Transamination reaction of 3-[(dimethylamino)methylidene]- 5-arylfuran-2(3H)-thiones with the participation of 2-amino-4-methylphenol

Introduction

Interest in enamine systems, particularly dimethylaminomethylidene derivatives, is currently growing due to their high reactivity, owing to the presence of a dimethylamino group, which is a readily reactive leaving group. The presence of an additional reactive center in the form of a thiocarbonyl group allows for the modification of compounds in various ways. Compounds containing a furan moiety possess unique physicochemical properties, allowing them to be used as the basis for many pharmaceutical and therapeutic agents.

Experimental details

We have developed the synthesis conditions and studied the reaction of 3-[(dimethylamino)methylene]-5-(3,4-dimethylphenyl)furan-2(3H)-thione, 5-(4-bromophenyl)-3-[(dimethylamino)methylene]furan-2(3H)-thione, 3-[(dimethylamino)methylene]-5-(4-methoxyphenyl)furan-2(3H)-thione with 2-amino-4-methylphenol under conditions of thermal activation of the reaction mixture in isopropyl alcohol medium. The final products of the transformation are (Z)-3-{[(2-hydroxy-4-methylphenyl)amino]methylidene}-5-arylfuran-2(3H)-thiones. The composition and structure of the obtained compounds were established on the basis of comprehensive elemental analysis data, IR, 1H, 13C NMR, HSQC, HMBC spectroscopy.

Results and Discussion

The reaction under study proceeds as a primary attack of the amino atom of the aromatic amine at the double bond according to Michael, followed by elimination of the dimethylamine molecule, with the formation of (Z)-3-{[(2-hydroxy-4-methylphenyl)amino]methylidene}-5-arylfuran-2(3H)-thiones.