Primary degradation products

In general, stabilizers function by reaction with proplnt decompn products. A number of methods have been described and a preliminary evaluation of these methods was conducted by several labs under a cooperative program. Based on results from these screening tests, the PicArsn spec tropho tome trie methods for available stabilizer and primary degradation products were selected for further study. The initial phase of this program was an attempt to standardize the necessary spectrophotometric factors. Significant differences with regard to the factors obtained... 

Marches JR, SA Owen, GF White, WA House, NJ Russell (1994) SDS-degrading bacteria attach to riverine sediment in response to the surfactant or its primary degradation product dodecan-l-ol. Microbiology (UK) 140 2999-3006. 

Detection, identification and quantification of these compounds in aqueous solutions, even in the form of matrix-free standards, present the analyst with considerable challenges. Even today, the standardised analysis of surfactants is not performed by substance-specific methods, but by sum parameter analysis on spectrophotometric and titrimetric bases. These substance-class-specific determination methods are not only very insensitive, but also very unspecific and therefore can be influenced by interference from other compounds of similar structure. Additionally, these determination methods also often fail to provide information regarding primary degradation products, including those with only marginal modifications in the molecule, and strongly modified metabolites. 

Helstege, A., Kurz, M., Weinbeck, M. and Gerok, W. 1993. Excretion of caffeine and its primary degradation products into bile. Journal of Hepatology, 17 61-1 i. 

Smock, L. A., Stoneburner, D. L. Clark, J. R. (1976). The toxic effects of trinitrotoluene (TNT) and its primary degradation products on two species of algae and the fathead minnow. Water Research, 10, 537—43. 

Creamer, L. K. and Richardson, B. C. (1974). Identification of the primary degradation product of asl-casein in Cheddar cheese. NZ J. Dairy Sci. Technol. 9,9-13. 

The API methoxamine hydrochloride, which contains a benzyl hydroxyl, was found to decompose in aqueous solution to the primary degradation product 2,5-dimethoxybenzaldehyde, presumably via a benzylic radical autoxidation pathway (Fig. 100) (142). 

Shang, D.Y., Macdonald, R.W., Ikonomou, M.G., 1999. Persistence of nonylphenol et-hoxylate surfactants and their primary degradation products in sediments from near a municipal outfall in the strait of Georgia, British Columbia, Canada. Environ. Sci. Technol. 33, 1366-1372. 

Organo-tin compounds have been used as catalysts, stabilisers for plastics and biocides. Tributyltin (TBT) species are very effective biocides, and have been incorporated as active agents in antifouling compounds for marine applications. However, TBT has seriously affected other marine organisms such as oysters, crabs and fish even at parts per billion and lower concentrations in water. Consequendy, the determinations of low levels of TBT and dibutyl tin (DBT), its less toxic primary degradation product in water and in biological materials, are very important. 

More detailed studies of the metabolic pathways of diflubenzuron in soils have been carried out with radioactive preparations labeled in four different positions of the molecule for a study of the ultimate fate of the primary degradation products. 

Facile loss of CO from the primary degradation product [51] is reported, but this does not occur in 3-acylpyrroles.41... 

Lobelia alkaloids, e.g., lobelanine (140), can easily lose one of the side chains. The primary degradation product [141] is further cleaved by a McLafferty rearrangement to [142]. Other key fragments corre-... 

Another typical fission proceeds with loss of cyclopropylcarbinol or CH2==CHCH2CH2OH from the primary degradation product [144], forming a fragment of mass 97. 

Compounds of the emetine class containing a double bond in ring D, e.g., psychotrine (174), are cleaved by a McLafferty rearrangement. The primary degradation product [175] can easily lose the side chain, producing an allylic carbonium ion [176].84... 

The absence of the carbonyl group in vobasinol (230) causes another type of rearrangement of the primary degradation product [231],115 (230)->[231]->[232]. 

The connection of C-21 to C-2 as in aspidofractinine123,138 (253) prevents the formation of the fragment [249] in the same way as shown for aspidospermidine. Hence the intensity of the primary degradation product [254], formed by loss of ethylene, is enhanced. It decomposes by fission of the C-3—C-4 and C-10—C-11 bonds, producing a fragment of mass 109 [255].123... 

The most significant correlation to the influence of yeast material is the identification of 4-methyl-5-vinyl-thiazol (11) in fraction 3 the liquid-liquid extract (SP I). This compoimd is a dehydration product of sulfurol, which is a primary degradation product of thiamine with roasty, fatty, peanut-like flavor notes 24) ... 

The sample solvent can be the source of instability and rapid degradation of the relevant impurity can occur. In the case of one development compound, an imine process-related impurity was a primary degradation product. The imine was stable in acetonitrile, but would readily hydrolyze in aqueous media. In fact, on-column degradation was observed when screening... 

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