New efficient synthesis, spectroscopic characterization, and X-ray analysis of novel β-enaminocarboxamide derivatives

Abstract

A new series of β-enaminocarboxamide was synthesized via the addition of chlorosulfonyl isocyanate to β-enaminones. The prepared intermediates were converted to corresponding β-enaminocarboxamides by removal of the chlorosulfonyl group using methanol. The resulting compounds were obtained in excellent yields in the range of (80-92%) and were characterized by 1 H, 13 C, HMBC, HSQC NMR spectroscopy, and IR spectroscopy as well as elemental analysis. 1 H-NMR spectrum showed a non-equivalence of the primary amide protons which was due to H-bonding. β-enaminocarboxamide 5h was obtained as a crystal and was subjected to X-ray analysis. Results showed that 5h crystallizes in the monoclinic crystal system with C2/c space group and the ORTEP confirmed the presence of intramolecular H-bonds.

BiCl3-catalyzed green synthesis of 4-hydroxy-2-quinolone analogues under microwave irradiation

“…In a continuation of our investigation of the use of microwave irradiation in synthesizing heterocyclic-based derivatives, 55 as well as the use of β-enaminones as reactive synthetic intermediates leading to interesting compounds, 56 we have developed a new, rapid, and environmentally friendly method for synthesizing hydroxyquinolone analogues. This method involves the condensation of β-enaminones with diethyl malonate CH 2 (CO 2 Et) 2 , catalyzed by BiCl 3 under microwave irradiation in the presence of EtOH.…”