Deprotonation de N-oxydes d'amines aliphatiques: schéma réactionnel général et nouvelle synthèse de pyrrolidines

1985 ◽  
Vol 63 (3) ◽  
pp. 725-734 ◽  
Author(s):  
René Beugelmans ◽  
Leïla Benadjila-Iguertsira ◽  
Jacqueline Chastanet ◽  
Guillermo Negron ◽  
Georges Roussi
Keyword(s):  
Tertiary Amine ◽  
Amine Oxide ◽  
Secondary Amines ◽  
Lithium Diisopropylamide ◽  
Efficient Synthesis ◽  
Remarkable Property ◽  
Amine Oxides ◽  
Trimethylamine Oxide ◽  
First Time ◽  
Hydrolysis Of

Amine oxides, 1, 5, 10, 15, 21, 23, when treated by lithium diisopropylamide undergo deprotonation. Monodeprotonation gives rise either to secondary amines and benzaldehyde resulting from the hydrolysis of an intermediate immonium (I) or to hydroxylamines via a Stevens-like rearrangement observed for the first time on an amine oxide. Double deprotonation gives an immonium ylid (Y) which, depending upon the structure of the initial tertiary amine yields either "head to head" piperazines (biradical-like behavior of (DD)) or aziridines. The immonium ylid (Y5) derived from trimethylamine oxide, whose formation and reactivity are reported for the first time, has the remarkable property of undergoing cycloaddition reactions with unactivated olefins, leading to a new and efficient synthesis of various pyrrolidines.

Studies in Amine Oxide Rearrangement: Meisenheimer Rearrangement of m-Substituted Tertiary Amine Oxides.

ChemInform ◽  
2006 ◽  
Vol 37 (28) ◽  
Author(s):  
K. C. Majumdar ◽  
B. Roy ◽  
P. K. Basu ◽  
P. Biswas
Keyword(s):  
Tertiary Amine ◽  
Amine Oxide ◽  
Amine Oxides

Chemistry of the Podocarpaceae. XVII. Ring-A modifications of O-methylpodocarpic acid

1968 ◽  
Vol 21 (10) ◽  
pp. 2473 ◽  
Author(s):  
CR Bennett ◽  
RC Cambie ◽  
TJ Fullerton
Keyword(s):  
Sulphuric Acid ◽  
Oxidation State ◽  
Tertiary Amine ◽  
Acid Chloride ◽  
Nitrous Acid ◽  
Amine Oxide ◽  
Curtius Reaction ◽  
Hydrolysis Of

Methods for the conversion of 0-methylpodocarpic acid (I) into 12-methoxy-16-norpodocarpa-8,11,13-trien-4-amine (11) have been examined, a Curtius reaction on the acid chloride (IV) followed by hydrolysis of the isocyanate (111) with 85% w/w sulphuric acid affording the highest overall yield (44%). Some "simple deaminations" involving no change in oxidation state, have been investigated as possible routes to alkenes suitable for further modification of the A ring of podocarpio acid. These include nitrous acid deamination, treatment of the N-benzoate (VIII) with phosphorus pentabromide or pentachloride, and pyrolysis of the tertiary amine oxide (VII) or quaternary methylammonium iodide.

scholarly journals Optimisation of Recombinant Myrosinase Production in Pichia pastoris

2021 ◽  
Vol 22 (7) ◽  
pp. 3677
Author(s):  
Zuzana Rosenbergová ◽  
Kristína Kántorová ◽  
Martin Šimkovič ◽  
Albert Breier ◽  
Martin Rebroš
Keyword(s):  
Pichia Pastoris ◽  
Plant Defence ◽  
Plant Secondary Metabolites ◽  
Specific Productivity ◽  
Fermentation Conditions ◽  
Threefold Increase ◽  
Dry Cell Weight ◽  
First Time ◽  
Hydrolysis Of ◽  
Dry Cell

Myrosinase is a plant defence enzyme catalysing the hydrolysis of glucosinolates, a group of plant secondary metabolites, to a range of volatile compounds. One of the products, isothiocyanates, proved to have neuroprotective and chemo-preventive properties, making myrosinase a pharmaceutically interesting enzyme. In this work, extracellular expression of TGG1 myrosinase from Arabidopsis thaliana in the Pichia pastoris KM71H (MutS) strain was upscaled to a 3 L laboratory fermenter for the first time. Fermentation conditions (temperature and pH) were optimised, which resulted in a threefold increase in myrosinase productivity compared to unoptimised fermentation conditions. Dry cell weight increased 1.5-fold, reaching 100.5 g/L without additional glycerol feeding. Overall, a specific productivity of 4.1 U/Lmedium/h was achieved, which was 102.5-fold higher compared to flask cultivations.

Cellulose organic solvents: V. Conformational aspects of N,N-dimethyl ethanolamine N-oxide in its crystalline and diluted states

1984 ◽  
Vol 62 (1) ◽  
pp. 6-10 ◽  
Author(s):  
E. R. Maia ◽  
A. Péguy ◽  
S. Pérez
Keyword(s):  
Tertiary Amine ◽  
Amine Oxide ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
Cyclic Form ◽  
Asymmetric Unit ◽  
Ir And Nmr Spectroscopy ◽  
Conformational Investigation ◽  
Intramolecular Hydrogen ◽  
Strong Intramolecular Hydrogen Bond

N,N-Dimethyl ethanolamine N-oxide (DMEAO) belongs to the class of tertiary amine oxide molecules that are good solvents for cellulose, although not being cyclic. Crystallographic investigation shows that anhydrous DMEAO is monoclinic, space group Cc, a = 25.725(9), b = 7.023(4), c = 9.483(5) Å, β = 101.16(10)°, Z = 12. The crystal structure has been solved by direct methods and refined to a final R value of 0.063 for 575 observed reflexions. Three independent molecules are found within the asymmetric unit; one of these displays a pseudo-cyclic form dictated by the occurrence of a strong intramolecular hydrogen bond. Conformational investigation of DMEAO in solution, using ir and nmr spectroscopy shows that this pseudo-cyclic form is more likely to occur in diluted states. These findings are related to the ability of this tertiary amine oxide to act as a good solvent, up to a water content of one water molecule per DMEAO molecule.

scholarly journals Biosynthesis of anandamide and N-palmitoylethanolamine by sequential actions of phospholipase A2 and lysophospholipase D

2004 ◽  
Vol 380 (3) ◽  
pp. 749-756 ◽  
Author(s):  
Yong-Xin SUN ◽  
Kazuhito TSUBOI ◽  
Yasuo OKAMOTO ◽  
Takeharu TONAI ◽  
Makoto MURAKAMI ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Brain Homogenate ◽  
Wide Distribution ◽  
Rat Tissues ◽  
Lysophospholipase D ◽  
Pla2 Enzyme ◽  
First Time ◽  
Hydrolysis Of ◽  
The Brain

Anandamide (an endocannabinoid) and other bioactive long-chain NAEs (N-acylethanolamines) are formed by direct release from N-acyl-PE (N-acyl-phosphatidylethanolamine) by a PLD (phospholipase D). However, the possible presence of a two-step pathway from N-acyl-PE has also been suggested previously, which comprises (1) the hydrolysis of N-acyl-PE to N-acyl-lysoPE by PLA1/PLA2 enzyme(s) and (2) the release of NAEs from N-acyllysoPE by lysoPLD (lysophospholipase D) enzyme(s). In the present study we report for the first time the characterization of enzymes responsible for this pathway. The PLA1/PLA2 activity for N-palmitoyl-PE was found in various rat tissues, with the highest activity in the stomach. This stomach enzyme was identified as group IB sPLA2 (secretory PLA2), and its product was determined as N-acyl-1-acyl-lysoPE. Recombinant group IB, IIA and V of sPLA2s were also active with N-palmitoyl-PE, whereas group X sPLA2 and cytosolic PLA2α were inactive. In addition, we found wide distribution of lysoPLD activity generating N-palmitoylethanolamine from N-palmitoyl-lysoPE in rat tissues, with higher activities in the brain and testis. Based on several lines of enzymological evidence, the lysoPLD enzyme could be distinct from the known N-acyl-PE-hydrolysing PLD. sPLA2-IB dose dependently enhanced the production of N-palmitoylethanolamine from N-palmitoyl-PE in the brain homogenate showing the lysoPLD activity. N-Arachidonoyl-PE and N-arachidonoyl-lysoPE as anandamide precursors were also good substrates of sPLA2-IB and the lysoPLD respectively. These results suggest that the sequential actions of PLA2 and lysoPLD may constitute another biosynthetic pathway for NAEs, including anandamide.

Enzyme system of Clostridium stercorarium for hydrolysis of arabinoxylan: reconstitution of the in vivo system from recombinant enzymes

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2257-2266 ◽  
Author(s):  
Helmuth Adelsberger ◽  
Christian Hertel ◽  
Erich Glawischnig ◽  
Vladimir V. Zverlov ◽  
Wolfgang H. Schwarz
Keyword(s):  
Extracellular Enzymes ◽  
Enzyme System ◽  
Thermophilic Bacterium ◽  
Recombinant Enzymes ◽  
Type Mode ◽  
Complete Set ◽  
First Time ◽  
Hydrolysis Of

Four extracellular enzymes of the thermophilic bacterium Clostridium stercorarium are involved in the depolymerization of de-esterified arabinoxylan: Xyn11A, Xyn10C, Bxl3B, and Arf51B. They were identified in a collection of eight clones producing enzymes hydrolysing xylan (xynA, xynB, xynC), β-xyloside (bxlA, bxlB, bglZ) and α-arabinofuranoside (arfA, arfB). The modular enzymes Xyn11A and Xyn10C represent the major xylanases in the culture supernatant of C. stercorarium. Both hydrolyse arabinoxylan in an endo-type mode, but differ in the pattern of the oligosaccharides produced. Of the glycosidases, Bxl3B degrades xylobiose and xylooligosaccharides to xylose, and Arf51B is able to release arabinose residues from de-esterified arabinoxylan and from the oligosaccharides generated. The other glycosidases either did not attack or only marginally attacked these oligosaccharides. Significantly more xylanase and xylosidase activity was produced during growth on xylose and xylan. This is believed to be the first time that, in a single thermophilic micro-organism, the complete set of enzymes (as well as the respective genes) to completely hydrolyse de-esterified arabinoxylan to its monomeric sugar constituents, xylose and arabinose, has been identified and the enzymes produced in vivo. The active enzyme system was reconstituted in vitro from recombinant enzymes.

scholarly journals Studies on Tertiary Amine Oxide. IX

1961 ◽  
Vol 81 (4) ◽  
pp. 574-578 ◽  
Author(s):  
Masatoxno Hamana ◽  
Motoyoshi Yamazaki
Keyword(s):  
Tertiary Amine ◽  
Amine Oxide
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