A modified McLafferty rearrangement in the electron impact mass spectra of dansylated amino-acid methyl esters

1996 ◽  
Vol 14 (8-10) ◽  
pp. 1031-1035 ◽  
Author(s):  
R. Oprean ◽  
L. Roman ◽  
R. Sandulescu
Keyword(s):  
Amino Acid ◽  
Electron Impact ◽  
Mass Spectra ◽  
Methyl Esters ◽  
Mclafferty Rearrangement ◽  
Acid Methyl ◽  
Electron Impact Mass ◽  
Impact Mass ◽  
Amino Acid Methyl Esters

scholarly journals N-Acylated amino acid methyl esters from marine Roseobacter group bacteria

2018 ◽  
Vol 14 ◽  
pp. 2964-2973 ◽  
Author(s):  
Hilke Bruns ◽  
Lisa Ziesche ◽  
Nargis Khakin Taniwal ◽  
Laura Wolter ◽  
Thorsten Brinkhoff ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mass Spectra ◽  
Antibiotic Production ◽  
Methyl Esters ◽  
Structural Similarity ◽  
Structural Motif ◽  
Acid Methyl ◽  
Signalling Compounds ◽  
Fragmentation Patterns ◽  
Amino Acid Methyl Esters

Bacteria of the Roseobacter group (Rhodobacteraceae) are important members of many marine ecosystems. Similar to other Gram-negative bacteria many roseobacters produce N-acylhomoserine lactones (AHLs) for communication by quorum sensing systems. AHLs regulate different traits like cell differentiation or antibiotic production. Related N-acylalanine methyl esters (NAMEs) have been reported as well, but so far only from Roseovarius tolerans EL-164. While screening various roseobacters isolated from macroalgae we encountered four strains, Roseovarius sp. D12_1.68, Loktanella sp. F13, F14 and D3 that produced new derivatives and analogs of NAMEs, namely N-acyl-2-aminobutyric acid methyl esters (NABME), N-acylglycine methyl esters (NAGME), N-acylvaline methyl esters (NAVME), as well as for the first time a methyl-branched NAME, N-(13-methyltetradecanoyl)alanine methyl ester. These compounds were detected by GC–MS analysis, and structural proposals were derived from the mass spectra and by derivatization. Verification of compound structures was performed by synthesis. NABMEs, NAVMEs and NAGMEs are produced in low amounts only, making mass spectrometry the method of choice for their detection. The analysis of both EI and ESI mass spectra revealed fragmentation patterns helpful for the detection of similar compounds derived from other amino acids. Some of these compounds showed antimicrobial activity. The structural similarity of N-acylated amino acid methyl esters and similar lipophilicity to AHLs might indicate a yet unknown function as signalling compounds in the ecology of these bacteria, although their singular occurrence is in strong contrast to the common occurrence of AHLs. Obviously the structural motif is not restricted to Roseovarius spp. and occurs also in other genera.

Highly Stereoselective Synthesis of Optically Pure C-Aryl Imines from α-L-Amino Acid Methyl Esters.

ChemInform ◽  
2004 ◽  
Vol 35 (17) ◽  
Author(s):  
Antonella Leggio ◽  
Adolfo Le Pera ◽  
Angelo Liguori ◽  
Anna Napoli ◽  
Claudio Romeo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Stereoselective Synthesis ◽  
Methyl Esters ◽  
Acid Methyl ◽  
Optically Pure ◽  
Amino Acid Methyl Esters
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