Phytotoxic Neocassane Diterpenes from <i>Eragrostis plana</i>.
Klein Hendges, Ana Paula P.; Dos Santos, Elaine Fernanda; Teixeira, Sirlei D.; Santana, Francielli S.; Trezzi, Michelangelo M.; Batista, Andrea N. L.; Batista, Jr, Joao M; de Lima, Vanderlei A.; de Assis Marques, Francisco; Maia, Beatriz Helena L N Sales; Journal of natural products  (2020) –; doi:10.1021/acs.jnatprod.0c00324

data_1559535
_publ_section_title
;
 Phytotoxic Neocassane Diterpenes from <i>Eragrostis plana</i>.
;
_journal_name_full               'Journal of natural products'
_journal_paper_doi               10.1021/acs.jnatprod.0c00324
_journal_year                    2020
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C20 H28 O2'
_chemical_formula_structural     C20H28O2
_chemical_formula_sum            'C20 H28 O2'
_chemical_formula_weight         300.42
_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   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2017/1
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   6.4025(4)
_cell_length_b                   11.0913(7)
_cell_length_c                   23.6652(14)
_cell_measurement_reflns_used    9913
_cell_measurement_temperature    288(2)
_cell_measurement_theta_max      26.11
_cell_measurement_theta_min      3.17
_cell_volume                     1680.51(18)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX3 (2015)'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'ORTEP (Johnson, 1976 and Farrugia, 2012)'
_computing_publication_material
'SHELXL-97 (Sheldrick, 2008) and WINGX (Farrugia, 2012)'
_computing_structure_refinement  'SHELXL-2017/1 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT-2015 (Sheldrick, 2015a)'
_diffrn_ambient_temperature      288(2)
_diffrn_detector_area_resol_mean 10.4167
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker D8 Venture/Photon 100 CMOS'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0708
_diffrn_reflns_av_unetI/netI     0.0203
_diffrn_reflns_Laue_measured_fraction_full 0.997
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -29
_diffrn_reflns_number            74131
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.996
_diffrn_reflns_theta_min         3.169
_diffrn_source                   'fine-ocus sealed tube'
_exptl_absorpt_coefficient_mu    0.074
_exptl_absorpt_correction_T_max  0.7455
_exptl_absorpt_correction_T_min  0.7057
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2012/1 - Bruker AXS area detector scaling and absorption correction 
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.187
_exptl_crystal_description       parallelepiped
_exptl_crystal_F_000             656
_exptl_crystal_size_max          0.314
_exptl_crystal_size_mid          0.228
_exptl_crystal_size_min          0.116
_refine_diff_density_max         0.190
_refine_diff_density_min         -0.149
_refine_diff_density_rms         0.035
_refine_ls_abs_structure_details
;
 Flack x determined using 1026 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.1(5)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.062
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     311
_refine_ls_number_reflns         3276
_refine_ls_number_restraints     6
_refine_ls_restrained_S_all      1.066
_refine_ls_R_factor_all          0.0548
_refine_ls_R_factor_gt           0.0411
_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^)+(0.0511P)^2^+0.2382P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0941
_refine_ls_wR_factor_ref         0.1001
_reflns_Friedel_coverage         0.714
_reflns_Friedel_fraction_full    0.999
_reflns_Friedel_fraction_max     0.999
_reflns_number_gt                2731
_reflns_number_total             3276
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            np0c00324_si_003.cif
_cod_data_source_block           shelx
_cod_database_code               1559535
_shelx_shelxl_version_number     2017/1
_shelx_res_checksum              25064
_shelx_hkl_checksum              86979