Water mediated synthesis, spectral and structural studies of ethyl 6-amino-4-aryl-5-cyano-2-propyl-4H-pyran-3-carboxylates: Single crystal X-ray structure of ethyl 6-amino-4-(2-chlorophenyl)- 5-cyano-2-propyl-4H-pyran-3-carboxylate C. Udhaya Kumar a , A. Sethukumar a , R. Agilandeshwari a , B. Arul Prakasam a,b,⇑ , T. Vidhyasagar a , Mika Sillanpää b a Department of Chemistry, Annamalai University, Annamalainagar, Chidambaram 608 002, India b Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli, Finland highlights  Water mediated synthesis of ethyl 6-amino-4-aryl-5-cyano-2-propyl-4H-pyran-3-carboxylates.  Spectral characterization by IR, 1D and 2D NMR (HSQC and HMBC).  Single crystal XRD analysis of ethyl 6-amino-4-(2-chlorophenyl)-5-cyano-2-propyl-4H-pyran-3-carboxylate. article info Article history: Received 24 October 2013 Received in revised form 13 November 2013 Accepted 13 November 2013 Available online 23 November 2013 Keywords: MCR K 2 CO 3 HSQC HMBC XRD abstract An efficient and multifunctional three component synthetic protocol was developed to synthesize ethyl 6-amino-4-aryl-5-cyano-2-propyl-4H-pyran-3-carboxylates from ethyl 3-oxohexanoate, malononitrile and corresponding aldehydes (1a–11a) using K 2 CO 3 as a catalyst under water solvent in good yields. The derived compounds have been analyzed by IR and NMR (1D and 2D) spectra. Single crystal X-ray structural analysis of 2a, evidences the flattened-boat conformation of pyran ring and the phenyl group is nearly perpendicular to the pyran ring. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction Multi Component Reactions (MCR’s) involving the simultaneous molecular interaction between three or more components and the issue of selectivity is of particular significance due to the high probability of multi potential parallel reaction pathways leading to different product classes [1,2]. In recent years MCRs have received considerable attention due to their advantages over con- ventional multistep synthesis [3]. These reactions constitute an especially useful synthetic strategy since they provide mild, easy and rapid access to large libraries of organic molecules with di- verse substitution patterns. In addition, multicomponent reactions are more environmentally benign and atom economic as they avoid time-consuming and costly purification processes, as well as protection and deprotection steps [4,5]. Interesting progress has been achieved in areas of selectivity control, connectivity and catalysis, etc. [6,7]. In multistep organic synthesis, several difficult issues arise such as isolation of the products, the corrosive nature of reagents and solvents [8–15]. There is a need for facile, nonpolluting and effi- cient synthetic procedures that reduce the use of organic solvents, tedious work-up processes and toxic reagents [16]. Although a large number of new synthetic procedures were reported for 4H- pyrans, relatively few examples are known for the preparation of substituted 4H-pyrans [17–24]. Pyran based heterocyclic compounds are having an important place due to their distinct structures and great potential for further transformations. Active 2-amino-4H-pyrans are particularly privi- leged pharmacological scaffolds among the heterocyclic family members [25]. 2-Amino-4H-Pyran derivatives are an important 0022-2860/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.molstruc.2013.11.040 ⇑ Corresponding author at: Department of Chemistry, Annamalai University, Annamalainagar, Chidambaram 608 002, India. Tel.: +91 9443583619. E-mail address: arul7777@yahoo.com (B. Arul Prakasam). Journal of Molecular Structure 1059 (2014) 159–168 Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc