THE MOLECULAR AND CRYSTAL STRUCTURE OF DEGRADATION PRODUCT ARTEMISININE-ENDOCYCLIC KETONE SESQUITERPENE LACTONE

This compound is a QINGHAOSU degradation product. The molecule consists of 14 carbon, 20 hydrogen, and 3 oxygen atoms. It crystallizes in the orthorhombic system with space group P21 21 21. There are four molecules in a unit cell, the lattice parameters are a = 16.997?, b = 10.298?, and c = 7.394?.The three-dimensional intensity data were collected by using PW-1100 four-circle diff-ractometer and the number of the independent diffractions amounts to 1377. The crystal structure was solved by direct methods. The positions of 14 atoms were given by E map and the additional carbon atom sites were obtained by cycle of Fourier synthses. The structure was refined by block-diagonal least square method. The final R-factor is 0.084.