Cl[C:2]1[O:3][C:4]2[CH:10]=[CH:9][CH:8]=[CH:7][C:5]=2[N:6]=1.C([O-])([O-])=O.[K+].[K+].[N:17]12CCCNC1CCCC=C2.[H-].[Na+]>C1COCC1.CN(C=O)C.COCCOC.C(N(CC)CC)C>[NH2:17][C:2]1[O:3][C:4]2[CH:10]=[CH:9][CH:8]=[CH:7][C:5]=2[N:6]=1A mixture of an appropriate 2-chlorobenzoxazole, A1 (1 eq), and appropriate amine (2 eq) and optional base (e.g. K2CO3, triethylamine, disopropylamine, 1,8-diazabicyclo[5.4.0]undecene, or sodium hydride) in THF (or DME, DMF) was heated in the range of 20 to 80° C. up to 24 h. After cooling to room temperature, the reaction mixture was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (typical eluents include 9:1 dichloromethane/methanol, ethyl acetate, hexanes) to afford the desired product 2-aminobenzoxazole. Product structure was confirmed by 1H NMR or by mass analysis.
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