Synthesis and spectroscopic studies of 5-arylidene-3-substituted tetramic acids as possible substrates for catalytic asymmetric hydrogenation

A new series of 5‐arylidene‐3‐substituted tetramic acids 6–19 have been synthesized by a condensation reaction of 3‐butanoyl tetramic acid 3, 3‐ethoxycarbonyl tetramic acid 4 and 3‐acetyl tetramic acid 5 with a variety of substituted benzaldehydes. The structures of the isolated compounds 6–19 have been elucidated using FT‐IR, 1H and 13C‐NMR spectroscopy, FAB‐MS spectroscopy as well as elemental analyses.