Chemistry Department, Faculty of Science, University of Kuwait, PO Box 5969, Safat 13060, Kuwait.
Molecules. 2012 Jan 18;17(1):897-909. doi: 10.3390/molecules17010897.
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.
3-芳酰基和 3-杂芳酰基取代的 3-氧代链烯腈通过在醋酸酐存在下用氰基乙酸与活化的芳族和杂芳族物质反应合成。作为专注于制备氰乙酰-1-N-甲基苯并咪唑研究的一部分，我们观察到 N-甲基苯并咪唑与由氰基乙酸与醋酸酐缩合形成的氰基乙酰胺反应，导致形成 2-(1,3-二乙酰基-2,3-二氢-1H-苯并[d]-咪唑-2-基)乙腈 (5)，其结构通过 X 射线晶体学分析得到确认。观察到 3-氧代链烯腈 3a,b 与二甲基甲酰胺二甲缩醛 (DMFDMA) 发生缩合反应，得到相应的亚氨基腈，这些亚氨基腈与丙二腈反应通过涉及新的、出乎意料的重排过程，生成 2-二烷基氨基吡啶。发现 3-氧代链烯腈与乙酰乙酸乙酯的反应生成 2-氧代吡喃-3-氰基，也通过这种意想不到的重排过程发生。提出了两种重排反应的机制。此外，在醋酸存在下，3-氧代链烯腈与乙酰丙酮和醋酸铵反应，形成吡啶-3-氰基。最后，在沸石存在下加热 3-氧代链烯腈 3b,c，自三聚化生成相应的苯胺衍生物 23b,c。
