Substitutent Effects in Non-Aromatic Nitrogen Heterocycles: Alkaline Hydrolysis of Methyl N-Methyl (oxo)dihydropyridinecarboxylates and Diaza Analogues

1985 ◽  
Vol 38 (4) ◽  
pp. 637 ◽  
Author(s):  
LW Deady
Keyword(s):  
Alkaline Hydrolysis ◽  
Nitrogen Heterocycles ◽  
Reaction Rates ◽  
Ester Hydrolysis ◽  
Pyrimidine Derivatives ◽  
Polyfunctional Compounds ◽  
Hydrolysis Of ◽  
Derivatives Of

Ester hydrolysis studies on some isomeric methoxycarbonyl derivatives of N-methylpyridin-2- and 4-ones show that reaction rates are affected by the relative positions of CO2Me, =O and NMe functions in ways which could not be predicted. However, from limited result for analogous pyrimidine derivatives, it seems that reactivity in these polyfunctional compounds can be predicted from the pyridine data by assuming additivity of effects.

The Chemical Evolution of a Nitrogenase Model, 20 Alkyl Molybdates(VI) and the Mechanism of Hydrocarbon Production by Nitrogenase [1]

1982 ◽  
Vol 37 (3) ◽  
pp. 380-385 ◽  
Author(s):  
G. N. Schrauzer ◽  
Laura A. Hughes ◽  
Norman Strampach
Keyword(s):  
Aqueous Solution ◽  
Alkaline Hydrolysis ◽  
Room Temperature ◽  
Bond Cleavage ◽  
Model Compounds ◽  
Hydrocarbon Production ◽  
Acidic Solutions ◽  
Reducing Conditions ◽  
Hydrolysis Of ◽  
Derivatives Of

Abstract Colorless alkylmolybdates(VI) of composition R-MoO3-are generated in aqueous solutions by the alkaline hydrolysis of complexes R-Mo(Bpy)(0)2Br(Bpy = 2,2′-bipyridyl, R = CH3 and higher alkyl). At room temperature in alkaline aqueous solution, the new organometallic derivatives of oxomolybdate(VI) are remarkably resistant against Mo-C bond hydrolysis. Decomposition occurs more rapidly on heating, affording unrearranged alkanes according to the eq.: R-MoO3- + OH-→RH + Mo04=. In acidic solutions, the methylmolybdate(VI) species decomposes with the formation of a mixture of methane and ethane while higher alkylmolybdates carrying hydrogen in the β-position relative to molybdenum undergo Mo-C bond heterolysis by way of β-elimina-tion: R-CH2CH2-MoO3 → Mo+4 (aq) + H+ + R-CH = CH2. The Mo-C bond of alkylmolybdates is resistant to oxidants but is very sensitive to cleavage under reducing conditions. Reductive Mo-C bond cleavage occurs particularly rapidly in the presence of thiols and reduced ferredoxin model compounds. The latter reactions simulate the terminal steps of hydrocarbon producing reactions of nitrogenase with alternate substrates such as CN-, R-CN or R-NC, confirming previous mechanistic conclusions concerning the mechanism of nitrogenase action.

Isocarbostyrils. II. The Conversion of 2-Methyl-4-acyl-5-nitroisocarbostyrils to 2-Substituted Indole-4-carboxylic Acids

1971 ◽  
Vol 49 (17) ◽  
pp. 2797-2802 ◽  
Author(s):  
D. E. Horning ◽  
G. Lacasse ◽  
J. M. Muchowski
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Alkaline Hydrolysis ◽  
Mannich Reaction ◽  
Reductive Cyclization ◽  
Acid Catalyzed ◽  
Acid Anhydrides ◽  
Hydrolysis Of ◽  
Derivatives Of

The sulfuric acid catalyzed acylation of 2-methyl-5-nitroisocarbostyril with carboxylic acid anhydrides gave the corresponding 4-acylated derivatives 3, which underwent reductive cyclization to 2-substituted derivatives of 4-methyl-1,3,4,5-tetrahydropyrrolo[4.3.2.de]isoquinolin-5-one (4). Alkaline hydrolysis of the six-membered lactam in 4 was accompanied by a retro-Mannich reaction to produce 2-substituted indole-4-carboxylic acids in about 40 % overall yield from 3.

Immobilisierung von Adenosinacetalen mit variablem Alkylidenrest — die Funktion des Spacers bei enzymatischer Desaminierung / Immobilization of Adenosine-Acetals with Variable Alkylidene Residues — the Function of the Spacer during Enzymatic Deamination —

1979 ◽  
Vol 34 (5-6) ◽  
pp. 350-358 ◽  
Author(s):  
Frank Seela ◽  
Johann Ott ◽  
Helmut Rosemeyer
Keyword(s):  
Alkaline Hydrolysis ◽  
Hydrocarbon Chain ◽  
Ester Group ◽  
Spacer Length ◽  
Methylene Groups ◽  
Chain Lengths ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Deamination Reaction

Abstract Acetalation of the cis-diol moiety of adenosine or inosine with aliphatic ketoesters of different chain lengths leads to alkylidene derivatives of the nucleosides, which differ in the number of methylene groups in the hydrocarbon chain. By alkaline hydrolysis of the ester group in 1a - c or 3a - c the corresponding acids 2a - c and 4a - c have been prepared.The configuration of the new chiral centres has been determined as R.Enzymatic deamination of the alkylidene derivatives of adenosine leads to the inosine compounds. The rate of deamination reaction is raised by an increasing number of methylene groups in the alkylidene residues or by use of the esters instead of the acids.The alkylidene derivatives of adenosine were coupled with 6-aminohexylagarose yielding polymers with adenosine as ligands.No enzymatic deamination of the polymer with the shortest spacer was observed. The polymers with the longer spacers were converted to the corresponding inosine derivatives. The velocity of the deamination reaction was raised by an increasing spacer length.

Studies on the BAL2 mechanism for ester hydrolysis

1993 ◽  
Vol 71 (11) ◽  
pp. 1841-1844 ◽  
Author(s):  
Judy E. Douglas ◽  
Grant Campbell ◽  
Donald C. Wigfield
Keyword(s):  
Spectral Analysis ◽  
Carboxylic Acid ◽  
Alkaline Hydrolysis ◽  
Ester Hydrolysis ◽  
Mass Spectral Analysis ◽  
Mass Spectral ◽  
Hydrolysis Of

The preparation and alkaline hydrolysis of 18O-methyl 2,2-dimethylpropanoate and 18O-methyl triphenylacetate are reported. From mass spectral analysis of the carboxylic acid products, it is concluded that the former substrate is hydrolyzed exclusively by the BAC2 mechanism, whereas the latter substrate proceeds 95% by the BAC2 mechanism and 5% by the BAL2 mechanism. The balance between these two mechanisms is discussed.

scholarly journals Modeling the Alkaline Hydrolysis of Diaryl Sulfate Diesters: A Mechanistic Study

2020 ◽  
Author(s):  
Klaudia Szeler ◽  
Nicholas Williams ◽  
Alvan C. Hengge ◽  
Shina Caroline Lynn Kamerlin
Keyword(s):  
Alkaline Hydrolysis ◽  
Computational Study ◽  
Transition States ◽  
Building Blocks ◽  
Ester Hydrolysis ◽  
Mechanistic Study ◽  
Phosphate Ester ◽  
Sulfate Ester ◽  
The Impact ◽  
Hydrolysis Of

<div> <div> <div> <p>Phosphate and sulfate esters have important roles as biological building blocks and in regulating cellular processes. However, while there has been substantial experimental and computational investigation of the mechanisms and the transition states involved in phosphate ester hydrolysis, there is far less (in particular computational) work on sulfate ester hydrolysis. Here, we report a detailed computational study of the alkaline hydrolysis of diaryl sulfate diesters, using different DFT functionals and both pure implicit solvation as well as mixed implicit/explicit solvation with varying numbers of explicit water molecules. We consider both the impact of how the system is modeled on computed linear free energy relationships (LFER) and the nature of the transition states. Although our calculations consistently underestimate the absolute activation free energies, we obtain good agreement with experimental LFER data when using pure implicit solvent, and excellent agreement with experimental kinetic isotope effects for all models used. Our calculations suggest that the hydrolysis of sulfate diesters proceeds through loose transition states, with minimal bond formation to the nucleophile and with bond cleavage to the leaving group already initiated. Comparison to prior work indicates that these transition states are similar in nature to those of analogous reactions such as the alkaline hydrolysis of neutral arylsulfonate monoesters or charged phosphate diesters and fluorophosphates. Obtaining more detailed insight into the transition states involved assists in understanding the selectivity of enzymes that hydrolyze these reactions; however, this work also highlights the methodological challenges involved in reliably modeling sulfate ester hydrolysis. </p> </div> </div> </div>

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