Umsetzung von (Z/E)‐1‐Aryl‐4‐arylmethylen‐pyrrolidin‐2,3,5‐trionen mit Enaminocarbonylverbindungen

Abstract

Reaction of (Z/E)‐1‐Aryl‐4‐arylmethylene‐pyrrolidine‐2,3,5‐triones with Enaminocarbonyl Compounds Treatment of the α, β‐unsaturated ketones (Z/E)‐1a–e with alicyclic or aliphatic enamines afforded cyclic Michael adducts 2 and 3a–e, respectively. By dehydration of the N,O‐hemiacetals 3b–d the corresponding 1,4‐dihydropyridines 4a–c were obtained. The acid‐catalyzed reaction of aminosubstituted maleimides with (Z/E)‐1e, aldehydes or indan‐1,2,3‐trione led to 5a–c, 6a–c, 7a–c and 8. O‐Methylation of the aryl‐bis(maleinimidyl)methanes 5c, 6c by using diazomethane gave 5d, 6d, whereas 5a cyclized spontaneously to the 1,4‐dihydropyridine 9a. Further 1,4‐dihydropyridines were prepared by cyclocondensation of 6a, b in the presence of ammonium acetate and oxidized to the pyridine derivative 10.

Synthesis of new chiral lactam-fused pyridine derivatives

“…Our initial attempt to elaborate chiral diol 1 to the corresponding C 2 -symmetric lactam-fused pyridine 2 was to examine the cyclisation in the presence of an ammonium salt 12 (Table S1, Supporting Information). Treatment of 1a (R 1 = Bn, R 2 = H) with an equimolar amount of ammonium acetate in AcOH at 100 °C led to an almost 1:1 mixture of pyridine derivatives, 2a and its epimer, in 62% yield, whereas no reaction occurred without heating (Table S1, entries 1 and 2).…”