“…The residue was purified by silica gel flash column chromatography (eluent: 0–50% EtOAc in petroleum ether) to give the desired product. Compounds 3a , 3e , 3i , 3j , 3k , 3l , 3o , 3q , 3r , 3s , 5a , 5c , 5e , 5f , 5g , 5i , 5n , 7a , 7b , 7d , 7f , 7g , 7h , 7j , 7k , and 7l are known compounds. Result of MS was given for known compounds, and the result of HRMS was given for unknown compounds.…”