Ionic Liquid Catalysed Synthesis of 1-benzyl-7-(but-2-yn-1-yl)-3-methyl-8- (4-methylenepiperidin-1-yl)-1H-purine-2,6(3H,7H)-dione
Nitin Pawar, Devendra Wagare, Gorakhnath Mitkari, Anis Ahmed Shaikh, Varad Lingampalle, Dinesh LingampalleIntroduction:
A new environmentally benign ionic liquid-catalysed protocol has been designed for the synthesis of 1-benzyl-7-(but-2-yn-1-yl)-3-methyl-8-(4-methylenepiperidin-1-yl)- 1H-purine-2,6(3H,7H)-dione
Methods:
This method proceeds smoothly under mild conditions using N-methylpyridinium tosylate (NMPyT) as a green ionic liquid medium, which enhances both the speed and yield of the reaction. This reaction involves the coupling of 7-(but-2-yn-1-yl)-1-benzyl-3-methylxanthine with 1- (chloromethyl)-4-methylenepiperidine in the presence of a NMPYT as an ionic liquid.
Results:
The reactions were found to proceed efficiently with relatively short reaction times ranging from 1 to 1.5 hours. Ionic liquids used as catalysts and media not only facilitated the reaction but also provided cleaner reaction profiles and moderate to good yields ranging from 75% to 78%.
Discussion:
It was observed that substituted benzyl chlorides bearing electron-donating groups (e.g., –OMe, –CH₃) on the benzene ring generally offered higher yields than those with electronwithdrawing substituents (e.g., –Cl, –NO₂)
Conclusion:
N-methylpyridinium-tosylate used as an ionic liquid, in the presence of potassium carbonate as a base, offered a mild, eco-friendly, and effective environment to complete the reaction.