(3beta,5xi,9xi,13xi,17xi,18xi,19xi)-lup-20(29)-ene-3,28-diol Betulin InChI=1/C30H50O2/c1-19(2)20-10-15-30(18-31)17-16-28(6)21(25(20)30)8-9-23-27(5)13-12-24(32)26(3,4)22(27)11-14-29(23,28)7/h20-25,31-32H,1,8-18H2,2-7H3/t20?,21?,22?,23?,24-,25?,27-,28+,29+,30?/m0/s lup-20(29)-ene-3,28-diol, (3beta,5xi,9xi,13xi,17xi,18xi,19xi)-