ent-Pimarane diterpenoids from the aerial parts of Sigesbeckia pubescens and their myocardial protective activity
Li, Wanting; Xia, Guiyang; Xia, Jinyu; Liu, Qiyao; Wu, Xuefen; Zhou, Linnan; Wei, Xiaohong; Xia, Huan; Lin, Sheng; RSC Advances 16 (2026) 17310–17321; doi:10.1039/D5RA09664B

data_7251838
_publ_section_title
;
 ent-Pimarane diterpenoids from the aerial parts of Sigesbeckia pubescens
 and their myocardial protective activity
;
_journal_issue                   19
_journal_name_full               'RSC Advances'
_journal_page_first              17310
_journal_page_last               17321
_journal_paper_doi               10.1039/D5RA09664B
_journal_volume                  16
_journal_year                    2026
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C20 H34 O4'
_chemical_formula_sum            'C20 H34 O4'
_chemical_formula_weight         338.47
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_audit_creation_date             2023-01-11
_audit_creation_method
;
Olex2 1.5-beta
(compiled 2022.04.07 svn.rca3783a0 for OlexSys, GUI svn.r6439)
;
_audit_update_record
;
2025-05-21 deposited with the CCDC.	2026-03-06 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.3800(4)
_cell_length_b                   12.1066(4)
_cell_length_c                   20.3919(10)
_cell_measurement_reflns_used    10603
_cell_measurement_temperature    149.99(10)
_cell_measurement_theta_max      73.7820
_cell_measurement_theta_min      4.2230
_cell_volume                     1821.95(15)
_computing_cell_refinement       'CrysAlisPro 1.171.38.43f (Rigaku OD, 2015)'
_computing_data_collection       'CrysAlisPro 1.171.38.43f (Rigaku OD, 2015)'
_computing_data_reduction        'CrysAlisPro 1.171.38.43f (Rigaku OD, 2015)'
_computing_molecular_graphics    'Olex2 1.5-beta (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5-beta (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXS  (Sheldrick, 2008)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      149.99(10)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 5.2684
_diffrn_detector_type            AtlasS2
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.989
_diffrn_measurement_details
;
List of Runs (angles in degrees, time in seconds):

  # Type    Start    End  Width  t~exp~   \w     \q     \k     \f   Frames
  1  \w     17.00 115.00   1.00    1.00    --   40.92  37.00 120.00   98
  2  \w    -31.00  69.00   1.00    1.00    --   40.92 -57.00  60.00  100
  3  \w     13.00 113.00   1.00    1.00    --   40.92  57.00-150.00  100
  4  \w     94.00 178.00   1.00    2.15    --  107.58 125.00 120.00   84
  5  \w     25.00 109.00   1.00    2.15    --  107.58 -94.00-150.00   84
  6  \w     35.00 133.00   1.00    2.15    --  107.58 -45.00   0.00   98
  7  \w     82.00 178.00   1.00    2.15    --  107.58  45.00-120.00   96
  8  \w     75.00 178.00   1.00    2.15    --  107.58  77.00 150.00  103
  9  \w     13.00 113.00   1.00    1.00    --   40.92  57.00   0.00  100
 10  \w     23.00  97.00   1.00    1.00    --   40.92-125.00 -30.00   74
 11  \w     55.00 178.00   1.00    2.15    --  107.58  15.00  90.00  123
 12  \w     35.00 133.00   1.00    2.15    --  107.58 -45.00-180.00   98
 13  \w     34.00 122.00   1.00    2.15    --  107.58-125.00-180.00   88
 14  \w     79.00 178.00   1.00    2.15    --  107.58  30.00 -30.00   99
 15  \w    -69.00  32.00   1.00    1.00    --  -40.92  57.00-120.00  101
 16  \w     13.00 113.00   1.00    1.00    --   40.92  57.00 -90.00  100
 17  \w     82.00 178.00   1.00    2.15    --  107.58  45.00 120.00   96
 18  \w     75.00 178.00   1.00    2.15    --  107.58  77.00 -30.00  103
 19  \w     78.00 160.00   1.00    2.15    --  107.58  61.00 -90.00   82
 20  \w     82.00 178.00   1.00    2.15    --  107.58  45.00-150.00   96
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'SuperNova, Dual, Cu at zero, AtlasS2'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.0936599000
_diffrn_orient_matrix_UB_12      0.1039723000
_diffrn_orient_matrix_UB_13      0.0273492000
_diffrn_orient_matrix_UB_21      0.0568770000
_diffrn_orient_matrix_UB_22      -0.0649646000
_diffrn_orient_matrix_UB_23      0.0615940000
_diffrn_orient_matrix_UB_31      0.1777677000
_diffrn_orient_matrix_UB_32      -0.0339142000
_diffrn_orient_matrix_UB_33      -0.0341271000
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.1125
_diffrn_reflns_av_unetI/netI     0.0672
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.989
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -25
_diffrn_reflns_number            20517
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.985
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         74.161
_diffrn_reflns_theta_min         4.247
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'SuperNova (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    0.667
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.26424
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.38.43f (Rigaku Oxford Diffraction, 2015)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            'light colourless'
_exptl_crystal_density_diffrn    1.234
_exptl_crystal_description       block
_exptl_crystal_F_000             744
_exptl_crystal_size_max          0.14
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.11
_refine_diff_density_max         0.457
_refine_diff_density_min         -0.412
_refine_diff_density_rms         0.095
_refine_ls_abs_structure_details
;
 Flack x determined using 1226 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.03(17)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.036
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     225
_refine_ls_number_reflns         3654
_refine_ls_number_restraints     255
_refine_ls_restrained_S_all      1.040
_refine_ls_R_factor_all          0.0822
_refine_ls_R_factor_gt           0.0765
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1251P)^2^+2.0777P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2042
_refine_ls_wR_factor_ref         0.2114
_reflns_Friedel_coverage         0.727
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.981
_reflns_number_gt                3361
_reflns_number_total             3654
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5ra09664b5.cif
_cod_data_source_block           xjy-53
_cod_database_code               7251838
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_max   0.930
_shelx_estimated_absorpt_t_min   0.912
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups, All O(H) groups
2. Uiso/Uaniso restraints and constraints
Uanis(C5) \\sim Ueq, Uanis(C4) \\sim Ueq, Uanis(C7) \\sim Ueq, Uanis(C6) \\sim
Ueq, Uanis(C14) \\sim Ueq, Uanis(C8) \\sim Ueq: with sigma of 0.0005 and sigma
for terminal atoms of 0.001
Uanis(O4) \\sim Ueq, Uanis(C16) \\sim Ueq: with sigma of 0.00006 and sigma for
terminal atoms of 0.00012
3. Rigid body (RIGU) restrains
 O1, H1, O2, H2, O3, H3, O4, H4, C1, H1A, H1B, C2, H2A, H2B, C3, H3A, C4, C5,
 H5, C6, H6, C7, H7A, H7B, C8, C9, H9, C10, C11, H11A, H11B, C12, H12A, H12B,
 C13, C14, H14, C15, H15, C16, H16A, H16B, C17, H17A, H17B, H17C, C18, H18A,
 H18B, H18C, C19, H19A, H19B, H19C, C20, H20A, H20B, H20C
 with sigma for 1-2 distances of 0.001 and sigma for 1-3 distances of 0.002
4.a Ternary CH refined with riding coordinates:
 C3(H3A), C5(H5), C6(H6), C9(H9), C15(H15)
4.b Secondary CH2 refined with riding coordinates:
 C1(H1A,H1B), C2(H2A,H2B), C7(H7A,H7B), C11(H11A,H11B), C12(H12A,H12B),
 C16(H16A,H16B)
4.c Aromatic/amide H refined with riding coordinates:
 C14(H14)
4.d Idealised Me refined as rotating group:
 C17(H17A,H17B,H17C), C18(H18A,H18B,H18C), C19(H19A,H19B,H19C), C20(H20A,H20B,
 H20C)
4.e Idealised tetrahedral OH refined as rotating group:
 O1(H1), O2(H2), O3(H3), O4(H4)
;
_shelx_res_checksum              18072
_olex2_date_sample_data_collection 2023-01-10
_olex2_submission_special_instructions 'No special instructions were received'
_oxdiff_exptl_absorpt_empirical_details
;
Empirical correction (ABSPACK) includes:
- Absorption correction using spherical harmonics
- Frame scaling
;
_oxdiff_exptl_absorpt_empirical_full_max 4.556
_oxdiff_exptl_absorpt_empirical_full_min 0.246