Linkage isomers yields

Metabolism of the 2,S -isomers proceeds sequentially hydroxylation at the phenoxy group, hydrolysis of the cyano group, and cleavage of the ester linkage (Coats et al. 1989). Fenvalerate and the IS-isomers yield two ester metabolites in feces from hydroxylation at the 4 - and 2 -phenoxy positions. Other significant metabolites were 3-phenoxybenzoic acid and its hydroxy derivatives from the alcohol moiety, 3-(4-chlorophenyl) isovaleric acid and its hydroxy derivatives from the acid moiety, and thiocyanate and carbon dioxide from the cyano moiety (Ohkawa et al. 1979). A slow elimination rate characterizes fenvalerate and other a-cyano pyrethroids when compared with... 

The formation of diphenyl ether linkages may be accomplished at intermediate points in the reaction sequence, as in the total syntheses of obaberine (80) and the related triply bridged alkaloids trilobine (220) and isotrilobine (30). A key feature of this work was the judicious use of protecting groups. The common intermediate 405a was converted to a mixture of the diastereomers 406 and 407 (5 2 crude isomer ratio). The (S,R) isomer yielded obaberine (80), and the (S,S) isomer was transformed to trilobine (220). Since trilobine had already been N-... 

In a complimentary study, Bitterwolf [128], examined the photochemistry in a triethyloctylammonium hexafluorophosphate matrix at ca. 90 K by IR spectroscopy. Irradiation > 450 nm did not yield products however, an irradiation wavelength of 400 nm led to a mixture of linkage isomers of Re-NO, i.e., in addition to the N-bound form, the O-bound and side-bound (rj2) prod-... 

In some cases the synthesis has yielded a mixture of the two linkage isomers this is certainly the case with thiosulfatopentaamminecobalt (III) chloride 32) and possibly with hydrogen thiosulfatopentacyanocobaltate (III) also 34). It has also been found that an equilibrium between the two isomers is sometimes established in the solid 6) or in solution 19, 4.O, 44) in the latter the position of equilibrium depends greatly on the solvent. 

Novel linkage isomers of thiocyanate ion are also reported from studies of the reaction of Hgi with the [Co(NH8)6SCN] + ion. The immediate product is the [Co(NH3)s(SCNHg)] + ion, which undergoes aquation and isomerization to yield the [Co(NH3)5HaO] + and [Co(NH8)6(NCSHg)] + ions respectively. ... 

The iodoacetyl group of both isomers reacts with sulfhydryls under slightly alkaline conditions to yield stable thioether linkages (Figure 9.7). They do not react with unreduced disulfides in cystine residues or with oxidized glutathione (Gorman et al., 1987). The thioether bonds will be hydrolyzed under conditions necessary for complete protein hydrolysis prior to amino acid analysis. 

---