving solvent-free or the use of alternative solvents, such as water, ionic liquids and polyethylene glycol (PEG), has increased in recent years. 7 Despite several advantages, the solvent-free methods are restricted to systems where at least one of the reagents is liquid at room temperature, whereas the use of ionic liquids, especially imidazolium systems with PF 6 and BF 4 anions, have some drawbacks, such as the high cost and liberation of hazardous HF during recycling. Thus, the use of PEG and other alternative non-volatile solvents has been shown as an attractive way to cleaner organic synthesis.…”

Absolute configuration of the hydroxyfarnesylethyl group of haem A, determined by X-ray structural analysis of bovine heart cytochromecoxidase using methods applicable at 2.8 Å resolution

“…However, the chiral centre of haem A, which has a H atom as one of the four functional groups surrounding the chiral C atom, should have a tetrahedral configuration that is slightly flatter than normal. Analysis of 13 X-ray structures that had R factors less than 0.05 (El-Feraly et al, 1983;Chattopadhyay et al, 2001;Chen & Wu, 1999;Kohl et al, 1985;Ober et al, 1987;Mossa et al, 1990;Ortega et al, 1991;Stewart et al, 1997;Banwell et al, 1992;Shi et al, 1997;Fahmy et al, 2003;Yang & Chen, 2000) and were similar to the structure of the chiral centre of haem A deposited in the Cambridge Structural Data Base (Allen & Kennard, 1993) (Fig. 1; i.e.…”