The constitutions of seven metabolites formed during anaerobic degradation of n-hexane by the denitrifying betaproteobacterium strain HxN1 were elucidated by comparison of their GC and MS data with those of synthetic reference standards. The synthesis of 4-methyloctanoic acid derivatives was accomplished by the conversion of 2-methylhexanoyl chloride with Meldrum's acid. The β-oxoester was reduced with NaBH4 , the hydroxy group was eliminated, and the double bond was displaced to yield the methyl esters of 4-methyl-3-oxooctanoate, 3-hydroxy-4-methyloctanoate, (E)-4-methyl-2-octenoate, and (E)- and (Z)-4-methyl-3-octenoate. The methyl esters of 2-methyl-3-oxohexanoate and 3-hydroxy-2-methylhexanoate were similarly prepared from butanoyl chloride and Meldrum's acid. However, methyl (E)-2-methyl-2-hexenoate was prepared by Horner-Wadsworth-Emmons reaction, followed by isomerization to methyl (E)-2-methyl-3-hexenoate. This investigation, with the exception of 4-methyl-3-oxooctanoate, which was not detectable in the cultures, completes the unambiguous identification of all intermediates of the anaerobic biodegradation of n-hexane to 2-methyl-3-oxohexanoyl coenzyme A (CoA), which is then thiolytically cleaved to butanoyl-CoA and propionyl-CoA; these two metabolites are further transformed according to established pathways.

中文翻译：

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β-变形杆菌菌株HxN1反硝化，正己烷厌氧降解的代谢物。

通过反硝化β变形杆菌HxN1菌株在正己烷厌氧降解过程中形成的七种代谢物的组成，通过将它们的GC和MS数据与合成参考标准品进行了比较。4-甲基辛酸衍生物的合成通过将2-甲基己酰氯与麦德鲁姆酸转化而完成。用NaBH4还原β-氧代酸酯，消除羟基，并置换双键，生成4-甲基-3-氧代辛酸酯，3-羟基-4-甲基辛酸酯，（E）-4-甲基酯-2-辛烯酸酯，以及（E）-和（Z）-4-甲基-3-辛烯酸酯。类似地，由丁酰氯和Meldrum酸制备2-甲基-3-氧己酸酯和3-羟基-2-甲基己酸酯的甲酯。然而，通过Horner-Wadsworth-Emmons反应制备（E）-2-甲基-2-己烯酸甲酯，然后异构化为（E）-2-甲基-3-己烯酸甲酯。除了在培养物中无法检测到的4-甲基-3-氧代辛酸酯外，这项研究完成了对正己烷厌氧降解为2-甲基-3-氧代己酰基辅酶A（CoA）的所有中间体的明确鉴定。 ），然后将其硫解切割成丁酰基-CoA和丙酰基-CoA；这两种代谢物根据已建立的途径进一步转化。完成对正己烷厌氧生物降解为2-甲基-3-氧代己酸辅酶A（CoA）的所有中间体的明确鉴定，然后将其硫解裂解为丁酰基-CoA和丙酰基-CoA; 这两种代谢物根据已建立的途径进一步转化。完成对正己烷厌氧生物降解为2-甲基-3-氧代己酸辅酶A（CoA）的所有中间体的明确鉴定，然后将其硫解裂解为丁酰基-CoA和丙酰基-CoA; 这两种代谢物根据已建立的途径进一步转化。