The Structural Basis for Hydrolysis Resistance in the Esters of (2-Formylphenyl)boronic Acid 2,4-Dinitrophenylhydrazones

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Title:The Structural Basis for Hydrolysis Resistance in the Esters of (2-Formylphenyl)boronic Acid 2,4-Dinitrophenylhydrazones
Creators:
Groziak, Michael P.
Robinson, Paul D.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 67, 7, pp. 1084-1094
Uncontrolled Keywords:Cyclizations, Steroid analogues, Hydrazones, Boron, Crystal structure determination, Boraheterocycles, Heterocycles, Estrogen mimics

Abstract

Under conditions that typically afford bicyclic boron heterocycles directly, (2-formylphenyl)boronic acids react with 2,4-dinitrophenylhydrazine in ethanol to give highly waterresistant diethyl boronate esters. Two such 2,4-dinitrophenylhydrazones were prepared and their X-ray crystal structures determined. Contrary to a previous suggestion that their unusual stability is due to an intramolecular N→B coordination giving a six-membered BN<sub>2</sub>C<sub>3</sub> ring system based on a (<i>Z</i>)-hydrazone, these compounds instead were found to be (<i>E</i>)-hydrazones internally stabilized by a weak intramolecular interaction between nitrogen and boron from within a five-membered ring. Further study revealed that the electron deficiency of the starting hydrazine reagent plays a key role in determining the structure of the hydrazone isolated, and that the water-resistant boronate esters can be hydrolyzed under forcing conditions to the boronic acids. <p>

Title:The Structural Basis for Hydrolysis Resistance in the Esters of (2-Formylphenyl)boronic Acid 2,4-Dinitrophenylhydrazones
Creators:
Groziak, Michael P.
Robinson, Paul D.
Uncontrolled Keywords:Cyclizations, Steroid analogues, Hydrazones, Boron, Crystal structure determination, Boraheterocycles, Heterocycles, Estrogen mimics
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:67
Number:7
Page Range:pp. 1084-1094
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20021084UNSPECIFIED
ID Code:1974
Item Type:Article
Deposited On:06 Feb 2009 17:14
Last Modified:06 Feb 2009 16:14

Citation

Groziak, Michael P.; Robinson, Paul D. (2002) The Structural Basis for Hydrolysis Resistance in the Esters of (2-Formylphenyl)boronic Acid 2,4-Dinitrophenylhydrazones. Collection of Czechoslovak Chemical Communications, 67 (7). pp. 1084-1094. ISSN 0010-0765

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