Reaction of Pyridine with Phenylcyanoacetylene: A New Route to Functionalized Polyconjugated 1,4‐Dihydropyridine Systems

Abstract

Pyridine reacts with phenylcyanoacetylene under mild conditions (20–25 °C, no catalyst) to unexpectedly give the 2:3 adduct — a C,N‐functionalized polyconjugated 1,4‐dihydropyridine system — containing two 1,4‐dihydropyridine cycles and four vinylene units formed by three molecules of phenylcyanoacetylene (the yield is up to 46 %). Other products are higher oligomers of phenylcyanoacetylene terminated by 1,4‐dihydropyridine cycles (approx. 30 % yield). Assembly of the 2:3 adduct proceeds regio‐ and stereoselectively — only one of the possible isomers is formed. The oligomers show paramagnetic and electroconductive properties. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Barium nitrate catalyzed one pot synthesis of 1,4‐dihydropyridines under solvent free conditions at room temperature

“…DHP based drugs such as nifedipine, nicardipine, amlodipine and many others are used for the treatment of hypertension and cerebrocrast; a DHP derivative has been used as neuroprotective agent [6,7]. Due to the wide range of pharmacological and biological activities and the importance of these heterocycles in organic synthesis, medicinal chemistry, biochemistry, synthetic efforts in this field continues [8][9][10][11]. Although many methods for the synthesis of 1,4-DHP have been reported, which generated many DHP derivatives [12][13][14][15], the reported methods suffer from drawbacks such as longe reaction times, harsh reaction conditions, costly catalyst and low yield.…”