UPPW-7 November 28, 2003
Problem : ICDD 51-1948 C16H26O5 alpha-Methyldihydroartemisinine Wavelength 1.5406 A Filter : mono Ref : L. Chen, Inst. of Precious Metals, Kunming, P.R. China, Private Communication (1998) Pattern taken at room temperature. Sample provided by C. Wang, Kunming Pharmaceutical Corp., P.R. China. CAS #: 71963-77-4. Also called alpha-artemether Mwt : 298.38 d(A) intensities 8.716 100 8.410 47 7.688 7 6.959 26 6.722 20 5.793 7 5.590 8 5.254 8 5.151 9 4.921 97 4.761 42 4.647 24 4.502 14 4.345 16 4.261 8 3.927 19 3.689 5 3.466 3 3.314 7 3.123 8 3.009 2 2.897 3 2.792 6 2.727 4 2.690 4 2.506 3 2.241 3 2.174 2 2.151 3 2.048 2 NOTE : The structure of a C16H26O5 (arthemeter), antimalarial drug, is described in the Cambridge Structural Database. Apparently a different polymorph. Below are the d(hkl) calculated by HKLGEN : Artemether CSD WAVELENGTH 1.54060 SPACE GROUP : P 21 A= 9.8680 B= 18.3240 C= 10.1720 ALPHA= 90.000 BETA=117.550 GAMMA= 90.000 H K L MULT d(A) 2-theta(°) 0 2 0 2 9.1620 9.646 0 0 1 2 9.0186 9.800 1 0 0 2 8.7490 10.102 1 0 -1 2 8.5638 10.321 0 1 1 4 8.0916 10.925 1 1 0 4 7.8953 11.198 1 1 -1 4 7.7583 11.396 0 2 1 4 6.4272 13.767 1 2 0 4 6.3275 13.985 1 2 -1 4 6.2563 14.145 1 0 1 2 5.1930 17.061 1 0 -2 2 5.0770 17.454 0 3 1 4 5.0573 17.522 1 3 0 4 5.0083 17.695 1 1 1 4 4.9962 17.738 1 3 -1 4 4.9728 17.822 2 0 -1 2 4.9324 17.969 1 1 -2 4 4.8927 18.117 2 1 -1 4 4.7629 18.615 0 4 0 2 4.5810 19.361 1 2 1 4 4.5177 19.634 0 0 2 2 4.5093 19.672 1 2 -2 4 4.4408 19.978 0 1 2 4 4.3787 20.265 2 0 0 2 4.3745 20.284 2 2 -1 4 4.3430 20.433 2 0 -2 2 4.2819 20.727 2 1 0 4 4.2550 20.860 2 1 -2 4 4.1696 21.292 0 4 1 4 4.0843 21.742 1 4 0 4 4.0583 21.883 0 2 2 4 4.0458 21.952 1 4 -1 4 4.0394 21.987 1 3 1 4 3.9563 22.454 2 2 0 4 3.9476 22.505 1 3 -2 4 3.9043 22.757 2 2 -2 4 3.8792 22.907 2 3 -1 4 3.8374 23.160 0 3 2 4 3.6278 24.518 2 3 0 4 3.5565 25.018 2 3 -2 4 3.5062 25.383 RESULTS : consensus on an orthorhombic cell with volume close to the polymorph in the CSD database (~1600A**3). Most probable cell(s) according to the Participants : Program a b c alpha beta gamma V M(20) F 20 Unindexed Zero Spacegroup TREOR (NM) 13.898 11.135 10.520 90. 90. 90. 1627.2 M(20)= 10 F20 = 17 (0.02485, 49) P212121 ?
TREOR (SG) 13.943 11.149 10.519 90. 90. 90. 1635.3 M(16)= 12 F16 = 25 (0.02407, 27) TOPAS (AC) 13.840 10.493 11.118 90. 90. 90. 1614.6 FOM = 14.45 -0.059 Pmn21 AUTOX (VZ) 13.908 10.531 11.183 90. 90. 90. 1637.9 CRYSFIRE (RS) 11.132 13.826 10.483 90. 90. 90. 1613.5 P212121 ? McMaille (ALB) 10.502 13.896 11.158 90. 90. 90. 1628.3 M(20)=18 F20 = 29 (0.0096, 71) Results from SG (TREOR), Alan Coelho (TOPAS), Victor Zlokazov (AUTOX), Robin Shirley (CRYSFIRE) and Armel Le Bail (McMaille). Plot by using WinPlotr on the McMaille results :
ZERO LAMBDA A B C ALPHA BETA GAMMA 0.028 1.5406 10.5018 13.8962 11.1580 90.000 90.000 90.000 0.013 0.0000 0.0095 0.0097 0.0075 0.000 0.000 0.000 RECIPROCAL CELL : 0.09522 0.07196 0.08962 90.000 90.000 90.000 VOLUME (A**3) : 1628.345 H K L TH(OBS) TH-ZERO TH(CALC) DIFF. 0 1 1 10.141 10.169 10.159 0.010 1 1 0 10.511 10.539 10.550 -0.012 1 0 1 11.501 11.529 11.562 -0.033 0 2 0 12.710 12.739 12.730 0.008 1 1 1 13.160 13.189 13.204 -0.016 1 2 0 15.283 15.311 15.278 0.033 0 0 2 15.841 15.869 15.873 -0.003 2 0 0 16.861 16.890 16.871 0.018 1 2 1 17.201 17.229 17.230 0.000 2 1 0 18.011 18.040 18.045 -0.005 2 0 1 18.622 18.650 18.661 -0.011 1 1 2 19.083 19.111 19.097 0.014 2 1 1 19.704 19.732 19.732 0.000 2 2 1 22.624 22.653 22.654 -0.002 2 1 2 24.105 24.133 24.121 0.013 0 0 4 32.031 32.059 32.060 -0.001 1 5 0 33.280 33.308 33.321 -0.013 M(20) = 18.04 F(20) = 29.27 ( 0.0096, 71)