Comparative Study of the Synthesis of 7 Hydroxy-4-Methyl Coumarin Mannich Bases by Conventional and Microwave Method
Yashumati R. Bhardwaj *
Department of Pharmacy, Banasthali University, Banasthali, Rajasthan, India
Monika Chauhan
Department of Pharmacy, Banasthali University, Banasthali, Rajasthan, India
Ashutosh Pareek
Department of Pharmacy, Banasthali University, Banasthali, Rajasthan, India
Dharma Kishore
Department of Chemistry, Banasthali University, Banasthali, Rajasthan, India
*Author to whom correspondence should be addressed.
Abstract
Present work describes the synthesis of coumarin Mannich bases 4-7 by the application of Mannich reaction on 7-hydroxy-4-methyl coumarin 3 using conventional as well as microwave technology to compare the feasibility, reaction time and yield of the product. For this, 7-hydroxy-4-methyl coumarin 3 was prepared using Pechmann condensation reaction and Mannich bases (4-7) were synthesized by the reaction of 3 with various secondary amines. A comparison between the conventional and microwave methods demonstrated that the microwave assisted synthesis was more convenient and simpler method with better yield and lesser formation of by-products of compounds 4-7 as compared to conventional method of synthesis.
Keywords: Mannich bases, Pechmann condensation, 7-hydroxy-4-methyl coumarin, microwave