Synthesis of Organic Ligands via Reactions of 4-Benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione with N-Nucleophiles

Abstract

<jats:p>The reaction of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (<jats:bold>1</jats:bold>) with aminoheteroaryls, lamotrigine, 1,3-diaminoheteroaryls, dapsone, NH<jats:sub>2</jats:sub>R (hydroxylamine, <jats:italic>DL</jats:italic>-1-phenylethylamine, and metformin), and 4,4′-bipyridine in THF/H<jats:sub>2</jats:sub>O (1 : 1) at room temperature led to 3-<jats:italic>N</jats:italic>-phenylthiocarbamoyl-2-butenamides <jats:bold>2</jats:bold>–<jats:bold>5</jats:bold>, while that with naphthylamines and 1,3-phenylenediamine in ethanol at high temperature led to 5-phenylamino-2,5-dihydrothiophene-2-ones <jats:bold>6</jats:bold>–<jats:bold>8</jats:bold> as organic ligands in the medium to good yields. These showed the nucleophilic attacks of <jats:italic>N</jats:italic>-nucleophiles, except primary aromatic amines, on thioester carboxyl group (C-2) of thiophene-2,3-dione ring <jats:bold>1</jats:bold>. However, the nucleophilic attacks of primary aromatic amines on the carbonyl group (C-3) of thiophene-2,3-dione <jats:bold>1</jats:bold> occurred in the form of substituted thiophenes.</jats:p>