54798-85-5Relevant academic research and scientific papers
Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca
Dickschat, Jeroen S.,Bruns, Hilke,Riclea, Ramona
supporting information; experimental part, p. 1697 - 1712 (2012/02/04)
The volatiles released by Micromonospora aurantiaca were collected by means of a closed-loop stripping apparatus (CLSA) and analysed by GC-MS. The headspace extracts contained more than 90 compounds from different classes. Fatty acid methyl esters (FAMEs) comprised the major compound class including saturated unbranched, monomethyl and dimethyl branched FAMEs in diverse structural variants: Unbranched, α-branched, γ-branched, (ω-1)-branched, (ω-2)-branched, α-and (ω-1)-branched, γ-and (ω-1)-branched, γ-and (ω-2)-branched, and γ-and (ω-3)-branched FAMEs. FAMEs of the last three types have not been described from natural sources before. The structures for all FAMEs have been suggested based on their mass spectra and on a retention index increment system and verified by the synthesis of key reference compounds. In addition, the structures of two FAMEs, methyl 4,8-dimethyldodecanoate and the ethyl-branched compound methyl 8-ethyl-4-methyldodecanoate were deduced from their mass spectra. Feeding experiments with isotopically labelled [ 2H10]leucine, [2H10]isoleucine, [2H8]valine, [2H5]sodium propionate, and [methyl-2H3]methionine demonstrated that the responsible fatty acid synthase (FAS) can use different branched and unbranched starter units and is able to incorporate methylmalonyl-CoA elongation units for internal methyl branches in various chain positions, while the methyl ester function is derived from S-adenosyl methionine (SAM).
Volatile methyl esters of medium chain length from the bacterium Chitinophaga Fx7914
Nawrath, Thorben,Gerth, Klaus,Mueller, Rolf,Schulz, Stefan
experimental part, p. 2228 - 2253 (2011/05/17)
The analysis of the volatiles released by the novel bacterial isolate Chitinophaga Fx7914 revealed the presence of ca. 200 compounds including different methyl esters. These esters comprise monomethyl- and dimethyl-branched, saturated, and unsaturated fatty acid methyl esters that have not been described as bacterial volatiles before. More than 30 esters of medium C-chain length were identified, which belong to five main classes, methyl (S)-2-methylalkanoates (class A), methyl (S)-2,(ω-1)-dimethylalkanoates (class B), methyl 2,(ω-2)-dimethylalkanoates (class C), methyl (E)-2-methylalk-2-enoates (class D), and methyl (E)-2,(ω-1)-dimethylalk-2- enoates (class E). The structures of the compounds were verified by GC/MS analysis and synthesis of the target compounds as methyl (S)-2-methyloctanoate (28), methyl (S)-2,7-dimethyloctanoate ((S)-43), methyl 2,6-dimethyloctanoate (49), methyl (E)-2-methylnon-2-enoate (20a), and methyl (E)-2,7-dimethyloct-2- enoate (41a). Furthermore, the natural saturated 2-methyl-branched methyl esters showed (S)-configuration as confirmed by GC/MS experiments using chiral phases. Additionally, the biosynthetic pathway leading to the methyl esters was investigated by feeding experiments with labeled precursors. The Me group at C(2) is introduced by propanoate incorporation, while the methyl ester is formed from the respective carboxylic acid by a methyltransferase using S-adenosylmethionine (SAM).
