Cyano adducts of 1-substituted pyridinium salts

Abstract

Melting points were determined with a Thomas-Hoover capillary apparatus and are uncorrected. Ultraviolet spectra were recorded on a Beckman DK-2 spectrophotometer and evaporations were performed under diminished pressure at 40°with a Rotoevaporator unless otherwise stated. The MCD spectra were determined on the Cary Model 60 with MCD attachment. (30) U. S. Patent 3,121.092; Chem. Abstr., 60, 2030 (1964). (31) Baker silica gel, chromatographic quality, deactivated with 10% HzO and containing 0.5% by weight Du Pont 609 Phosphor: B Leov and M. Goodman, Chem. Ind. (London), 2026 (1967). (32) The synthesis of 10 has been reported (J. Zemlicka, Abstracts, 4th International Congress on Heterocyclic Chemistry, Salt Lake City, Utah, July 9-13, 1973, p 15) as the major product using different reaction conditions.

Unequivocal synthesis of N-substituted 1,4-dihydropyridines

“…Physical data are given in Table I. The product was extremely unstable; a sample stored under nitrogen at -20°would completely decompose within 6 hr.…”

Asymmetric Construction of Functionalized 1,2-Dihydropyridine and Pyridine Derivatives with Adjacent Stereocenters via a Unified Metal-Free Catalytic Approach

“…To a dried 10 mL reaction tube under a N 2 atmosphere were added compound 1 (0.2 mmol), MBH carbonate 2 (0.26 mmol), and o -xylene (0.2 mL). After being stirred at 0 °C for 10 min, the mixture was supplemented with catalyst (20 mol %).…”

Power of Cooperativity: Lewis Acid-Lewis Base Bifunctional Asymmetric Catalysis

“…For example, simple pyridine gave the Reissert product in only 25% yield using NaCN as a nucleophile. 22 Even more reactive 3-acetylpyridine gave the product in up to 30-45% yield using TMSCN and benzoyl chloride in the presence of a catalytic amount of AlCl 3 . 23 Based on the investigations of catalytic enantioselective Reissert reactions of quinolines and isoquinolines, we expected that bifunctional asymmetric catalysis would overcome these potential difficulties in reactivity, regioselectivity, and enantioselectivity in the Reissert reaction of pyridines; when TMSCN is activated close to one specific electrophilic carbon on an acyl pyridinium, high regio-and enantioselectivity should be obtained (Figure 5).…”