title: Studies on 3-oxoalkanenitriles: novel rearrangement reactions observed in studies of the chemistry of 3-heteroaroyl-3-oxoalkanenitriles as novel routes to 2-dialkylaminopyridines.
abstract: 3-Aroyl and 3-heteroaroyl substituted 3-oxoalkanenitriles were synthesized by the reactions of activated aromatic and hetero-aromatic substances with cyanoacetic acid in the presence of acetic anhydride. As part of studies focusing on the preparation of cyanoacetyl-1-N-methylbenzimidazole, we observed that reaction of N-methyl-benzimidazole with the cyanoanhydride formed by condensation of cyanoacetic acid with acetic anhydride, leads to the formation of 2-(1,3-diacetyl-2,3-dihydro-1H-benzo[d]-imidazol-2-yl)acetonitrile (5), whose structure was confirmed by X-ray crystallographic analysis. 3-Oxoalkanenitriles 3a,b were observed to undergo condensation reactions with dimethylformamide dimethyl acetal (DMFDMA) to afford the corresponding enamino-nitriles, which react with malononitrile to give 2-dialkylaminopyridines through a pathway involving a new, unexpected rearrangement process. Reactions of 3-oxoalkanenitriles with ethyl acetoacetate were found to afford 2-oxopyran-3-carbonitriles, also occurring via this unexpected rearrangement process. Mechanisms to account for both rearrangement reactions are suggested. In addition, reactions of 3-oxoalkanenitriles with acetylacetone in acetic acid in the presence of ammonium acetate result in the formation of pyridine-3-carbonitriles. Finally, upon heating in the presence of zeolite 3-oxoalkanenitriles 3b,c self-trimerized to produce the corresponding aniline derivatives 23b,c.
authors.affiliation: Chemistry Department, Faculty of Science, University of Kuwait, PO Box 5969, Safat 13060, Kuwait. h.almatar@ku.edu.kw
authors.forename: Hamad M
authors.initials: HM
authors.lastname: Al-Matar
authors.forename: Khaled D
authors.initials: KD
authors.lastname: Khalil
authors.forename: Mona F
authors.initials: MF
authors.lastname: Al-Kanderi
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Elnagdi
mesh_terms: D000085:Acetates / Q000737:chemistry; D000107:Acetylation; D000631:Aminopyridines / Q000138:chemical synthesis* / Q000737:chemistry; D001562:Benzimidazoles / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008968:Molecular Conformation; D009570:Nitriles / Q000138:chemical synthesis* / Q000737:chemistry; D044366:Transition Temperature
chemical_list: D000085:Acetates; D000631:Aminopyridines; D001562:Benzimidazoles; D009570:Nitriles; C007170:cyanoacetic acid