The Research In NaHSO₃-Promoted Ring Openings Of N-tosylaziridines With H₂O

The structure of β-amino alcohols was widely found in natural products as well as many synthetic products.The amino and hydroxyl groups in this molecule can undergo many reactions such as alkylation or acylation,and optically active β-amino alcohols were widely used in asymmetric synthesis.As an important organic product,P-amino alcohols had of great value in organic and pharmaceutical synthesis.In this paper,sodium bisulfite was used as a catalyst for the ring-opening reaction of aziridines and epoxides with water,affording the β-amino alcohols and diols under mild conditions.The reaction conditions of N-tosylcyclohexylaziridine with water including solvents,loading of NaHSO3,temperature were optimized.The product was characterized by thin-layer chromatography,infrared spectroscopy,1HNMR,high resolution mass spectrometry.The optimal reaction condition:N-tosylcyclohexylaziridine 0.2 mmol as model substrate,NaHSO3 2.0 equiv.as catalyst,3.0 mL mixture solvent(Vacetone:Vwater=1:1),55℃ for 24 h,the yield of trans-2-(N-Tosylamino)-1-cyclohexanol was up to 99%.Varieties of aziridines and epoxides,which including thirteen aromatic substituted aziridines,five aliphatic substituted aziridines and two epoxides,were chosen under screened conditions.Good yield of most products were obtained.For the reaction activity,the electron-donating substituted aziridines was higher than those that electron-withdrawing substituted.Of all substituted aziridines,those which substituted in para position was fastest,meta-position was faster than ortho-position.Epoxides were also good substrate for this transformation.Sodium bisulfite can be realized as a catalyst for the ring opening reaction of aziridines with water,this transformation had the following advantages:(1)sodium bisulfite was cheap and high catalytic efficiency;(2)mild reaction conditions,easily to control,no side effects.The method was effective in improving the ring opening of aziridines with water and with potential applications in the synthesis of β-amino alcohols.