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Synthesis, Characterization of Mannich base Products Using 1,2,4-Triazolium Methane Sulfonate Based Brønsted Acidic Ionic Liquids as Catalyst

Author(s):

Vijayakumar Veeraragavan, Nagarajan Sankaranarayanan * and Ramesh Kumar Chidambaram   Pages 1 - 8 ( 8 )

Abstract:


Aim and Objective: Synthesis of longer alkyl chain 1,2,4-triazole methanesulfonate based Bronsted acidic ionic liquids and its catalytic applications of one-pot Mannich reactions using various aldehyde, aniline and acetophenone.

Materials and Methods: A direct neutralization of 1-hexyl-1,2,4-triazole/1-octyl-1,2,4-triazole and methanesulfonic acid with 80 ˚C for 12 hours. The synthesized Bronsted acidic ionic liquids used as catalyst for Mannich reaction. The reusability studies was also been carried out.

Results: The synthesized ionic liquids were investigated its catalytic efficiency. Substituted aryl aldehydes bearing an electron withdrawing group are proceeds to give the desired products (entry 4, 15 and 16) with moderate yield. Acetophenone substituted with electron withdrawing group (entry 7) could also be employed for getting a good yield. Substituted anilines bearing a weak electron withdrawing group (entry 6 & 14 (Cl), 13 (I)) and strong electron withdrawing group (NO2, entry 4) also provided a good yield. However, aniline substituted with electron withdrawing group such as fluoride and bromide proceeds to give less yield as compared to other electron withdrawing groups (entry 15-17) due to the strong electronegativity. 1-hexyl-1,2,4-triazolium methanesulfonate (1a) has shown better catalytic efficiency.

Conclusion: Two ionic liquids was synthesized, characterized and investigated it’s catalytic efficiency of Mannich reactions. Based on the outcome of the investigation synthesized catalyst is potential candidate for acid catalyzed organic transformation reactions. In addition, catalysts were recovered efficiently from the reaction mixture without any significant loss of quantity and reused up to a four run.

Keywords:

1, 2, 4-Triazole, Ionic Liquids, Catalysis and Mannich Base Reaction.

Affiliation:

Organic Chemistry Lab, Dept. of Chemistry, Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Avadi, Chennai-62, Tamil Nadu, Department of Chemistry, PSN College of Engineering and Technology, Tirunelveli-627152, Tamil Nadu, Organic Chemistry Lab, Dept. of Chemistry, Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Avadi, Chennai-62, Tamil Nadu



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