Isolation, Structure Elucidation and Racemization of (+)- and (−)-Pratensilins A–C, Unprecedented Spiro Indolinone-naphthofuran Alkaloids from a Marine Streptomyces sp.
Zhang, Shumin; Yang, Qin; Guo, Lin; Zhang, Ying; Feng, Lingling; Zhou, Ling; Yang, Shengxiang; Yao, Qingshou; Pescitelli, Gennaro; Zeping, Xie; Chem. Commun.  (2017) –; doi:10.1039/C7CC04983H

data_7120580
_publ_section_title
;
 Isolation, Structure Elucidation and Racemization of (+)- and
 (&#x2212;)-Pratensilins A--C, Unprecedented Spiro Indolinone-naphthofuran
 Alkaloids from a Marine Streptomyces sp.
;
_journal_name_full               'Chem. Commun.'
_journal_paper_doi               10.1039/C7CC04983H
_journal_year                    2017
_chemical_formula_moiety         'C20 H15 N O4'
_chemical_formula_sum            'C20 H15 N O4'
_chemical_formula_weight         333.33
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2017-06-22 deposited with the CCDC.
2017-08-18 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 98.7570(10)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   12.3534(2)
_cell_length_b                   12.5563(2)
_cell_length_c                   20.7245(4)
_cell_measurement_reflns_used    3835
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      57.35
_cell_measurement_theta_min      6.28
_cell_volume                     3177.17(10)
_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-2014 (Sheldrick 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_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  0.1162
_diffrn_reflns_av_unetI/netI     0.1257
_diffrn_reflns_Laue_measured_fraction_full 0.991
_diffrn_reflns_Laue_measured_fraction_max 0.991
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            22703
_diffrn_reflns_point_group_measured_fraction_full 0.991
_diffrn_reflns_point_group_measured_fraction_max 0.991
_diffrn_reflns_theta_full        58.089
_diffrn_reflns_theta_max         58.089
_diffrn_reflns_theta_min         6.048
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.805
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.394
_exptl_crystal_description       block
_exptl_crystal_F_000             1392
_exptl_crystal_size_max          0.220
_exptl_crystal_size_mid          0.220
_exptl_crystal_size_min          0.060
_exptl_transmission_factor_max   0.7514
_exptl_transmission_factor_min   0.5542
_refine_diff_density_max         0.515
_refine_diff_density_min         -0.578
_refine_diff_density_rms         0.119
_refine_ls_extinction_coef       0.0024(6)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   1.112
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     458
_refine_ls_number_reflns         4413
_refine_ls_number_restraints     12
_refine_ls_restrained_S_all      1.116
_refine_ls_R_factor_all          0.1606
_refine_ls_R_factor_gt           0.0997
_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^)+(0.1989P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2435
_refine_ls_wR_factor_ref         0.3106
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2701
_reflns_number_total             4413
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c7cc04983h2.cif
_cod_data_source_block           cu_xzp_r8631_0m
_cod_database_code               7120580
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.843
_shelx_estimated_absorpt_t_max   0.953
_shelx_res_checksum              61264