About the reaction of β‐dimethylamino‐α,β‐enones with active methylene nitriles

Abstract

magnified imageThe reaction of 3‐dimethylamino‐1‐arylpropenone derivatives with active methylene nitriles was reinvestigated and a plausible mechanism to account for the results is suggested. X‐ray crystallographic study supported the suggested mechanism. Based on these findings, the reaction of 3‐acetylamino‐4‐dimethylaminobut‐3‐en‐2‐one with malononitrile was also reinvestigated and the correct structures verified. J. Heterocyclic Chem., (2009).

Chitosan as an eco-friendly heterogeneous catalyst for Michael type addition reactions. A simple and efficient route to pyridones and phthalazines

“…Although it was proposed earlier that these products are conjugated amino nitriles, A, [12], we recently established on the basis of both Xray and 15 N NMR analysis that the products actually are the enedienes 12a,b (Scheme 2). Recently Abdelrazik [13] and Gorobets [14] have reached the same conclusion based on Xray crystallographic analysis results. Further support of the newly assigned structures comes from the observation that enediene12c undergoes cyclization to give 14 when stirred in refluxing glacial acetic acid.…”

“…However, the acyclic substance 23 could be readily ruled out on the basis of both IR and 13 C NMR spectroscopic properties, which ruled out the presence of a cyano group in the products. However, in spite of reports to the contrary, [13] pyraneimines like 24 are highly unstable substances. This consideration led us to propose that the products of these reactions have the pyridone structures 25a,b.…”

“…Infrared spectra (KBr) were determined on a Perkin-Elmer 2000 FT-IR system. NMR measurements were determined on a Bruker DPX spectrometer, at 400 MHz for 1 H NMR and 125 MHz for 13 C NMR, in DMSO-d6 as solvent and using TMS as internal standard. Mass spectra were measured on MS 30 and MS 9 (AEI) spectrometers, with EI 70 eV.…”

The Behavior of 3-Anilinoenone and N-Phenyl Cinnamamide toward Carbon Nucleophiles: Spectroscopy and X-Ray Studies Reveal Interesting New Synthesis Routes to Nicotinonitriles and Tetrahydropyridine-3- Carbonitrile

“…Due to their biological activities and pharmacological properties, pyridines and pyridones represent an important class of compounds that have been developed using functionally substituted enaminones [16][17][18][19][20][21][22]. In continuation of our interest in the synthesis of functionally substituted heteroaromatic compounds such as pyridines and pyridones, utilizing enaminones as starting materials [22][23][24][25][26][27][28][29][30][31][32][33], we report here the behavior of 3-anilinoenone and N-phenyl cinnamamide derivative toward malononitrile in the synthesis of pyridine derivatives.…”

“…On the other hand, Abdelrazek and Elsayed [20] have reported that the reaction of enaminones 1a-b with active methylene nitriles afforded pyridone 8 through the isolated intermediate 7. The authors proposed a synthetic pathway for the formation of 2-pyridone 8 includes 1,4-addition of active methylene in malononitrile to dimethylamino group of enaminone 1 rather than 1,2-addition to the carbonyl group (Scheme 2).…”