Biomimetic approach for the synthesis of N,N 0 -diarylsubstituted formamidines catalyzed by b-cyclodextrin in water Dipak R. Patil, Dipak S. Dalal * Department of Organic Chemistry, North Maharashtra University, Jalgaon 425 001, M.S., India Received 31 May 2012 Available online 23 September 2012 Abstract An environmentally benign and highly efficient biomimetic approach for the synthesis of N,N 0 -diarylsubstituted formamidines in water catalyzed b-cyclodextrin is described under neutral condition with quantitative yields of products. b-Cyclodextrin has been recovered and reused. # 2012 Dipak R. Patil. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: b-Cyclodextrin (b-CD); N,N 0 -Diarylsubstituted formamidines Formamidines are important class of compounds that features in biosynthesis of purines, catabolism of histidines [1], synthesis of imidazole salts [2]. They also act as good reactive synthons for various chemical transformations [3]. Formamidines show antimicrobial activity effectively against chloroquino-resistant strain [4]. Amidine containing moieties have applications in various fields like building blocks in polymer synthesis [5], protecting group for primary amines [6], etc. N,N 0 -Disubstituted hydroxyamidines have been studied for their biological activities (antitubercular, hypotensive) and pharmacological properties (bactericidal, fungicidal, local anesthetic, etc.) [7]. Literature survey indicates that several methods have been reported for synthesis of formamidines includes use of solvents like acetic acid under thermal condition [2,8], use of cerric ammonium nitrate [9], reduction of carbodiimides with sodium borohydride in iso-propanol [10], use of microwave, fluorinated solvent, refluxing in ethanol [11], etc. However some of them require long reaction time, tedious purification process, use of inorganic metal catalyst and hazardous organic solvents. Therefore, there is strong demand for highly efficient environmentally benign method to prepare N,N 0 -diarylformamidines. With green chemistry becoming central issue in both academic and industrial research in the 21st century [12], the development of environmentally benign and clean synthetic procedures has become the goal of present day organic synthesis. b-Cyclodextrin is a cyclic heptamer of glucose possessing hydrophobic cavity, which binds substrate selectively and catalyze the reaction with high selectivity. b-CD catalyze the reaction by supramolecular catalysis involving reversible formation of host–guest complex by non-covalent bonding as seen in enzymes [13]. In continuation of our work in the field of cyclodextrin [14] and inspiration from Rama Rao, Nageswar, Atul Kumar and Shi [15], we herein reported the synthesis of N,N 0 -diarylformamidines from reaction of anilines with www.elsevier.com/locate/cclet Available online at www.sciencedirect.com Chinese Chemical Letters 23 (2012) 1125–1128 * Corresponding author. E-mail address: dsdalal2007@gmail.com (D.S. Dalal). 1001-8417/$ – see front matter # 2012 Dipak R. Patil. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. http://dx.doi.org/10.1016/j.cclet.2012.08.003