Preparation and Properties of (Hydroxymethyl)boronic Acid and its Pinanediol Ester

2011 ◽  
Vol 64 (11) ◽  
pp. 1425 ◽  
Author(s):  
Donald S. Matteson
Keyword(s):  
Nmr Spectroscopy ◽  
Asymmetric Synthesis ◽  
Sodium Hydroxide ◽  
Isotope Effect ◽  
Boronic Acid ◽  
Efficient Route ◽  
The Stability ◽  
Hydrolysis Of

Hydrolysis of diisopropyl (bromomethyl)boronate followed by reaction with pinanediol provides an efficient route to pinanediol (hydroxymethyl)boronate (12), a useful intermediate for asymmetric synthesis. The stability of (hydroxymethyl)boronic acid (10) and its ester 12 have been examined by NMR spectroscopy. Heating for 1 h in acidic D2O does not degrade 10 and only affects the pinanediol moiety of 12. Base does not degrade 10 or 12 in several days at 20–25°C, but converts either to DCH2OD and CH3OD in a few h at 90–98°C, with a large H/D isotope effect. Pinanediol (bromomethyl)boronate with sodium hydroxide in D2O yields a gross mixture of products.

scholarly journals Antitumour Metallocenes: Effect of DMSO on the Stability of Cp2TiX2 and Implications for Anticancer Activity

1998 ◽  
Vol 5 (4) ◽  
pp. 207-215 ◽  
Author(s):  
George Mokdsi ◽  
Margaret M. Harding
Keyword(s):  
Nmr Spectroscopy ◽  
Aqueous Solutions ◽  
Anticancer Activity ◽  
Active Species ◽  
Aromatic Rings ◽  
Cyclopentadienyl Ligands ◽  
Rate Of Hydrolysis ◽  
The Stability ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

The rate of hydrolysis of the aromatic rings of Cp2TiX2 [X = CI 1, O2CCCl3  8 and O2CCH2NH3Cl  13], in aqueous solutions, 10%DMSO and 100% DMSO have been studied by H1NMR spectroscopy. Rapid hydrolysis of both the carboxylate and cyclopentadienyl ligands in Cp2TiX2[X = O2CCCl3,O2CCH2NH3Cl] occurs in DMSO to give biologically inactive species. The rate of these reactions are concentration dependent as dilution of these samples with saline or water to give the therapeutic conditions of 10%DMSO/90%H2O slows the hydrolysis chemistry. In contrast, samples of Cp2TiX2 [X = CI 1, O2CCH2NH3Cl  13], dissolved in water give solutions containing the presumed antitumour active species in which the halide or glycine ligands have been hydrolysed but the Cp rings remain metal bound.

Hydrolysis of ethylenediphosphinetetraacetate anions

1983 ◽  
Vol 48 (6) ◽  
pp. 1552-1557
Author(s):  
Jana Podlahová ◽  
Jaroslav Podlaha
Keyword(s):  
Nmr Spectroscopy ◽  
Aqueous Solutions ◽  
Stability Of Solutions ◽  
Laboratory Temperature ◽  
H Nmr ◽  
Isolation And Characterization ◽  
Acid And Base ◽  
The Stability ◽  
Hydrolysis Of

The anions of ethylenediphosphinetetraacetic acid are hydrolyzed in aqueous solutions at 80 °C in the two following reactions: ((OOCCH2)2PCH2CH2P(CH2COO)2)4- → (OOCCH2(O)HPCH2CH2PH(O)CH2COO)2- → (O(O)HPCH2CH2PH(O)O)2-. Both reactions are acid and base catalyzed so that, at pH < 12, the first reaction is much faster than the second. The reaction course was studied by 1H NMR spectroscopy and by isolation and characterization of the products. The effect of both reactions on the stability of solutions of ethylenediphosphinetetraacetic acid and their salts is negligible at laboratory temperature.

Deinking of recycled paper by coupling of the enzyme endo-β-1,4-D-glucanasa and the cellulose, and by using a laboratory flotation column

MRS Advances ◽  
2020 ◽  
Vol 5 (52-53) ◽  
pp. 2669-2678
Author(s):  
Jeovani González P. ◽  
Ramiro Escudero G
Keyword(s):  
Amino Acids ◽  
Sodium Hydroxide ◽  
Paper Industry ◽  
Computational Simulation ◽  
Cellulose Fibers ◽  
Residual Water ◽  
Chemical Reagent ◽  
Recycled Paper ◽  
Flotation Column ◽  
Hydrolysis Of

AbstractDeinking of recycled office (MOW) paper was carried out by using a flotation column and adding separately sodium hydroxide, and the enzyme Cellulase Thricodema Sp., as defibrillators.The de-inked cellulose fibers were characterized according to the standards of the paper industry, to compare the efficiency of the deinking of each chemical reagent used to hydrolyze the fibers and defibrillate them.The computational simulation of the molecular coupling between the enzyme and cellulose was performed, to establish the enzyme-cellulose molecular complex and then to identify the principal amino-acids of endo-β-1,4-D-glucanase in this molecular link, which are responsible for the hydrolysis of the cellulose.Experimental results show the feasibility to replace sodium hydroxide with the enzyme Cellulase Thricodema Sp., by obtaining deinked cellulose with similar optical and physical properties.The use of the enzyme instead of sodium hydroxide avoids the contamination of the residual water; in addition to that, the column is operated more easily, taking into consideration that the pH of the system goes from alkaline to neutral.

Schiff base equilibria. II. Beryllium complexes of N-n-butylsalicylideneimine and the hydrolysis of the Be2+ ion

1965 ◽  
Vol 18 (5) ◽  
pp. 651 ◽  
Author(s):  
RW Green ◽  
PW Alexander
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Complex Formation ◽  
Distribution Coefficient ◽  
Dilute Aqueous Solution ◽  
The Stability ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Beryllium Complexes ◽  
Equilibria In Aqueous Solution

The Schiff base, N-n-butylsalicylideneimine, extracts more than 99.8% beryllium into toluene from dilute aqueous solution. The distribution of beryllium has been studied in the pH range 5-13 and is discussed in terms of the several complex equilibria in aqueous solution. The stability constants of the complexes formed between beryllium and the Schiff base are log β1 11.1 and log β2 20.4, and the distribution coefficient of the bis complex is 550. Over most of the pH range, hydrolysis of the Be2+ ion competes with complex formation and provides a means of measuring the hydrolysis constants. They are for the reactions: Be(H2O)42+ ↔ 2H+ + Be(H2O)2(OH)2, log*β2 - 13.65; Be(H2O)42+ ↔ 3H+ + Be(H2O)(OH)3-, log*β3 -24.11.

Neutral Solvolysis of Acyl Carbon and the Temperature Dependence of the Kinetic Solvent Isotope Effect

1975 ◽  
Vol 53 (6) ◽  
pp. 869-877 ◽  
Author(s):  
B. Rossall ◽  
R. E. Robertson
Keyword(s):  
Temperature Dependence ◽  
Isotope Effect ◽  
Solvent Isotope Effect ◽  
Acyl Carbon ◽  
Rate Of Hydrolysis ◽  
Solvent Isotope ◽  
Neutral Conditions ◽  
Hydrolysis Of

The temperature dependence of the rate of hydrolysis of benzoic, phthalic, and succinic anhydrides have been determined in H2O and D2O under "neutral" conditions. Corresponding data have been obtained for methyl trifluoroacetate. While both series supposedly react by the same BAc2 mechanism, remarkable differences are made obvious by this investigation. Possible sources of such differences are proposed.

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