Carpedilactones A-D, Four New Isomeric Sesquiterpene Lactone Dimers with Potent Cytotoxicity from Carpesium faberi.
Yang, Yong-Xun; Shan, Lei; Liu, Qing-Xin; Shen, Yun-Heng; Zhang, Jian-Ping; Ye, Ji; Xu, Xi-Ke; Li, Hui-Liang; Zhang, Wei-Dong; Organic letters 16 (2014) 4216–4219; doi:10.1021/ol501923k

data_1517265
_publ_section_title
;
 Carpedilactones A-D, Four New Isomeric Sesquiterpene Lactone Dimers with
 Potent Cytotoxicity from Carpesium faberi.
;
_journal_issue                   16
_journal_name_full               'Organic letters'
_journal_page_first              4216
_journal_page_last               4219
_journal_paper_doi               10.1021/ol501923k
_journal_volume                  16
_journal_year                    2014
_chemical_absolute_configuration ad
_chemical_formula_sum            'C30 H38 O6'
_chemical_formula_weight         494.60
_space_group_crystal_system      tetragonal
_space_group_IT_number           96
_space_group_name_Hall           'P 4nw 2abw'
_space_group_name_H-M_alt        'P 43 21 2'
_symmetry_space_group_name_Hall  'P 4nw 2abw'
_symmetry_space_group_name_H-M   'P 43 21 2'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2013
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   14.34420(10)
_cell_length_b                   14.34420(10)
_cell_length_c                   26.2596(3)
_cell_measurement_reflns_used    8246
_cell_measurement_temperature    140(2)
_cell_measurement_theta_max      68.04
_cell_measurement_theta_min      4.57
_cell_volume                     5403.07(8)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      140(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0754
_diffrn_reflns_av_unetI/netI     0.0415
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            40030
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.990
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         70.205
_diffrn_reflns_theta_min         4.565
_exptl_absorpt_coefficient_mu    0.673
_exptl_absorpt_correction_T_max  0.7533
_exptl_absorpt_correction_T_min  0.4950
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.216
_exptl_crystal_description       prism
_exptl_crystal_F_000             2128
_exptl_crystal_size_max          0.200
_exptl_crystal_size_mid          0.080
_exptl_crystal_size_min          0.060
_platon_squeeze_details
;
;
_refine_diff_density_max         0.341
_refine_diff_density_min         -0.339
_refine_diff_density_rms         0.093
_refine_ls_abs_structure_details
; 
 Flack x determined using 1910 quotients [(I+)-(I-)]/[(I+)+(I-)] 
 (Parsons and Flack (2004), Acta Cryst. A60, s61). 
;
_refine_ls_abs_structure_Flack   -0.02(9)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.133
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     330
_refine_ls_number_reflns         5101
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.133
_refine_ls_R_factor_all          0.0558
_refine_ls_R_factor_gt           0.0518
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0878P)^2^+1.3735P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1485
_refine_ls_wR_factor_ref         0.1522
_reflns_Friedel_coverage         0.709
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.983
_reflns_number_gt                4767
_reflns_number_total             5101
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ol501923k_si_005.cif
_cod_data_source_block           dm14056
_cod_depositor_comments
'Adding full bibliography for 1517265--1517268.cif.'
_cod_original_cell_volume        5403.07(10)
_cod_database_code               1517265
_shelx_estimated_absorpt_t_min   0.877
_shelx_estimated_absorpt_t_max   0.961
_shelxl_version_number           2013-4
_shelx_res_checksum              43744
_shelx_hkl_checksum              94395