Construction of 6-amino-2,2-dimethyl-3,4,6-trisubstituted-2H-1-benzopyran library by solid phase synthesis

We report the solid-phase library construction of 2000 analogues of 6- amino-2,2-dimethyl-3,4,6-trisubstituted-2H-1-benzopyran. The polymer-bound hydroxyalkoxychromanes 5, produced by nucleophilic reactions with various alcohols on epoxides generated in situ, served as key intermediates for subsequent diversification. Further reactions on these hydroxyalkoxychromanes 5 with various electrophiles, such as alkyl halides and acid halides, produced the desired 6-amino-2,2-dimethyl-3,4,6-trisubstituted-2H-1-benzopyran analogues 9, 10, and 11. The progress of reactions could be monitored as solid-bound intermediates by ATR-FTIR or HR-MAS-NMR spectroscopy. The final compounds, obtained in good yields and high purity upon cleavage from the resins, were characterized by LC/MS, HRMS, H-1 NMR, and C-13 NMR spectroscopy.