Abstract
The kinetics of the addition of hydrazine to the double bond of some chalcones have been studied using UV-visible technique. The reaction is considered as a pseudo-first order process which includes a nucleophilic attack by hydrazine at the β-carbon of the α,β-unsaturated carbonyl system to afford the expected heterocycle “pyrazoline”. The rate constants were found to depend on different variables such as variation of different substituents. Arrhenius parameters and entropy of activation for all reactions have been computed. A suitable mechanism which is consistent with the experimental results is suggested for the reactions
Highlights
The kinetics of the addition of hydrazine to the double bond of some chalcones have been studied using UV-visible technique
The present investigation is concerned with the kinetics of the addition of hydrazine to the α, βdouble bond of some chalcones and to study the effect of substituent in the phenyl ring of the chalcone on the stability of the presumed transition state, in order to obtain information that should be of assistance in understanding the suggested mechanism which occurs under mild conditions of experiments
The hydrazine used was of analar grade as supplied by Fluka company, ethanol (Commercial scale) was purified and dried by CaCl2 until it became almost absolute
Summary
The kinetics of the addition of hydrazine to the double bond of some chalcones have been studied using UV-visible technique. For chalcones (A-E), the electronic effects of the substituents play an important role in affecting the rate of reaction, since they either enrich or pauperize the reaction centre at the α, β-double bond with electrons.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
