REISSERT COMPOUND STUDIES .66. REGIOSELECTIVE SYNTHESIS OF PYRIDINE REISSERT ANALOGS

The reaction of ethyl chloroformate and pyridine with diethylaluminum cyanide as the cyanide source gave the Reissert analog, 1-ethoxycarbonyl-4-cyano-1,4-dihydropyridine and not the expected 1,2-dihydro regio isomer. Under the same conditions, 3-bromopyridine also directly gave the corresponding 1,4-dihydro Reissert analog. Reinvestigation of trimethylsilylcyanide, as the cyanide source, resulted in the observation that both regio isomers are formed and the ratio of these isomers are affected by both solvent polarity and by copper(I) iodide.