1,n-Diamines. Part 3: Microwave-assisted synthesis of N-acyl-N′-arylhexahydropyrimidines and hexahydro-1,3-diazepines
                                
                                    
                                        作者:Juan Á. Bisceglia、Jimena E. Díaz、Romina A. Torres、Liliana R. Orelli                                    
                                    
                                        DOI:10.1016/j.tetlet.2011.07.131
                                    
                                    
                                        日期:2011.10
                                    
                                    In this Letter we present a method for the synthesis of N-acyl-N'-arylhexahydropyrimidines 1, by ring closure of N-acyl-N'-aryl-1,3-propanediamines 3 with formaldehyde. Cyclodehydrations were performed in aqueous medium under microwave irradiation, and led to high yields of the desired compounds in remarkably short reaction times. The method also allowed for the synthesis of hitherto unreported N-acyl-N'-arylhexahydro-1,3-diazepines 2. The acyclic tetramethylenic precursors 4 were synthesized by selective functionalization of N-arylputrescines. (C) 2011 Elsevier Ltd. All rights reserved.