Design, Synthesis, and Antitumor Activity of Novel Acylate of 6-OH at 1- O-acetylbritannilactone

N-(α-Alkyloxime-3-phenylpropionyl) proline was designed and synthesized as an acylating agent to modify the 6-OH of 1-O-acetylbritannilactone. Eight intermediates and eight target compounds were obtained. The structures of sixteen novel compounds were characterized by (1)HNMR, IR and HRMS. The activities against HL-60 and Bel-7402 cell lines were tested, the IC50 values of compound IVg were 2.7 μM and 4.3 μM, respectively.