Simple Synthetic Approach to IN/I-iminonitriles as Intermediates

• Published in: Molecules (Basel, Switzerland) Vol. 28; no. 8
• Main Authors: Chaidali, Andriani G, Lykakis, Ioannis N
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.04.2023
• Subjects: Ethylenediamines; Oxazoles
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28083321

A facile, green, synthetic protocol of several substituted N-(pyridin-2-yl)imidates from nitrostyrenes and 2-aminopyridines via the corresponding N-(pyridin-2-yl)iminonitriles as intermediates is reported. The reaction process involved the in situ formation of the corresponding α-iminontriles under heterogeneous Lewis acid catalysis in the presence of Al[sub.2]O[sub.3]. Subsequently, α-iminonitriles were selectively transformed into the desired N-(pyridin-2-yl)imidates under ambient conditions and in the presence of Cs[sub.2]CO[sub.3] in alcoholic media. Under these conditions, 1,2- and 1,3-propanediols also led to the corresponding mono-substituted imidates at room temperature. The present synthetic protocol was also developed on one mmol scale, providing access to this important scaffold. A preliminary synthetic application of the present N-(pyridin-2-yl)imidates was carried out for their facile conversion into the N-heterocycles 2-(4-chlorophenyl)-4,5-dihydro-1H-imidazole and 2-(4-chlorophenyl)-1,4,5,6-tetrahydropyrimidine in the presence of the corresponding ethylenediamine and 1,3-diaminopropane.