Six 5-arylidene-3-methylrhodanine derivatives were synthesized by the crossed aldolization of aromatic aldehydes with 3- methylrhodanine using 1-butyl-3-methylimidazolium chloride ([BMI]Cl) as phase transfer catalyst in water. | Science & Technology Development, Vol 19, Synthesis of 5-arylidene-3-methylrhodanines catalyzed by 1-butyl-3-methylimidazolium chloride in water under microwave irradiation condition Le Hoang Giau Ngo Thi Thuy Duong Thach Ut Dong Nguyen Kim Phi Phung University of Science, VNU-HCM Fritz Duus Roskilde University, Denmark (Received on August 7th 2015, accepted on April 14 th 2016) ABSTRACT Six 5-arylidene-3-methylrhodanine derivatives were synthesized by the crossed aldolization of aromatic aldehydes with 3methylrhodanine using 1-butyl-3methylimidazolium chloride ([BMI]Cl) as phase transfer catalyst in water. The reactions, under microwave irradiation (160 watts) during 10 minutes, afforded the yield of 59–83 %. This is the first time [BMI]Cl was used as phase transfer catalyst in the aldol condensation. Keywords: 3-Methylrhodanine, 5-arylidene-3-methylrhodanine, ionic liquid, microwave irradiation condition, aldol condensation INTRODUCTION Rhodanine derivatives have showed a wide range of biological activities which include anticonvulsant, antibacterial, antiviral and antidiabetic effects [1]. These have also been reported as Hepatitis C virus (HCV) protease inhibitors [2] and used as inhibitors of uridine diphospho-N-acetylmuramate/L-alanine ligase [3]. Recently, substituted rhodanines were investigated for tau aggregation inhibitor properties [4]. Rhodanines, classified as nonmutagenic and a long-term study on the clinical effects of the rhodanine-based Epalrestat as an anti-diabetic showed that it was well tolerated [5]. Due to various possibilities the rhodanine derivatives, these compounds will Trang 58 probably remain a privileged scaffold in drug discovery. Therefore, the synthesis of these compounds is of considerable interest. Condensation of aldehydes at the active methylene C-5 of 3-methylrhodanine has been performed using piperidinium benzoate in toluene or sodium acetate in glacial acetic acid [6, 7]. Recently, Sim et al. .
