535-83-1Relevant articles and documents
Ab initio and DFT calculations of the structure and vibrational spectra of trigonelline
Szafran,Koput,Dega-Szafran,Pankowski
, p. 97 - 108 (2002)
The geometries, frequencies and infrared intensities of the vibrational bands of trigonelline its monohydrate and dimer have been computed by the MP2 and B3LYP approaches using the cc-pVDZ and 6-31G(d,p) basis sets. The computed geometry of the pyridine ring is slightly affected by hydration and dimerization, and satisfactorily agrees with the X-ray data. In contrast, the geometry of the COO group changes significantly on hydration and dimerization. All the measured IR bands were assigned in terms of the calculated vibrational modes. Most computed bands are predicted to lie at higher wavenumbers than the experimental bands. R.M.S. deviation between the experimental and the calculated harmonic frequencies is 69 cm-1 for all of the bands, and 46 cm-1 for all bands except those corresponding to v(OH), δ(OH) and v(CH).
Conversion of nicotinic acid to trigonelline is catalyzed by N-methyltransferase belonged to motif B′ methyltransferase family in Coffea arabica
Mizuno, Kouichi,Matsuzaki, Masahiro,Kanazawa, Shiho,Tokiwano, Tetsuo,Yoshizawa, Yuko,Kato, Misako
, p. 1060 - 1066 (2014)
Trigonelline (N-methylnicotinate), a member of the pyridine alkaloids, accumulates in coffee beans along with caffeine. The biosynthetic pathway of trigonelline is not fully elucidated. While it is quite likely that the production of trigonelline from nicotinate is catalyzed by N-methyltransferase, as is caffeine synthase (CS), the enzyme(s) and gene(s) involved in N-methylation have not yet been characterized. It should be noted that, similar to caffeine, trigonelline accumulation is initiated during the development of coffee fruits. Interestingly, the expression profiles for two genes homologous to caffeine synthases were similar to the accumulation profile of trigonelline. We presumed that these two CS-homologous genes encoded trigonelline synthases. These genes were then expressed in Escherichia coli, and the resulting recombinant enzymes that were obtained were characterized. Consequently, using the N-methyltransferase assay with S-adenosyl[methyl-14C]methionine, it was confirmed that these recombinant enzymes catalyzed the conversion of nicotinate to trigonelline, coffee trigonelline synthases (termed CTgS1 and CTgS2) were highly identical (over 95% identity) to each other. The sequence homology between the CTgSs and coffee CCS1 was 82%. The pH-dependent activity curve of CTgS1 and CTgS2 revealed optimum activity at pH 7.5. Nicotinate was the specific methyl acceptor for CTgSs, and no activity was detected with any other nicotinate derivatives, or with any of the typical substrates of B′-MTs. It was concluded that CTgSs have strict substrate specificity. The Km values of CTgS1 and CTgS2 were 121 and 184 μM with nicotinic acid as a substrate, and 68 and 120 μM with S-adenosyl-l-methionine as a substrate, respectively.
The chemistry of the N-methyl-3-dehydropyridinium ylid
Pan, Weitao,Shevlin, Philip B.
, p. 5091 - 5094 (2007/10/03)
The reaction of atomic carbon with N-methylpyrrole, 5b, at 77 K generates the N-methyl-3-dehydropyridinium ylid, 6b, which can be trapped with added hydrogen halides or CO2. The addition of CO2 is strong evidence for the ylid 6b rather than cumulene 7. Deuterium and 13C labeling studies demonstrate that 6b rapidly rearranges to the N-methyl-2-dehydropyridinium ylid, 13, by an intermolecular mechanism. Ylid 13 can be trapped with added acids or with O2 to form 1-methyl-2-pyridone.
Syntheses et proprietes de tensioactifs zwitterioniques
Chevalier, Y.,Brunel, S.,Perchec, P. Le
, p. 1025 - 1042 (2007/10/02)
Structure - properties relationhips are systematically investigated on zwitterionic surfactants at interfaces.Our methodology is based on a comparison of properties over series of homologuous surfactants.The respective influences of various molecular parameters can then be deduced.Such series of compounds are available from organic synthesis which can involve some interesting chemical reactions from the organic chemist point of view.This is illustrated with two examples.Simple surface tension measurements allow to study the main thermodynamic and structural effects.Complementary micellar size measurements show the influence of parameters as measured at the air-water interface on the interfacial curvature.The influence of the dipole moment beared by the zwitterionic polar part is thus demonstrated by this way.Other important molecular parameters in the polar heads are their size, the hydrophobic character and the flexibility of the spacer linking the two charges of the zwitterion. - Keywords: Zwitterionic surfactants, synthesis, micelles, surface tension, light scattering.
Pharmaceutical formulations for parenteral use
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, (2008/06/13)
Aqueous parenteral solutions of drugs which are insoluble or only sparingly soluble in water and/or which are unstable in water, combined with hydroxypropyl-β-cyclodextrin, provide a means for alleviating problems associated with drug precipitation at the injection site and/or in the lungs or other organs following parenteral administration.
Pharmaceutical formulations for parenteral use
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, (2008/06/13)
Aqueous parenteral solutions of drugs which are insoluble or only sparingly soluble in water and/or which are unstable in water, combined with cyclodextrin selected from the group consisting of hydroxypropyl, hydroxyethyl, glucosyl, maltosyl and maltotriosyl derivatives of β- and γ-cyclodextrin, provide a means for alleviating problems associated with drug precipitation at the injection site and/or in the lungs or other organs following parenteral administration.
Redox systems for brain-targeted drug delivery
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, (2008/06/13)
Inclusion complexes of hydroxypropyl, hydroxyethyl, glucosyl, maltosyl and maltotriosyl derivatives of β- and γ-cyclodextrin with the reduced, biooxidizable, blood-brain barrier penetrating, lipoidal forms of dihydropyridine pyridinium salt redox systems for brain-targeted drug delivery provide a means for stabilizing the redox systems, particularly against oxidation. The redox inclusion complexes also provide a means for decreasing initial drug concentrations in the lungs after administration of the systems, leading to decreased toxicity. In selected instances, complexation results in substantially improved water solubility of the redox systems as well.
COVALENT ADDUCTS FROM 1,3-DISUBSTITUTED PYRIDINIUM SALTS AND PIPERIDINE
Moracci, F. Micheletti,Rienzo, B. Di,Tortorella, S.,Liberatore, F.
, p. 785 - 789 (2007/10/02)
Covalent adducts 3a-f have been isolated from the reaction between piperidine and pyridinium salts 1a-f. 3a-f are stable both in the solid state and in apolar solvents, whereas their fast dissociation back to piperidine and pyridinium ions occurs in aqueous solution.The latter, in the alkaline environment produced by the amine, yields the correspondent pseudobases, which are key intermediates of the subsequent reactions.For instance, the pseudobases from 1a,b can undergo either a ring-opening reaction or a redox process with the corresponding pyridinium cations.
