Synthesis of Pyridazine Derivatives by Suzuki-Miyaura Cross-Coupling Reaction and Evaluation of Their Optical and Electronic Properties through Experimental and Theoretical Studies.

Sara Fernandes,João Aires-De-Sousa,Michael Belsley,M Raposo

doi:10.3390/molecules23113014

Abstract

A series of π-conjugated molecules, based on pyridazine and thiophene heterocycles 3a–e, were synthesized using commercially, or readily available, coupling components, through a palladium catalyzed Suzuki-Miyaura cross-coupling reaction. The electron-deficient pyridazine heterocycle was functionalized by a thiophene electron-rich heterocycle at position six, and different (hetero)aromatic moieties (phenyl, thienyl, furanyl) were functionalized with electron acceptor groups at position three. Density Functional Theory (DFT) calculations were carried out to obtain information on the conformation, electronic structure, electron distribution, dipolar moment, and molecular nonlinear response of the synthesized push-pull pyridazine derivatives. Hyper-Rayleigh scattering in 1,4-dioxane solutions, using a fundamental wavelength of 1064 nm, was used to evaluate their second-order nonlinear optical properties. The thienylpyridazine functionalized with the cyano-phenyl moiety exhibited the largest first hyperpolarizability (β = 175 × 10−30 esu, using the T convention) indicating its potential as a second harmonic generation (SHG) chromophore.

Highlights

Few reactions have contributed to enhancing the efficiency of organic synthesis as much as the palladium-catalyzed cross-couplings
A Synthesis new series six thienylpyridazine derivatives 3a–e were synthesized through palladium catalyzed
3a–e were synthesized through2 palladium halogenated coupling component, which was3-bromo-6-(thiophen-2-yl)pyridazine prepared by the reaction of thienylpyridazinone catalyzed Suzuki–Miyaura coupling, using

Summary

Introduction

Few reactions have contributed to enhancing the efficiency of organic synthesis as much as the palladium-catalyzed cross-couplings. Suzuki coupling is a versatile method of synthesis, possessing a large number of advantages It employs readily available reagents (about 1800 compounds: Boronic acids, boronate esters, etc.) that are commercially available, it occurs under mild reaction conditions, it is largely unaffected by the presence of water, it tolerates a wide variety of functional groups, it generally proceeds regio- and stereoselectively, while the inorganic. Molecules 2018, 23, 3014 by-products are non-toxic and removed from the reaction mixture. All of these qualities contribute to make the Suzuki coupling suitable for laboratories, and for myriad industrial processes [1,2,3,4,5,6,7]

Methods

Results

Conclusion