Efficient Access to the Iboga Skeleton: Optimized Procedure to Obtain Voacangine from Voacanga africana Root Bark
González, Bruno; Fagúndez, Catherine; Peixoto de Abreu Lima, Alejandro; Suescun, Leopoldo; Sellanes, Diver; Seoane, Gustavo A.; Carrera, Ignacio; ACS Omega  (2021) –; doi:10.1021/acsomega.1c00745

data_4518835
_publ_section_title
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 Efficient Access to the Iboga Skeleton: Optimized Procedure to Obtain
 Voacangine from Voacanga africana Root Bark
;
_journal_name_full               'ACS Omega'
_journal_paper_doi               10.1021/acsomega.1c00745
_journal_year                    2021
_chemical_absolute_configuration ad
_chemical_formula_moiety         'Cl, C20 H27 N2 O'
_chemical_formula_sum            'C20 H27 Cl N2 O'
_chemical_formula_weight         346.88
_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   mixed
_atom_sites_solution_primary     dual
_audit_creation_date             2020-12-10
_audit_creation_method
;
Olex2 1.2
(compiled 2018.05.29 svn.r3508 for OlexSys, GUI svn.r5506)
;
_audit_update_record
;
2020-12-10 deposited with the CCDC.	2021-02-09 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   9.3860(5)
_cell_length_b                   10.6137(8)
_cell_length_c                   18.3018(10)
_cell_measurement_reflns_used    4468
_cell_measurement_temperature    100
_cell_measurement_theta_max      66.67
_cell_measurement_theta_min      4.82
_cell_volume                     1823.2(2)
_computing_cell_refinement       'SAINT V8.38A (?, 2016)'
_computing_data_reduction        'SAINT V8.38A (?, 2016)'
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'XL (Sheldrick, 2008)'
_computing_structure_solution    'ShelXT (Sheldrick, 2015)'
_diffrn_ambient_temperature      100
_diffrn_detector                 'Bruker APEXII CCD area detector'
_diffrn_detector_type            'CCD area detector'
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device       'kappa diffractometer'
_diffrn_measurement_device_type  'Bruker Kappa/ApexII CCD'
_diffrn_measurement_method       'profile data from \f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0707
_diffrn_reflns_av_unetI/netI     0.0372
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            25396
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         68.075
_diffrn_reflns_theta_min         4.816
_diffrn_source                   'fine-focus sealed X-ray tube'
_diffrn_source_target            Mo
_diffrn_source_type              'Siemens fine-focus sealed tube'
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    1.910
_exptl_absorpt_correction_T_max  0.7530
_exptl_absorpt_correction_T_min  0.5948
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1073 before and 0.0778 after correction.
The Ratio of minimum to maximum transmission is 0.7899.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            'clear colourless'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.264
_exptl_crystal_description       irregular
_exptl_crystal_F_000             744
_exptl_crystal_size_max          0.26
_exptl_crystal_size_mid          0.201
_exptl_crystal_size_min          0.158
_refine_diff_density_max         0.372
_refine_diff_density_min         -0.366
_refine_diff_density_rms         0.053
_refine_ls_abs_structure_details
;
 Flack x determined using 1201 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.014(11)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.085
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     245
_refine_ls_number_reflns         3318
_refine_ls_number_restraints     76
_refine_ls_restrained_S_all      1.085
_refine_ls_R_factor_all          0.0632
_refine_ls_R_factor_gt           0.0604
_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^)+(0.0562P)^2^+1.6268P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1459
_refine_ls_wR_factor_ref         0.1482
_reflns_Friedel_coverage         0.734
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                3127
_reflns_number_total             3318
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ao1c00745_si_001.cif
_cod_data_source_block           19_a
_cod_database_code               4518835
_shelx_shelxl_version_number     2016/6
_shelx_estimated_absorpt_t_max   0.752
_shelx_estimated_absorpt_t_min   0.637
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups, All N(H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2. Restrained distances
 C18-C19
 1.53 with sigma of 0.01
3. Rigid bond restraints
 C3, C4, C5, N1, C18, C19
 with sigma for 1-2 distances of 0.01 and sigma for 1-3 distances of 0.01
 N1, C5
 with sigma for 1-2 distances of 0.02 and sigma for 1-3 distances of 0.02
4. Uiso/Uaniso restraints and constraints
C3 \\sim C4 \\sim C5 \\sim N1 \\sim C19 \\sim C18: within 1.7A with sigma of
0.04 and sigma for terminal atoms of 0.08
C17 \\sim C18 \\sim C19 \\sim C18A \\sim C19A: within 2A with sigma of 0.005
and sigma for terminal atoms of 0.01
5. Same fragment restrains
{C17, C18A, C19A} sigma for 1-2: 0.005, 1-3: 0.04
as
{C17, C18, C19}
6. Others
 Sof(H17A)=Sof(C18A)=Sof(H18C)=Sof(H18D)=Sof(C19A)=Sof(H19D)=Sof(H19E)=
 Sof(H19F)=1-FVAR(1)
 Sof(H17)=Sof(C18)=Sof(H18A)=Sof(H18B)=Sof(C19)=Sof(H19A)=Sof(H19B)=Sof(H19C)=
 FVAR(1)
7.a Ternary CH refined with riding coordinates:
 C15(H15), C9(H9), C10(H10), C17(H17), C17(H17A)
7.b Secondary CH2 refined with riding coordinates:
 C11(H11A,H11B), C12(H12A,H12B), C13(H13A,H13B), C14(H14A,H14B), C16(H16A,
 H16B), C18(H18A,H18B), C18A(H18C,H18D)
7.c Me refined with riding coordinates:
 C20(H20A,H20B,H20C)
7.d Aromatic/amide H refined with riding coordinates:
 C1(H1A), C3(H3), C4(H4)
7.e Idealised Me refined as rotating group:
 C19(H19A,H19B,H19C), C19A(H19D,H19E,H19F)
;
_shelx_res_checksum              95909
_shelx_hkl_checksum              49374
_olex2_submission_special_instructions 'No special instructions were received'