6312-54-5Relevant articles and documents
Triple C-H activation of 1,5-bis(di-tert-butylphosphino)-2-(S)-dimethylaminopentane on ruthenium gives a chiral carbene complex
Kuznetsov, Vladimir F.,Lough, Alan J.,Gusev, Dmitry G.
, p. 2432 - 2433 (2002)
This communication reports the preparation of a novel trans-chelating diphosphine, 1,5-bis(di-tert-butylphosphino)-2-(S)-dimethylaminopentane, that undergoes triple C-H activation in reaction with [RuCl2(p-cymene)]2 to give a chiral square-pyramidal 16-electron carbene complex of ruthenium.
Metal-catalyzed reductive deamination of glutamic acid to bio-based dimethyl glutarate and methylamines
De Schouwer, Free,Cuypers, Thomas,Claes, Laurens,De Vos, Dirk E.
supporting information, p. 1866 - 1876 (2017/06/09)
Glutamic acid is a promising renewable platform molecule which is abundantly available in biomass waste streams; it is also efficiently manufactured by fermentation. Here we report the reductive deamination of glutamic acid to bio-based dimethyl glutarate and methylamines. In order to recycle nitrogen in an industrially relevant co-product, glutamic acid was modified to N,N-dimethylglutamic acid by a mild reductive alkylation with Pd/C. Subsequently, selective C-N hydrogenolysis in methanol resulted in dimethyl glutarate and trimethylamine. A wide screening of transition metals (Pt, Pd, Rh and Ru) immobilized on various supports showed that the highest yields of dimethyl glutarate were obtained with Pt/TiO2. An FTIR study and kinetic experiments on metal-loaded and unloaded supports demonstrate that the interplay between the metal and the moderate acidity of the support results in the excellent C-N hydrogenolysis activity and selectivity. Finally, reaction parameter optimization resulted in 81% yield of dimethyl glutarate with 1 wt% Pt/TiO2 at 225 °C, 30 bar H2 after 8 h.
Characterization of N,N-dimethyl amino acids by electrospray ionization-tandem mass spectrometry
Naresh Chary,Sudarshana Reddy,Kumar, Ch. Dinesh,Srinivas,Prabhakar
, p. 771 - 781 (2015/08/18)
Methylation is an essential metabolic process for a number of critical reactions in the body. Methyl groups are involved in the healthy function of the body life processes, by conducting methylation process involving specific enzymes. In these processes, various amino acids are methylated, and the occurrence of methylated amino acids in nature is diverse. Nowadays, mass-spectrometric-based identification of small molecules as biomarkers for diseases is a growing research. Although all dimethyl amino acids are metabolically important molecules, mass spectral data are available only for a few of them in the literature. In this study, we report synthesis and characterization of all dimethyl amino acids, by electrospray ionization-tandem mass spectrometry (MS/MS) experiments on protonated molecules. The MS/MS spectra of all the studied dimethyl amino acids showed preliminary loss of H2O+CO to form corresponding immonium ions. The other product ions in the spectra are highly characteristic of the methyl groups on the nitrogen and side chain of the amino acids. The amino acids, which are isomeric and isobaric with the studied dimethyl amino acids, gave distinctive MS/MS spectra. The study also included MS/MS analysis of immonium ions of dimethyl amino acids that provide information on side chain structure, and it is further tested to determine the N-terminal amino acid of the peptides.
Stable-isotope dimethylation labeling combined with LC-ESI MS for quantification of amine-containing metabolites in biological samples
Guo, Kevin,Ji, Chengjie,Li, Liang
, p. 8631 - 8638 (2008/03/15)
One of the challenges associated with metabolome profiling in complex biological samples is to generate quantitative information on the metabolites of interest. In this work, a targeted metabolome analysis strategy is presented for the quantification of amine-containing metabolites. A dimethylation reaction is used to introduce a stable isotopic tag onto amine-containing metabolites followed by LC-ESI MS analysis. This labeling reaction employs a common reagent, formaldehyde, to label globally the amine groups through reductive animation. The performance of this strategy was investigated in the analysis of 20 amino acids and 15 amines by LC-ESI MS. It is shown that the labeling chemistry is simple, fast (13C-dimethylation does not show any isotope effect on either RPLC or HILIC LC, indicating that 13C-labeling is a preferred approach for relative quantification of amine-containing metabolites in different samples. The isotopically labeled 35 amine-containing analogues were found to be stable and proved to be effective in overcoming matrix effects in both relative and absolute quantification of these analytes present in a complicated sample, human urine. Finally, the characteristic mass difference provides additional structural information that reveals the existence of primary or secondary amine functional groups in amine-containing metabolites. As an example, for a human urine sample, a total of 438 pairs of different amine-containing metabolites were detected, at signal-to-noise ratios of greater than 10, by using the labeling strategy in conjunction with RP LC-ESI Fourier-transform ion cyclotron resonance MS.
