1Wang B,Jiang Z.Study of Oleanolic acid[J].Chin Pharm J(中国药学杂志),1992,27(7):393—397.
2Mehrotra R,Singh C,Popli S P.Cetylt methylammonium bromide catalyzed sodium periodate oxidation of olean—12en—·28-ols and urs-12en-28-ols construction of △11-13β,28-epoxy system of saikogenins partial synthesis of 16-deoxysaiko-genin-F [J],Indian,Chem Sect B,1990,29B(5):425-429.
3Puntambekar H M.Naik D G,Kapadi A H,Pot—pot conversion of carboxylic acids into esters using phase transfer catalysis[J],Indian,Chem,1993,32B(7):793—794.
4Nishino H,Nishino A,Takayasu J,et al.Inhibition of the tumor—promoting action of 12—-O-tetradecanoylphorborbol—13—-acetate by some oleanane—type triterpenoid compounds [J],Cancer Res,1988,48(9):5210—5215.
8[6]Bore L,Honda T,Gribble GW.Synthesis of β-Boswellic Acid Analogues with a Carboxyl Group at C-17 Isolated from the Bark of Schefflera octophylla[J].J Org Chem,2000,65(19):6278-6282.
9[7]Parish RC,Stock LM.A method for the esterification of sterication hindered carboxylic acids[J].Tetra Lett,1964 (20):1285-1288.
10[8]Bourne JE,Stacey M,Tatlow JC,et al.Studies on Trifluoroacetic Acid.Part Ⅰ.Trifluoroacetic Anhydride as a Promoter of Ester Formation between Hydroxy-compounds and Carboxylic Acids[J].J Chem Soc,1949:2976-2979.
