Organic Reactions in Ionic liquids: N-Alkylation of Phthalimide and Several Nitrogen Heterocycles
Zhang-Gao Le, Zhen-Chu Chen*, Yi Hu, Qin-Guo Zheng
*Department of Chemistry, Zhejiang University (xi xi campus), Hangzhou,
310028, P. R. China, Email: zhenchucmail.hz.zj.cn
Z.-G. Le, Z.-C. Chen, Y. Hu, Q.-G. Zheng, Synthesis, 2004, 208-212.
DOI: 10.1055/s-2003-44383
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Abstract
A convenient, efficient, and selective N-Alkylation of N-acidic heterocyclic compounds with alkyl halides is accomplished in ionic liquids in the presence of potassium hydroxide as a base. In this manner, phthalimide, indole, benzimidazole, and succinimide can be successfully alkylated.
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Details
The document discusses the N-alkylation of phthalimide and various nitrogen heterocycles using ionic liquids as reaction media. The study highlights the use of ionic liquids such as [bmim]BF4, [bmim]PF6, and [buPy]BF4 in the presence of potassium hydroxide as a base to achieve efficient N-alkylation with alkyl halides. The reactions were conducted at moderate temperatures (20-80°C) and yielded high product purity and efficiency. The method was found to be general and applicable to primary alkyl iodides, bromides, and activated chlorides, with lower yields for secondary alkyl halides. The ionic liquids could be recovered and reused without significant loss in yield, making the process environmentally friendly. The study also compared the new method with traditional methods, demonstrating advantages such as milder conditions, higher yields, and shorter reaction times. The products were characterized using IR and NMR spectroscopy, confirming their consistency with literature data. Overall, the research presents a convenient, efficient, and environmentally benign approach for the N-alkylation of phthalimide and nitrogen heterocycles, with potential applications in synthetic and polymer chemistry.
Organic Reactions in Ionic Liquids: A Simple and Highly Regioselective N-Substitution of Pyrrole
Z.-G. Lea, Z.-C. Chen, Y. Hu, Q.-G. Zheng Synthesis, 2004, 1951-1954.
Key Words
ionic liquids, N-alkylation, imides, Gabriel synthesis, Phthalimides
ID: J66-Y2004-1920