Biosynthesis of (2-nitroethyl)benzene and (Z)- and (E)-(2-nitroethenyl)benzenes from (Z)- and (E)-phenylacetaldoximes and phenylacetonitrile; defense allomone of Eutrichodesmus elegans and Eutrichodesmus armatus(Polydesmida: Haplodesmidae)

Abstract

The defense allomones of two haplodesmid millipedes, Eutrichodesmus elegansand E. armatus(Polydesmida: Haplodesmidae), are known as a mixture of the following three nitro compounds: (2-nitroethyl)benzene and (Z)- and (E)-(2-nitroethenyl)benzenes. Administrations of a mixture of 2 H-labeled (Z)- and (E)-phenylacetaldoximes and of 2 H-labeled phenylacetonitrile as precursors resulted in the same production of three 2 H-labeled nitro compounds, [2'-nitroethyl][2,3,4,5,6-2H5 ] benzene and [(Z)- and (E)-2'-nitroethenyl][2,3,4,5,6-2H5 ]benzenes, in both species. Oxime administration at an appropriate dose resulted in the production of three nitro compounds with similar natural ratios more effectively than nitrile administration. Conversion from oximes to nitrile and vice versawas evidenced during administration. Occurrences of three precursors (Z- and E-oximes and nitrile) were detected sporadically in millipede extracts by selected ion chromatography.