Polychlorinated amino acids

Unson, M.D. Rose, C.B. Faulkner, D.J. Brinen, L.S. Steiner, J.R. Clardy, J. (1993) New polychlorinated amino acid derivatives from the marine sponge Dysidea herbacea. J. Org. Chem., 58, 6336-43. 

The dysideathiazoles A-E (331-335) are a series of polychlorinated amino acid derivatives from Pacific Island collections of D. herbacea. The structures were determined by X-ray analyses and the absolute configurations were determined by X-ray crystallography of a brominated derivative [301]. Herbamide A (336), a chlorinated amide was isolated from a Papua New Guinean sample of D. herbacea as a minor component [302]. D. herbacea from the southern Great Barrier Reef contained a thiazole (337) amongst other known metabolites [303]. A Dysidea sp. 

The polybrominated diphenyl ether derivatives have also been reported to inhibit enzymes implicated in tumor development and artherosclerotic plague which indicates their potential as promising candidates for therapeutic agents [186]. It was previously shown that the symbiotic cyanobacterium, Oscillatoria spongeliae produces the polybrominated diphenyl ether [187, 188]. The marine sponge Dysidea herbacea collected from Indonesia, yielded a series of polybrominated diphenyl ether congeners [189, 190]. D. herbacea occurs in two chemotypes [188] - one chemotype contains both polychlorinated amino acid derivatives [191, 192] and sesquiterpenes [193, 194], while the second chemotype contains... 

The polychlorinated cyclic hexadepsipeptides kutznerides 1-9 (1036-1044), which contain both the novel 6.7-d i c h I oroh e x ah yd ropy rro I o 12.3 -/< i n do I e core and several unusual amino acids, are found in the actinomycete Kutzneria sp. 744 inhabiting the roots of Picea abies (1071,1072). These compounds show moderate activity against root-rotting fungi. Another chlorinated he xahydropvitoIo12.37 indole cyclohexapeptide is the dimeric chloptosin (1045) isolated from a Streptomy-... 

A few other biologically interesting and naturally occurring peptides and amino acids of rather simple structure were synthesized using the Ugi four-component reaction (Figure 12.5) the phosphonic acid antibiotics plumbemycin A 249 and B 250 [126], both epimers of the polychlorinated antihypertensive peptide (+)-demethyldysidenin 251 [127], and the nucleoside antibiotic nikkomycin 252 [128]. 

Botelho LH, Ryan DE, Levin W. 1979. Amino acid compositions and partial amino acid sequences of three highly purified forms of liver microsomal cytochrome P-450 from rats treated with polychlorinated biphenyls, phenobarbital... 

Pharamaceuticals Biochemicals Food products Industrial chemicals Pollutants Forensic chemistry Clinical medicine Antibiotics, sedatives, steroids, analgesics Amino acids, proteins, carbohydrates, lipids Artificial sweeteners, antioxidants, aflatoxins, additives Condensed aromatics, surfactants, propellants, dyes Pesticides, herbicides, phenols, polychlorinated biphenyls (PCBs) Dmgs. poisons, blood alcohol, narcotics Bile acids, drug metabolites, urine extracts, estrogens... 

Angus WGR, Mousa MA, Vargas VM, et al. 1997. Inhibition of L-aromatic amino acid decarboxylase by polychlorinated biphenyls. Neurotoxicology 18 857-868. 

Acrylonitrile, a precursor of acrylic fibers. A typical PCB (one of 209 different polychlorinated biphenyls). Lysine, one of about 20 amino acids that occur in proteins. 

In conclusion, the all-up conformation appears to be the one leading to high enantioselectivities. One side of the metal center is shielded by the side chains of the amino acids, whereas the other forms part of the tight reactive pocket created by the ligands. Most importantly, in the case of the polychlorinated ligands, this favorable conformation is likely supported by halogen bonding. 

Botanical extracts such as lanolin. Aloe vera, Centella asiatica or glycyrrhetic acid are studied. Vitamins such as A, C, B5 and E have also been reported. Studies on the following compounds used as ingredients can also be found heterocyclic compounds, organic acids, thiocompounds, alkanolamines, amines, amino acids, alcohols, peroxides, amides, polymers, peptides and ceramides. Analytical methods to determine toxic compounds present as impurities or as by-products such as nitrosamines, phenols, pesticides, polychlorinated biphenyls, etc. have also been proposed in literature. 

A thiazole nucleus or a diketopiperazine is associated with one or two trichloromefhyl groups, and munerous examples of such structures have been found in species of Dysidea. Most of these molecules contain 5,5,5-trichloro-N-mefhyl-leucine or 5,5-dichloro-N-methyl-leucine, which thus appear to be specific a-amino acids in the genus Dysidea, but are not present in peptides or depsipeptides. Figures 19.109 and 19.110 show some examples of these polychlorinated nitrogen derivatives. 

The role of polychlorinated gem-dichlorocyclohexadienones as reaction intermediates which can then produce desired me/a-chlorinated products or imdesired coupled products has been described.17 Chlorination of phenol and sometimes the ether complicates the hydrolysis of some primary alkyl phenyl ethers in concentrated aqueous perchloric acid solution.18 Unexpected chlorination has also been established in the reaction of 2-amino-5-chlorobenzophenone with HC1 in aqueous methanol (1 1 v/v), 2-amino-3,5-dichlorobenzophenone being amongst the products.19... 

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