Research Of The Organic Reactions Catalyzed By Proazaphosphatrane

Proazaphosphatranes are nonionic super bases, which have received great attention in organic synthesis. Proazaphosphatranes can be used as chemical reagents and catalysts in organic reactions mainly taking advantages of the basicity of atom P and N. Proazaphosphatranes with the same arm length have been reported for a long time, however, there were few reports about the research of proazaphosphatranes with unequal arms. We document herein the synthesis of a proazaphosphatrane with unequal arms,2,8,9-triisobutyl-2,5,8,9-tetraaza-l-phosphorus bicyclo[4.3.3] dodecane. And it was supplyed as a catalyst of the intramolecular cyclization of1-aryl-4-oxoheptyl-1,6-diyne. The main content of this article is as follows:Bis(2-aminoethyl)-(3-aminopropyl) is an important pharmaceutical intermediate and organical material. It was prepared by the reaction of diethylenetriamine and ethyl acetate to protect the primary end amino and the yield was over100%. Then the intermediate obtained was reacted with excessive acacetonitrile under reflux condition to obtain the nitrile product. The nitrile group was then reducted by80%hydrazine hydrate at0℃with Raney Ni as the catalyst. After that, the acylamino was deprotected in alkaline condition to form bis(2-aminoethyl)-(3-aminopropyl).By reacting bis(2-aminoethyl)-(3-aminopropyl) with isobutyraldehyde followed by reducing the resulting tri-amide with NaBH4at0-5℃, we obtained [(CH3)2CHNHCH2CH2CH2]N[CH2CH2NHCH(CH3)2]2and the yield was about80%. In the present of HMPT and PC13,[(CH3)2CHNHCH2CH2CH2]N[CH2CH2NHCH(CH3)2]2proceeded the ring closing reaction under N2to form the corresponding salt which was then dehydrogenized to produce2,8,9-triisobutyl-2,5,8,9-tetraaza-l-phosphorus bicyclo[4.3.3] dodecane.1-aryl-4-oxoheptyl-1,6-diynes were prepared by halogenating reactions of arylamines with potassium iodide, then the Sonagashira reaction of the obtained aryl iodides and propargyl alcoholand afterwards the Williamson reaction of the formed intermediate with propargyl bromide. Through investigation, the optimized catalyst system for the intramolecular cyclization of1-aryl-4-oxoheptyl-1,6-diyne was2,8,9-triisobutyl-2,5,8,9-tetra aza-1-phosphorus bicyclo[4.3.3] dodecane with Pd(PPh3)4in DMSO. And the final products of the intramolecular [4+2] cyclization reaction were naphthofurans and were confirmed by1HNMR.